guest speakers lectures, oral presentations, clinical case presentations

48
© Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&JOURNAL - quarterly december 2012 - Vol. 24 - N°3-4 Focus 95 17th ArgoSpine Symposium Scientific Book LECTURE Day 1/ 9:00>9:10 Dynamic fixation of the cervical spine Dynamic fixation of the cervical spine J.M. Casamitjana Ferrandiz University Hospital, Vall d’Hebron, Barcelona, Spain Anterior cervical spine surgery was introduced in the late 1950s by Smith and Robinson and by Cloward. The goals of this surgery include decompression of neural structures, reduction of deformity, immediate stability, and creation of a conducive environment for osseous fusion to occur. Recently, anterior plating systems have been used in the hope of improving outcomes following anterior cervical discectomy or corpectomy for degen- erative, traumatic, and oncologic disorders. Proponents of plating systems have cited numerous advantages, including earlier patient mobilization, cost-effectiveness, a decreased need for orthotics, a diminished rate of graft dislodgment and migration, superior fusion rates, immediate stabilization, and the preven- tion of spinal deformity. These potential benefits are much more evident in patients who undergo multilevel surgery, such as cor- pectomy and reconstruction, than those who undergo single- level surgery. The designs of anterior cervical plates have evolved substantially. The initial plate designs required bicor- tical fixation, as the screws were not locked to the plate. Constrained systems, in which the screw locked to the plate, enabled unicortical fixation and reduced the problem of screw back-out. More recently, pseudarthrosis has been noted in association with static plates, which had been thought to bridge and unload the interface between a subsided graft and the end plate. Dynamic cervical plates were developed in response to this problem. Rotationally dynamic plates allow the screws to pivot or toggle yet continue to prevent screw back- out. Translational dynamic plates not only allow the screws to pivot but also to slide vertically in the plate. Graft subsidence is common during healing after anterior cervical fusion surgery. Dynamic plates, in theory, allow con- tinued contact between the graft and the end plate after graft subsidence has occurred, thus improving the chance of obtaining a fusion by maintaining a compressive load on the graft. Subsidence and its effects on the stiffness of a plating system have received little attention from both clinical and bio- mechanical standpoints. A major concern for spine surgeons is the effect of dynamic plating on stability and clinical outcome, both in the immediate postoperative period and the long term. For one or two-level degenerative disease, the type of plating system used is pri- marily dependent on surgeon preference as the existing data have supported static or dynamic systems equally. However, for more extensive spondylotic decompression, oncologic resec- tions, and traumatic injuries, some surgeons have advocated the rigid, static constructs. We know of no study, either clinical or biomechanical, that supports one system over another. Further studies with an instability model, fatigue testing, and follow-up of clinical outcomes will help to clarify the advantages and dis- advantages of static and dynamic cervical plate designs. Cervical plates, which minimize micromotion, have been demon- strated to improve the fusion rate after the ACDF. Wang et al. had reported a 0% nonunion for two-level ACDF with the use of anterior cervical plating. Similarly, Bolesta et al. reported the fusion rate of 97.5% when a cervical plate with segmental fixation was used for two-level ACDF. However, one of the crit- icisms of static cervical plates has been their rigidity which, in theory, might distract the fusion site and prevent graft settling, thereby increasing the chance for a pseudarthrosis. To address this problem, dynamic plates have been developed. The theo- retical advantage of dynamic plates is greater graft loading with less stress shielding, which should increase fusion rates. Nunley and colleagues performed a randomized controlled trial of a heterogeneous mix of patients undergoing single or mul- tilevel ACDF with rigid or dynamic fixation. They found no dif- ference in outcomes for the groups undergoing single level ACDF, but did find an advantage to dynamic instrumentation for multilevel ACDF. In contrast, DuBois and colleagues reviewed 52 patients undergoing 2 and 3 level ACDF, comparing rigid with dynamic anterior cervical plating. They found an increase in the rate of nonunion when using the dynamic cervical plate (P 5 .05). They measured the amount of construct settling over 1 to 2 years, and found no difference between the plating systems, thus questioning the compressive properties of the plate in vivo. Clinical outcomes were similar among the groups, which led the investigators to conclude that the more expen- sive dynamic plates do not offer any clear benefit compared with rigid plates. Anterior cervical plating is associated with adjacent level ossi- fication which may be due to impingement from the plate on the adjacent level disc space. Although comparative series have shown no difference in incidence of this complication when comparing rigid with dynamic cervical plating, special attention must be paid to technique when using a dynamic plate. Park and colleagues noted that the incidence of moderate to severe adjacent level ossification was increased with less than 5 mm Guest speakers lectures, oral presentations, clinical case presentations FOCUS

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Page 1: Guest speakers lectures, oral presentations, clinical case presentations

© Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&JOURNAL - quarterly december 2012 - Vol. 24 - N°3-4

Focus 9517th ArgoSpine Symposium Scientific Book

LECTURE Day 1/ 9:00>9:10

Dynamic fixation of the cervical spine

Dynamic fixation of the cervical spineJ.M. Casamitjana FerrandizUniversity Hospital, Vall d’Hebron, Barcelona, Spain

Anterior cervical spine surgery was introduced in the late 1950s

by Smith and Robinson and by Cloward. The goals of this

surgery include decompression of neural structures, reduction

of deformity, immediate stability, and creation of a conducive

environment for osseous fusion to occur. Recently, anterior plating

systems have been used in the hope of improving outcomes

following anterior cervical discectomy or corpectomy for degen-

erative, traumatic, and oncologic disorders. Proponents of plating

systems have cited numerous advantages, including earlier

patient mobilization, cost-effectiveness, a decreased need for

orthotics, a diminished rate of graft dislodgment and migration,

superior fusion rates, immediate stabilization, and the preven-

tion of spinal deformity. These potential benefits are much more

evident in patients who undergo multilevel surgery, such as cor-

pectomy and reconstruction, than those who undergo single-

level surgery. The designs of anterior cervical plates have

evolved substantially. The initial plate designs required bicor-

tical fixation, as the screws were not locked to the

plate. Constrained systems, in which the screw locked to the

plate, enabled unicortical fixation and reduced the problem of

screw back-out. More recently, pseudarthrosis has been noted

in association with static plates, which had been thought to

bridge and unload the interface between a subsided graft and

the end plate. Dynamic cervical plates were developed in

response to this problem. Rotationally dynamic plates allow the

screws to pivot or toggle yet continue to prevent screw back-

out. Translational dynamic plates not only allow the screws to

pivot but also to slide vertically in the plate.

Graft subsidence is common during healing after anterior

cervical fusion surgery. Dynamic plates, in theory, allow con-

tinued contact between the graft and the end plate after graft

subsidence has occurred, thus improving the chance of

obtaining a fusion by maintaining a compressive load on the

graft. Subsidence and its effects on the stiffness of a plating

system have received little attention from both clinical and bio-

mechanical standpoints.

A major concern for spine surgeons is the effect of dynamic

plating on stability and clinical outcome, both in the immediate

postoperative period and the long term. For one or two-level

degenerative disease, the type of plating system used is pri-

marily dependent on surgeon preference as the existing data

have supported static or dynamic systems equally. However, for

more extensive spondylotic decompression, oncologic resec-

tions, and traumatic injuries, some surgeons have advocated

the rigid, static constructs. We know of no study, either clinical

or biomechanical, that supports one system over another. Further

studies with an instability model, fatigue testing, and follow-up

of clinical outcomes will help to clarify the advantages and dis-

advantages of static and dynamic cervical plate designs.

Cervical plates, which minimize micromotion, have been demon-

strated to improve the fusion rate after the ACDF. Wang et al.

had reported a 0% nonunion for two-level ACDF with the use

of anterior cervical plating. Similarly, Bolesta et al. reported the

fusion rate of 97.5% when a cervical plate with segmental

fixation was used for two-level ACDF. However, one of the crit-

icisms of static cervical plates has been their rigidity which, in

theory, might distract the fusion site and prevent graft settling,

thereby increasing the chance for a pseudarthrosis. To address

this problem, dynamic plates have been developed. The theo-

retical advantage of dynamic plates is greater graft loading with

less stress shielding, which should increase fusion rates.

Nunley and colleagues performed a randomized controlled trial

of a heterogeneous mix of patients undergoing single or mul-

tilevel ACDF with rigid or dynamic fixation. They found no dif-

ference in outcomes for the groups undergoing single level

ACDF, but did find an advantage to dynamic instrumentation for

multilevel ACDF. In contrast, DuBois and colleagues reviewed

52 patients undergoing 2 and 3 level ACDF, comparing rigid

with dynamic anterior cervical plating. They found an increase

in the rate of nonunion when using the dynamic cervical plate

(P 5 .05). They measured the amount of construct settling over

1 to 2 years, and found no difference between the plating

systems, thus questioning the compressive properties of the

plate in vivo. Clinical outcomes were similar among the groups,

which led the investigators to conclude that the more expen-

sive dynamic plates do not offer any clear benefit compared

with rigid plates.

Anterior cervical plating is associated with adjacent level ossi-

fication which may be due to impingement from the plate on

the adjacent level disc space. Although comparative series have

shown no difference in incidence of this complication when

comparing rigid with dynamic cervical plating, special attention

must be paid to technique when using a dynamic plate. Park

and colleagues noted that the incidence of moderate to severe

adjacent level ossification was increased with less than 5 mm

Guest speakers lectures, oral presentations,clinical case presentations

FOCUS

Page 2: Guest speakers lectures, oral presentations, clinical case presentations

Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6

96 Focus 17th ArgoSpine Symposium Scientific Book

of space between the adjacent disc and plate. The implication

for those using dynamic plates is that the subsidence of the

bodies and graft must be accounted for at the time of surgery,

as the plates may encroach on the adjacent levels in follow-up,

as the graft is compressed. This problem requires the surgeon

to know the amount of subsidence allowed by the plate, and

to understand the method of dynamization to optimize plate and

screw placement.

The clinical evidence for cervical dynamic plating remains mixed.

The literature supports a compressive role of the dynamic

cervical plate. However, there is little evidence for improvement

of fusion rates or clinical outcomes compared with rigid fixation.

The loss of segmental lordosis and potential for adjacent

segment impingement is a significant limitation of cervical

dynamic stabilization. Personal experience in more 200 cases

using ABC dynamic plate, the main problem was uncon-

trolled subsidence over the graft, adjacent disc lesion due the

progress of the plate, and kyphotic deformities, over 20% of

the series. In fractures instability was detected in extension after

graft bone height loosening. Moreover, the fusion time was not

shorter in our patients compared with the rigid plate cases. Due

to these reasons, I only use rigid plates. �

/+/ AboutJ.M. Casamitjana Ferrandiz

Cervical Spine Pathology, Spine Surgery Unit,

Trauma and Rehabilitation, University Hospital,

Ciutat Sanitaria Universitaria, Vall d’Hebron

Psg. Vall d’Hebron 119-129

08035 Barcelona, Spain

Dr. José Casamitjana, Born August 20th, 1949 in Barcelona, he was

registered as an orthopedic surgeon in 1979. Since 1980 he has been

a staff member of the department of Traumatology and Orthopedic

surgery of the Vall d’Hebron Educational Hospitals in Barcelona. He

became initiated in cervical spine surgery in 1985 and for the past 20

years he has dedicated himself exclusively to this specialty. As of 1998

he is head of Cervical Spine Pathology within the Spine Surgery Unit

at the Vall d’Hebron Traumatology and Rehabilitation Hospital in

Barcelona. Besides contributing to many articles, he is frequently invited

as a speaker to national and international meetings. He is also involved

as a teacher in several international spine courses. As well as organ-

izing the CSRS-ES 2003 Annual Meeting in Barcelona, Dr. José

Casamitjana, was President of the Cervical Spine Research Society

from 2009 to 2011. He is the Chairman and organizer of the Society�s

Instructional Hands on Cadaver Course and has organized nine cadaver

courses in Barcelona all extremely well rated by the participants.

LECTURE Day 1/ 9:10>9:20

Dynamic fixation of the cervical spine

Biomechanics, kinematic concepts andmotion preservation with total discreplacementCédric Barrey1, Wafa Skalli21 Hospital P. Wertheimer, Lyon, France2 Laboratory of Biomechanics, Arts et Métiers-ParisTech, Paris, France

Still considered as an emerging technology, cervical arthroplasty

has been progressively introduced to address the adverse

effects of traditional spinal fusion. In addition to provide clinical

results and outcomes at least as good as fusion, cervical total

disc replacement (TDR) intends to preserve intervertebral motion

with the ultimate objective to decrease the incidence of adjacent

degenerative disease.

The lecture will focus on the capacity of current TDR to restore

native kinematics of the cervical spine. Many questions are still

under investigations: what is the amount of motion actually

restored in vivo after cervical TDR? Does the TDR design influ-

ence the kinematics of the instrumented spine? What is the

quality of motion at adjacent levels? What are the benefits of

TDR versus arthrodesis for the adjacent levels? Are cervical

TDRs efficient to restore the sagittal balance of the cervical

spine? Are uncinatectomies necessary to preserve motion during

TDR surgery? Has the surgical technique any impact on the

biomechanical behaviour of the implanted device? Is there a

correlation between kinematics of TDR and clinical results?

Should we prefer hybrid or 2-levels TDR constructs?

Figures: Biomechanical investigational methods include experimental tests (left), numerical simulation methods (centre) and in vivo investigations (right).

Page 3: Guest speakers lectures, oral presentations, clinical case presentations

© Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&JOURNAL - quarterly december 2012 - Vol. 24 - N°3-4

Focus 9717th ArgoSpine Symposium Scientific Book

Many biomechanical studies have been performed in the last

years, including in vitro experiments, numerical simulations and

in vivo investigation (medical imaging) in order to provide a

better understand of the biomechanical behaviour of cervical

TDR and give us some responses to the aforementioned ques-

tions. �

/+/ References.a Ishihara H, Kanamori M, Kawaguchi Y et al. (2004) Adjacent segment

disease after anterior cervical interbody fusion. Spine J 4: 624-8

z Dmitriev AE, Cunningham BW, Hu N et al. (2005) Adjacent level

intradiscal pressure and segmental kinematics following a cervical

total disc arthroplasty: an in vitro human cadaveric model. Spine 30:

1165-72

e Barrey C, Campana S, Persohn S et al. (2012) Cervical disc

prosthesis versus arthrodesis using one-level, hybrid and two-level

constructs: an in vitro investigation. Eur Spine J 21(3): 432-42

r Galbusera F, Bellini CM, Brayda-Bruno M, Fornari M (2008)

Biomechanical studies on cervical total disc arthroplasty: a literature

review. Clin Biomech 23: 1095-104

t Sasso RC, Best NM (2008) Cervical kinematics after fusion and Bryan

disc arthroplasty. J Spinal Disord Tech 21: 19-22

y Rousseau MA, Cottin P, Levante S et al. (2008) In Vivo kinematics of

two types of ball-and-socket cervical disc replacements in the sagittal

plane. Cranial versus caudal geometric center. Spine 33:E6-E9

u Johnson JP, Lauryssen C, Cambron HO et al. (2004) Sagittal

alignment and the Bryan cervical artificial disc. Neurosurg Focus 17:

E4

i Snyder JT, Tzermiadianos MN, Ghanayem AJ, et al. (2007) Effect of

uncovertebral joint excision on the motion response of the cervical

spine after total disc replacement. Spine 32: 2965-9

o Barrey C, Champain S, Campana S, et al. (2012) Sagittal alignment

and kinematics at instrumented and adjacent levels after total disc

replacement in the cervical spine. Eur Spine J 21(8):1648-59

/+/ AboutCédric Barrey

Neurosurgery-Spinal Surgery

Hospital P. Wertheimer

59 boulevard Pinel

69394 Lyon, France

Dr. Barrey performed his residency at University Claude Bernard in

Lyon, France and is currently senior assistant professor in the

Department of Spine Surgery, Prof. G. Perrin, P Wertheimer Hospital

in Lyon since 2004 (around 400 spine surgeries each year). He spent

6 months fellowship in the department of Prof. B. George, at Lariboisière

Hospital, Paris, to get used with Vertebral Artery Surgery and also 6

other months in the unit of Dr. P. Roussouly who is specialized in the

management of Spinal Deformities in Lyon. His Research Activities are

dedicated to: cervical posterior stabilization, spino-pelvic alignment

and sagittal balance, lumbar dynamic devices and cervical disc pros-

thesis. In 2008, he was a research fellow at Thomas Jefferson University,

Department of Spine Surgery, Prof. AR Vaccaro, Philadelphia (USA).

He performed a biomechanical PhD thesis on cervical disc prosthesis

in 2011 in collaboration with the Laboratory of biomechanics, Arts et

Metiers-PARISTECH, Paris, with Prof. W. Skalli as programme director.

Main Spine Society affiliations: SFNC, SNCLF, ArgoSpine, SFCR,

AO-SPINE and SSE.

LECTURE Day 1/ 9:20>9:30

Dynamic fixation of the cervical spine

Dynamic Cervical Implant (DCI).Indications and resultsGuy MatgéNational Neurosurgical Department, Centre Hospitalier de Luxembourg, Luxembourg

Although cervical arthroplasty with total disc replacement (TDR)

has shown equivalence or superiority over anterior cervical dis-

cectomy and fusion (ACDF) in cervical disc disease, potential

problems include: non-physiologic motion which may accelerate

degeneration of the facet joints, particulate wear, and compro-

mise of the endplate mechanical integrity during device fixation.

Dynamic cervical stabilization with DCI is a novel motion-pre-

serving concept that facilitates controlled, limited flexion and

extension, but prevents axial rotation and lateral bending, thereby

reducing motion across the facet joints. Consequently, DCI may

provide the benefit of motion-preservation and reduced risk for

adjacent segment degeneration, while providing a surgical alter-

native to patients with facet arthrosis who would otherwise be

contra-indicated to receiving TDR. The purpose of the current

study is to report the safety and initial clinical and radiographic

results of the DCI in the treatment of 1 to 3-level cervical disc

disease at a single institution.

Prospective evaluation of 50 consecutive patients (26 females

and 24 males) with an average age of 50 years (range: 25-79)

who underwent dynamic cervical stabilization using the 2nd

generation DCI device between 06/2008 and 12/2010 at a single

institution for the treatment of one-level (n=41), two-level (n=7)

and three-level (n=2) cervical disc disease. All patients com-

pleted clinical and radiographic outcomes at 12 months, and

42 at 24 months. Clinical outcomes consisted of Neck Disability

Index (NDI), Visual Analog Scale (VAS) scores at baseline and

at latest follow-up and in addition patient satisfaction. Flexion-

extension radiography was evaluated for the presence of the

device-level motion, device failures, device subsidence and het-

erotopic ossification.

Indications for surgery were patients with failed medical therapy

in disc herniation, DDD, stenosis and adjacent-level protection.

Interesting points concerning device, instrumentation and oper-

ative technique were developed up 2004.

NDI and VAS neck and arm pain scores were significantly

reduced at each post-operative time point compared with

Page 4: Guest speakers lectures, oral presentations, clinical case presentations

Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6

98 Focus 17th ArgoSpine Symposium Scientific Book

baseline. At 12 months post-operatively, 92% of patients were

very satisfied and 8% somewhat satisfied while 100% would

elect to have the surgery again. The radiographic assessment

comparing pre- and postoperative dynamic radiographies

showed good motion of the device in 84%, reduced motion in

12% and fusion in 4%. There was one asymptomatic anterior

device migration that required revision due to device under

sizing (2%), 1 case of adjacent segment disease requiring

another DCI 2 years later (2%), 3 cases of minor (non-bridging)

heterotopic ossification (6%), 1 case of asymptomatic endplate

subsidence (2%). There were no device failures.

In conclusion, preliminary results indicate that DCI is safe and

facilitates excellent clinical outcomes, maintains mostly index-

level range of motion, and may be suitable for patients with

facet arthrosis who would otherwise not be candidates for TDR.

Protection for adjacent-level degeneration or slow fusion over

years need longer and systematic follow-up. At this time, DCI

represents an exciting alternative to ACDF and TDR, with a wider

range of indications in the treatment of patients with 1 to 3-

level cervical disc disease. Biomechanical and clinical studies

of other users are shortly presented. �

/+/ References.a Auerbach JD, Jones KJ, Fras CI et al. (2008) The prevalence of

indications and contraindications to cervical total disc replacement.

Spine J 8: 711-6

z Bertagnoli R, Yue JJ, Pfeiffer F et al. (2005) Early results after

ProDisc-C cervical disc replacement. J Neurosurg. Spine 2: 403-10

e Chang UK, Kim DH, Lee MC et al. (2007) Changes in adjacent-level

disc pressure and facet joint force after cervical arthroplasty

compared with cervical discectomy and fusion. J Neurosurg Spine 7:

33-9

r Cunningham BW, Hu N, Zorn CM et al. (2010) Comparative fixation

methods of cervical disc arthroplasty versus conventional methods of

anterior cervical arthrodesis: serration, teeth, keels, or screws? J

Neurosurg Spine 12: 214-20

t Goffin J, van LJ, Van CF et al. (1995) Long-term results after anterior

cervical fusion and osteosynthetic stabilization for fractures and/or

dislocations of the cervical spine. J Spinal Disord 8: 500-8

y Hilibrand AS, Carlson GD, Palumbo MA et al. (1999) Radiculopathy

and myelopathy at segments adjacent to the site of a previous

anterior cervical arthrodesis. J Bone Joint Surg Am 81: 519-28

u Leung C, Casey A, Goffin J et al. (2005) Clinical significance of

heterotopic ossification in cervical disc replacement: a prospective

multicenter clinical trial. Neurosurgery 57: 759-63

i Matgé G (2002) Cervical cage fusion with 5 different implants: 250

cases. Acta Neurochir 144: 539-50

o Robertson JT, Papadopoulos SM, Traynelis VC (2005) Assessment of

adjacent-segment disease in patients treated with cervical fusion or

arthroplasty: a prospective 2-year study. J Neurosurg Spine 3: 417-23

p Wigfield C, Gill S, Nelson R, et al. (2002) Influence of an artificial

cervical joint compared with fusion on adjacent-level motion in the

treatment of degenerative cervical disc disease. J Neurosurg Spine

96: 17-21

/+/ AboutGuy Matgé

National Neurosurgical Department

Centre Hospitalier de Luxembourg

4 rue Barblé, L-1210 Luxembourg

E-mail: [email protected]

Dr. Matgé started to practice as a neurosurgeon in Luxembourg in

1985. He subspecialised through the years in Spinal Surgery with a

large experience in cage fusion and dynamic instrumentation (9 pub-

lications, 4 book chapters). Dr. Matgé is actually practising as a full-

time neurosurgeon in the National Neurosurgical Department, with about

70% of spinal and 30% of cranial surgery. He has a major interest in

cervical and lumbar reconstructive surgery for degenerative, traumatic

and tumour cases. He was developing a dynamic cervical implant

called DCI, actually used in a multi-centre study to evaluate adjacent-

level protection.

Through EANS (European Association of Neurosurgeons), UEMS (Union

of European Medical Specialists) and JRRAC (harmonisation of neu-

rosurgical training in Europe) he was involved in Education, Examination

and Site Visiting of Departments. He was a Vice-President of EANS

from 2003–2007 (organising Meeting 2006 subject Spine) and President

of the Francophone Society of Spinal Surgery from 2005–2008 (organ-

ising Meeting 2003).

Dr Matgé is a member of five Neurosurgical Societies.

LECTURE Day 1/ 9:40>10:00

Dynamic fixation of the cervical spine

Prevention and management of perioperativecomplications in cervical spine surgeryUfuk AydinliMedicabil Hospital, Bursa, Turkey

ELECTIVE SURGERYMain therapeutic targets to reach before surgery:

– Diabetes: maintain HbA1 < 7% (optimal 6.2%) and/or fasting

blood glucose <150 mg/dL (optimal <126)

– Cardiovascular diseases: optimal management of fluids and

compensation of anaemia

– Pulmonary diseases: ensure pO2 > 60 and/or pCO2 < 50

– Hypertension: adjust therapy to obtain PAS < 150 mmHg

and/or PAD < 90 mmHg

– Smoking/alcohol/drug abuse: quit!

EMERGENCY SURGERY– Diabetes: compensation by IV Insulin (GKI) to maintain blood

glucose between 150 and 200 mg/dL during the first 3-5 days

postsurgery. Resume preoperative therapy as soon as possible

– Cardiovascular diseases: optimal management of fluids and

compensation of anaemia. Continuous cardiologic consulta-

tion

Page 5: Guest speakers lectures, oral presentations, clinical case presentations

© Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&JOURNAL - quarterly december 2012 - Vol. 24 - N°3-4

Focus 9917th ArgoSpine Symposium Scientific Book

– Pulmonary diseases: optimal airways and ventilation manage-

ment during and after surgery

– Correction of anaemia: transfusions if Hgb < 9 g/dL

ANAESTHESIOLOGY– The endotracheal tube must be carefully anchored to the

mouth

– Posterior cervical surgery may be performed in a seated

position (increasing the risk of gaseous embolism)

– In the prone position (increasing the risk of ocular compres-

sion)

– In the oblique lateral position (increasing the risk of damage

to the nerves and vessels of the axilla)

POSITIONING– Intra-operative bleeding

– Compression of the bony prominences

– Peripheral nerve damage

– Fall of the lower extremities from the table

– Movements of the head during surgery

MAJOR DETERMINANTS OF COMPLICATIONS OF SURGICALTECHNIQUES TO THE ANTERIOR CERVICAL SPINE– Incomplete decompression – Eccentric or too deep

– Kyphosis and/or loss of drilling

lordosis – Vascular and soft tissue

– Implant failure lesions

– Screw mobilisation – Plate rupture

– Plate or graft mobilisation – Cage or graft subsidence

– Implant failure or dislocation

– Vertebral artery injury – Nerve root injury

– Wrong-level surgery – Epidural haematoma

– Wound haematoma – Spinal instability

– CSF leak. �

/+/ AboutUfuk Aydinli

Medicabil Hospital

Mudanya Yolu, Fethiye Mah

Küre Sok, No: 1 Nilüfer

Bursa, Turkey

Prof. Ufuk Aydinli is currently the Head of the Depar tment of

Orthopaedics and Trauma at Medicabil Hospital, Bursa (Turkey).

He graduated from the Medical Faculty of Ondokuz Mayis University

in Samsun (Turkey) where he underwent his orthopaedic training. He

pursued his medical education at the University of Charlottesville,

Virginia (USA).

In 1991 he was a Visiting Fellow at the Minnesota Spine Center,

Minneapolis (USA).

In 2000 he was a Travelling Fellow appointed by the Scoliosis Research

Society (SRS).

Prof. Aydinli is involved in a number of national and international projects

and has contributed to numerous publications and peer-reviewed

articles.

He is the member of several scientific societies, including AOSpine for

which he is in charge of education and was the President of the Spine

Expert Group in 2010.

LECTURE Day 1/ 10:35>10:45Dynamic fixation of the lumbar spine

Non-fusion dynamic fixation for stablespondylolisthesis of the degenerated lumbarspineMatjazv Vorsv icv

University Hospital Maribor, Maribor, Slovenia

AIM OF THE STUDYThe surgical treatment of the degenerated lumbar spine may

require transpedicular fixation together with fusion in order to

achieve the rigid stability of the affected motion segment. The

spondylodesis may lead to adjacent segments degeneration,

therefore the development of the new dynamic systems, needing

no fusion, occurred.

The aim of the study was to determine the clinical results and

the outcome in the patients treated for the stable spondylolis-

thesis of the degenerated lumbar spine using the dynamic

transpedicular fixation system.

METHODSIn the study, 40 patients with painful, stable lumbar spondy-

lolisthesis (Grade I) were treated with dynamic transpedicular

fixation system. Clinical outcomes were assessed before, one

year and two years after the procedure using neurological exam-

ination, the Oswestry Disability Index (ODI) and Visual analogue

score (VAS) for back and leg pain, with 15 % improvement in

ODI and 20 % in VAS defined as clinically significant.

RESULTSForty patients with stable lumbar spondylolisthesis, treated with

the Cosmic system were included in the study with a minimum

follow-up of two years. There was a significant improvement for

back and leg pain according to ODI (74.3% of patients in the

group achieved ≥ 15% improvement) and VAS score.

CONCLUSIONSThe Cosmic is a dynamic non-fusion fixation system. Stabilization

with this system and without spinal fusion reduces the surgical

trauma, shortens the duration of the surgery, avoids pain from

the bone extraction site and preserves the intervertebral disc

and part of its function. It can efficiently replace the classic

spondylodesis in the treatment of painful, stable spondylolis-

thesis (Grade I) of the lumbar spine. Long-term follow-up studies

will help determine the definitive treatment. �

Page 6: Guest speakers lectures, oral presentations, clinical case presentations

Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6

100 Focus 17th ArgoSpine Symposium Scientific Book

/+/ AboutMatjaz

v

Vorsv

icv

University Hospital Maribor

Ljubljanska 5, 2000 Maribor, Slovenia

E-mail: [email protected]

Matjazv

Vorsv

icv

graduated from the University Medical School of Ljubljana.

He then trained in Neurosurgery at the Neurosurgical Department

University Clinical Hospital Ljubljana where he also completed his post-

graduate studies.

His main area of interest is degenerative spinal pathology. His research

encompasses dynamic stabilization of the lumbar spine, cervical arthro-

plasty and tumours of the spinal cord.

He authored and co-authored two books and more than 50 papers in

national as well as international journals.

He is a member of Spine Society of Europe, Slovenian Medical Society,

Slovenian Association of Surgeons, Slovenian Association of

Neurosurgeons, Slovenian Spine Society, European Association of

Neurosurgeons, World Federation of Neurosurgeons, AO Spine and the

American Association of Neurological Surgeons.

He organized several international symposiums and congresses and

cadaver workshops dealing with spinal instrumentation.

He is currently appointed as spinal surgeon at University Hospital

Maribor and as an assistant of neurosurgery at Medical School,

University of Maribor.

LECTURE Day 1/ 10:45>10:55Dynamic fixation of the lumbar spine

Non-fusion devices in patients over 80 yearsof ageL. Balabaud1, I. Caux1, C. Dova1, B. Richard1,P. Antonietti1, C. Mazel1,21 Department of Orthopaedics, Institut Mutualiste Montsouris, Paris, France2 Paris 13 University-Sorbonne Paris Cité, France

INTRODUCTIONLife expectancy increased during the last four decades in

western countries, and is associated with an improvement of

quality of life. Many octogenarians have an active life, and want

to preserve it. However the surgical treatment of degenerative

lumbar pathologies among older patients is debatable. It is clear

that non-surgical treatment must be favored, but patients not

responding favorably to it require surgical treatment.

Decompression is often enough but fusion with instrumentation

cannot be avoided in patients with associated spinal instability.

The instrumented fusion in the elderly is limited by some

problems: the comorbidities, the weaker general state of wealth,

frequent multisegmental discopathies, and poor bone quality.

These parameters necessitate adapting our indications or tech-

niques, so we limit the indications of instrumented fusions. In

case of potential or real lumbar instability, an instrumented fusion

is necessary. But we prefer to limit to one or two segments

fusion and we avoid long instrumented fusion. Osteoporotic frac-

tures and disc degeneration at adjacent motion segments are

frequent and undeniable problems of instrumented fusion in

elderly, and more particularly over 80 years of age.

In the last years, many authors [1-6] showed good functional

results in using dynamic stabilisation for patients with degener-

ative lumbar instability. Thus, dynamic stabilisation seems to be

an alternative technique to instrumented fusions in selected

cases of degenerative lumbar instability. In our eyes, the theo-

retical advantages of dynamic stabilisation were interesting more

particularly in the elderly, and it would solve some problems of

instrumented fusion. It would conserve a segmental mobility

avoiding degeneration at adjacent motion segments. This point

was very attractive because it would allow limiting the stabili-

sation to one or two segments and that would avoid the long

instrumented fusion in patients with multisegmental discopathies.

Moreover, dynamic stabilisation would maintain sufficient sta-

bility to prevent progression of degenerative lumbar instability

and enable wide laminectomy. Finally, dynamic stabilisation would

be less aggressive than instrumented fusion. The purpose of

our study is to evaluate functional, radiographic and morbidity

results of lumbar dynamic stabilisation surgery in patients 80

years of age or older.

MATERIALS AND METHODSFrom November 2009 to May 2012, 35 consecutive patients 80

years of age or older, who had undergone posterior decom-

pression associated with lumbar non-fusion devices, were

included into the study. We excluded all patients with fracture,

neoplasm or spinal sepsis. The average age at the time of

surgery was 82.7 ± 2.4 years (range, 80 to 89 years). There

were 12 men and 23 women. 3 patients had undergone a

previous surgical procedure on their lumbar spine. All the

patients presented stenosis with spondylolisthesis and/or degen-

erative scoliosis. Preoperative symptoms included radicular pain

in 20, and neurogenic claudication in 15 patients. Neurologic

deficits were found in 15 patients, which included sensory deficit,

motor weakness, or a combination of both. 2 patients presented

with bowel and bladder dysfunction preoperatively. 14 patients

took oral anticoagulants or platelet aggregation inhibiting drugs,

which were stopped or relayed by heparin preoperatively in the

usual period of time.

The indications for surgery were lumbar spinal stenosis with or

without spondylolisthesis and/or degenerative scoliosis, in

patients with incapacitating back and radicular pain, non respon-

sive to nonoperative management. Dynamic stabilisations were

always associated to laminectomy. Two devices were used

Dynesys (Zimmer, Warsaw, IN) and Isobar TTL (Scient’x, Paris,

France) in 28 and 7 patients respectively. All procedures were

performed by 1 of 3 senior orthopaedic spine surgeons (CM,

PA, LB). All the patients discharged to a nursing home or reha-

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Focus 10117th ArgoSpine Symposium Scientific Book

bilitation facility. Patients were evaluated preoperatively, postop-

eratively at 3 months, and then 6-, 12-month and one-year inter-

vals. The records of these 35 patients were analysed for

demographics, preoperative comorbidities (Charlson score) [7]

and risk assessment, primary diagnoses, perioperative and post-

operative complications, pre- and postoperative 100-mm visual

analog scale (VAS) and Oswestry Disability Index (ODI), pre-

and postoperative standard and dynamic X-ray. Among the pre-

operative clinical parameters, the American Society of

Anesthesiologists (ASA) classification of physical status was

evaluated. Hospital records were studied looking for other hos-

pitalisations or outpatient treatments for any complications, both

medical and surgical, related to the index procedure within the

first year after discharge. According to Raffo and Carreon [8,

9], we considered as major complications: death, paralysis or

neurologic injury, epidural haematoma, wound infection, pneu-

monia or pulmonary oedema, a new-onset cardiac arrhythmia,

myocardial infarction, cerebrovascular accident, thromboembolic

disease, or gastrointestinal haemorrhage. Minor complications

were defined as no life threatening and no compromise or

dramatic change in treatment, including delirium, ileus, urinary

tract infection, etc. Diagnostic criteria for delirium were according

to Diagnostic and Statistical Manual of Mental Disorders, Fourth

Edition (DSM-IV). Blood transfusion was not considered as com-

plication, but was recorded for descriptive analysis.

STATISTICAL ANALYSESData were entered onto EXCEL software (Microsoft, Seattle, WA).

Descriptive data are expressed as mean ± standard deviation.

Data were analysed using the SPSS 15.0 (Chicago, IL) software

package. Statistical significance was established at a P value

less than 0.05.

RESULTSDistribution of the 35 patients was as follow: 22 patients were

ASA class II and 13 ASA class III. The average comorbidities

(Charlson score) was 1.6 ± 1.2 (range, 0 to 5). The average

BMI was 26.6 ± 3.6 (range, 20 to 34). Laminectomies were per-

formed in 8 patients (one level), 14 patients (2 levels), 12 patients

(3 levels) and one patient (4 levels). Levels of dynamic stabili-

sations were listed in Table I. The average estimated blood loss

was 483 ± 276 mL (range, 150 to 1500 mL). Analysis of peri-

operative and postoperative transfusion requirements demon-

strated that 8 patients were treated by an average of 2.3 units

of packed red blood cells (range, 1 to 5). The average opera-

tive time was 136 ± 31 minutes (range, 78 to 235 minutes). The

operative time was associated significantly with dural tears (174

± 40 minutes versus 134 ± 31 minutes, p=0.04). Dural tears

occurred in 5 patients. No major intraoperative complication was

noted. Major complications occurred in 3 patients: 2 epidural

haematomas, one wound infection (Escherichia coli), and one

new-onset cardiac arrhythmia. The two patients, who had

epidural haematoma, presented no persistent neurologic deficit.

Minor complications occurred in 36 patients and are listed in

Table II. The mean back pain and leg pain VAS and ODI scores

improved significantly from the baseline to one-year follow-up

evaluation, as follows: back pain improved from 50.5 ± 16.3 to

29.6 ± 15.7 mm (P=0.01), leg pain from 74.9 ± 17.3 to 25.3 ±

18.1 mm (P<0.0001), and ODI score from 59.7 ± 8.3 to 22.4 ±

13.6 % (p<0.001). Radiographically, spondylolisthesis and

degenerative scoliosis did not progress and the motion segments

remained stable at last follow-up. But 2 patients showed junc-

tional disc degeneration at the upper adjacent level. The mean

range of motion (ROM) at the index level was significantly

reduced post-operatively from 6.1 ± 3.2 to 2.6 ± 1.5° (p<0.01).

No implant-related complications (screw loosening or breakage)

were observed and no implant removal was necessary. The

average hospital stay was 10.7 ± 8.3 days (range, 7 to 54 days),

with a median of 8 days. The average follow-up was 20.9 ± 9.7

months (range, 7 to 37 months). No patients died after a post-

operative period of one year.

No relation was found for the studied parameters: gender, ASA

classification, BMI, comorbidity Charlson score, anticoagulants,

neurologic deficit, number of laminectomy levels, and number

of instrumented levels, the minor or major complications, the

VAS and ODI scores.

DISCUSSION AND CONCLUSIONDynamic stabilisation devices in addition to decompressive

laminectomy allow to decrease back and leg pain while avoiding

the morbidity of donor site and the use of poor bone quality in

patients 80 years of age or older. Moreover, dynamic stabilisa-

tion would seem to be less invasive than instrumented fusion,

but we showed no shorter operative time and less blood loss

in our short series. Dynamic stabilisation devices allow per-

forming a wide laminectomy in maintaining enough stability to

prevent progression of spondylolisthesis. But junctional disc

degeneration at the upper adjacent level remains a problem,

which is not resolved by the dynamic stabilisation devices. The

results of this study are comparable to fusion procedures at

last follow-up.

Table I: LEVELS OF DYNAMIC STABILISATIONS.

Levels of dynamic stabilisation Number of patients

L4L5 26

L3L5 4

L3L4 3

L2L4 2

Table II: MINOR COMPLICATIONS FOR THE 35 PATIENTS.

Minor complications Numbers

Urinary retention 9

Delirium 8

Urinary tract infection 4

Hyponatremia 1

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102 Focus 17th ArgoSpine Symposium Scientific Book

In conclusion, the dynamic stabilisation devices are a safe and

effective alternative technique to lumbar fusion in selected cases

of degenerative lumbar instability, more particularly the spondy-

lolisthesis in patients 80 years of age or older. Our experience

of dynamic stabilisation in lumbar degenerative scoliosis is too

limited to draw conclusions. Long-term follow-up care is still rec-

ommended but studies might be limited by the advanced age

of the patients. �

/+/ References.a Schaeren S, Broger I, Jeanneret B (2008) Minimum four-year

follow-up of spinal stenosis with degenerative spondylolisthesis

treated with decompression and dynamic stabilization. Spine 33:

E636-42

z Di Silvestre M, Lolli F, Bakaloudis G, Parisini P (2010) Dynamic

stabilization for degenerative lumbar scoliosis in elderly patients.

Spine 35: 277-34

e Welch WC, Cheng BC, Awad TE et al. (2007) Clinical outcomes of the

Dynesis dynamic neutralization system: 1-year preliminary results.

Neurosurg focus 22: E8

r Sapkas GS, Themistocleous GS, Mavrogenis AF et al. (2007)

Stabilization of the lumbar spine using the dynamic neutralization

system. Orthopedics 30: 859-65

t Fay LY, Wu JC, Tsai TY et al. (2012) Dynamic stabilization for

degenerative spondylolisthesis: Evaluation of radiographic and

clinical outcomes. Clin Neurol Neurosurg 21 [Epub ahead of print]

y Stoll TM, Dubois G, Schwarzenbach O (2002) The dynamic

neutralization system for the spine: a multi-center study of a novel

non-fusion system. Eur Spine J 11: S170-8

u Charlson ME, Pompei P, Ales KL et al. (1987) A new method of

classifying prognostic comorbidity in longitudinal studies:

development and validation. J Cron Dis 40: 373-83

i Raffo CS, Lauerman WC (2006) Predicting morbidity and mortality of

lumbar spine arthrodesis in patients in their ninth decade. Spine 31:

99-103

o Carreon LY, Puno RM, Dimar JR et al. (2003) Perioperative

complications of posterior lumbar decompression and arthrodesis in

older adults. J Bone Joint Surg Am. 85-A: 2089-92

/+/ AboutLaurent Balabaud

Department of Orthopaedics

Institut Mutualiste Montsouris

42 boulevard jourdan

75014 Paris, France

E-mail: [email protected].

Laurent Balabaud is an orthopaedic surgeon specialized in spine

surgery at Institut Mutualiste Montsouris of Paris. He got his orthopaedic

Specialty Diploma at the University of Strasbourg in 2002. He holds a

master of Biomechanics in the Laboratory of Biomechanics Arts et

Métiers ParisTech in 2000. He has conducted clinical and basic

research studies. His special areas of interest are degenerative, tumour

and deformities of the spine. He is the co-founder and the secretary

of the DIU of Spine Surgery (French Spine Surgery Diploma). He is

an active member of SFCR (French Surgical Spine Society), GSTSG

(Global Spine Tumour Study Group) and SOFCOT (French Society of

Orthopaedic surgery and traumatology). He has authored and co-

authored eight peer-reviewed publications and seven book chapters.

He has given over 30 presentations in national and international

meetings.

LECTURE Day 1/ 10:55>11:05Dynamic fixation of the lumbar spine

The rationale, relevance and clinicalperspective of dynamic systems for improvingthe spinal fixation reliability, for promotinglumbar fusion and for preventing ASDGilles PerrinSpine Surgery Depar tment, Hôpital Neurologique, GHE-HCLyon, University

Claude Bernard Lyon 1, France

Dynamic semi-rigid technologies for vertebral stabilization have

been progressively introduced to address the adverse effects

of traditional spinal fusion: stiffness, pseudoarthrosis, mechan-

ical failure, and/or adjacent degenerative disease. The basic

concept of pedicle screw-based systems for posterior dynamic

stabilization is to reduce the stiffness of the instrumentation to

allow for load sharing between the instrumentation and the

functional spine unit (FSU) at the instrumented levels. Most

pedicle screw-based dynamic stabilization devices were

initially designed to improve interbody fusion success in com-

bination with an interbody bone graft or intervertebral cages.

Rigid construct by eliminating mechanical loads on an inter-

body graft may result in negative bone remodelling,

pseudarthrosis and osteoporosis. This “stress-shielding” phe-

nomenon at the disc space level may be due to the excessive

stiffness of traditional rigid instrumentation. In 1993, with

F. Lavaste we demonstrated by using a finite element model of

the lumbar spine, that dynamic posterior instrumentation,

compared to rigid instrumentation, increases the amount of

load transmission through the anterior column. Dynamic

fusion using semi-rigid devices to improve rates of interbody

fusion success is now well-documented through clinical

studies with long-term follow-up. Since 1993, our clinical

experience with this dynamic system has been over 1000

implanted patients. Prevention of potential fixation complications

remains a challenge in poor quality and severely osteoporotic

bone. PMMA cement augmention or the use of expandable

screws may reinforce the screw purchase, but too rigid poste-

rior pedicular fixation may also explain high likelihood of pedicle

screw loosening and pullout in patients with osteoporosis

requiring instrumented arthrodesis. Semi-rigid dynamic inter-

pedicular systems by matching the construct with the elastic

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Focus 10317th ArgoSpine Symposium Scientific Book

bone residence seems to be able to reduce the risk of fixation

failure.

Rigid fusion is often associated with adjacent segment degen-

eration (ASD). Dynamic stabilization devices may palliate this

drawback, by preventing mechanical failures and stress-shielding

phenomena. However, there are few comparative studies avail-

able, regarding ASD after rigid fusion versus dynamic stabi-

lization. With a retrospective comparative study, we were able

to report that Dynamic stabilization is an efficient procedure for

preserving adjacent levels from early degeneration. A better

load sharing pattern results in less mechanical complications,

mostly due to the neo-hinge phenomenon between a fused

spinal segment and an adjacent overstressed and hypermobile

intervertebral segment.

Distractive PLIF or ALIF and posterior fixation in compression

by using dynamic interpedicular systems is an efficient tech-

nique for decompression and stabilization with an optimal fusion

rate and a significantly reduced risk of degenerative lesions at

the level above the instrumentation after long-term follow-up.

Fusion with large cages, restoration of lumbar lordosis, semi-

rigid dynamic stabilization for protection of pathological adjacent

disc, avoidance of postoperative corset collectively meet all the

requirements not only for pain relief but also for definitive sta-

bilisation without iatrogenic spinal complication or fur ther

adjacent degeneration. �

/+/ AboutGilles Perrin

Spine Surgery Department

Hôpital neurologique, GHE-HCLyon

University Claude Bernard Lyon 1

59 boulevard Pinel

69677 Bron Cedex, France

Email: [email protected]

Gilles Perrin is a professor in Neurosurgery and a fulltime senior neu-

rosurgeon at the University Claude Bernard in Lyon, France.

Since 1990 he is the Chairman of the “C” Neurosurgical Department

in the Hospices Civils of Lyon and the President of the Medical

Committee of the Neurological Hospital.

His main topics of interest, teaching and clinical research are pituitary

pathology, cerebral blood flow, spinal disorders and some experimental

research on different areas.

The topics he uses for his lectures and workshops about spinal surgery

are “Surgical management of degenerative, tumoral or traumatic spinal

lesions” and “Stabilization techniques: posterior fixation and anterior

reconstruction”. He gave 30 different lectures about these topics in

more than 25 countries.

Professor Perrin has been on multiple foreign missions organized by

the French Minister of Foreign Affairs, to countries such as Saudi Arabia,

Kuwait and Poland.

Gilles Perrin published numerous papers in international and national

journals.

LECTURE Day 1/ 11:20>11:30Controversial round table: is there still a place for dynamicfixation of the lumbar spine?

The role of sagittal profile in dynamicstabilization and topping-off syndromeYann Philippe Charles, Jean-Paul SteibSpinal Surgery, University Hospital, Strasbourg, France

Posterior dynamic stabilization systems are aimed to reduce

the risk for the postoperative development of adjacent

segment degeneration (ASD) by limiting the range of motion

of an instrumented segment without suppressing it. Different

types of implants exist, using ligaments and spacers, hinged

screws or spring mechanisms. Numerous studies have investi-

gated the kinematic features of pedicle screw-based dynamic

stabilization systems since their clinical application. However,

there is a lack of literature concerning their influence on the

sagittal spinopelvic alignment, which has been proved to be

important in the development of future ASD. This feature

could be particularly interesting in hybrid systems, using a

caudal fusion associated with a cranial transitional dynamic

fixation towards the uninstrumented spine, in order to avoid a

topping off mechanism.

A retrospective study was conducted to analyse and compare

the sagittal spinopelvic alignment variation after implantation of

purely dynamic and hybrid pedicle screw-based stabilization

systems, seeking for its clinical implication.

Lateral standing lumbar radiographs of 29 patients (17 males,

12 females, 27 to 64 y) who were implanted with purely

dynamic (Dynesys™: group A, n=15) or hybrid (FlexPlus™:

group B, n=14) stabilization systems, and with a minimum

follow-up of 1 year, have been reviewed. These parameters

were measured using Spineview® software and were

compared within and between groups: L1 to S1 lordosis,

lordosis of instrumented segments (ISL), cranial adjacent

segment lordosis (CASL) next to the instrumentation, highest

instrumented segment lordosis (HISL), pelvic incidence, sacral

slope, and pelvic tilt.

Preoperative lordosis parameters were not significantly different

between group A and B. The average L1 to S1 lordosis

decreased from 55.3 degrees preoperatively to 52.6 degrees

postoperatively in group A (P=0.007) and from 60.2 degrees

to 59.3 degrees in group B (P=0.054). There was no significant

difference between both groups (P=0.083). The average ISL

decreased from 25.9 degrees preoperatively to 21.7 degrees

postoperatively (P=0.00002) in group A and from 30.0 degrees

to 28.6 degrees in group B (P=0.153). The pre/postoperative

ISL variation was significantly different between group A and

B (P=0.015). The average HISL decreased from 9.5 degrees

to 6.2 degrees in group A (P=0.0007) and from 13.1 degrees

to 12.4 degrees in group B (P=0.295). The loss of HISL was

significantly greater (P=0.010) in group A than in group B. The

average CASL increased from 6.9 degrees to 9.2 degrees

(P=0.013) in group A. The CASL variation from 10.6 degrees

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104 Focus 17th ArgoSpine Symposium Scientific Book

to 10.4 degrees was not significant (P=0.763) in group B.

When comparing both groups, the difference of CASL variation

was statistically significant (P=0.043). The pelvic incidence,

sacral slope, and pelvic tilt did not change significantly before

and after instrumentation in both groups.

On the basis of the result of this study, the hybrid stabiliza-

tion system could better preserve the lordosis of instru-

mented segments and subsequently reduce the extent of

compensatory lordosis increase at the cranial adjacent

segment. This could theoretically prevent the development of

an ASD. The long-term outcome and the correlation between

lordosis preserving capacity and ASD need to be further

prospectively analysed. �

/+/ References.a Schmoelz W, Huber JF, Nydegger T et al. (2003) Dynamic

stabilization of the lumbar spine and its effects on adjacent

segments: an in vitro experiment. J Spinal Disord Tech. 16:

418-23

a Schwarzenbach O, Berlemann U, Stoll TM et al. (2005) Posterior

dynamic stabilization systems: DYNESYS. Orthop Clin North Am 36:

363-72

a Cakir B, Carazzo C, Schmidt R et al. (2009) Adjacent segment

mobility after rigid and semirigid instrumentation of the lumbar spine.

Spine 34: 1287-91

r Legaye J (2005) Unfavorable influence of the dynamic neutralization

system on sagittal balance of the spine. Rev Chir Orthop Reparatrice

Appar Mot 91: 542-50

t Min JH, Jang JS, Jung B et al. (2008) The clinical characteristics

and risk factors for the adjacent segment degeneration in

instrumented lumbar fusion. J Spinal Disord Tech 21: 305-9

y Kumar A, Beastall J, Hughes J et al. (2008) Disc changes in the

bridged and adjacent segments after Dynesys dynamic stabilization

system after two years. Spine. 33: 2909-14

u Schaeren S, Broger I, Jeanneret B (2008) Minimum four-year

follow-up of spinal stenosis with degenerative spondylolisthesis

treated with decompression and dynamic stabilization. Spine 33:

E636-42

i Umehara S, Zindrick MR, Patwardhan AG et al. (2000) The

biomechanical effect of postoperative hypolordosis in instrumented

lumbar fusion on instrumented and adjacent spinal segments.

Spine 25: 1617-24

o Oda I, Cunningham BW, Buckley RA et al. (1999) Does spinal

kyphotic deformity influence the biomechanical characteristics of the

adjacent motion segments? An in vivo animal model. Spine 24:

2139-46

p Kumar MN, Baklanov A, Chopin D (2001) Correlation between sagittal

plane changes and adjacent segment degeneration following lumbar

spine fusion. Eur Spine J. 10: 314-9

/+/ AboutYann Philippe Charles

Service de Chirurgie du Rachis

Hôpitaux Universitaires de Strasbourg

1, Place de l’Hôpital, BP 426

67091 Strasbourg Cedex, France

Email: [email protected]

Phone: +33 3 88 11 68 26

Fax: +33 3 88 11 52 33

Yann Philippe Charles is an orthopaedic surgeon specialized in spine

surgery. He completed his orthopadic residency at the University of

Heidelberg, Germany, and the University of Montpellier, France. He is cur-

rently Assistant Professor at the Department of Spine Surgery at the

University of Strasbourg, Fance, under Professor Jean-Paul Steib.

Dr Charles is an active member of scientific societies dedicated to

orthopaedics and spine care. He has conducted a large number of clinical

and basic research studies related to spinal growth and skeletal maturity,

scoliosis, spinal trauma and minimal invasive surgery, as well as dynamic

instrumentation and sagittal balance. He has performed a PhD thesis on

posterior facet supplementation in collaboration with the Laboratory of

Biomechanics Arts et Métiers ParisTech under Professor Wafa Skalli.

LECTURE Day 1/ 11:30>11:40Controversial round table: is there still a place for dynamicfixation of the lumbar spine?

Why I do not use dynamic stabilisationSamo K. FokterDepartment of Orthopaedics, University Clinical Centre Maribor, Slovenia

BACKGROUNDFusion of involved vertebral dynamic units represents the gold

standard in the treatment of degenerative spinal conditions.

Unfortunately, spinal fusion is believed to accelerate the degen-

eration of the vertebral segment above or below the fusion site,

a condition called adjacent segment disease [1].

BIOMECHANICAL DATAThe premise of dynamic stabilisation is that motion preservation

at bridged level allows for less loading on the discs and facet

joints at the cranial and caudal adjacent segments [2]. In theory,

this should decrease the rate of adjacent segment disease.

However, a retrospective radiographic analysis of lumbar spine

range of motion (ROM) after fusion as compared to a pedicle-

based dynamic neutralisation screw system demonstrated no

significant change of the adjacent level ROM in both groups [3].

CLINICAL STUDIESEven if some of the posterior dynamic stabilisation devices have

been implanted worldwide for more than 10 years, only a few

studies reported on patient-oriented outcome. The results of

earlier clinical studies reported significant positive changes in

pain and disability [4-6]. However, most of the studies from dis-

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Focus 10517th ArgoSpine Symposium Scientific Book

interested research groups question the advantage of dynamic

stabilisation. Grob et al. reported on the data of 31 patients and

noted that with the 2-year follow-up period, 6 of 31 (19%) patients

had required or were scheduled for a further surgical interven-

tion [7]. Schaeren et al. reported on 26 consecutive patients

(mean age 71 years) with symptomatic lumbar spinal stenosis

and degenerative spondylolisthesis treated with interlaminar

decompression and dynamic stabilisation [8]. Nine of 19 (47%)

patients that could be evaluated at 4-year follow-up showed

some degeneration at adjacent levels. Kumar et al. have reported

on progressive disc degeneration on bridged and adjacent levels

on MRI 2 years after dynamic stabilisation (Fig.) [9].

A systematic search and review of the literature was undertaken

recently to identify studies on dynamic stabilisation versus fusion

of degenerative spine conditions [10]. As most published reports

were case series, only four relatively small comparative studies

on different dynamic stabilisation systems were analysed. No

significant differences were identified between fusion and

dynamic stabilisation with regard to VAS, ODI, complications,

and reoperations. Further on, the authors noted that there are

currently no long-term data available to show whether dynamic

stabilisation decreases the rate of adjacent segment disease.

CONCLUSIONTo summarize, clinical evidence of the above-mentioned theo-

retical advantage of dynamic stabilisation systems over standard

fusion techniques is (still) lacking. �

/+/ References.a Shono Y, Kaneda K, Abumi K et al. (1998) Stability of posterior spinal

instrumentation and its effects on adjacent motion segments in the

lumbosacral spine. Spine 23: 1550-8

z Freudiger S, Dubois G, Lorrain M (1999) Dynamic neutralization of

the lumbar spine confirmed on a new lumbar spine simulator in vitro.

Arch Orthop Trauma Surg 119: 127-2

e Cakir B, Carrazo C, Schmidt R et al. (2009) Adjacent segment

mobility after rigid and semirigid instrumentation in the lumbar spine.

Spine 34: 1287-91

r Putzier M, Schneider SV, Funk JF et al. (2005) The surgical treatment

of the lumbar disc prolapse: Nucleotomy with additional transpedicular

dynamic stabilization versus nucleotomy alone. Spine 30: E109-14

t Schnake KJ, Schaeren S, Jeanneret B (2006) Dynamic Stabilization in

addition to decompression for lumbar spinal stenosis with

degenerative spondylolisthesis. Spine 31: 442-9

y Welch WC, Cheng BC, Awad TE (2007) Clinical outcomes of the

Dynesys dynamic neutralization system: 1-year preliminary results.

Neurosurg Focus 22: E8-16

u Grob D, Benini A, Junge A, Mannion AF (2005) Clinical experience

with the Dynesys semirigid fixation system for the lumbar spine:

surgical and patient-oriented outcome in 50 cases after an average of

2 years. Spine 30: 324-31

i Schaeren S, Broger I, Janneret B (2008) Minimal four-year follow-up

of spinal stenosis with degenerative spondylolisthesis treated with

decompression and dynamic stabilization. Spine 33: E636-42

o Kumar A, Beastall J, Hughes J et al. (2008) Disk changes in the

bridged and adjacent segments after Dynesys dynamic stabilization

system after two years. Spine 33: 2909-14

p Chou G, Lau D, Skelly A, Ecker E (2011) Dynamic stabilization versus

fusion for treatment of degenerative spine conditions.

Evidence-Based Spine-Care J 2: 33-42

/+/ AboutSamo K. Fokter

Maribor University Clinical Centre

Ljubljanska ulica 5

2000 Maribor, Slovenia

Samo K. Fokter graduated from the University of Ljubljana School of

Medicine. He was trained in Orthopaedic Surgery at the Orthopaedic

Clinic of University of Ljubljana. He was a research fellow at the

Orthopaedic Clinic of University of Zagreb, Croatia, and visiting fellow in

Basel, Switzerland, and Köln, Germany. His main area of interest is spinal

pathology and arthroplasty. His research encompasses degenerative

lumbar spinal stenosis, osteoporosis, and BMD analysis around different

arthroplasty models. He edited two books and authored or co-authored

more than 50 papers in Slovenian as well as international journals. He is

current Immediate Past President of the Slovenian Orthopaedic Society

at Slovenian Medical Association. He is a Founding Member of the Board

of the Slovene Spine Society and Cofounder of the European Society of

Tissue Regeneration in Orthopaedics and Trauma, and is also a member

of ArgoSpine, AO Spine, EFORT, and SICOT. He currently serves as an

Associate Editor in Chief of European Journal of Orthopaedic Surgery

and Traumatology. He is currently appointed as Assistant Professor of

Surgery at the University of Maribor School of Medicine and Assistant

Professor of Orthopaedic Surgery at the University of Ljubljana School

of Medicine. He dedicates a large part of his free time to active volun-

tary work at the Mountain Rescue Service of Slovenia.

Figure: A) Preoperative MRI of a patient with disc degeneration andprotusion at L4-L5 level. B) MRI of the same patient 2 yearsafter limited discectomy and dynamic stabilisation.

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106 Focus 17th ArgoSpine Symposium Scientific Book

CLINICAL CASE Day 1/ 11:50>12:05

Life threatening stroke due to internal carotidartery dissection as a vascular complication ofcervical total disc replacementJean-Edouard LoretCHU de Tours, Tours, France

We report the first case of stroke due

to internal carotid artery ICA dissec-

tion in a patient with complete Circle

of Willis after anterior cervical total

disc replacement.

A 41-year-old woman visited with neck

pain, radiculopathy and progressive

weakness of the left arm. Cervical

spine MRI showed spinal stenosis at

C4C5, C5C6 and C6C7 levels (Fig. 1:

sagittal cervical spine T2 weighted

MRI). She underwent discectomy and

total disc replacement at C4C5 and

C5C6 levels and fusion at C6C7 level

through a right side approach.

Intraoperatively carotid pulsation

cephalad to the caspar retractor blade

was confirmed. Mean arterial blood

pressure was 65.8 mmHg. No major

bleeding occured and procedure was

accomplished in 155 minutes. The

patient initially recovered full con-

sciousness but had vertigo and left

nystagmus. Five hours later she

suddenly presented left hemiplegia

and facial palsy. Diffusion weighted

MRI revealed a right internal carotid

infarct (Fig. 2). Digital subtraction

angiography (DSA) showed dissection

of the right extracranial ICA at its origin causing a complete

occlusion with patent anterior communicant artery but insufi-

cient flow to the right cerebral hemisphere (Fig. 3: anterior view

of right carotid artery DSA).

There is no standard treatment protocol or guidelines for treat-

ment of Carotid Artery Dissection. There are only recomman-

dations and no evidence to suppor t the routine use of

anticoagulants or antiplatelets or the superiority of each for treat-

ment of extracranial dissection. Endovascular procedures are

mainly reserved for traumatic dissection.

The patient was put under systemic heparinization and given

intravenous aspirin. Through a femoral access, a self-expanding

stent was deployed in the internal carotid. Percutaneous trans-

luminal angioplasty and mechanical thrombectomy were per-

formed. The control angiography showed a flow restoration

in the ICA (Fig. 4: anterior view of right carotid artery DSA

after treatment). The patient was put under high dose of low

molecular weight heparin for a week with double antiplatelets

for three months followed by aspirin for another three months.

The patient improved gradually, significant left arm and facial

palsy persisted. She was discharged to a rehabilitation

department. The control at 6 months showed mild left arm

spasticity. Cervical X-rays (Fig. 5: anteroposterior cervical spine

X-Rays) and cerebral magnetic resonance angiography was

adequate. �

ORAL PRESENTATION Day 1/ 12:05>12:15

Ball and socket semiconstrained cervical discreplacement. A prospective clinical andradiological comparison of two designsEly AshkenaziIsrael Spine Center, Jerusalem, Israel

A prospective clinical and radiological study of 65 patients who

underwent total cervical disc replacement (TDR) with the prestige

(30) and with the ProDisc-C (35). Range of motion in the sagittal

plane and pain on the visual analog scale before and after the

operation were studied.

To evaluate the intervertebral sagittal ROM we used the Kodak

Carestream PACS Software. In 20 patients who underwent TDR

with the Prestige disc (Medtronic Sofamor Danek, Memphis, TN,

USA) and in 26 with the ProDisc-C (Synthes, West Chester, PA,

USA) ROM was investigated.

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Focus 10717th ArgoSpine Symposium Scientific Book

SUMMARY OF BACKGROUND DATA49 out of the 65 patients were available for follow up. Two of

them underwent subsequent surgical fusion and one disc dis-

location fused spontaneously. Patients were followed between

24-60 months. 40% of the patients in the Prestige group had

less than 50 of motion and were considered fused. In the

ProDisc group only 15% had less then 50 of motion. No bone

or instrumentation failure was recorded in the Prestige group.

In 14% of the ProDisc group instrumentation and bone failure

were identified (two cases of split fracture of the vertebral body,

2 cases of posterior vertebral wall fracture and one case of

prosthesis dislocation). The VAS was administered to all patients

prior to the operation and at all routine follow up visits. There

was no statistical difference in pain relief between the fused

and unfused patients.

Cervical disc replacement after ACD represents an exciting

tool in the management of spinal cord compression. The

results obtained in this study add further weight to the poten-

tial role of cervical disc replacement for cervical myelopathy.

Longer follow up will reveal any delayed problems with this

procedure, for the short term, this technique offers an excellent

outcome. �

ORAL PRESENTATION Day 1/ 12:15>12:25

Radiological and clinical evaluation 12 monthsafter anterior cervical discectomy anddynamic stabilisationMartin Dostal, Denis Laurent KaechKantonsspital CHUR, Neurosurgery, CHUR, Switzerland

Anterior cervical discectomy (ACD) is an established therapy

for degenerative cervical radiculopathy and myelopathy. We

studied our first 31 patients treated with ACD plus Dynamic

Cervical Implant (DCI) as an alternative to fusion or to arthro-

plasty.

MATERIAL AND METHODSBetween February 2009 and April 2011, 39 DCI were implanted:

24 monosegmental, 6 bisegmental, and 1 trisegmental. Five

patients underwent hybrid surgery with DCI implantation and

fusion with a cage (ACDF), four patients receiving a DCI had

been treated with ACDF previously. The mobility of the segment

was evaluated by comparing the inter-spinous distance on the

post-operative flexion-extension radiographs at 12 months.

At the one-year follow-up after DCI implantation there was a

quite high fusion rate, however the formation of heterotopic ossi-

fications is comparable with that of arthroplasty. Both could not

be predicted by viewing the pre-operative MRI studies and had

no impact on the clinical outcome. As an alternative to arthro-

plasty, DCI does maintain some flexion-extension mobility after

one year in only 77% of the cases. �

LECTURE Day 1/ 14:05>14:15Infection and hardware

The different protocols to prevent infectionT. Ferry1,2,3, F. Laurent1,2,3, S. Lustig1,2,3,C. Barrey1,2,3, C. Chidiac1,2,3, on behalf of the“Lyon Bone and Joint Infection Study Group”1 Hospices Civils de Lyon, Lyon, France2 Université Claude Bernard Lyon 1, Lyon, France3 Inserm U851, Pathogénie Bactérienne et Immunité Innée, Lyon, France

A Surgical Site Infection (SSI) is one the most serious postop-

erative complications in clean orthopaedic and spinal surgery.

SSI is associated with increased morbidity, the need for further

surgery, and a significant additional cost for the society [1].

Staphylococci are the most frequent bacteria involved in post-

operative bone and joint infection, and are particularly associ-

ated with relapse in implant-associated bone and joint infection

[2]. We present here a review of the different protocols that

exist or that have to be discussed to prevent hardware-associ-

ated bone infection.

First of all, as the occurrence of infection is infrequent in clean

bone surgery, most of epidemiological data come from patients

who undergo one of the most frequent orthopaedic surgery in

developed countries: elective primary hip of knee arthroplasty.

It has been clearly demonstrated that some patients are at high

risk of post-operative infection, especially obese patients,

patients with diabetes, smokers, patients with poor nutritional

status or with immunosuppression [3, 4]. Pre-operative inter-

ventions such as weight loss, control of the glycemia, stop

smoking and nutrition might limit the risk of post-operative infec-

tion in these patients.

Secondly, as most of patients with post-operative S. aureus infec-

tion are permanent carriers of these bacteria, it could be of

great interest to eradicate the carriage of S. aureus before the

surgery to prevent infection. Bode et al. recently reported that

the number of SSI acquired in the hospital (especially deep

surgical infections) can be reduced by rapid screening and

decolonizing of nasal carriers of S. aureus on admission. Rapid

identification of nasal carriers was done using a PCR assay,

followed by mupirocin nasal ointment and chlorhexidine soap

for a total body-wash during five preoperative days [5]. This

strategy might be of importance for patients who undergo spine

implant surgery, but data are lacking in this patient population.

Finally, antimicrobial prophylaxis is clearly considered beneficial

for preventing infection in clean orthopaedic surgery. Use of

prophylactic antibiotics with an antimicrobial spectrum that is

effective against the pathogens likely to contaminate the pro-

cedure is recommended [6]. S. aureus has to be always targeted

by antimicrobial prophylaxis, but also Enterobacteriaceae, par-

ticularly in spine surgery involving L4, L5, or the sacrum [7].

The growing emergence of methicillin-resistant staphylococci

leads to discuss the use of glycopeptides, but these antimi-

crobials are less bactericidal than betalactams, and might lack

of efficacy to prevent infection. �

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108 Focus 17th ArgoSpine Symposium Scientific Book

/+/ References.a Grammatico-Guillon L, Baron S, Gettner S et al. (2012) Bone and

joint infections in hospitalized patients in France, 2008: clinical and

economic outcomes. J Hosp Infect 82(1): 40-8

z Lew DP, Waldvogel FA (2004) Osteomyelitis. Lancet 364(9431):

369-79

e Singh JA. (2011) Smoking and outcomes after knee and hip

arthroplasty: a systematic review. J Rheumatol 38(9): 1824-34

r Lübbeke A, Stern R, Garavaglia G et al. (2007) Differences in

outcomes of obese women and men undergoing primary total hip

arthroplasty. Arthritis Rheum 15; 57(2): 327-34

t Bode LG, Kluytmans JA, Wertheim HF et al. (2010) Preventing

surgical-site infections in nasal carriers of Staphylococcus aureus.

N Engl J Med 7; 362(1): 9-17

y Yamada K, Matsumoto K, Tokimura F et al. (2011) Are bone and

serum cefazolin concentrations adequate for antimicrobial

prophylaxis? Clin Orthop Relat Res 469(12): 3486-94. Epub 2011

Oct 4

u Liu C, Abdul-Jabbar A, Takemoto S et al. Microbiology of

Postoperative Spine Infections: A Retrospective Study of 239 Cases.

Poster presentation K-261. 52th Interscience Conference on

Antimicrobial Agents and Chemotherapy, San Francisco 2012

/+/ AboutTristan Ferry

Hospices Civils de Lyon and

Université Claude Bernard Lyon 1

Lyon, France

E-mail: [email protected]

Tristan Ferry graduated from the Lyon 1 Claude Bernard University,

Lyon, France and has trained in Internal Medicine and Infectious and

Tropical Diseases in Hospices Civils de Lyon, France. He completed

his postgraduate studies in Geneva, Switzerland by working in the field

on HIV and S. aureus bone and joint infections.

His main area of interest is the pathogenesis and treatment of severe

S. aureus infections, especially sepsis, toxic shock syndrome, and

implant-associated bone and joint infections. He authored over 60 pub-

lications in international journals and is member of the French Society

of Infectious Diseases. He is currently associate Professor in the

Infectious Diseases Unit in Hospices Civils de Lyon, which became in

2008 the regional reference centre for the treatment bone and joint

infection (400 infected patients are hospitalized each year). He recently

created the “Lyon Bone and Joint Infection study group” with colleagues

specialized in infectious disease, surgery, microbiology, imaging, nuclear

medicine and drug’s pharmacokinetic.

LECTURE Day 1/ 14:15>14:25Infection and hardware

A case of suppurative spondylitis after2 instrumentation surgeries for osteoporoticburst fractures probably due to trigger pointinjectionShigeo SanoSpine Center, Sanraku Hospital, Tokyo, Japan

The objectives of this case presentation are: 1). to discuss the

consensus for using hardware (cage and instrument) to surgical

site infection (SSI) and infectious spondylitis, particularly the dif-

ference between Japanese and European consensus, and might

discuss surgical treatment of osteoporotic burst fracture (Fx)

and junctional kyphosis (JK).

A 74-year-old female who suffered from osteoporotic burst Fx

of L4 was treated with single stage anterior (A-) and posterior

(P-) surgery on November 2009. The surgery was A-decom-

pression/reconstruction with an expansive cage and P-spinous

plate (“S-plate”) fixation of L3-5 (Fig. 1). Two years later she

suffered from LBP and kyphotic deformity with new compres-

sion fractures of L2 and old fused compression Fx of L1(Fig.

2). She was treated by L1 PSO and correction/fusion with hooks

and pedicle screws (PSs) from T10 to L3 on September 2011.

LBP and kyphosis recurred gradually and she was treated by

trigger point injection in another hospital. Ten months after the

second surgery, she was admitted in our hospital with severe

back pain and fever. CR showed kyphosis with L3 PSs pulled-

out (Fig. 3), CT showed severe destruction of L3 vertebral body

and MRI showed puddling of liquid at L3 body and L2/3 disc

(Fig. 4). She was diagnosed with SSI developed into suppura-

tive spondylitis

Surgery was planned for removal of S-plate and L3 PSs, inser-

tion of S1 and iliac screws, fixation from T10 to ilium using

previous hooks and PSs, and posterior vertebral column resec-

tion (P-VCR) of L3 using Titanium mesh cage, and the third

surgery was performed on September 2012. During surgery

after inserting S1 PSs and 4 iliac screws were inserted, it was

found that infection spreaded to all the hardwares and all PSs

were loosened.

Therefore all the hardwares were removed and new PSs were

inserted in T4,5,6,7 and fixed to S1,ilium with long rods (Fig. 5).

Pain decreased and infection got better so far. Our principle of

surgical treatment for suppurative spondylitis was anterior

debridement and reconstruction with simple cage such as

Titanium mesh cage, and minimal posterior instrumentation

avoiding PS insertion into infection site. However p-VCR might

be an option of choice in such a case as previous anterior

surgery. �

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Focus 10917th ArgoSpine Symposium Scientific Book

/+/ AboutShigeo Sano

Sanraku Hospital

2-5, Surugadai, Kanda, Chiyoda

Tokyo, 101, Japan

Ph. 00 81-3-3292-3981

Fax 00 81-3-3292-5023

E-mail: [email protected]

Shigeo Sano graduated from Tokyo University. He was trained in the

Orthopaedic Department of Tokyo University and completed his post-

graduate studies in several affiliated hospitals of Tokyo University. He

was also trained as a visiting fellow in Toronto General Hospital (Canada)

under Prof. J. Kostuik in 1984. His main area of interest is spinal instru-

mentation surgery, particularly the correction of adult spinal deformity

using the technique of Corrective TLIF (PLIF), PSO and VCR. He per-

formed over 2000 instrumentation surgery, over 500 Corrective TLIF and

over 100 PSO. He developed several original techniques such as

Meshplate for spondylolysis repair, Rod-offset method for anterior cor-

rection reconstruction fusion, Corrective TLIF (PLIF) for degenerative defor-

mity and S-plate for short spinal fusion. Dr Sano authored one book and

co-authored more than 10 books. He is also the author of 150 papers,

200 presentations and 70 lectures mainly in Japan. He is executive

director of the JPSTSS (Japan Society for the Study of Surgical Technique

for Spine and Spinal nerves), and was twice president of the JPSTSS

meeting. He organizes JPSTSS Pedicle screw seminar once a year for

the education of young doctors. He is also a member of other main

Japanese spine societies, such as Japan Spine Research Society,

Japanese Society of Lumbar Spine Disorders, Japan Scoliosis Research

Society and Japanese Spinal Instrumentation Society. His hobby is Karate.

He recently gained 5th grade of black belt (5-Dan).

LECTURE Day 1/ 14:45>14:55Infection and hardware

How to deal with acute infection afterinstrumentation surgery?MRI-based decision-making of implant removalMasahiro KanayamaSpine Center, Hakodate Central General Hospital, Hakodate, Japan

INTRODUCTIONImplemented spinal instrumentation makes infection treatment

more complicated. Although appropriate strategy and timely

decision-making are essential for successful treatment of wound

infections after instrumentation surgeries, the key problem is a

lack of consensus for implant removal or retention.

The objectives of this study are to retrospectively review the

treatment of deep wound infection after instrumented lumbar

fusion, and thereby to advocate appropriate infection treatment

strategy based on MRI assessment.

METHODS1445 consecutive patients who underwent instrumented lumbar

fusion were reviewed retrospectively. Type of surgery was PLIF

in 1037 patients, PLF in 268, TLIF in 118, and posterior fusion

in 39 patients. There were 23 deep wound infections (1.6%)

requiring surgical treatment. MRI images were used to evaluate

the presence or absence of osteomyelitis of instrumented

vertebra and intervertebral abscess.

RESULTSSix patients in the negative MRI group (n=7) were successfully

treated by a single salvage surgery without implant removal; a

solid fusion was achieved in 86%. In the positive MRI group

(n=13), four patients underwent implant removal at the initial

surgery; five eventually required implant removal after a mean

of 2.4 salvage surgeries. Although four patients had a retained

implant, three of them eventually lost fixation stability due to

screw loosening with progressive destruction of instrumented

vertebra. Fusion rate was 23% in the positive MRI group.

Inappropriate decision-making of implant removal increased the

number of required salvage surgeries, and frequently resulted

in progressive bone destruction and pseudarthrosis.

CONCLUSIONThe current study showed that inappropriate retaining of spinal

implant frequently complicated postoperative wound infection.

Once osteomyelitis of instrumented vertebra or intervertebral

abscess was evident on MRI, all the spinal implants should be

removed. Otherwise, loss of fixation stability due to screw loos-

ening and progressive bone destruction might eliminate feasi-

bility of future revision surgery. �

/+/ AboutMasahiro Kanayama

Spine Center

Hakodate Central General Hospital

Hakodate, Japan

Masahiro Kanayama graduated from Hokkaido University School of

Medicine. He completed his orthopaedic residency and spine fellowship

in Hokkaido University chaired by Prof. Kiyoshi Kaneda, and research

fellowship at the Union Memorial Hospital (Baltimore, USA) under the

mentorship of Dr. Paul C. McAfee. He is currently Director of Spine Center

of Hakodate Central General Hospital, and Affiliate Associate Professor

of Hokkaido University. His main areas of interest are clinical issues and

biomechanical aspects of spinal instrumentation surgery. His research

encompasses motion-preservation surgery, adult spinal deformity inclu-

ding sagittal imbalance, osteoporosis and related spinal fractures, and

management of postoperative infection. He presented 118 papers at

international conferences (AAOS, ISSLS, etc), and authored 35 interna-

tional publications in peer-review journals (16 in SPINE; 7 in JNS; 4 in

JSDT; 2 in CORR; one in JBJS-A, TSJ, etc.). He is an active member of

the International Society for the Study of the Lumbar Spine (ISSLS),

Orthopaedic Research Society (ORS), Japan Spine Research Society

(JSRS) and Japanese Othropaedic Association (JOA).

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110 Focus 17th ArgoSpine Symposium Scientific Book

LECTURE Day 1/ 15:05>15:15Infection and hardware

When to stop the treatment and the follow-upafter postoperative spinal infection?T. Ferry1,2,3, F. Laurent1,2,3, S. Lustig1,2,3,C. Barrey1,2,3, C. Chidiac1,2,3, on behalf of the“Lyon Bone and Joint Infection Study Group”1 Hospices Civils de Lyon, Lyon, France2 Université Claude Bernard Lyon 1, Lyon, France3 Inserm U851, Pathogénie Bactérienne et Immunité Innée, Lyon, France

Implant-associated bone and joint infection is one of the most

difficult-to-treat infectious diseases [1]. A multidisciplinary

approach is required to determine the best strategy to obtain

the functional and microbiological cure. The duration of antimi-

crobial therapy in bone and joint infection is prolonged, at least

several weeks, but some patients required “suppressive” antimi-

crobial therapy throughout life [2]. We present here a review of

the different treatment duration options, which mainly depend

on the risk of relapse, and discuss the duration of the follow-

up required after the treatment of implant-associated bone and

joint infection.

For patients with early-onset infections, surgical debridement with

implant retention, followed by at least three months of optimal

antimicrobial therapy is the preferred option [2, 3]. In patients

with risk factor for relapse, this duration could be extended to

6 months [2, 4, 5]. In patients with late-infection, the implant has

to be removed to obtain the cure. Indeed, in such patients, reten-

tion of the implant is strongly associated with persistent infec-

tion and relapse during the follow-up. In patients for whom the

surgical therapy is not optimal (i.e. late-infection without removal

of the implant), most of the authors considered that the antimi-

crobial therapy has to be “suppressive” throughout life, but sup-

pressive therapy is binding for the patients, not always prevents

relapse, and is not always safe [2, 4, 5].

As patients with early- or late-onset post-operative spinal infec-

tion might experience a relapse after discontinuation of antimi-

crobials, especially if S. aureus is involved, at least two-years

of follow-up seem to be required. Patients with suppressive

therapy have to be continuously followed to detect antimicrobial

adverse event and relapse of the infection [2, 4, 5].

As F-18 FDG PET/CT has an excellent negative predictive value

for the diagnosis of spinal infection [6], “monitoring” the duration

of antimicrobial therapy using F-18 FDG PET/CT beyond the 6

months after surgery is a promising approach in patients with

implant-associated spine infection requiring long-term suppres-

sive therapy [7, 8]. �

/+/ References.a Lew DP, Waldvogel FA (2004) Osteomyelitis. Lancet 364(9431):

369-79

z Zimmerli W (2010) Clinical practice. Vertebral osteomyelitis. N Engl J

Med 362(11): 1022-9

e Dubée V, Lenoir T, Leflon-Guibout V et al. (2012) Three-Month

Antibiotic Therapy for Early-Onset Postoperative Spinal Implant

Infections. Clin Infect Dis 55(11): 1481-7

r Kowalski TJ, Berbari EF, Huddleston PM et al. (2007) The management

and outcome of spinal implant infections: contemporary retrospective

cohort study. Clin Infect Dis 44(7): 913-20

t McHenry MC, Easley KA, Locker GA (2002) Vertebral osteomyelitis:

long-term outcome for 253 patients from 7 Cleveland-area hospitals.

Clin Infect Dis. 34(10): 1342-50. Epub 2002 Apr 22

y de Winter F, Van de Wiele C, Vandenberghe S et al. (2001) Coincidence

camera FDG imaging for the diagnosis of chronic orthopedic infections:

a feasibility study. J Comput Assist Tomogr 25(2): 184-9

u Valour F, Baudry T, Sénéchal A et al. F-18 FDG PET/CT during the

follow-up of patients with complicated hematogenous vertebral

osteomyelitis. SpineWeek 2012, Amsterdam

i Baudry T, Valour F, Morelec I et al. Prediction of residual disease

using F18 FDG PET/CT In patients with staphylococcal

implant-associated spine infection requiring long-term suppressive

therapy. SpineWeek 2012, Amsterdam

ORAL PRESENTATION Day 1/ 15:30>15:40

Clinical outcomes and biomechanicalcomplications after pedicle-anchored dynamicor hybrid lumbar spine stabilization:a systematic reviewMarion Prud’homme1, Carlos Barrios2, Philippe Rouch1,Yann Philippe Charles3, Jean-Paul Steib3, Wafa Skalli11 Laboratoire de Biomécanique Arts et Metiers ParisTech, Clamart, France2 Orthopaedics and Trauma Unit, Department of Surgery, University of Valencia,

Valencia, Spain3 Department of Spine Surgery, University Hospital of Strasbourg, Strasbourg, France

STUDY DESIGNSystematic Medline literature review.

OBJECTIVETo have an overview of the clinical outcomes of pedicle-

anchored dynamic stabilization devices in comparison with fusion

devices in terms of clinical outcomes, safety and adjacent

segment protection.

SUMMARY OF BACKGROUND DATAThe current surgical gold standard for the treatment of most

conditions of the lumbar spine is segmental fusion. Worrying

rates of failure, including the degeneration of adjacent segment,

have consistently been reported. The interest for dynamic sta-

bilization came from the need of minimizing the long term com-

plications related to the restriction of lumbar motion. Among the

motion-preserving solutions, while pedicle-anchored devices are

widespread, the advantages and drawbacks of these devices

remain controversial.

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Focus 11117th ArgoSpine Symposium Scientific Book

METHODSArticles about clinical outcomes of pedicle-based dynamic sta-

bilization devices were identified by a comprehensive search

on PubMed database up to September 2012. Inclusion criteria

were a minimum follow-up of 12 months, indications for lumbar

dynamic stabilization and assessment of clinical outcomes and

adverse events. The studied outcomes included self-reported

outcomes in terms of pain, disability and satisfaction, and report

of biomechanical complications.

RESULTSA total of 43 articles fulfilling the inclusion criteria were reviewed

providing results for 1827 patients with a mean follow-up of 27.3

months. The improvements in terms of pain and disability after

surgery were statistically significant: the mean VAS evolved from

7.4/10 to 2.3/10 (p<0.001) and the mean ODI score decreased

from 53.8% preoperatively to 22.0% at last follow-up (p<0.001).

Subjective assessment (“Would you choose to undergo the

surgery again?”) showed an overall patient satisfaction of 83.7%.

Adjacent segment diseases occurred in 5.1% of patients with

a mean hindsight of 34.2 months. Device breakage occurred

in 3.9%, and device loosening in 9.6% of patients. The global

amount of revision surgeries reaches 10.6% mainly for breakage,

adjacent segment disease or persistent pain, not always asso-

ciated with screw loosening.

CONCLUSIONSPedicle based dynamic stabilization devices show clinical results

similar to fusion and no clear evidence of advantages for the

protection of adjacent segment arose through this mid-term

review. Technical failures are not only design related but also

linked with patient specificity. Correlations between sagittal

balance and surgery outcomes are still rarely reported but an

in-depth biomechanical analysis would allow a refinement of

surgical strategy. Dynamic stabilization might display advantages

in dedicated indications such as moderate disc or facet degen-

eration and beginning instability. �

ORAL PRESENTATION Day 1/ 15:40>15:50

Benefits of Minimally Invasive TransforaminalLumbar Interbody FusionGregor RecnikUkc Maribor, Maribor, Slovenia

Minimally incision techniques of lumbar interbody fusion have

been in recent years gaining popularity among spine surgeons

due to their less invasive approach. Our study has been con-

ducted with the purpose to quantify possible advantages of a

minimally invasive TLIF (MIS-TLIF) over an open TLIF procedure.

Twenty-seven patients were recruited into this prospective study

since January 2012 until August 2012. Only patients with single

or two-level fusions were considered for inclusion in the survey.

An open TLIF procedure was performed in 11 subjects with

mean age 56.4 years. MIS-TLIF was used in 16 subjects with

mean age of 53.2 years. Amount of blood loss, muscle damage,

postoperative pain and speed of early rehabilitation were

recorded and compared between the two groups. Lower blood

loss was observed in a group with MIS-TLIF during the opera-

tion (187 ml vs. 476 ml) and after the procedure (71 ml vs. 463

ml). Higher increase in creatine kinase levels, suggesting more

muscle damage, was recorded in the open TLIF group (29 mg/L

vs. 13 mg/L). Less pain was reported postoperatively on the

visual analogue scale by patients in the MIS-TLIF group (4.8 vs.

5.8). Subjects in the open TLIF group left the hospital on average

2 days later (6th vs. 4th day).

Early advantages of minimally invasive spine procedures include

less muscle damage, less blood loss, less postoperative pain

and faster early rehabilitation. Any advantages that these pro-

cedures might bring in the later rehabilitation period have not

been documented to date and remain a focus of fur ther

research. �

ORAL PRESENTATION Day 1/ 15:50>16:00

Recurrent HNP causing contralateral leg pain,treated by PELDSang Soo Eun, Sang-Ho LeeWooridul Spine Hospital, Seoul, Korea

We present 2 cases with recurrent HNP after open lumbar dis-

cectomy which resulted in contralateral leg radiating pain.

A 53-year-old male patient underwent right side open lumbar

discectomy with diagnosis of L34 right HNP on August 1st,

2011. Nine months later, the patient presents with left lower

extremity radiating pain. MRI showed huge disc herniation on

right L34 level. A 57-year-old male patient underwent L45 left

open lumbar discectomy on December 2nd, 2011. Eight months

later, the patient complained of mainly right lower extremity radi-

ating pain with mild left buttock radiating pain. MRI showed

down migrated disc herniation from left side to right side.

Decision for surgical approach was challenging for contralateral

leg pain and postoperative adhesion from previous surgery.

Percutaneous endoscopic lumbar discectomy is a good solution

due to its transforaminal new surgical route, and the possibility

of a contralateral approach. We avoided potentially dangerous

revision open lumbar discectomy, and bilateral laminectomy

which would result in instability. �

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112 Focus 17th ArgoSpine Symposium Scientific Book

LECTURE Day 1/ 16:20>16:30Minimally invasive spine surgery and unusual approaches tothe spine

The AxiaLIF ProcedureD. ZeilstraNedspine (Ede) and Bergman Clinics (Naarden), The Netherlands

INTRODUCTIONDiscectomy and fusion have a long-standing history as a treat-

ment option for invalidating chronic discogenic back pain.

Standard procedures include anterior and posterior lumbar inter-

body fusion (ALIF and PLIF), whether or not combined with

pedicle screw fixation. All of these procedures are invasive with

potential damage to muscles, facet joints, nerve roots, scar for-

mation, etc. The transaxial approach (AxiaLIF™) is a novel

minimal invasive way of gaining access to the L5/S1 disc space

with the possibility to remove disc, clear endplates, fill it with a

graft and achieve fusion.

MATERIAL AND METHODSSince March 2006, 187 patients were treated with the transaxial

procedure. In 165 patients the indication was discogenic back

pain. Sixteen were not eligible for study purposes, mainly sur-

geries abroad. The remaining 149 consisted of 101 females and

49 males with an average age of 41,9 years (23-57). All patients

had discopathy of only the lumbosacral segment. Six patients

had had previous disc surgery. Pre-operative work-up included

plain films, MRI, discography (provocation and anesthetizing),

VAS, Oswestry Disability Index (ODI) and SF-36 scores, demo-

graphic features.

Fixation was achieved by the transaxial presacral approach,

filling the disc space after removal with osteogenic bone matrix

substitute. The procedure was stand-alone in 72 cases and facet

screws were added in 77. Average operating time was 39

minutes. Patients were discharged after one or two days, there

was no specific post-operative treatment.

RESULTSOf the 149 patients 115 were followed up for at least one year.

Complications include one haematoma discharge from the

wound, one case of halo around the rod only in L5 and two

cases of minimal subsidence. All of these patients were without

complaints. Average VAS scores dropped from 7.7 pre-opera-

tive to 3.8 after 6 weeks and 2.8 after one year. For ODI the

scores were: 43, 25 and 13. In 81% of the patients with at least

one-year follow-up an improvement of 25 points or more on the

ODI was noted.

In 126 patients a CT-scan was obtained after one year. In four

patients the CT-scan showed clear pseudarthrosis. In 12 patients

fusion was unclear, half of these were without complaints. In

the other 110 patients (87%) a fusion varying from beginning

bone bridging to solid fusion was demonstrated. On average

the unclear or non-fused patients had higher discs than those

with a successful fusion.

CONCLUSIONTransaxial fixation is a minimal invasive approach that bypasses

many of the known disadvantages of fusion procedures. In this

limited study it can be seen that the stand-alone fixation is

feasible, safe and effective, at least with this limited follow-up.

In patients with a disc height of 4 mm or more additional fixation

with facet screws is recommended. Stand-alone fixation is not

suitable in cases of spondylolisthesis and/or spondylolysis. �

/+/ AboutDick Zeilstra

Bergman Clinics

Rijksweg 69

1411 Ge Naarden

The Netherlands

Born 1950 in Plaju (Indonesia), he was educated in The Netherlands.

He completed his medical education at the University of Groningen,

where he graduated in 1975. He was trained in neurology in Groningen

and thereafter in neurosurgery in Duisburg (Germany). Dr Zeilstra suc-

cessfully defended his thesis at the University of Cologne in 1987.

From 1986 to 1989, he was a staff member at the neurosurgical depart-

ment of the University Hospital Groningen, and from 1989 to 2011 at

the Neurosurgical Center Zwolle. Dr Zeilstra is in active practice in

general neurosurgery, with an emphasis on spinal surgery. From 2011

he is in spine practice at Nedspine Ede and Bergman Spine Clinics

Naarden. He is a member of the Dutch (past board member) and

European Spine Society. He is (co)-author of 30 articles and poster

presentations, a few book chapters and has lectures and guest oper-

ations of all over the world about degenerative spine surgery.

LECTURE Day 1/ 16:30>16:40Minimally invasive spine surgery and unusual approaches tothe spine

Current state of facet replacementYann Philippe Charles, Jean-Paul SteibSpinal Surgery, University Hospital, Strasbourg, France

Lumbar motion preservation systems are aimed to reduce the

risk of Adjacent Segment Degeneration (ASD) after spinal fusion.

Total disc replacement represents an effective treatment for low-

back pain caused by discopathy. Nevertheless, load sharing

between the disc and facet joint complex leads to facet degen-

eration which may arise as a consequence of discopathy. Facet

degeneration may also develop after total disc replacement

resulting in secondary pain. This has spawned an interest in

the development of posterior non-fusion systems, facet resur-

facing and replacement devices, which address the problem of

osteoarthritis and subsequent stenosis.

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Focus 11317th ArgoSpine Symposium Scientific Book

Instrumentation is required after facetectomy or arthrectomy

because of segmental destabilization in axial rotation and under

shear loading. Facet replacement systems were primarily

designed for the surgical treatment of lumbar stenosis. In vitro

studies and Finite Element Models (FEM) indicated that these

implants could stabilize a lumbar segment and maintain mobility

after partial or total facet resection and laminectomy [12-15].

Preliminary results from clinical trials indicate an improvement

of the Visual Analog Scale (VAS) for pain and the Oswestry

Disability Index (ODI) in degenerative spondylolisthesis [16-18].

Büttner-Janz [9] reported on single posterior facet replacement

in patients with sufficient disc height, but also on additional total

disc replacement at the same level to treat disc and facet degen-

eration. It is not clear to what extent decompression should be

performed, since shear forces are transmitted through the

implant and two device-related complications with pedicle fixation

fractures were reported for one system [19].

The NeoFacet™ (Clariance, Dainville, France) represents an

Auxiliary Facet System (AFS) which was designed for facet sup-

plementation in the following indications: facet osteoarthritis,

lateral recess stenosis treated by facetectomy and undercutting

laminectomy, degenerative spondylolisthesis grade I with a

remaining disc height. The AFS utilizes four pedicle screws with

two angulated rods fixed cranially. The rods are linked to caudal

screws by polyaxial connectors, allowing three-dimensional (3D)

movements. Both rods are cross-linked to restrain axial rotation.

Pedicle screws are made of titanium and other components

from a cobalt-chromium-molybdenum alloy (CrCoMo).

A previous in vitro study [20] demonstrated that this device

could preserve flexibility between lumbar vertebrae while adding

stability in axial rotation after facetectomy. A finite element

analysis showed that peak contact forces at adjacent facet joints

would be lowered with the AFS compared to fusion. The same

applied to von Mises stress at the annulus of adjacent discs.

Nevertheless, fusion would better relieve stress at the instru-

mented disc. Furthermore, in vitro testing demonstrated the AFS

seemed to lower displacements in posterior-anterior shear

compared to an uninstrumented lumbar segment after under-

cutting laminectomy and facetectomy. This condition could be

interesting for an eventual indication in degenerative spondy-

lolisthesis grade I with a moderate discopathy. �

/+/ References.a Büttner-Janz K (2010) Status quo of facet joint replacement.

Orthopade 39: 609-22. German

z Wilke HJ, Schmidt H, Werner K et al. (2006) Biomechanical

evaluation of a new total posterior-element replacement system. Spine

31: 2790-6

e Zhu Q, Larson CR, Sjovold SG et al. (2007) Biomechanical evaluation

of the Total Facet Arthroplasty System: 3-dimensional kinematics.

Spine 32: 55-62

r Phillips FM, Tzermiadianos MN, Voronov LI et al. (2009) Effects of

the Total Facet Arthroplasty System after complete

laminectomy-facetectomy on the biomechanics of implanted and

adjacent segments. Spine J 9: 96-102

t Goel VK, Mehta A, Jangra J et al. (2007) Anatomic Facet

Replacement System (AFRS) restoration of lumbar segment

mechanics to intact: a finite element study and in vitro cadaver

investigation. SAS Journal 1: 46-54

y McAfee PC, Khoo LT, Pimenta L et al. (2007) Treatment of lumbar

spinal stenosis with a total posterior arthroplasty prosthesis: implant

description, surgical technique, and a prospective report on 29

patients. Neurosurg Focus 22: E13

u Castellvi A. The treatment of symptomatic lumbar spinal stenosis with

ACADIA™. Clinical outcomes from worldwide cohort. North American

Spine Society Pre-Meeting Course 2009, San Fransisco

i Regan JJ, Hartjen CA, Dryer RF et al. ACADIA™ facet arthroplasty

pilot study: twelve months follow-up results for 20 patients at four

centers. Spine Arthroplasty Society Annual Global Symposium 2009,

London

o Palmer DK, Inceoglu S, Cheng WK (2011) Stem fracture after total

facet replacement in the lumbar spine: a report of two cases and

review of the literature. Spine J 11: E15-9

p Charles YP, Persohn S, Steib JP et al. (2011) Influence of an auxiliary

facet system on lumbar spine biomechanics. Spine 36: 690-9

LECTURE Day 1/ 16:40>16:50Minimally invasive spine surgery and unusual approaches tothe spine

Paraspinal approach for thoracolumbar(T10-S1) spine problemsMurat Aksakal1, Burak Akesen1, Ufuk Aydinli21 Dept. of Orthopaedics, University of Uludag, Bursa, Turkey2 Dept. of Orthopaedics, Medicabil Hospital, Bursa, Turkey

Various types of surgical approaches to the posterior spine have

been proposed. The single midline approach, which can be

accepted as the standard technique, necessitates detachment

of paraspinal muscles off the posterior spinal elements and sig-

nificant tissue retraction. Although today’s surgical tendencies

favour minimally invasive procedures with less damage to the

soft tissues. This approach, namely the Wiltse approach, allows

direct approach to the transverse processes and facet joints.

All patients underwent posterior instrumentation with pedicle

screw-rod construct.

37 patients were identified (27 AIS, 5 Trauma, 5 Degenerative)

for exposure and screw insertion. Average blood loss was 174

cc. (30-440) and surgery time was 32 min (25-45 min.).

CONCLUSIONComparing to percutaneous techniques, this approach is:

1. Cosmetically better (one midline incision instead of multiple

stab wound incisions).

2. Less traumatic to the muscles

3. Reduced C-arm time for surgeon and patients

4. Easy to apply and reduced cost. �

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114 Focus 17th ArgoSpine Symposium Scientific Book

LECTURE Day 1/ 16:50>17:00Minimally invasive spine surgery and unusual approaches tothe spine

Percutaneous transpedicular transcorporealapproach to the discAfshin Gangi, Georgia Tsoumakidou, Julien Garnon,Iulian Enescu, Fabrice BingInterventional Imaging, University Hospital Of Strasbourg, France

Percutaneous disc approach is performed on prone position

and with the standard extra-pedicular posterior-lateral approach.

This approach is crossing the nerve root. We describe a per-

cutaneous transpedicular transcorporeal approach to the disc

with a curve cannula.

The procedure is performed with bipedicular puncture with

trocars then insertion of working cannula in both pedicles.

Depending on the vertebral body height, curve coaxial wires

allow an approach of the lower disc. The flexible curve trephine

can then be drilled over the curved wires to the endplate and

to the disc.

This approach allows a bilateral transpedicular transcorporeal

disc access avoiding the paravertebral route and opens a new

field of procedures. The transpedicular transcorporeal disc

approach is an effective, safe, and precise minimally invasive

procedure that tends to preserve paravertebral structures. �

/+/ AboutAfshin Gangi

Radiologie B – Pavillon Clovis Vincent

Hôpitaux Universitaires de Strasbourg

67091 Strasbourg Cedex

Ph: +33 3 88 11 67 56

Afshin Gangi graduated from the Medical School of the University

Hospital of Reims (France). After his residency in the University of

Strasbourg in radiology, he specialized in the interventional radiology

and obtained his Master of Science in medical biology and PhD in

laser physics. He has been Professor of radiology since 2000 in the

University Hospital of Strasbourg. He was invited Professor in Kings

College of London in 2002. Since 2007, Afshin Gangi is Chairman of

Radiology and nuclear Medicine in the University Hospital of Strasbourg.

He is interventional radiologist, specialized in oncology, MSK and spine.

He is currently Responsible for the department of Interventional

Radiology of the University Hospital of Strasbourg.

He published over 170 scientific papers, contributed to 36 books, and

presented more than 370 lectures and scientific papers presentations.

He is a member of several societies: CIRSE (Cardiovascular and

Interventional Radiological Society of Europe), RSNA (Radiological

Society of North America), ECR (European Congress of Radiology),

SIR (Society of Interventional Radiology), ASSR (American Society of

Spine Radiology), ARRS (American Roentgen Ray Society), SFR (Société

Française de Radiologie).

LECTURE Day 1/ 17:10>17:20Controversial round table: interspinous devices

Percutaneous insertion of interspinous devicesfor spinal stenosis in the elderly populationMatjazv Vorsv icv, Gorazd Bunc, Janez RavnikUniversity Hospital Maribor, Maribor, Slovenia

AIM OF THE STUDYDecompressive laminectomy, hemilaminectomy or multiple

fenestrations represent possible surgical treatments for

symptomatic degnerative lumbar stenosis (DLSS) with neuro-

genic intermittent claudication in patients where conservative

treatment failed. Over the past years, a number of extension

limiting devices have also been utilized to treat DLSS. There

are certain groups of patients, especially elderly and patients

with severe accompanying diseases, where the lumbar

surgery alone represents a big risk for the patient, regarding

their health and outcome of the surgery. The less invasive

and percutaneous techniques in spinal surgery reduce the risk

in these patients.

The aim of the study was to analyze clinical results following

percutaneous insertion of the interspinous devices in patients

treated for DLSS with neurogenic intermittent claudication.

METHODSIn the study 30 patients with single or double level sympto-

matic degnerative lumbar stenosis were treated with percuta-

neous insertion of interspinous standalone system. Overall

26 single and 4 double-level procedures were performed

(34 prostheses).

Clinical outcomes were assessed before and 1 year following

the tretament using Zurich Claudication

Questionnaire, the Oswestry Disability Index (ODI) and visual

analogue scale (VAS) for back and leg pain and.

RESULTSThere was a statistically significant improvement in ODI and

VAS for back and leg pain (P < .05), and the Zurich

Claudication Questionnaire’s physical function score increased

1.37 over baseline 1 year following the tretament with inter-

spinous devices.

CONCLUSIONSPercutaneous interspinous standalone system is an effective

tool for less invasive surgical treatment in the patients with

intermitent spinal claudication due to degenerative lumbar

spinal stenosis. It provides good short term clinical results

that are comparable with the results achieved with decom-

pressive laminectomy. �

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Focus 11517th ArgoSpine Symposium Scientific Book

LECTURE Day 1/ 17:20>17:30Controversial round table: interspinous devices

Do I believe in interspinous devices?G. MatgéNational Neurosurgical Department, Centre Hospitalier de Luxembourg, Luxembourg

Posterior dynamic stabilization is focusing on the concept of

maintaining or restoring intervertebral motion in a controlled

fashion. The goal is to mimic the behaviour of the healthy spinal

column [5,6,9]. A classification of these newer devices is

required for better operative indications [3].

The U-shaped interspinous implant invented by Samani is in

clinical use since 1995 with changes in manufacturing tech-

nique to Coflex in 2005 [5]. This author has experience with

implantation since 1999 [4]. The basic concept of U-shaped

devices is non-rigid interspinolaminar (and not exclusively inter-

spinous) fixation following microsurgical canal decompression

(obligatory) in slight distraction (facet unloading) to reduce

buckling of soft tissue, narrowing of the canal and foramina,

and loading of the degenerated disc [7]. A biomechanical eval-

uation shows that Coflex can return a partially destabilized

specimen back to the intact condition in sagittal and axial

rotation [8].

Painful lumbar instability may result from natural degeneration

of discoarticular tripod or surgical decompression, mainly in

spinal canal stenosis. An alternative surgical treatment avoiding

fusion is a dynamic stabilization with interspinolaminar U-fixation

now called Coflex. This more conservative surgery allows a con-

trolled motion in flexion-extension and axial rotation. Main indi-

cations are symptomatic spinal canal stenosis with or without

discal involvement, recurrent DH with dystability and junction

syndrome above fusion (topping-off, the first indication in 95).

Trauma, severe osteopenia, lytic spondylolisthesis, significant

kyphosis are contraindications as well as a too large decom-

pression. Preoperative imaging with dynamic views, CT and MRI

help in patient selection.

Surgical technique is a simple muscle-sparing midline approach

with conservative microsurgical canal decompression (central

and lateral) including yellow ligament to visalize dura and exciting

nerve roots. Trials are introduced for adapted size selection,

followed by the implant advanced deep enough in the distracted

interspinolaminar space under direct vison, palpating the dural

plan with a nerve hook for security. Before parallel tightening

the wings of Coflex with a special forceps, a more lordotic

position may be induced using a dynamic table. Fluoro-control

is indicated at this stage for documentation. No disc is removed

except in rupture. With experience, implantation takes less than

10 minutes following a correct decompression, the main step

for success. Technical points to avoid implant migration are con-

servative spinous process handling, sufficient decompression,

deep implantation and adapted wing tightening in patients pre-

senting enough bone quality. Osteopenia may lead to fracture

of spinous process during decompression, distraction or wing

tightening with consecutive abortion of implantation. A major

contraindication leading to failure is instability in flexion on

antelisthesis, needing later pedicle screw fusion [4].

An earlier personal series (2001-2002) of 75 patients had a sys-

tematical follow-up for 1 year with a favourable clinical (78%)

and radiological outcome (93%). Only 40 patients had an irreg-

ular later review up 1 to 9 years (33 stayed stable over time

with long term motion, 7 had a further operation: evolution in

stenosis in 4, new DH in 2 and progressive instability in 1

patient). A multicentre study from 2007 [1] with Coflex (209

patients with lumbar stenosis, back pain and neurogenic clau-

dication) documented that 75 % of patients are clearly improved

and 89% are satisfied at short and long term follow-up (1 to 10

years). Complications are few including device migration (mainly

a technical fault), spinous process fracture or non-device-related

incident needing reoperation. A recent FDA study comparing

Coflex stabilization to posterior pedicle instrumentation in spinal

stenosis and grade I degenerative spondylolisthesis concluded

same decompressive efficacy but improved perioperative

outcome, and maintenance of motion at operative and adjacent

levels compared to fusion [2].

Coflex posterior dynamic stabilization after microsurgical decom-

pression for selected indications (discussed above) demon-

strates excellent shor t and long term results concerning

improvement in back pain, neurogenic claudication and patient

satisfaction. Coflex-F, a minimal invasive fusion device mostly

combined with disc replacement is shortly presented for patients

needing more stabilization, but avoiding internal fixation [10].

My personal experience allows me to believe in some `inter-

spinous devices` for above discussed indications, although

mostly limited to one system. As most patients need first a good

decompression, I do not believe in minimal invasive purely inter-

spinous devices for long term success. �

/+/ References.a Adelt D, Samani J, Kim WK, et al. (2007) Coflex interspinous

stabilization: Clinical and radiological results from an international

multicenter retrospective study. Paradigm Spine Journal 1

z Davis RJ, Errico TJ, Bae H, Auerbach JD. Coflex interlaminar

stabilization compared to posterior spinal fusion for spinal stenosis

and spondylolisthesis. Two-year results from aprospective randomized

multicenter FDA IDE trial. ISASS12

e Khoueir P, Kim A, Wang M (2007) Classification of posterior dynamic

stabilization devices. Neurosurg Focus 22(1)

r Matgé G. Dynamic interspinous U fixation. An alternative surgical

treatment for degenerative lumbar instability. Scientific Session 2,

Swiss Spine Institute, June 21, 2002

t Samani J (2000) Study of a semi-rigid interspinous U fixation system.

Spinal Surgery, Child Orthopaedics: 1707

y Senegas J (2002) Mechanical supplementation by non-rigid fixation in

degenerative interverbebral lumbar segments: the Wallis system.

Eur Spine J: 164-9

u Swanson KE, Lindsey DP, Hsu KY et al. (2003) The effects of an

interspinous implant on intervertebral disc pressure. Spine: 26-32

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116 Focus 17th ArgoSpine Symposium Scientific Book

i Tsai KJ, Murakami, Lowery GL, Hutton W (2006) A biomechanical

evaluation of an interspinous device (CoflexTM) used to stabilize the

lumbar spine. J Surg Orthop Adv: 167-72

o Zuchermann JF, Hsu KY, Hartjen CA et al. (2004) A prospective

randomized multi-center study for the treatment of lumbar stenosis

with the X-STOP interspinous implant: 1-year results. Eur Spine J: 22-31

p Kettler A, Drumm J, Heuer F and al. (2008) Can a modified

interspinous spacer prevent instability in axial rotation and lateral

bending? A biomechanical in vitro study resulting in a new idea.

Clin Biomech: 242-7

ORAL PRESENTATION Day 2/ 08:30>08:40

Avoiding lumbar instability with the U-forcedeviceIñaki ArroteguiHospital General Universitario de Valencia, Valencia, Spain

Our purpose was to evaluate the mechanisms of action and

effectiveness of interspinous distraction in managing sympto-

matic Degenerative Lumbar Disc Herniation, to determine the

safety and efficacy of the U-Force implant, and to prevent the

last step of disc degeneration as described by White & Panjabi

and Kirkalldy-Willis, i.e. lumbar instability.

METHODSA prospective controlled trial (2010- 2011) was conducted in a

cohor t of 200 patients with Degenerative Lumbar Disc

Degeneration. 100 underwent surgical treatment during which

the U device was placed, and 100 control individuals were

treated with discectomy alone. Patients underwent serial follow-

up evaluations (clinical tests), and radiographic assessment was

used to determine the outcome. Follow-up data for a maximum

of one year were obtained for all patients.

Our aim was to use the device in order to prevent or delay the

clinical symptoms after discectomy: last step being Lumbar

Instability.

RESULTSA minimum of 1-year follow-up: statistically significant improve-

ment was seen in patients treated with the U device. A). It is

an excellent idea to use it for lumbar pain in ’kissing’ spine. B)

With a 7-year follow-up, 85% vs. 70% without any evidence of

clinical or radiological instability. None of the U-force group

needed to be reoperated for lumbar instability. Control: 8% need

to be reoperated due to lumbar instability.

Our study shows that the U device was more effective than

discectomy in the management of Degenerative Lumbar Disc

Herniation, regarding lumbar instability. Easy learning curve.

The best was to use it at L4/L5; at L5/S1, it depends on the

spinous process of S1. We developed a new device of

6mm. Improvement with Coflex was statistically significant

(p< 0.01). �

ORAL PRESENTATION Day 2/ 08:40>08:50

Disc degenerative cascade. Do interspinousdevices prevent it after a discectomy?MRI retrospective study with a 4-yearfollow-upAngel Escamez, Cesar HernandezCieza (Murcia), Spain

Interspinous devices have been used in spine surgery for several

indications. Since they are supposed theorically to support sta-

bilization to the spine and perform an indirect decompression

increasing the foraminal height they have been used after dis-

cetomy in large disc herniations. The aim of this study is to

analyse the effects ot the interspinous devices after a simple

discectomy in terms of degeneration of the disc.

24 patients were included in this study. Mean age was 37-years-

old (range: 25-49). They were operated at our Department

between 2007 and 2009. 12 underwent simple discectomy and

12 underwent discectomy plus DIAM at the same level. In 17

patients the level operated was L4-L5 and in 7 patients L5-S1.

We analysed pre-operative and post-operative MRI (mean follow-

up: 4.1 years). The items analysed were: 1). nerve-root fibrosis;

2). Disc height; 3). Degenerative changes in disc and end plates;

4). cross-sectional area of the canal.

The outcomes are being analysed at this moment. We will be

able to present our results in December. There is some con-

troversy on the real effectiveness of this devices. We are trying

to clear up the objective role of the interspinous devices in term

of the disc degeneration. �

ORAL PRESENTATION Day 2/ 08:50>09:00

The effect of Bone Morphogenetic Protein-7with iliac crest bone graft on fusion in revisionsurgery for lumbar pseudarthrosis.Stephan Werle, Dirk Wiese, Heinrich BoehmZentralklinik Bad Berka, Bad Berka, Germany

Altough there is only few evidence of the effectivity of Bone

Morphogenetic Protein (BMP)-7 in fusion procedures for the spine,

the attempt to reach fusion with revision surgery renders BMP-7

attractive for this purpose. Potential adverse and unknown long-

term effects as well as additional costs on one and subtotal fusion

rates of standard procedures as PLIF/TLIF on the other side are

the limits to use BMPs in primary fusion procedures. Although

the potential of BMP-7 to promote fusion of the lumbar spine has

not yet been evaluated with large-scale studies, at our institution

BMP-7 is used to achieve solid fusion through revision for symp-

tomatic pseudarthrosis since several years. This study aims to

retrospectively evaluate the outcome after revision of lumbar

pseudarthrosis using BMP-7 with iliac crest bone graft (ICBG).

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Focus 11717th ArgoSpine Symposium Scientific Book

114 of 149 fusion procedures using BMP-7 + ICBG between

05/2003 and 03/2011 were revisions due to symptomatic lumbar

pseudarthrosis after interbody fusion and posterior instrumen-

tation. Thereafter, 100 patients had either reached fusion or

reached a minimum follow up of at least 12 months (mean 29

months, range 5 to 98) in the case of pseudarthrosis. These

cases were evaluated retrospectively. Prior to revision, L5-S1

and L4-5 were the levels most frequently pseudarthrotic (55%

and 26% respectively) in this group of 61 male and 39 female

patients with mean age of 57.9 years (range 31-81). While 69%

of the patients reached fusion (see Figure), in 22 pseudarthrosis

persisted or fusion was questionable after at least 12 months.

With 21 persisting of 55 non-unions the level L5-S1 was the

most difficult one to treat successfully with the BMP-7 + ICBG

procedure. The number of fused levels above a pseudarthrosis

increased the risk for persisting non-union. Patient age had no

influence on the success of the revision surgery.

Using BMP-7 with ICBG in revision surgery for lumbar

pseudarthrosis in general can lead to fusion in a large number

of patients. However, successful outcome regarding osseous

fusion depends on the individual history of the patient. Treatment

of pseudarthrosis of the lumbosacral junction remains difficult

especially in cases with fusions above. �

/+/ References.a Carragee EJ, Hurwitz EL, Weiner BK (2011) A critical review of

recombinant human bone morphogenetic protein-2 trials in spinal

surgery: emerging safety concerns and lessons learned. Spine J

11(6): 471-91

z Vaccaro AR, Lawrence JP et al. (2008) The safety and efficacy of

OP-1 (rhBMP-7) as a replacement for iliac crest autograft in

posterolateral lumbar arthrodesis: a long-term (>4 years) pivotal

study. Spine 15; 33(26): 2850-62

LECTURE Day 2/ 09:00>09:15Bone graft substitutes

Physiology of bone healing (considering theage of the patient, use of bisphosphonatesand other factors)G.M. Calori, E. Mazza, M. Colombo, C. RipamontiC.O.R., Orthopaedic Institute, G. Pini, University of Milan, Italy

Fracture healing is a physiological process that leads bone

fracture to union. However, it has been estimated that 5-10% of

all fractures are associated with difficulty in healing resulting in

delayed union or non-union development. Many studies have

been carried out on the matter of non-union since the 1920s,

when non-union was defined to occur when consolidation cannot

be completed without new biological or mechanical stimulation.

Since then, several authors have contributed with their knowl-

edge to osteogenetic mechanisms, placing the emphasis on the

risk factors of a non-union. In general terms the risk factors

contributing to non-union can be separated into general and

local factors. The purpose of this study is to identify and report

on the different factors which have been implicated in the patho-

genesis of non-union.

Delayed fracture consolidation and non-union can be due to

factors related to the magnitude of trauma and the subsequent

treatment interventions. Age, sex, mechanism of injury and type

of fracture, associated injuries, co-morbidities, lifestyle and phar-

macological agents are all factors that could interfere with the

fracture healing response. Different types of non-union exist and

reflect different pathways of developing this complication.

Atrophic non-unions are associated with factors acting directly

on the early phases of fracture healing, while hypertrophic non-

unions relate mostly with factors acting on the ”reorganisation”

phase of bone healing.

Local factors that can aid the evolution of non-union are linked

to the trauma mechanism, to the type of fracture produced and

to any associated injuries. These factors are considered to be

essential and their careful evaluation can help to plan suc-

cessfully the treatment interventions in order to avoid the devel-

opment of non-unions. [1]

Over the years many classifications, all based on a radiological

evaluation, have been proposed in an attempt to obtain a correct

classification of such complications. Recently, it has been

proposed a new classification: Non Union Scoring System

(NUSS) that focuses not only on the quality of the bone and

the problems of osteosynthesis, but on the condition of the

patient as a whole (diseases, lifestyle and use of drugs) and

those of soft tissues. The final score, obtained from the sum of

the individual scores, in fact, allows to compare different patients

with different non-unions, making them objectively comparable

according to a principle of complexity and providing an algo-

rithm of care in identifying which patients is more appropriate

to the use of biotechnology. [2] �

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118 Focus 17th ArgoSpine Symposium Scientific Book

/+/ References.a Calori GM, Albisetti W, Agus A, et al. (2007) Risk factors contributing

to fracture non-unions Injury 38(S2): S11-8

z Calori GM, Phillips M, Jeetle S, et al. (2008) Classification of

non-union: need for a new scoring system? Injury 39(S2): S59-63

/+/ AboutGiorgio Maria Calori

G. Pini, University of Milan

P.Za Cardinal Ferrari 1

20122-Milan, Italy

Ph: +39-02-58296903

Fax: +39-02-58296905

E-mail: [email protected]

Professor Giorgio Maria Calori received his MD from the University of

Milan in 1982 and later obtained a specialty in orthopaedic surgery,

physical therapy and rehabilitation, as well as hand surgery, the latter

from the University of Florence.

He has conducted extensive research in spine surgery and has gained

both national and international recognition for his work on bone healing

and bone regeneration processes with a focus on biotechnologies

applications such as growth factors, bone graft substitutes and mes-

enchymal stromal cell therapy.

Prof. Calori is Head of the Orthopaedic Reparative Surgery and Risk

Management Unit at Gaetano Pini Orthopaedic Institute, Milan (Italy).

He has authored and co-authored many articles in scientific and peer-

reviewed journals and is an active member of several societies including

The Italian Society of Orthopaedics and Traumatology (Società Italiana

di Ortopedia e Traumatologia) for which he is Chief of the scientific

committee on tissue regeneration. He is also the scientific director of

CIO, the official journal of the Osteosynthesis Italian Society.

LECTURE Day 2/ 09:15>09:35Bone graft substitutes

Biomaterials for bone reconstruction:general characteristics, efficiency, reliabilityand follow-upDidier MainardHôpital Central, Nancy, France

Orthopaedic surgeons are often confronted with bone defects.

To fill a bone defect, they have at their disposal a large array

of bone substitutes from human, animal, mineral or synthetic

origin. A bone substitute is a biomaterial or a bioengineering

product which can fill a bone defect in order to achieve healing

and preservation of function.

Autograft still remains the gold standard to fill bone defects. Its

supply may sometimes be insufficient and autograft harvesting

causes morbidity. Deep frozen allografts may be used under

various modalities; they can be used to address virtually any

clinical situation, without limitations related with the volume of

the bone defect. Serological screening decreases the risk of

virus transmission. Allografts may also undergo a special pro-

cessing to enhance microbiological safety, which prevents vir-

tually all risks of viral diseases. Decalcified allografts appear to

have osteoinduction properties. The use of processed xenografts

is very limited.

Synthetic bone substitutes are essentially calcium phosphates.

Two of these are used in clinical application: hydroxyapatite and

beta-tricalcium phosphate. They are also available in a biphasic

form. They are now widely used and dispense with autograft

harvesting. In some indications, they may be used instead of

allografts. They have a macroporous structure which allows for

bone ingrowth, i.e. osteoconduction. Their most important

property is bioactivity, i.e. the ability to establish a chemical link

with bone, without interposition of fibrous tissue at the interface.

Calcium phosphate bone cements, recently proposed, have not

been widely used so far. With their injectable form, they have

the advantage of allowing percutaneous bone filling. They must

be used following a specific handling procedure. Calcium

sulphate may be associated with antibiotics and employed in

septic situations.

Calcium carbonate has been very popular but it is now in com-

petition with calcium phosphates. The choice of a bone sub-

stitute cannot be the same whatever the clinical indication. The

choice will depend upon the site and volume of the bone defect

upon local and general conditions, upon the aetiology of the

bone defect and upon the properties of the bone substitute.

Although, bone substitutes are now widely used in orthopaedic

and trauma surgery, comparative, prospective and multicentric

studies are missing for their validation in clinical practice. Other

new products are now available such as BMPs, in association

or not with bone substitutes for which clinical evaluation will also

be necessary. Research in tissue engineering is very promising

for filling bone loss. �

/+/ AboutDidier Mainard

Service de Chirurgie Orthopédique et

Traumatologique

Hôpital Central

Avenue de Lattre de Tassigny

54000 Nancy, France

Prof. Didier Mainard graduated from the Medical University of Nancy.

He is the Head of the Orthopaedic and Trauma Surgery Department

of the University Hospital of Nancy, and Professor of Orthopaedic and

Trauma surgery at the University of Lorraine. His main clinical areas

of interest are hip, knee, foot and ankle surgery.

He is member of the research unit UMR CNRS 756I 1 “Pathophysiology,

Pharmacology and Engineering of the cartilage” and the Head of the

federation of research “molecular, cellular and therapeutic

Bioengineering”. His research topics are role of adiponectin in patho-

physiology of osteoarthritis and bone substitutes.

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Focus 11917th ArgoSpine Symposium Scientific Book

He published 174 papers in peer reviews and authors of more than

700 communications.

He is member of the board of the french society of orthopaedic and

trauma surgery and vice president of the GECO (study group in

orthopaedic surgery). He is associated editor of European J. of

Orthopaedic Surgery and Traumatology.

LECTURE Day 2/ 09:45>10:00Bone graft substitutes

Selection criteria for bone graft substitutesG.M. Calori, E. Mazza, M. Colombo, C. RipamontiC.O.R., Orthopaedic Institute, G. Pini, University of Milan, Italy

INTRODUCTIONThe treatment that has been long considered the gold standard

to restore bone defects is autologous bone grafting. However,

donor site complications have been shown to be elevated,

clinical benefits are not guaranteed and there is an associated

large rate of complications [1]. This is the reason why medical

scientists have reached an important level of development in

alternative bone substitutes (biological or synthetic).

MATERIALS AND METHODThe aim of this review is to provide a complete overview of the

literature data on bone substitutes used in traumatology and

orthopaedic surgery for large bone defects. For this reason we

have used two available databases: Embase and PubMed,

including manuscripts written in English dealing with bone sub-

stitutes and reporting on structural, biological or biomechanical

proper ties of the pure product or its use in trauma and

orthopaedic surgery; we have even considered brand names

of selected products as search terms.

RESULTSAll the products included possess osteoconductive activities but

have different resorption time and biomechanical properties. Of

each one, structural, biological and biomechanical characteris-

tics as well as their clinical indications in trauma and orthopaedic

surgery are provided. They are still used for a wide range of

clinical applications even if the level of clinical evidence is low.

The size, location of the defect and type of devices implanted

are the main factors related to the requirements of an optimal

bone substitute. [2]

CONCLUSIONTo date, there are no extensive studies that can validate a single

substitute as the optimal option. Moreover, some questions

remain unsolved, especially in real critical bone defects where

the application of polytherapy (scaffold, MSC, growth factors)

seems to give the best results. [3] �

/+/ References.a Younger EM, Chapman MW (1989) Morbidity at bone graft donor

sites.J Orthop Trauma 3: 192-5

z Calori GM, Mazza E, Colombo M, Ripamonti C (2011) The use of

bone graft substitutes in large bone defects: any specific needs?

Injury 42 Suppl 2: S56-63. Epub 2011 Jul 12

e Calori GM, Mazza E, Colombo M et al. (2011) Treatment of long bone

non unions with polytherapy: indications and clinical results - Injury 42

(6): 587-90

LECTURE Day 2/ 10:00>10:15Bone graft substitutes

Bone cement with chemotherapeutic agents:a new tool in the management of malignanttumours of the spine? An experimentalapproachMatías AlfonsoMedical Faculty of University of Navarra, Pamplona, Spain

INTRODUCTIONThe possibility of performing vertebroplasty with the use of

cement containing antineoplastic agents implies the potential to

perform local metastasis control together with stabilisation of

the fracture. In vitro studies have shown that cement containing

methotrexate, doxorubicin, or cisplatin maintains its mechanical

characteristics, allows diffusion of the active form of these

agents from the cement, and is able to inhibit growth of breast

carcinoma cells, particularly in the first 24 hours and up to 15

days following exposure.

THE AIMS OF THIS STUDY WERE:1. To investigate the feasibility of performing percutaneous verte-

broplasty with methotrexate-loaded and cisplatin-loaded cement

in a porcine model.

2. To determine the concentration of methotrexate and cisplatin

in blood following vertebroplasty.

3. To study the clinical outcome and histological changes in mielo-

radicular structures and perivertebral muscles alter vertebroplasty

with polymethyl-metacrylate (PMMA) loaded with antiblastic drugs

in pigs.

4. To determine the concentration of methotrexate and cisplatin

in vertebral body following vertebroplasty and correlation with time.

MATERIALS AND METHODSIn the first Group, vertebroplasty of two vertebrae was per-

formed in ten female pigs using vertebroplasty cement to which

1 g of powdered methotrexate had been added. After creating

the mixture, the monomer was added and cement was injected

in two vertebrae, provoking an anterior leak to the psoas and

another leak to the vertebral canal. Methotrexate concentration

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120 Focus 17th ArgoSpine Symposium Scientific Book

in blood following cement administration was measured in serial

determinations, and animals were sacrificed at 3 weeks. In the

second Group the same procedure than group 1 was performed

on 11 female pigs using vertebroplasty cement to which 0.5 g

of powdered cisplatin had been added. Three weeks later the

pigs were put to death. We did a histological study of the soft

tissue that came into contact with the cement.

RESULTSIn the Group 1 there were no major incidents associated with

the technique and none of the animals had cord lesions fol-

lowing cement leakage. The mean circulating methotrexate

values were recorded during 7 days. In the group 2 four animals

presented paraparesis (1 immediate and 3 later). Mean cisplatin

values in blood were recorded during 7 days.

Histological resultsMetotrexate group: normal spinal cord and the same changes

found in control group were observed.

Cysplatin group: spinal cord necrosis was observed in the whole

group of pigs. Wide areas of muscular necrosis were observed.

CONCLUSIONThe use of methotrexate-loaded cement is feasible in a porcine

model. There were no clinical complications following leakage

to the canal, and diffusion to the blood was detectable for up

to 3 days. Despite massive epidural leakage, no neurological

compromise was observed in MTX group. Also no changes in

the spinal cord were observed; it is likely that the dura and the

cerebrospinal fluid are enough to isolate the neural structures

from the cement. Dura and muscle showed inflammatory

reaction, foreign body reaction, fibrosis and synovial metaplasia.

Cisplatin can diffuse to the circulation from cement injected in

the vertebra for around 72 hours. In this group we observed

extensive areas of cord and muscle necrosis associated with

slight inflammatory reaction. The use of cisplatin-loaded cement

in this porcine model did not yield favourable results because

of the incidence of late paraparesis, probably due to the neu-

rotoxic potential of this agent. �

/+/ AboutMatías Alfonso

Medical Faculty of University of Navarra

Pamplona, Spain

Dr. Matías Alfonso obtained his medicine degree in 1993 at the

University of Navarre, where he also completed his residency in

Orthopaedics in 1999. He earned his PhD degree in 2005.

He is Associate Professor of Orthopaedics at the Medical Faculty of

the University of Navarra. Nowadays he is conducting several exper-

imental studies in vertebroplasty with chemotherapy and TGF-Beta

inhibitors for the treatment of fibrosis.

He is a member of the council of AOSpine in Spain and active member

of the Spanish Spine Society (GEER) for which he is also a former

member of the Scientific Committee.

Dr. Alfonso authored 12 book chapters and over 30 peer-reviewed pub-

lications in scientific journals.

LECTURE Day 2/ 11:00>11:15Controversial round table: Bone Morphogenic Protein (BMP)

BMP: What is it? How to use it? What are itseffects? Carcinogenic effect?Franz E. WeberUniversity Hospital Zurich, Switzerland

Hippocrates, the father of medicine, noted around 400 B.C. that

bone heals without scarring. It was not until the year 1965 that

the underlying molecules were recognized as such by Marshal

Urist [1] and concentrated in a crude extract derived from dem-

ineralized bone. In the following years initial clinical trials were

performed in the orthopedic field using this rather crude extract,

focusing mainly on the treatment of nonunions from the femur

or the tibia [2, 3]. These trials were proof that underlying mol-

ecules for the “bone inducing principle” had potential to be

used in clinics to induce bone formation and healing. It was not

until 1988 that a team independent from Marshal Urist isolated

sufficient protein from 1 ton of bovine bone to be able to clone,

express and to patent the first bone morphogenetic protein

(BMP) [4]. In the end, it became clear that there is a family of

BMP-like proteins which belongs to the transforming-growth

factor superfamily due to structural similarities. This family binds

to a family of BMP-receptors and signals mainly via the phos-

phorylation of Smads and p38 [5].

In preclinical trials the potential of BMP to induce bone forma-

tion and repair has been demonstrated in numerous animal

models. However, in humans huge amounts of BMP exceeding

the natural concentration by a factor of 200-1000 is needed to

show sufficient effect or to measure up to the results normally

achieved by the use of the “gold standard” autologous bone.

Since, high BMP dosages induce side effects like swelling and

increase the cost of the treatment; several strategies have been

developed to reduce the amount of BMP needed for clinical

applications: optimization of the BMP release by the delivery

system [6-8], inhibition of BMP antagonists, enhancing BMP

activity by small chemicals [9] or other means.

Just recently it became evident by the results of the clinical

trials which led to the approval of BMP-2 for lumbar spine fusion

in 2002 by the FDA that male sterility by retrograde ejaculation

is increased more than 3 fold in the BMP group compared to

male patients treatment with autologous bone [10-12]. Therefore,

a critical reevaluation of the results of the clinical trial plus an

evaluation of the clinical outcome with infuse® from Medtronic

is needed to decide on the pros and cons of the currently used

BMP-based treatments of the spine and beyond. �

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Focus 12117th ArgoSpine Symposium Scientific Book

/+/ References.a Urist MR (1965) Bone: formation by autoinduction. Science 150: 893-9

z Johnson EE, Urist MR (1989) Distal metaphyseal tibial nonunions

associated with significant bowing deformity and cortical bone loss:

treatment with human bone morphogenetic protein (h-BMP) and

internal fixation. Nihon Seikeigeka Gakkai Zasshi 63: 613-20

e Johnson EE, Urist MR, Finerman GA (1988) Repair of segmental

defects of the tibia with cancellous bone grafts augmented with

human bone morphogenetic protein. A preliminary report. Clin Orthop

Relat Res: 249-57

r Wozney JM, Rosen V, Celeste AJ et al. (1988) Novel regulators of

bone formation: molecular clones and activities. Science 242: 1528-34

t Reddi AH (1998) Role of morphogenetic proteins in skeletal tissue

engineering and regeneration. Nat Biotechnol 16: 247-52

y Lutolf MP, Weber FE, Schmoekel HG et al. (2003) Repair of bone

defects using synthetic mimetics of collagenous extracellular

matrices. Nat Biotechnol 21: 513-8

u Weber FE, Eyrich G, Gratz KW et al. (2002) Slow and continuous

application of human recombinant bone morphogenetic protein via

biodegradable poly(lactide-co-glycolide) foamspheres. Int J Oral

Maxillofac Surg 31: 60-5

i Hanseler P, Jung UW, Jung RE et al. (2012) Analysis of hydrolyzable

polyethylene glycol hydrogels and deproteinized bone mineral as

delivery systems for glycosylated and non-glycosylated bone

morphogenetic protein-2. Acta Biomater 8: 116-23

o Miguel BS, Ghayor C, Ehrbar M et al. (2009) N-methyl pyrrolidone as

a potent bone morphogenetic protein enhancer for bone tissue

regeneration. Tissue Eng Part A 15: 2955-63

p Carragee EJ, Ghanayem AJ, Weiner BK et al. (2011) A challenge to

integrity in spine publications: years of living dangerously with the

promotion of bone growth factors. Spine J 11: 463-8

q Carragee EJ, Hurwitz EL, Weiner BK (2011) A critical review of

recombinant human bone morphogenetic protein-2 trials in spinal surgery:

emerging safety concerns and lessons learned. Spine J 11: 471-91

s Carragee EJ, Mitsunaga KA, Hurwitz EL, Scuderi GJ (2011)

Retrograde ejaculation after anterior lumbar interbody fusion using

rhBMP-2: a cohort controlled study. Spine J 11: 511-6

/+/ AboutFranz E. Weber

Division of Cranio-Maxillofacial and Oral Surgery

Oral Biotechnology & Bioengineering

University Hospital Zurich

Zurich, Switzerland

Franz Weber graduated from the University Konstanz (Germany) with

a PhD in Biology/Muscle Biochemistry. He completed a 3-year post-

doctoral training on muscle cell biology at Cornell University Medical

College in New York City and served as a lecturer in the Department

of Cell Biology and Anatomy. He spent the following two years at the

ETH Zurich (École Polytechnique Fédérale) working on the lipid uptake

from the small intestine. In 1995, he joined the Department of Cranio-

Maxillofacial and Oral Surgery at the University Hospital in Zurich, and

the Dental School of the University of Zurich. Besides his obligations

at the University of Zurich, he became Director of the European

Technical Center of Inion Ltd, in Cambridge (UK) in 2005 and occupied

this position until 2009. His main area of interest is bone regeneration.

His research encompasses bone morphogenetic proteins, delivery

systems, bone substitute materials, and in vitro bone tissue engineering.

Franz E. Weber has authored 69 publications published in international

journals amounting to more than 2423 citations and has an h-index of

25. He is member of TERMIS (Tissue Engineering international &

Regenerative Medicine Society), IADR (International Association for

Dental Research), and SSB (Swiss Society for Biomaterials).

He is currently appointed as Professor of Craniofacial and Oral

Biotechnology at the University of Zurich and as an honorary Professor

at the University of Hong Kong.

LECTURE Day 2/ 11:15>11:25Controversial round table: Bone Morphogenic Protein (BMP)

The Japanese experience: can we perform afusion without BMP?Kazuhiro HasegawaNiigata Spine Surgery Center, Niigata, Japan

The use of bone morphogenetic protein (BMP) has been shown

to achieve better clinical outcomes in anterior lumbar interbody

fusions procedures, which led to its Food and Drug

Administration approval for this indication in 2002. Since then,

significant off-label use has occurred, without a full description

of the results [6]. Surprisingly, BMP was used in approximately

25% of all spinal fusions nationally in 2006 in USA [1] and has

been increasingly used year by year. In the beginning of its

usage, BMP was reported safe in the perioperative period, with

no increase in major medical complications but also increased

health care costs at postoperative 1 year [2,4]. Contrary to these

merits, the markedly elevated complication rate in anterior

cervical fusion was reported and BMP usage emphasizes the

need to evaluate risks and benefits of bioactive technologies in

a site-specific and procedure-specific manner [1,7]. BMP has

been gradually recognized to cause early inflammatory changes,

ectopic bony formation, adjacent level fusion, radiculitis, and

osteolysis [3], possibly resulting in even a life-threatening com-

plication such as acute airway obstruction in the postoperative

period following cervical spine fusion [8].

Unfortunately or fortunately, BMP has not been officially per-

mitted for clinical use in Japan. Therefore our routine fusion pro-

cedure has been limited to the one with autologous bones,

mostly from iliac bone, with high purity beta-tricalcium phos-

phate (OSferion, Olympus Terumo Biomaterials Corp., Tokyo,

Japan) augmented by a interbody suppor t (Ti-alloy

cases/spacers) and pedicle screws, if necessary. In this pres-

entation, we would like to report the Japanese experience of

cervical ASF, MIS-TLIF, and spinal deformity surgeries, with the

recent results in comparison with the previous papers in which

fusion was performed using BMP. �

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122 Focus 17th ArgoSpine Symposium Scientific Book

/+/ References.a Cahill KS, Chi JH, Day A, Claus EB (2009) Prevalence, complications,

and hospital charges associated with use of bone-morphogenetic

proteins in spinal fusion procedures. JAMA 302(1): 58-66

a Cahill KS, Chi JH, Groff MW et al. (2011) Outcomes for single-level

lumbar fusion: the role of bone morphogenetic protein. Spine 36:

2354-62

a Choudhry OJ, Christiano LD, Singh R et al. (2012) Bone

morphogenetic protein-induced inflammatory cyst formation after

lumbar fusion causing nerve root compression. J Neurosurg Spine 16:

296-301

a Deyo RA, Ching A, Matsen L et al. (2012) Use of bone

morphogenetic proteins in spinal fusion surgery for older adults with

lumbar stenosis: trends, complications, repeat surgery, and charges.

Spine 37: 222-30

a Helgeson MD, Lehman RA Jr, Patzkowski JC et al. (2011) Adjacent

vertebral body osteolysis with bone morphogenetic protein use in

transforaminal lumbar interbody fusion. Spine J 11: 507-10

a Lad SP, Nathan JK, Boakye M (2011) Trends in the use of bone

morphogenetic protein as a substitute to autologous iliac crest bone

grafting for spinal fusion procedures in the United States. Spine 36:

E274-81

a Williams BJ, Smith JS, Fu KM et al. (2011) Does BMP increase the

incidence of perioperative complications in spinal fusion?

A comparison of 55,862 cases of spinal fusion with and without BMP.

Spine [Epub ahead of print]

a Yaremchuk K, Toma M, Somers M (2010) Acute airway obstruction

associated with the use of bone-morphogenetic protein in cervical

spinal fusion. Laryngoscope 120 Suppl 4: S140

/+/ AboutKazuhiro Hasegawa

Niigata Spine Surgery Center

2-5-22 Nishi-Machi

950-0165 Niigata, Japan

Ph: +81-25-382-3111

Kazuhiro Hasegawa graduated in 1987 at the Medical School of the

Niigata University (JP) where he completed his residency as well as

postgraduate training. He is currently Director of the Niigata Spine

Surgery Center in Japan. He was a research fellow in USA from 1992

to 1994 at the Department of Anatomy and Biomechanics Research

Center of the Indiana University. Then he became clinical fellow at the

School of Medicine of the Niigata University (JP). Kazuhiro Hasegawa

is very much involved in subjects such as all spine diseases covering

spinal neural elements and bone and joints, from pediatric through

adult, from cervical though sacrum, including spinal cord tumors and

biomechanics in normal spine, osteoporotic spine, segmental insta-

bility, or spinal instrumentations. He is an active member of several

specialized societies such as Scoliosis Research Society, the

International Society of the Study of Lumbar Spine, North American

Spine Society, or ArgoSpine, etc. He received several awards such as:

Encouragement Award of Japanese branch office of International

Society of the Study of Lumbar Spine (ISSLS) in 2006, Best Poster

Presentation Award of ArgoSpine in 2007, and European Cervical Spine

Research Society, The Mario Boni Award (Best presentation award) in

2008, etc. More than one hundred fifty papers were presented by K.

Hasegawa in the last five years at Japanese or international meetings.

LECTURE Day 2/ 11:50>12:10Stem cells

Stem cells: Where to use them in the spine?Is there a future (short and long term)?M.N. Helder, R.J.W. Hoogendoorn, R.J. Kroeze,P.P.A. Vergroesen, C.P.L. Paul, S.E.L. Detiger,B.J. Vanroyen, T.H. SmitDept. of Orthopaedics, VU University Medical Centre, Amsterdam, The Netherlands.

Part of Research Institute Move, Vu University Amsterdam

Adipose stem cells (ASCs), due to their abundant availability

and high frequency, allow one-step surgical procedures for tissue

engineering and regenerative medicine [1]. This innovative

concept effectively employs the body’s own regenerative poten-

tial, and overcomes the need for in vitro expansion, high costs,

and repeated surgeries.

For severely degenerated intervertebral discs, we evaluated and

validated this concept for feasibility, safety and efficacy in a

spinal fusion model in large animal studies [2]. In these studies

we combined freshly isolated ASC-preparations with the clini-

cally innovative and hitherto unexplored use of a radiolucent

70:30 poly(L-lactide-co-caprolactone) (PLCL) scaffold. This

scaffold was shown to rapidly and selectively sequester ASCs,

thereby preventing ASC “shedding” in the body [3]. Our results

showed early and strong angiogenesis, excellent biocompati-

bility and a complete absence of adverse events. Guided bone

formation was well detectable on X-rays, and matched macro-

scopic and histological evaluations. In the cell-seeded scaffolds,

solid bone bridging occurred in several cases after 3 months,

increasing to 60% at 6 months. Acellular PLCL showed inferior

fusion when compared to ASC-supplemented scaffolds [2].

To evaluate the use of ASCs for mild degeneration, we devel-

oped a large animal model in goats using chondroitinase ABC

induction [4-6]. This model is currently employed in the EU FP7-

project “NPmimetic” to evaluate treatments consisting of (com-

binations of) hydrogel scaffolds, growth factors and ASCs. Last

but not least we developed an ex vivo organ force-controlled

disc culture model (LDCS) [7]. This model will allow us to study

treatment concepts under tightly controlled conditions.

We conclude that stem cell-mediated spinal tissue engineering

in one-step surgeries is feasible, safe, and effective in spinal

fusion settings. For mildly degenerated discs, treatment with this

concept appears also feasible and effective, which was tested

by other groups in dogs as well [8]. New tools, such as the

loaded disc culture system, will allow a shift from empirical to

well-defined treatment concepts. There is a future for stem cells

in the spine! �

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Focus 12317th ArgoSpine Symposium Scientific Book

/+/ References.a Helder MN, Knippenberg M, Klein-Nulend J, Wuisman PIJM (2007)

Stem cells from adipose tissue allow challenging new concepts for

regenerative medicine. Tissue Eng 13(8): 1799-808

z Vergroesen PP, Kroeze RJ, Helder MN, Smit TH (2011) The Use of

Poly(L-lactide-co-caprolactone) as a Scaffold for Adipose Stem Cells

in Bone Tissue Engineering: Application in a Spinal Fusion Model.

Macromol Biosci 11(6): 722-30

e Jurgens WJ, Kroeze RJ, Bank RA et al. (2011) Rapid attachment of

adipose stromal cells on resorbable polymeric scaffolds facilitates the

one-step surgical procedure for cartilage and bone tissue engineering

purposes. J Orthop Res 29(6): 853-60

r Hoogendoorn RJW, Wuisman PIJM, Smit TH et al. (2007) Experimental

Intervertebral Disc Degeneration induced by Chondroitinase ABC in the

Goat. Spine 32(17): 1816-25

t Hoogendoorn RJW, Helder MN, Kroeze RJ et al. (2008) Reproducible

long term disc degeneration in a large animal model. Spine 33(9): 949-54

y Hoogendoorn RJW, Zandieh Doulabi B, Huang CL et al. (2008)

Molecular changes in the degenerated goat intervertebral disc. Spine

33(16): 1714-21

u Paul CPL, Zuiderbaan HA, Zandieh Doulabi B et al. (2012)

Simulated-physiological loading conditions preserve biological and

mechanical properties of caprine lumbar intervertebral discs in ex

vivo culture. PloS One 7(3): E33147

i Ganey T, Hutton WC, Moseley T et al. (2009) Intervertebral disc repair

using adipose tissue-derived stem and regenerative cells: experiments

in a canine model. Spine (Phila Pa 1976) 34(21): 2297-304

/+/ AboutMarco N. Helder

VU University Medical Center (VUMC)

Amsterdam, The Netherlands

Marco Helder obtained his PhD in 1994 at the Vrije Universiteit

Amsterdam, and subsequently performed post-doctoral studies at the

Rijksuniversities of Leiden and Groningen. He became a senior

researcher in 2002 at the Dept. of Orthopaedics at the VUMC, where

he was appointed as an Assistant Professor in 2007. His main interest

is the development of therapeutic modalities employing adipose stem

cell (ASC) technologies for musculoskeletal disorders (spinal fusion,

intervertebral disc and articular cartilage regeneration), cardiac repair,

and pelvic organ prolapse. A phase I/II clinical trial on ASC bone tissue

engineering is currently ongoing. He published about 65 articles in

international peer-reviewed journals, and three patents. Marco Helder

is director of the foundation “Skeletal Tissue Engineering Group

Amsterdam (STEGA)”, secretary of the Dutch society for biomaterials

and tissue engineering, scientific director of the European network

“REGENERATE”, and coordinator of an EU FP7 project on Degenerative

Disc Disease (NPMimetic). In addition, he is member of the European

Technology platform “Nanomedicine”, and various international soci-

eties such as the ORS, IFATS, ICRS, and TERMIS.

ORAL PRESENTATION Day 2/ 13:45>13:55

Unusual stabilization of the ageingdegenerated spineMarton Ronai, Gabor JakabNational Center For Spinal Disorders, Budapest, Hungary

How to treat an elderly patient with co-morbidities to minimize

risks but to achieve an acceptable result?

CASE PRESENTATIONA 75-year-old woman with myocarditis, WPW syndrome, high

blood pressure, osteoporosis, need of hormone substitution

because of hysterectomy in her medical history. Her present

complaint is low back pain under load without significant lower

extremity pain. On physical examination we can observe diffi-

culty to walk, there is no neurological injury. On radiological

examination, polysegmental disc degeneration can be seen,

causing vertical instability (Fig.1-4.) As repeated conservative

treatment failed, the treatment options are surgical:

Figure 3: Preoperative MRI. Figure 4: Preoperative CT.

Figure 1: Preoperative lateralXray.

Figure 2: Preoperative APXray.

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124 Focus 17th ArgoSpine Symposium Scientific Book

Long stabilization and fusion with lordosis correction - high risk

Minimally invasive discoplasty - acceptable compromise

RESULTSAlmost 2 years after Percutan. Cement Discoplasty (Fig. 5).

Good results: she walks without support, she does not need to

take painkillers permanently. �

ORAL PRESENTATION Day 2/ 13:55>14:05

Osteoporotic vertebral compression fractures(OVCF): kyphoplasty or conservativetreatment?Jean-François CazeneuveCentre Hospitalier, Laon, France

The purpose of this prospective and mono-centric study, per-

formed between January 2009 and June 2011, is to assess

clinical and radiological outcomes 12 months after kyphoplasty

or conservative treatment for osteoporotic vertebral compres-

sion fractures (OVCF) which have a highly negative influence in

terms of morbidity in elderly patients.

Thirty-six patients, mean age 74 years (range, 55-92 years),

86% of women, involving according the Magerl’s classification

twenty-seven A.1.2 and nine A.3.1 vertebral fractures, from T

12 to L 5, were allocated to eighteen kyphoplasties (Medtronic)

and eighteen conservative treatments consisting in a one-month

bed rest principally in ventral position with physiotherapy and

early mobilization in a swimming pool; then, walking was author-

ized with a back brace for two months. All the patients were

followed for a minimum of twelve months. We collected data by

examining Visual Analogue Pain Scale (VAS), Oswestry score,

Hospital Anxiety and Depression Scale (HADS), vertebral and

kyphosis angles. In the kyphoplasty group, free of complica-

tions, from the pre- and postoperative periods to twelve-month

follow-up, VAS dropped from 8.7 to 3.9 then 2.9, Oswestry score

from 53 to 48 then 31, HADS score from 12.0 to 10.1 then 9.8,

the mean vertebral angle decreased from -15° to -5° then -10°

and the kyphosis angle improved from - 20° to + 3° then

dropped to -5°. Asymptomatic leakage of cement was found in

4 cases (22%). In the conservative treatment group, at twelve-

month follow-up, the VAS, Oswestry and HADS scores were

respectively 4.2, 41 and 12 points. The mean vertebral angle

increased from 15° to 25° in 45% of the patients with a kyphosis

angle remaining always negative. Each group was free of recur-

rent fractures.

For OVCF, the Laon experience demonstrates that kyphoplasty

can improve pain and functional status, may help correct ver-

tebral deformity and thereby encourages further recruitment for

kyphoplasty instead of conservative treatment. �

ORAL PRESENTATION Day 2/ 14:05>14:15

Robotic assisted spine surgery – Ephemeralgadget or rather sustainable technology?Our experience with the SpineAssist® platformfor the treatment of various spinalpathologiesYaron Zaulan, Vitaly Alexandrovsky, Boris Zilberstein,Alex Puhov, Fadi Khazin, Ali Sulliman,Benjemin Bernfeld, Alexander BruskinCarmel Medical Center Haifa Israel, Haifa, Israel

BACKGROUNDRobots have been known for thousands of years. As described

in a Taoist Chinese manuscript, written by Liezi at the 4th century

B.C. which is the earliest reference to a “robot” in the form of

an organic robot developed by an “artificer” called Yan Shi.

Robotic surgery was first performed by Kwoh in 1985. Puma

560 robotic arm was used to place a needle for a CT guided

brain biopsy. Since then, the use of robots in surgeries has

become a common practice.

PURPOSEIn our institute we have been using the “SpineAssist” platform

for more than 10 years. Gaining experience using this platform

we describe collective data gathered following a variety of spinal

procedures such as vertebroplasty, biopsy, pedicle screws inser-

tion and an intervertebral fusion – GOLIF procedures.

Figure 5: Postoperative CT.

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Focus 12517th ArgoSpine Symposium Scientific Book

RESULTSAltogether we preformed 133 robotic assisted vertebroplasty

procedures using the “SpineAssist” platform. During this period

a distinct learning curve was observed and analyzed. For the

first ten vertebroplasties an average of 12 fluoro-images were

taken with a net operation time of 53.6 min per procedure.

Analyzing the first 40 procedures has shown less fluoro-images

per procedure (5 fluoro images) and a net operation time of

48.6 min/procedure. Data drawn from the 51 following verte-

broplasties has set the standards of 4 fluoro-images with a net

operation time of 25.8 min/procedure. During a six years period

830 screws were inserted, of which 98 were inserted using per-

cutaneous technique. Comparing the insertion of a set of 4

screws we found a significant improvement regarding the number

of fluoro-images, fluoro exposure time and the net operation

time between the first ten procedures and the rest with a mean

of 20 fluoro/4 fluoro images and net screw insertion time of 82

min/ 25 min respectively. We found no difference in the param-

eters comparing percutaneous vs. open

pedicle screws inser tion. The mean

accuracy of all procedures was 0.3 mm

compared to the pre-planned screw tra-

jectory

CONCLUSIONSThe essence of robotic assisted surgery

is a pre-planned needle/screw trajectory

aiming to reduce the possible intra-opera-

tive complication, inaccuracies and

possible mishaps emerging during “free

hand” procedures. One cannot dismiss the

down sides using this platform as the need

to overcome the psychological “hesitation

effect” of the surgeon while learning how

to use a new technology, the need for addi-

tional technical personal in the O.R., the

increase in overall surgical time and the

learning curve needed to master the tech-

nique as the use of additional CT scan for

the pre-planning. On the other side of the

scale one should take into consideration

the overall benefits of this technique;

reduction of the surgeon exposure to radi-

ogenic dose, ultra-accurate procedures as

the percutaneous intervertebral fusion –

GOLIF and vertebroplasty for burst frac-

tures, in cases of anatomical and post-

surgical malformations where finding the

“entry point” can be difficult. This benefit

is obtained when applying the technique

in more than 4 pedicle screws insertion in

a single session. �

LECTURE Day 2/ 14:15>14:25Controversial round table: intraoperative 3D imaging andnavigation

Preliminary results with intraoperativenavigation in spinal deformitiesIbrahim Obeid, Jean-Marc VitalBordeaux University Hospital, Bordeaux, France

In recent years, the importance of intraoperative navigation in

spine surgery has been increasing. Multiple studies have proven

the advantages and safety of computer-assisted spinal surgery.

Using preoperative CT Scan navigation has become a trend in

spinal surgery instrumentation since 2007. The usefulness of

navigation system was largely evaluated and treated in the lit-

erature for transpedicle screw. It was also evaluated in tumour

resection, kyphoplasty, corpectomy for degenerative disease,

etc. [1-6].

Case 1: Severe thoracic scoliosis in a young adult man, preoperative CT Scan showed that freehand technique is possible and navigation was not used.

Case 2: 17-year-old girl, revision for pseudoarthrosis. Small amount of bone graft was used in theprevious surgery and anatomical landmarks were visualized. Free hand technique was used.

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126 Focus 17th ArgoSpine Symposium Scientific Book

In deformity spinal surgery operative navigation is used mainly

to decrease the risk of transpedicle screw misplacement.

However, in the same period of time many papers confirmed

the efficacy and safety of the free hand transpedicle screw

technique. This technique seems to be safe in paediatric and

adult deformities but also in revision spinal surgery [7-9].

The use of navigation has to decrease operative time, decrease

the risk of screw misplacement, and decrease the radiation

exposure time for the surgical team. [1-3].

The question we would like to raise is in which cases naviga-

tion use will be of some benefit and in which it could be a

waste of time and a source of morbidity and radiation for the

patient?

The answer to this question is very difficult because it depends

mainly on the surgeon experience and the complexity of the

cases.

In our experience, spinal navigation is used only in very complex

cases. We reserve it for:

1- Revision spinal deformity cases when massive autologous

bone graft was used in previeus surgery and all anatomical

landmarks completely disappeared

2- Severe deformity with thin pedicle less than 4mm in strategic

vertebra or when cervical pedicle screw is necessary

3- Modified or poor anatomical landmarks in congenital malfor-

mations

4- Specific and precise vertebral body resection in some non-

conventional osteotomy

In these indications, spinal navigation provides a real benefit

and permit to do very complex surgery with less difficulty for

the surgeon and less morbidity and risk for the patient. To

confirm usefulness of the navigation in those indications, pre-

operative CT Scan is necessary to check the pedicle diameter,

to identify possible landmarks or to evaluate the nature and

amount of bone resection in non-conventional osteotomies.

In conventional deformity case, free hand technique and classic

bone resection seem to be safe and accurate in experienced

hands. �

/+/ References.a Silbermann J, Riese F, Allam Y et al. (2011) Computer tomography

assessment of pedicle screw placement in lumbar and sacral spine:

comparison between free-hand and O-arm® based navigation

techniques. Eur Spine J 20(6): 875-81

z Wood M, Mannion R (2011) A Comparison of CT-based navigation

techniques for minimally invasive lumbar pedicle screw placement.

J Spinal Disord Tech 24(1): E1-5

Case 4: 7th revision surgery in completely fused spine. Completedisappearance of anatomical landmarks. Navigation allowed safeinstrumentation and correction osteotomy.

Case 3:Angular kyphosis and myelopaty in a 25-year-old man.Navigation guided bone resection in closing opening PSO.

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Focus 12717th ArgoSpine Symposium Scientific Book

e Metz L, Burch S (2008) Computer-assisted surgical planning and

image-guided navigation in refractory adult scoliosis surgery. Spine

33(9): E287-92

r Ishikawa Y, Kanemura T, Yoshida G et al. (2011) Intraoperative,

full-rotation, three-dimensional image (O-arm)-based navigation system

for cervical pedicle screw insertion. J Neurosurg Spine 15(5): 472-8

t Schils F (2011) O-arm guided balloon kyphoplasty: preliminary

experience of 16 consecutive patients. Acta Neurochir 109: 175-8

y Costa F, Tomei M, Sassi M et al. (2011) Evaluation of the rate of

decompression in anterior cervical corpectomy using an

intra-operative computerized tomography scan (O-arm® system).

Eur Spine J 21(2): 359-63

u Boachie-Adjei O, Girardi FP, Bansal M, Rawlins BA. Safety and

efficacy of pedicle screw placement for adult spinal deformity with a

pedicle-probing conventional anatomic technique. J Spinal Disord

13(6): 496-500

i Kim YJ, Lenke LG, Bridwell KH et al. (2004) Free hand pedicle screw

placement in the thoracic spine: is it safe? Spine (Phila Pa 1976) 1;

29(3): 333-42

o Kim YW, Lenke LG, Kim YJ et al. (2008) Free-hand pedicle screw

placement during revision spinal surgery analysis of 552 screws.

Spine (Phila Pa 1976) 33(10): 1141-8

/+/ AboutIbrahim Obeid�

Unite de Pathologie Rachidienne

Hôpital Tripode

Place Amélie Raba-Leon

33076 Bordeaux Cedex, France

After completing his degree in Medicine (Lebanon) in 1998, Ibrahim

Obeid was appointed as an intern at the University Hospital Hotel Dieu

de France (Beirut, Lebanon), where he became interested in paedi-

atric orthopaedic surgery and child deformities. Dr. Obeid obtained a

grant from the Groupe International Cotrel Dubousset and spent time

in Berck, Nancy and Nantes hospitals.

His fellowship began first in Paris in 2003 at the St. Joseph Hospital

and was dedicated to adult spine deformity; since 2004, Dr. Obeid is

part of Prof. Vital’s department in the Bordeaux Tripode Hospital. In

2008, he was promoted to staff physician, specialised in adult and

adolescent spine deformity. Dr. Obeid is an active member of GES

(Scoliosis Study Group) since 2007 and assumed in May 2008 the

presidency of the Vertebral Column Institute (ICV, created by Prof.

Sénégas in the Bordeaux Spinal Surgery unit).

Moreover, he has been an active member of the French Society of

Spine Surgery, French Society of Orthopaedic surgery and the Spine

Society of Europe

Since July 2012 Dr Obeid became a core member of the European

Society Study Group (ESSG) specialised in adult spine deformity

Dr Obeid has several publications in basic research and clinical spine

pathologies, he is invited as guest speaker to many national and inter-

national meetings especially for spinal deformity, osteotomy and spinal

balance.

LECTURE Day 2/ 14:25>14:35Controversial round table: intraoperative 3D imaging andnavigation

Principle and possibilities of the isocentricC-armAfshin Gangi, Julien Garnon, Georgia Tsoumakidou,Iulian EnescuInterventional Imaging, Univesrity Hospital of Strasbourg, France

Three-dimensional ISO-C systems are able to provide computed

tomographic (CT) images with high resolution and excellent contrast.

The last decade witnessed a proliferation of cone-beam CT imaging

technologies based on flat-panel detectors in a broad scope of

clinical applications, ranging from diagnostic imaging to image-

guided interventions.

All surgeons and interventionists are able to use fluoroscopic images

in routine practice. However, CT images and 3D images are not

used systematically. The 3D images before, during the procedure

and at the end of procedure can increase the safety and preci-

sion of the interventions.

In a classical operation theatre, an ISO-C imaging fluoroscopy can

be used routinely if the exposed part of the table is radiolucent.

In more recent hybrid theatres, the ISO-C system is integrated to

the room and allow a faster acquisition of the images and reduce

the radiation compared to a mobile fluoroscopy. The association of

3D imaging to customized software for the calculation of trajectory,

axis, and rotation make the system a valuable tool before, during

and after the procedure. Iso-C significantly decreased surgical time

[2]. Yang et al. [1] compared Isocentric C-Arm 3-dimensional nav-

igation and conventional fluoroscopy for C1 lateral mass and C2

pedicle screw placement for atlantoaxial instability and concluded

that using Iso-C 3D navigation can significantly improve the

accuracy of screw placement and decrease intraoperative fluoro-

scopic time and blood loss. During this lecture the authors will illus-

trate different applications and capability of cone beam CT systems.

C-arm systems with 3D-capabiltity offer a promising tool for intra-

operative near real-time image guidance. Intraoperative cone-beam

CT using a high-performance mobile C-arm or hybrid room provides

image quality suitable to guidance of spinal surgery and interven-

tions. �

/+/ References.a Yang YL, Zhou DS, He JL (2011) Comparison of isocentric C-arm

3-dimensional navigation and conventional fluoroscopy for C1 lateral

mass and C2 pedicle screw placement for atlantoaxial instability.

J Spinal Disord Tech Nov 18 [Epub ahead of print]

z Martirosyan NL, Kalb S, Cavalcanti DD et al. (2011) Comparative

analysis of isocentric 3-dimensional C-arm fluoroscopy and biplanar

fluoroscopy for anterior screw fixation in odontoid fractures. J Spinal

Disord Tech Dec 5 [Epub ahead of print]

e Schafer S, Nithiananthan S, Mirota DJ et al. (2011) Mobile C-arm

cone-beam CT for guidance of spine surgery: image quality, radiation

dose, and integration with interventional guidance. Med Phys 38(8):

4563-74

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128 Focus 17th ArgoSpine Symposium Scientific Book

LECTURE Day 2/ 14:35>14:45Controversial round table: intraoperative 3D imaging andnavigation

Preliminary results with Siemens 3D systemSamo K. FokterDepartment of Orthopaedics, University Clinical Centre Maribor, Slovenia

BACKGROUNDAfter the basic model Siremobil™ IsoC-3D, the ARCADIS™

Orbic 3D model of surgical imaging system was released

to the market by the Siemens Corporation (Siemens AG,

Medical Solutions, Erlangen, Germany) in 2005. The intra -

operative system is able to produce both two-dimensional (2D)

and three-dimensional (3D) views. Namely, in these devices

the source of rays and the camera of the C-arm are aligned

in such a way that the centre point of a connection line

between the two units always remains focused on one point,

the iso-centre, when the C-arm is turned, unlike conventional

devices, where this centre-point describes a line. Since

proper screw placement is vital both for structural stability

and to avoid crucial anatomical structures, especially 3D

fluoroscopy performed intraoperatively is often used as a means

to evaluate screw placement during spinal instrumentation

[1, 2].

PROCEDUREIn most cases of our lumbar spine surgeries, the patient is

positioned prone on a metal-free carbon spinal surgical

table. The 2D mobile C-arm images of the appropriate level

in the frontal and lateral views are obtained during placement

of spinal instrumentation as usual. The system allows for

intraoperative navigation, further increasing the accuracy of

screw placement, but special equipment and software is nec-

essary for this task and we have no experience with it [3].

However, after all the pedicle screws are placed, the system

is placed in a position where the mobility of the C-arm is

unrestricted in a 190° arc of motion. This is manually checked

by the technician. Afterwards, the C-arm is brought to the

starting point, the staff is cleared from the theatre, and the

system is operated through a long wire thus reducing the

radiation exposure to the surgical personnel. During a motor-

controlled automatic continuous orbital rotation of the C-arm

around the patient by 190°, a defined number of fluoroscopy

images (optionally 50 or 100) is taken at fixed angular inter-

vals. The “scan” takes about 2 minutes. From these 2D fluo-

roscopy images, a 3D reconstruction of the examination area

is calculated in a connected computer. In this way, a 3D data

cube is produced in the iso-centre of the C-arm with an edge

length of about 12cm. Thus, the system allows for up to two

level (6 screws) checking of the lumbosacral spine at one

session. If more levels are to be checked, the C-arm is repo-

sitioned accordingly and additional scanning is made. The

images are then transferred to the computer workstation

where they are reconstructed into axial, sagittal, and coronal

views of the spinal anatomy. The position of each screw is

then carefully checked by the surgeon. If a breach is identified,

the screw(s) is (are) repositioned and the scanning is repeated.

After all the screws are positioned as appropriate, the surgical

procedure is completed with inserting the rods and metallic

cages in the case of PLIF or TLIF. If PEEK cages are used,

they can be inserted before the 3D-images have been obtained,

since those cages do not produce as significant image distor-

tion as the metallic cages do.

The maximum resolution in the centre of the cube is 0.5mm.

Thus, in experimental studies with calcaneus fractures, investi-

gators were not able to find any differences in the meaningful-

ness of Iso-C3D and CT with a view to the detection of joint

overlaps [4]. Intra-operative experience with 3D portrayal in foot

and ankle surgery was also good. However, Kluba et al. stated

a disadvantage of the Iso-C3D in comparison with a CT for the

imaging of pedicle screws [5]. We share the same experience:

subjectively the quality of the 3D images obtained in our clinical

setting is somewhat worse in comparison with the CT. The

quantity of the implants inserted may considerably impair the

image quality.

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Focus 12917th ArgoSpine Symposium Scientific Book

Although postoperative imaging is often not routinely performed

at every institution in the absence of new neurological deficit,

it was our standard to obtain a CT scan after instrumented spine

surgery. With the use of intraoperative 3D imaging we have

abandoned the routine CT scan [6, 7]. In this way radiation

exposure to patients compared with that resulting from a

standard CT scan might be reduced [8-10].

CONCLUSIONSTo summarize, using 3D fluoroscopy intraoperatively may

help decrease the number of patients who require additional

surgery for repositioning of a misplaced screw identified on

postoperative CT scans. This has important implications for

patient safety as return trips to the operating room increase

morbidity in patients undergoing spinal instrumentation proce-

dures.

/+/ References.a Zausinger S, Scheder B, Uhl E et al. (2009) Intraoperative computed

tomography with integrated navigation system in spinal stabilizations.

Spine 34: 2919-26

z Sugimoto Y, Ito Y, Tomioka M et al. (2010) Clinical accuracy of

three-dimensional fluoroscopy (IsoC-3D)-assisted upper thoracic

pedicle screw insertion. Acta Med Okayama 64: 209-12

e Geerling J, Gösling T, Gösling A,et al. (2008) Navigated pedicle

screw placement: experimental comparison between CT- and 3D

fluoroscopy-based techniques. Comput Aided Surg 13: 157-66

r Kotsianos D, Rock C, Euler E et al. (2001) 3-D imaging with a

mobile surgical image enhancement equipment (ISO-C-3D).

Initial examples of fracture diagnosis of peripheral joints in

comparison with spiral CT and conventional radiology. Unfallchirurg

104: 834-8

t Kluba T, Rühle T, Schulze-Bövingloh A et al (2009) Reproducibility of

readings of ISO C 3D and CT lumbar pedicle screw scans. Rofo 181:

477-82

y Rao G, Brodke DS, Rondina M, Dailey AT (2008) Comparison of

computerized tomography and direct visualization in thoracic pedicle

screw placement. J Neurosurg 97: 223-6

u Garber ST, Bisson EF, Schmidt MH (2012) Comparison of

three-dimensional fluoroscopy versus postoperative computed

tomography for the assessment of accurate screw placement after

instrumented spine surgery. Global Spine J 2: 95-8

i Rampersaud YR, Foley KT, Shen AC et al. (2000) Radiation exposure

to the spine surgeon during fluoroscopically assisted pedicle screw

insertion. Spine 25: 2637-45

o Smith HE, Welsch MD, Sasso RC, Vaccaro AR (2000) Comparison of

radiation exposure in lumbar pedicle screw placement with

fluoroscopy vs computer-assisted image guidance with

intraoperative three-dimensional imaging. J Spinal Cord Med 31:

532-7

p Richards PJ, George J, Metelko M, Brown M (2010) Spine computed

tomography doses and cancer induction. Spine 35: 430-3

ORAL PRESENTATION Day 2/ 15:10>15:20

Pelvic parameters: 2D and 3D measurementsFrédéric SailhanHôpital Cochin, Paris, France

Consideration of pelvic parameters (PP) is crucial in the surgical

planning of degenerative spinal disorders. Sacral Slope (SS),

Pelvic Tilt (PT) and Pelvic Incidence (PI) are commonly assessed

in 2D on a lateral (LAT) X-ray of the spine. We hypothesized

that a mispositioning of the patient (axial rotation of the pelvis)

could lead to errors when measuring PP.

OBJECTIVES1). To evaluate the impact of axial rotation of the pelvis on the

measurement of PP in 2D and 3D.

2) To quantify the difference between PP assessed in 2D and

in 3D in a population of patients with spinal disorders.

�Validation studyA phantom of a human pelvis was imaged in the biplane radi-

ographic system (EOS imaging) with axial rotations ranging from

30° rotation to the right to 30° rotation to the left with increments

of 3°. The LAT image of each acquisition was used to measure

the PP in 2D. A dedicated software was then used to perform

a 3D modeling of the pelvis and to measure PP in 3D. 2D and

3D PP were compared and the impact of axial rotation evalu-

ated.

�Clinical study80 patients (46y) who had a full spine acquisition with the

biplane system were retrospectively analyzed. Two independent

observers measured the pelvic parameters in 2D and 3D on

each patient. Axial rotation of each pelvis was also assessed

with the 3D software. 2D and 3D measurements of the PP were

compared and interobserver reliability of both 2D and 3D

methods were calculated (intraclass correlation coefficient, ICC).

RESULTS�Validation studyDepending on the rotation of the pelvis, 2D values of SS varied

between 45,2° and 49,8° while it remained between 43,8° and

45,1° in 3D. The 2D values of PT varied between -2° and 6°

while it remained between 1,2° and 2,2° in 3D. The 2D values

of PI varied between 45,3° and 53,6° while it remained between

45,5° and 47° in 3D.

�Clinical study22% of the patients were imaged while their pelvis had more

than 5° axial rotation. SS and PT were overestimated in 2D by

nearly 1° (p<0,01) on average. A discrepancy of more than 3°

between 2D and 3D measurement of PI occurred in more than

13% of the cases. ICCs for the interobserver reliability were

over 0,95 for all parameters in 2D and 3D.

The accuracy of the 2D measurement of the pelvic parameters

is affected by mispositioning the patient. It is not the case with

the 3D measurement. Further studies are needed to determine

if the difference is clinically relevant. �

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130 Focus 17th ArgoSpine Symposium Scientific Book

ORAL PRESENTATION Day 2/ 15:20>15:30

Discogenic classification of adult degenerativelumbar scoliosis: semantic, practical andtherapeutic benefitGilles NorotteHôpital de Gap, Gap, France

The semantic, pratical and therapeutic implications of disco-

genic classification of adult degenerative lumbar scoliosis will

be discussed.

The analysis of one hundred files containing two X-rays with at

least a one year follow-up can offer a classification of de-novo

degenerative lumbar scoliosis based on the deforming disco-

genic mechanism.

This classification helps to understand the deformity and its pro-

gression, as well as the geometry and anatomy of the spinal

column and to determine the indications of ALIF stand alone. �

LECTURE Day 2/ 16:10>16:20The EOS System

The radiologist’s point of view.Why is it useful?Did it change my daily practice?L. Mainard-SimardService de Radiologie, Hôpital d’Enfants, Vandœuvre-lès-Nancy, France

Scoliosis is a three-dimensional (3D) spinal deformity, which

according to the Scoliosis Research Society (SRS), needs a truly

3D diagnostic method that can properly diagnose and evaluate

scoliotic deformity in three planes. However, in clinical routine,

diagnosis and follow-up usually rely on conventional 2D X-ray

imaging, resulting in rather significant radiation exposure.

Moreover, 3D reconstructions are not achievable due to image

distorsion at the extremity of the film and photographic results

are often poor, especially in large patients. Even though some

radiographic tables make it possible to digitalize spinal radi-

ographs by simultaneous translation of X-ray tube and receptor

and 3D reconstructions, image quality remains poor with the

same comparatively high radiation dose. Therefore, computed

tomography (CT) scan imaging can be required for truly 3D

evaluation, but its use for routine scoliosis diagnosis is limited

because of the very high radiation dose and the supine position

during imaging.

EOS (EOS imaging, Paris, France) is an imaging system that

permits the simultaneous acquisition of frontal and lateral X-rays

of the whole body or a specified anatomical region. Additionally,

it reduces the dose by around 80-90% compared with a digi-

talized teleradiography system.

The EOS system is designed around a C-shaped vertically

travelling arm suppor ting two image acquisition systems

mounted at right angles. Each is composed of an X-ray tube

and a linear detector. Each X-ray beam is first collimated

as it exits the tube, and reaches the patient as a fan-

shaped beam half a millimeter thick. A few seconds of

scanning are sufficient to simultaneously acquire frontal

and lateral images of either the whole body or a selected

anatomical area.

Deschênes et al. [1] compared spinal frontal and lateral

X-rays in 50 young adults, acquired simultaneously with

EOS and a computed radiography system. They reported a

dose reduction by a factor of up to nine with EOS,

achieving an equivalent or better image quality in 97.2% of

the cases. Dose reduction compared with conventional X-ray

is mainlydue to the elimination of most of the scattered

radiation as a result of the fan-shaped beam geometry.

Dose reduction is also achieved thanks to the amplification

of the signal by the detectors, using the principle of the

multi-wire proportional chamber, based on Georges Charpak’s

work (Nobel Prize in Physics, 1992). Fur thermore, the

adjustable internal gain of the detectors makes it possible

to adapt their response to the patient’s morphology and

to the area to be radiographed, and therefore to obtain

very high contrast images in 30 000 gray levels. Dedicated

software (sterEOS, EOS imaging, Paris, France) uses the

simultaneity and or thogonality of the frontal and lateral

images to generate a three-dimensional model of the patient’s

bone envelope.

The minimally irradiating property of this device has made it

an obvious choice for idiopathic scoliosis management in

children and teenagers requiring repeated radiographs,

Moreover, studies can be performed in a standing weight

bearing position reflecting every day life. And, 3D models

automatically measure the standard frontal and sagittal

balance parameters as well as the axial rotation of each

vertebral level [2]. Hence, the EOS system with its sterEOS

3D reconstruction software is the first routine clinical diagnostic

tool allowing simultaneous visualization of spinal deformities

in an upright standing position in all three planes. �

/+/ References.a Deschenes S, Charron G, Beaudoin G et al. (2010) Diagnostic

imaging of spinal deformities. Reducing patients radiation dose with a

new slot-scanning X-ray imager. Spine 35: 989-94

z Illes T, Tunyogi-Csapo M (2011) Breakthrough in three-dimensional

scoliosis diagnosis : significance of horizontal plane view and

vertebra vectors. Eur Spine J 20: 135-43

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Focus 13117th ArgoSpine Symposium Scientific Book

/+/ AboutLaurence Mainard

Service de Radiologie

Hopital d’Enfants,

Allée du Morvan

54511 Vandœuvre-lès-Nancy, France

Laurence Mainard-Simard graduated from the Université Henri Poincaré

Medical School in Nancy, France. She is a radiologist and has spe-

cialised in paediatric and osteoarticular imaging. She heads the

Radiology Department of the Children’s Hospital at the Nancy University

Hospital Centre in France. She sits on the SFIPP (French –Speaking

Society for Paediatric and Prenatal Imaging) board. Dr. Mainard is a

SFR (French Society of Radiology) member and is an associate member

of SOFOP (French Paediatric Orthopaedic Society). She has published

41 papers in international peer-reviewed journals.

LECTURE Day 2/ 16:20>16:30The EOS System

The surgeon’s point of view.What are the indications, benefits and costs?Cedric Barrey, Gilles PerrinHospital P. Wertheimer, Lyon, France

To optimize the management of lumbar degenerative disorders

and reduce the risk to underestimate the severity of the disease,

it is now well-established that analysis of the sagittal balance

constitutes a crucial step. The evaluation of the sagittal balance

requires full spine standing radiographs to analyze the relative

position of the trunk above the pelvis and the lower limbs.

The EOSTM system was developed in the 90’s by G. Charpak

and J. Dubousset in collaboration with the Laboratory of

Biomechanics of Paris and the Laboratory of Orthopaedic

Imaging of Montréal. It consists of a low radiation imaging

system (8 to 10 times less in comparison to standard 2D X-

rays) allowing for examination of the whole body from head to

feet and providing high-resolution images. In addition, simulta-

neous AP and lateral X-rays of the osteo-articular system offer

the opportunity to obtain 3D reconstructions.

In fact, the EOSTM system represents a fantastic, if not indis-

pensable, tool for the spine surgeon. �

/+/ References.a Dubousset J, Charpak G, Dorion I et al. (2005) Le système EOS,

nouvelle imagerie ostéo-articulaire basse dose en position debout (in

French). Mem Acad Nat Chir 4(4): 22-7

z Barrey C, Jund J, Noseda O, Roussouly P (2007) Sagittal balance of

the pelvis-spine complex and lumbar degenerative diseases. A

comparative study about 85 cases. Eur Spine J 16: 1459-67

e Legaye J, Duval-Beaupère G, Hecquet J, Marty C (1998) Pelvic

incidence: a fundamental pelvic parameter for three-dimensional

regulation of spinal sagittal curves. Eur Spine J 7: 99-103

r Kobayashi T, Atsuta Y, Matsuno T, Takeda N (2004) A longitudinal

study of congruent sagittal spinal alignment in an adult cohort. Spine

29: 671-6

t Roussouly P, Gollogly S, Berthonnaud E, Dimnet J (2005)

Classification of the normal variation in the sagittal alignment of the

human lumbar spine and pelvis in the standing position. Spine 30:

346-53

y Lafage V, Schwab F, Skalli W et al. (2008) Standing balance and

sagittal plane spinal deformity: analysis of spinopelvic and gravity line

parameters. Spine 33: 1572-8

u Korovessis PG, Dimas A, Iliopoulos P, Lambiris E (2002) Correlative

analysis of lateral vertebral radiographic variables and medical

outcomes study short-form health survey: a comparative study in

asymptomatic volunteers versus patients with low back pain. J Spinal

Disord Tech 15: 384-90

i Barrey C, Roussouly P, Perrin G et al. (2011) Sagittal balance

disorders in severe degenerative spine. Can we identify the

compensatory mechanisms? Eur Spine J 20(5): 626-33

o Lazennec JY, Ramare S, Arafati N et al. (2000) Sagittal alignment in

lumbosacral fusion: relations between radiological parameters and

pain. Eur Spine J 9: 47-55

p Vital JM, Gille O, Gangnet N (2004) Equilibre sagittal et applications

cliniques (in French). Rev Rhum 71: 120-8

Figures: Pre- and post-operative assessment of the sagittal balancewith the EOS™ system after lumbar spine fusion surgery (TPOprocedure at L4).

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132 Focus 17th ArgoSpine Symposium Scientific Book

LECTURE Day 2/ 16:30>16:40The EOS System

Clinical applications of the EOS system indiseases of the spine: a 6 years experienceJ.M. Vital, J.S. Steffen, I. Obeid, O. GilleSpinal Unit 1, Tripode University Hospital, Bordeaux, France

The EOS system allows to view the skeletal structure and soft-

tissues of a patient in the standing position, from head to feet,

with 2D and 3D images capturing both the entire spine and the

lower limbs. Its main features are a great imaging accuracy

using a low dose of radiation. Combined with 3D technology, it

enables thorough examination fully comparable to the one

achieved with CT scan except for the dramatically reduced radi-

ation dosage (Fig. 1).

HISTORY OF EOS… [1, 2]Georges Charpak was awarded the Nobel Prize in 1992 for his

work on gaseous X-ray detectors.

The advantage offered by this technique is its high sensitivity

to X-ray which would allow to reduce dramatically radiation

exposure while delivering remarkably detailed imaging.

This device dedicated to the diseases of the locomotor appa-

ratus was developed through the collaboration of multidiscipli-

nary specialists: Profs. Dubousset (orthopaedist) and Kalifa (radi-

ologist) at the St. Vincent de Paul Hospital in Paris, with Profs.

Skalli and Lavaste at the ENSAM (Ecole Nationale des Arts et

Métiers de Paris), but also with Prof. Deguise at the LIO

(Laboratoire d’Imagerie Orthopédique in Montreal).

The system was initially used in clinical practice at the St. Vincent

de Paul Hospital in Paris then in Brussels and Montreal. As from

June 2006, we have adopted this system at the University

Hospital in Bordeaux. It is worth mentioning that the EOS device

is currently used in many places in Europe, USA and all the

continents.

OPERATING PRINCIPLESThe gaseous x-ray detectors enable to convert pressurized gas,

such as xenon, X photons into electrons. These electrons are

amplified with the avalanche effect, that is an increase in the

number of electrons in the electric field detected by a suitable

electronic chain.

The patient who may be examined standing (more rarely sitting),

is placed in the field with a total coverage of 1m70 high and

45 cm wide. Images may be obtained using 2D anteroposte-

rior and lateral orthogonal views. A 3D modelling software

(SterEOS) was developed using semi-automated reconstruction

of T1 to L5 vertebrae and at the level of lower limbs through

calibration on saw bone models and CT scans accuracy ranges

from 0.9 to 1.4 mm [3]. 2D images can be acquired within 20

seconds on average; whereas 3D images are taken by a radi-

ology technician or a practitioner and are obtained after 15 to

30 minutes on average.

Figure 1: Left lumbar scoliosis in 2D and 3D.

Figure 2: Control of head position with a mirror.Figure 3: Hands on clavicles with bad visibility of cervico-thoracicjunction.

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THE ASSETS OF THE EOS SYSTEMIt allows images to be obtained with a very low dose of

radiation (8 to 10 times less than with 2D imaging routinely

used in the surveillance of orthopaedic treatment of scoliosis

associated with serious medical consequences [4], 100 to

1000 times less radiation than with 3D imaging compared

with 3D CT scan system.

The level of imaging accuracy achieved is much higher than

with traditional images allowing satisfactory osseous and above

all soft-tissue assessment.

Simultaneous AP and lateral views are taken and 3D images

are unusually obtained since contrary to CT scan, it allows

imaging of patients in weight-bearing position (Fig. 1).

The EOS system can capture whole body images, with the

exception of very tall patients; in the section dedicated to

disorders affecting sagittal balance, we will see that the

accuracy of knee positioning is sufficient as well as an image

of the mid tibia. The patient is examined in the standing or

seated position (Fig. 3).

The flexion/extension dynamic views that can be obtained

with EOS are very useful in the cervical region allowing to

visualise the cervicothoracic junction.

CLINICAL INDICATIONS AND RESULTSWhatever the disease explored, it must be repeated that high-

accuracy can be achieved in regions usually non-visualised,

such as the cervicothoracic junction.

�Analysis of the sagittal balance [4, 5]It must be performed under reproducible circumstances and

if possible from head-to-feet, i.e. from the external auditory

meati (located near the gravity centre of the cranium) to the

ankles. Patient positioning should be carefully assessed; in

order to avoid changes in the position of the cervical spine,

it is recommended to the patient to keep his/her pupils fixed

and stare at a mirror (Fig. 2). The optimal position may be

with hands resting on clavicles or on malar bones; according

to J.S. Steffen there is no difference in global sagittal balance

between the 2 positions (hands on clavicles/ hands on malar

bones) with improved visualisation of the cervico-thoracic

junction hands on malar bones (Fig. 3-4); patients suffering

from balance disorders can use the anterior surface of the

imager for support. On the other hand if the arms are in flexion

lumbar lordosis automatically increases. In young adults we

can observe difference in sagittal balance between relaxed

and sthenic positions (Fig. 5). It is also of paramount impor-

Figure 4: Comparison of hands on malar bones and hands on clavicles : A) Lateral 2D view of hand on malar bones. B) AP 2D view of hand on malar bones.C) Lateral 2D view of hand on clavicles. D) AP 2D view of hand on clavicles. E) Lateral 3D view of hand on malar bones. F) Lateral 3D view of hand onclavicles. No difference in sagittal balance.

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134 Focus 17th ArgoSpine Symposium Scientific Book

tance to verify and adjust knee positioning: as far as possible,

knee flexion being a frequent automatic gesture to retain one’s

anterior balance (compensatory mechanism), must be adjusted

[6]. The patient should be examined with the knees in exten-

sion to appreciate the true imbalance (Fig. 6). A force platform

may be used to determine the gravity line position. In severe

anterior imbalance, the system’s limitations and its small field-

width in lateral view may lead to non-visualisation of the skull;

we emphasize that in very tall patients, simply checking that

knees are not flexed is made possible with images at the level

of the middle of the tibias.

�Scoliosis anatomical analysisThe EOS system is also well adapted to this pathological pattern,

notably for orthopaedic treatments during growth since the radi-

ation dose has been dramatically reduced/kept at a minimum.

An improved visualisation of the anatomy of the deformity can

be achieved with 3D images, especially dislocations of the lum-

bosacral spine in adult scoliosis, for which 3D reconstructions

obtained with EOS are much sharper with patients in a weight-

bearing standing position than CT scan images taken in a lying

position. The top view of the whole spine and chest provides

valuable and unobserved data on the natural development of

scoliosis. Recently, J.S. Steffen described the 3D anatomy of

hemivertebras (Fig. 7).

�Application to the scoliosis treatmentThe efficacy of the orthopaedic treatment may therefore be

assessed as suggested by Labelle [8]. Several studies (Gille

[9], Ilharreborde [10]) have indeed attested to the efficacy of

surgical treatments using 3D images in terms of angle and

rotation correction.

A detailed comparison of the various methods of osteosynthesis

with regard to angle as well as rotation correction is shown on

Figures 8-9.

�Preoperative calculation in osteotomiesPreoperative measurements prior to transpedicular subtraction

osteotomy can be readily obtained with 2D images: you can

correct the knees flexion and the pelvic tilt with the software

[11] (Fig. 10).

With the 3D images according J.S. Steffen it is possible to rec-

ognize exactly the position and the angulation of the osteotomes

especially in congenital kyphoscoliosis or for asymmetric

osteotomy (Fig. 11-12).

Figure 5: Different sagittal balance in case of relaxed (A) and sthenic(B) position.

Figure 6: Natural position (A) with knees flexion, corrected position (B)with knees extension.

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Focus 13517th ArgoSpine Symposium Scientific Book

Figure 7: 3D control of right T10 hemivertebra.

Figures 8: Pre- and post-operative 3D control of the same scoliosis.

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136 Focus 17th ArgoSpine Symposium Scientific Book

�Cervical spineCervical spine is the last explored part of spine with EOS system

[12]. It is necessary to include the “cranial vertebra” like the

“pelvic vertebra” in the gobal sagittal balance. Cervical spine

is mobile and like an adjustment spindle. It is very important to

control the position of the head with a mirror. External auditive

meati or conducts, sella turcica, Mac Gregor line (parallel to the

bony palate) are the more reproductible cranial landmarks.

Occipito-C2 angle (between Mac Gregor line and C2 inferior

end plate), C2-C7 Cobb angle, C7 slope (between horizontal

line and C7 superior end plate) are the more reproductible

cervical landmarks. In the recent thesis of H. Demezon [13],

C7 slope is the most important angle to determine the cervical

lordosis.

Figure 9: Pre- and post-operative 3D control of operated lumbar scoliosis on lateral and superior view.

Figure 10: Pre-operative calculation with 2D EOS (PT = pelvic tilt, FTA = femoro tobial angle or knee flexion angle).A) Pre-operative lateral view with pelvic retroversion and flexion of the knee. B) Correction of the flexion of the knees (FTA = 0°). C) Correction of thepelvic retroversion (PT = 12°). D) Effect of L3 osteotomy. E) Effect of L1 osteotomy. F) Performed L2 osteotomy.

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Focus 13717th ArgoSpine Symposium Scientific Book

Figure 12: Pre-operative 3D calculation with position of the osteotomes.

Figure 11: Pre-operative 3D calculation (yellow: pre-op, blue: post-op).

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138 Focus 17th ArgoSpine Symposium Scientific Book

CONCLUSIONWith EOS System there is a low radiation exposure for patient

with frequent X-ray follow-up.

We can obtain an excellent 2D image quality of the full skeleton.

Compensatory mechanisms (pelvic retroversion, knees flexion,

hyper-extension of the upper spine) can be recognized and cor-

rected to appreciate the true sagittal imbalance .

With the 3D image precise reconstruction of the deformity and

axial plane reconstruction the pre and post-operative spinal eval-

uation is improved. �

/+/ References.a Kalifa G, Charpak Y, Maccia C et al. (1998) Evaluation of a new

low-dose digital X-ray device: first dosimetric and clinical results in

children. Pediatr Radiol 28(7): 557-61

z Dubousset J, Charpak G, Skalli W et al. (2007) EOS

stereo-radiography system: whole-body simultaneous anteroposterior

and lateral radiographs with very low radiation dose. Rev Chir Ortho

93 (sup 6): 141-3

e Mitulescu A, Skalli W, Mitton D, Deguise J (2002) Three- dimensional

surface rendering reconstruction of scoliotic vertebrae using a non

stereo-corresponding points technique. Euro Spine J 39: 152-8

r Gangnet N, Dumas R, V Pomero et al. (2006) Three-dimensionnal

spinal and pelvic aligment in an asymptomatic population. Spine 31:

507-12

t Steffen JS, Obeid I, Aurouer N et al. (2010) 3D postural balance with

regard to gravity line: an evaluation in the transversal plane on 93

patients and 23 asymptomatic volunteers. Eur Spine J 19: 760-7

y Obeid I, Hauger O, Aunoble S et al. (2011) Global analysis of sagittal

spinal alignment in major deformities : correlation between lack of

lumar lordosis and flexion of the knee. Eur Spine J 20 S5: 681-5

u Barrey C, Roussouly P, Perrin G, Le Huec JC (2011) Sagittal balance

disorders in severe degenerative spine. Can we identify the

compenstory mechanisms? Eur Spine J 20 S5: 634-40

i Labelle H, Dansereau J, Bellefleur C, Poitras B (1996)

Three-dimensional effect of the Boston brace on the thoracic spine

and rib cage. Spine 21: 59-64

o Gille O, Champain N, Benchikh-El-Fegoun A et al. (2007) Reliability of

3D reconstruction of the spine of mild scoliotic patients. Spine 32:

568-73

p Ilharreborde B, Steffen JS, Nectoux E et al. (2011) Angle

measurement reproductibility using EOS 3D reconstructions in

adolescent idiopathic scoliosis treated by posterior instrumentation.

Spine 36 : 1306-13

q Aurouer N, Obeid I, Gille O et al. (2009) Computerized preoperative

planning for correction of sagittal deformity of the spine. Surg Radiol

Anat 30: 781-92

s Rousseau MA, Laporte S, Chavary-Bernier E et al. (2007)

Reproducibility of measuring the shape and three-dimensional

position of cervical vertebrae in upright position using the EOS

stereoradiography system. Spine 32: 2569-72

d Demezon H. Spinal global reference parameters calculated on

asymptomatic subjects with EOS System. Medicine Thesis n° 3042,

Bordeaux (France)

/+/ AboutJean-Marc Vital

Unite de Pathologie Rachidienne

Hôpital Tripode

Place Amélie Raba-Leon

Bordeaux, France

Ph +33 (0)5 56 79 56 79

Upon completing his residency with first class honours in 1980 in

Bordeaux, where he spent his whole career, Jean-Marc Vital was the

recipient of the Gold Medal Award of Surgery. Moreover, he earned a

MD in human biology in the field of anatomy. In 1981 he was appointed

Instructor of anatomy and organogenesis as well as intern in

orthopaedic surgery and traumatology. In the same year, he became

Senior Registrar of the Department run by Prof. Jacques Sénégas. He

also earned the National specialised Diploma in Sports Medicine (CES).

Since 1989, he has been an Intern and University Professor in

orthopaedic and traumatology surgery at the University of Medicine of

Bordeaux as well as Head of the department of spinal diseases and

anatomy laboratory Director at the Paul Broca faculty. His areas of

research encompass spinal growth (neurocentral cartilage) and inter-

vertebral foramen.

As a spine surgeon, Dr Vital has a special interest in spinal deformi-

ties (with particular emphasis on sagittal balance), and in cervical spine

surgery (cervical prostheses and myelopathy).

He has been an active member of several outstanding societies such

as the French Medical College of Anatomy since 1989, the European

Cervical Spine Research Society since 2003, and he is currently

President of the French Spinal Surgery Society (SOFCOT).

Furthermore, he serves in the editorial board of the European Spine

Journal, The Spine and The French Journal of Orthopaedic and

Traumatology Surgery.

LECTURE Day 2/ 16:40>16:50The EOS System

2D, 3D osteotomy planning with the EOSSystemIbrahim Obeid, Jean-Sebastien Steffen, Jean-Marc VitalSpine Unit, Bordeaux University Hospital, Bordeaux, France

The general principle of the planning is to define the surgical

programme in order to obtain PT and CAM overhang as close

as possible to the normal values. The theoretical planning is

based on a trigonometric construction which depends on

numerous factors and is challenging to use in daily practice

without the aid of a software tool.

GENERAL PRINCIPLES OF THE PLANNINGThe first step of the planning is the definition of the normal the-

oretical parameters for a given subject:

– tCAM overhang has to be between -2 cm and 2 cm.

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ç

– Pelvic tilt depends on PI according to the following equation:

tPT = 0.37PI - 7.

– L1–S1 lumbar lordosis depends on PI according to the fol-

lowing equation (Gille O, PhD Thesis, ENSAM, Paris, 2006):

tL1S1 = 0.54PI, 32.56.

The preoperative planning is based on an elementary trigono-

metric construction (Fig. 1). The spine is modelled as a rigid

beam and different osteotomies are simulated in order to nor-

malize the spino-pelvic parameters (PT and CAM overhang).

First, the compensated balance is reproduced by normalizing

the CAM overhang up to the target of -2 cm. Second, if it is

surgically feasible, either the PSO angle or the number of SPO,

TLIF is increased until the PT angulation is normalized.

ADJUSTMENTS OF THE METHODIn case of ankylosis spondylitis or flat back after extensive

arthrodesis, the spine can be considered a solid beam and the

trigonometric construction is a model which is theoretically close

to reality. If the thoracic spine is flexible, like in lumbar degen-

erative kyphosis, this model requires some modifications. The

spontaneous increase of thoracic kyphosis, which is induced

by the correction of lumbar lordosis, has to be considered.

Figure 2 shows that if the thoracic spine is flexible, PT is under-

estimated by the trigonometric construction, thus exposing to

the risk of under correction. In other words, simulated PT (sPT)

is an underestimation of postoperative PT. For this reason, in

this case, the correction targets of the planning are not only

the normalization of the CAM overhang and the PT, but also the

normalization of the L1–S1 lordosis. �

LECTURE Day 2/ 17:00>17:10Intraoperative monitoring and neuromonitoring

Pedicle screw monitoring by pediclestimulating probe in spinal surgeryBurak Akesen1, Müren Mutlu2, Kürsat Kara2,Aysun Yilmazlar3, Ufuk Aydinli21 Dept. of Orthopaedics, University of Uludag, Bursa, Turkey2 Dept. of Orthopaedics, Medicabil Hospital, Bursa, Turkey3 Dept. of Anaesthesiology, Medicabil Hospital, Bursa, Turkey

In lumbar spine, the spinal cord is not at risk of injury but nerve

roots which are responsible for lower extremity function can be

injured by malpositioned pedicle screws. In the present study

(level of evidence: retrospective clinical study, Level III),

we aimed to evaluate the pedicle screw malpositions by pedicle

probe and its use in lumbar spinal surgery cases.

Total number of pedicle screws applied was 126 all of which

were applied to the lumbar spine. All neuromonitoring was per-

formed using transcranial motor-evoked potentials, spontaneous

and triggered electromyography. Pedicle screw positions were

also checked by pedicle probe and fluoroscopy. Eight of the

126 pedicle screws were identified as malpositioned. One screw

position at fluoroscopy images suggested superolateral malpo-

sitioning but normal response. Position of one screw was inter-

preted as accurate by both pedicle stimulation and fluoroscopy

but screw violated the medial wall of the pedicle. Intraoperative

monitoring in adjunct with pedicle stimulation helps to decrease

the risk of neurologic injury. However, pedicle stimulation

response can be normal in lateral, supero-lateral, and even in

medial pedicle wall breech if the screw is not in contact with

the nerve root.

In conclusion, the treating physician should use all available

tools in order to detect screw malposition. �

Figure 1: General principles of the planning are based on atrigonometric construction.A) Sagittal trunk imbalance. The PI is equal to 70° and the PT is equal to62°. According to the PI angle, the PT should be equal to 19° (tPT =0.37PI - 7). B) Normalization of the CAM overhang due to a 10°osteotomy at a given level. C). At the same level, a correction angleequal to 50° would be required to normalize the PT. CAM centre of bothacoustic meati, PT pelvic tilt, PI pelvic incidence, HA hip axis.

Figure 2: Preoperative planning if the thoracic spine is flexible.A) Flat back deformity with sagittal trunk imbalance. IP = 70°, tPT =19°, tL1S1 = 70°. B) Preoperative planning according to the trigono-metric construction: spino-pelvic balance could be restored byincreasing the L1–S1 lordosis to 50° (sL1S1 = 50°). However, this plan isreliable only if the thoracic spine is fused. C) Postoperative results ifthe thoracic spine is flexible: the thoracic kyphosis increases and thePT is greater than the planned value, leading to a compensated balance(postoperative PT [sPT). D) Ideal sagittal balance is restored byincreasing L1–S1 lordosis to its normal theoretical value. CAM centre ofboth acoustic meati, PT pelvic tilt, PI pelvic incidence, L1S1 L1– S1lumbar lordosis, HA hip axis.

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140 Focus 17th ArgoSpine Symposium Scientific Book

LECTURE Day 2/ 17:10>17:20Intraoperative monitoring and neuromonitoring

The value of the PediGuardAndré J. KaelinClinique des Grangettes, Chêne-Bougeries, Switzerland

This presentation will emphasize why PediGuard® is the first

and only handheld disposable drilling instrument for pedicle

screw site preparation. It also features an audio signal to alert

surgeon of potential pedicular or vertebral breaches.

Modern spinal stabilisation by posterior approach is nowadays

based on bone anchorage by the use of transpedicular

screws. From cervical to sacro-iliac area this mean of fixation

is a routine procedure.

Transpedicular fixation is widely applied for a large spectrum

of pathology (degenerative, deformities, fracture and tumour)

with an increasing number of implants. This type of fixation is

used by open approach as well as for minimal invasive and

percutaneous techniques.

Free hand and fluoroscopic control leads to a large number

of misplaced screws (14% to 40%) with a risk of neurological,

vascular or soft tissue lesions and also a less than optimal

bony anchorage and possibility of secondary mobilisation which

can mainly occurs at the ends of the construct.

Navigation with pre-operative imaging or per-operative imaging

(O-Arm) in conjunction with navigation increases the safety of

transpedicular approach but has a high cost.

Neuro-monitoring records motor or sensory pathways, its value

is unique for osteotomies, cord manipulation or correction of

deformities, screw stimulation is only helpful for direct neural

contact.

PediGuard® is an original tool that allows surgeon to use his

habitual technique in order to find a safe path in the pedicle

and insert screws in the bone; PediGuard® used as pedicle

awl is compatible with all other navigation aids (pre- and per-

operative imaging recording) and neuro-monitoring systems.

PediGuard® has 3 diameters (2.5 mm for cervical, 3.2 for

thoracic, 4mm for lumbar), there are strait and curve drill

parts. Cannulated PediGuard® is also available for mini-invasive

and percutaneous procedures.

PediGuard® has 3 parts: 1) the ergonomic handle that fits

the surgeon’s hand increasing accurate aiming; 2) the original

electronic cartridge which includes a stimulator, a receptor

with signal processor, a noise and light generator and the

battery; 3) the drill par t with cutting edges and tip

sensor.

The emitted signal is analysed in real time, the change of elec-

trical conductivity at the tip of the drill induces changes in the

sound pitch and flashing LED cadence.

The volume that triggers changes of noise at the tip of the

drill is a sphere of 2 mm of diameter; it allows preventive

detection of breaches. PediGuard® thus detects bony breaches

before they occur allowing the surgeon to redirect his instru-

ment in its best direction.

Preliminary tests with PediGuard® on animal can detect 96.8%

of breaches when the clinician detects only 60% [1].

In an initial multicentre clinical trial, 11 surgeons performed

521 pedicle drillings on 97 patients. Initially there were 147

drillings with 23 breaches detected. The detection rate of

these breaches was 22/23 for the device compared to 10/23

by the surgeon. In both par ts of the study, 64 breaches

(12.3%) were confirmed on post-operative CT imaging. The

electrical conductivity detection device detected 63 of the

64 breaches (98.4%). The specificity is 99% and the sensitivity

98%. PediGuard® detected 52% of the breaches that were not

detected by the surgeon [2, 3].

In a large prospective series of 694-pedicle screws insertion,

(362 with PediGuard®), Bai achieved an accurate screw place-

ment in 95.9% [4].

In a recent publication, Chaput demonstrates the decreasing

30% fluoroscopic irradiation for the patient and the surgical team

by the use of this instrument with a high performance of screw

positioning: 97.5% [5].

This new pedicle-drilling device, which uses electrical conduc-

tivity differentiation at the tip for assessing bone versus soft

tissue, was used to improve the safe positioning of pedicle

screws; experimental data confirmed the effectiveness of breach

detection.

/+/ References.a Bolger C, Carozzo C, Roger T et al. (2006) A preliminary study of

reliability of impedance measurement to detect iatrogenic initial

pedicle perforation (in the porcine model). Eur Spine J 15: 316-20

z Bolger C, Kelleher MO, McEvoy L et al. (2007) Electrical conductivity

measurement: a new technique to detect iatrogenic initial pedicle

perforation. Eur Spine J 16(11): 1919-24

e Bolger C, Brayda-Bruno M, Kaelin A et al. (2003) A new device to

detect iatrogenic initial vertebral cortex perforation: first clinical results

[abstract]. Eur Spine J 12(3)

r Bai YS, Niu YF, Chen ZQ et al. (2012) Comparison of the pedicle

screws placement between electronic conductivity device and normal

pedicle finder in posterior surgery of scoliosis. J Spinal Disord Tech

[Epub ahead of print]

t Chaput CD, George K, Samdani AF et al. Reduction in radiation

(fluoroscopy) while maintaining safe placement of pedicle screws

during lumbar spine fusion. Spine (Phila PA 1976) 37(21): E1305-9

/+/ AboutAndré J. Kaelin

Paediatric Orthopaedics and Spine Surgeon

Clinique des Grangettes

7, Ch. des Grangettes

1224 Chêne-Bougeries, Switzerland

Prof. Kaelin earned his MD in 1975 and defended his Doctorate thesis

in 1985 at the University of Geneva (Switzerland).

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© Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&JOURNAL - quarterly december 2012 - Vol. 24 - N°3-4

Focus 14117th ArgoSpine Symposium Scientific Book

After his residency in Orthopedic Surgery and Pediatric Surgery in

Geneva, he was a Fellow in the Department of Paediatric Orthopedics

at Trousseau Hospital in Paris He was a Research and Clinical Fellow of

Pediatric Orthopedics at the Children’s Hospital, Harvard Medical School

in Boston in 1982, and in 1986 and also a Fellow at the Alfred I duPont

Hospital for Children, Wilmington (USA).

From 1987 to 2011 he developed the Pediatric Orthopedic Dept at

Children’s Hospital, University Hospital of Geneva (HUG) and became

its first chief and Professor (Geneva Medical School) until his retirement

in December 2011. Prof A J Kaelin was also consultant for Spinal surgery

at the HUG Adult Orthopedic Dept.

His areas of interest encompass spinal deformities in children, safety in

spinal surgery, general paediatric orthopaedics and traumatology, and

bones cysts.

Prof. Kaelin is the Founding Member and Past President of the Swiss

Paediatric Orthopaedic Association, he was also president of the Swiss

Orthopaedic Association (SSOT), of the Swiss Spine Surgeon Association

(SGS) and of the Eupopean Paediatric Orthopaedic Society (EPOS),

member of the board of Société Française d’Orthopédie Pédiatrique

(SOFOP) and Eurospine, Spine Society of Europe (SSE) and member of

several major societies, including the International Society of Orthopaedic

Surgery Traumatology (SICOT), La Société Française de Chirurgie

Orthopédique et Traumatologique (SOFCOT), the Paediatric Orthopaedic

Society of North America (POSNA).

Moreover, he sits in the editorial board of the European Spine Journal,

the Journal of Pediatric Orthopaedics (B), and the Journal of Children’s

Orthopaedics.

Prof. Kaelin authored and co-authored 76 book chapters, of 140 papers

published in national and international journals and of 220 invited lectures.

Prof. Kaelin is also involved in humanitarian activities in underdeveloped

countries.

LECTURE Day 2/ 17:20>17:30Intraoperative monitoring and neuromonitoring

How to use intraoperative neuromonitoringwithout a dedicated neurophysiologist?Kazuhiro HasegawaNiigata Spine Surgery Center, Niigata, Japan

INTRODUCTIONThe greater the complexity of spine surgery is, the greater the

attention to be paid to surgical complication. One of the coun-

termeasures to prevent surgical complication is intraoperative

neuromonitoring, especially multimodal intraoperative monitoring

(MIOM) [2,4-8]. To prepare the monitoring system in the oper-

ative theatre including dedicated neurophysiologists, however,

can be a burden to the hospital. Is it, however, really necessary

to have a sophisticated monitoring system with a neurophysiol-

ogist? NO! We thoroughly tested and approved a simple way

to achieve a neuromonitoring system without any experienced

neurologist [1].

METHODSWe have routinely been using MIOM with 14 channels for cere-

bromuscular evoked-potential (cm-EP) as a motor tract moni-

toring and 2 channels for neurocerebral evoked-potential (nc-EP)

as a sensory tract monitoring [7] using NeuroMaster (Nihon

Kohden Corp, Tokyo) for simultaneous multimodal monitoring.

For quantitative analysis of cm-EP, a stimulus electrode was

placed at the point 2cm anterior and 3cm lateral to Cz [3], and

stimulation was performed by an Electric Stimulator (SNE-4100,

Nihon Kohden Corp, Tokyo) at a voltage of 400V, with an interval

of 500Hz multi-train (5 trains/one stim), averaging the compound

muscle action potentials, filtering threshold of 20 to 1.5kHz, and

recoding time of 100ms. Recording electrodes were pasted over

the contralateral muscles of deltoid, abductor pollicis brevis

(APB), quadriceps femoris (QF), hamstrings, tibialis anterior (TA),

flexor hallucis longus (FHL), and anal sphincters (Anal) (Figure

2). The monitoring was routinely performed at baseline after

anaesthesia was stabilized, before and after decompression,

before and after instrumentation, during correction maneuvers,

and before wound closure, with additional stimulations when the

surgeon considered it is necessary to check neurofunction. The

latency, amplitude and shape of averaged cm-EP were analyzed.

A nc-EP is referred, just in case of cm-EP is not available.

Recording filters were not changed during the whole surgical

procedure for possible trend analysis. Anaesthesia was main-

tained with propofol plus fentanyl under a control of BIS monitor

(A-2000, Nihon Kohden Corp, Tokyo) with a level of 50 to 60.

Muscle relaxation was achieved with a constant infusion of the

agents, and the level of neuromuscular block was monitored by

observing the motor response after stimulation with a train of

four (TOF).

318 cases (mean age: 64.4y, M/F=159/159) with diagnoses of

191 cases of lumbar canal stenosis, 53 cervical spondylotic

myelopathy, 18 spinal deformities, 5 spinal cord tumors, and 51

others during the last year were analyzed. Surgical procedures

were 220 decompressions, 63 decompression & fusion, 18 spinal

correction & fusion, 12 fusion, and 5 tumor excisions. Regarding

alarm criteria, a 30% decrease in amplitude and/or a 10%

increase in latency compared to the immediately prior waves

are use as the significant alarm level. The prerequisite condi-

tion of the appraisal waves was determined as at least one

repeatable and stable wave in the upper or lower extremities

for spinal cord level, and the wave of the muscle belonging to

a nerve at risk by surgical manipulation, e.g. TA in the case of

pedicle screwing to L5, for nerve level. Regarding true positive

case determination, we defined it as a decrease over 30% of

the amplitude compared to base line cm-EP wave and post-

operative deterioration of symptoms.

RESULTSUsing the present MIOM, appraisal waves were obtained in 307

cases (96.4%). The causes of failure of the monitoring were

peeling off of the surface electrodes and change of anaes-

thetic condition due to additional anaesthetic agent. There were

138 patients (44.9%) that showed an increase of amplitude more

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Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6

142 Focus 17th ArgoSpine Symposium Scientific Book

than 50% of the baseline with a concomitant improvement of

the symptom following surgery. There were 292 true negative,

0 false negative, 1 true positive and 14 false positive, thus the

sensitivity of MIOM in this series was calculated at 100% and

the specificity was 95.4%.

DISCUSSIONAll of the preparation and the analyses of the neuromonitoring

were done by a single mechanical engineer (ME), a NEU-

ROMONITORING ASSISTANT, who did not receive any special

education in neuromonitoring. Therefore, it is not necessary to

have a sophisticated monitoring system with a neurophysiolo-

gist. All is needeed is a passion to prevent complication during

surgery, the basic knowledge on neuromonitoring, and a close

cooperation among surgeons, nurses, an anaesthesiologist, and

a neuromonitoring assistant in the operating theatre. The present

method of MION is not a burden to the hospital and has been

demonstrating high cost-performance in our institute. Why not

trying it? �

/+/ References.a Hasegawa K, Koike T, Shimoda H et al. (2011) A 534 cases

prospective study to determine an alarm point in intraoperative

neuromonitoring. J Spine Res 2: 291-6

z Hilibrand AS, Schwartz DM, Sethuraman DV et al. (2004)

Comparison of transcranial electric motor and somatosensory evoked

potential monitoring during cervical spine surgery. J Bone Joint Surg

Am 86: 1248-53

e Matsuda H, Shimazu A (1989) Intraoperative spinal cord monitoring

using electric responses to stimulation of caudal spinal cord or motor

cortex. In: Desmedt JE, editor. Neuromonitoring in surgery.

Amsterdam: Elsevier; pp 175-90

r Nakamae T, Tanaka N, Nakanishi K et al. (2010) Quantitative

assessment of myelopathy patients using motor evoked potentials

produced by transcranial magnetic stimulation. Eur Spine J 19:

685-90

t Nuwer MR, Dawson EG, Carlson LG et al. (1995) Somatosensory

evoked potential spinal cord monitoring reduces neurologic deficits

after scoliosis surgery: results of a large multicenter survey.

Electroencephalogr Clin Neurophysiol 96: 6-11

y Sala F, Palandri G, Basso E et al. (2006) Motor evoked potential

monitoring improves outcome after surgery for intramedullary spinal

cord tumors: a historical control study. Neurosurgery 58: 1129-43

u Sutter M, Eggspuehler A, Grob D et al. (2007) The diagnostic value of

multimodal intraoperative monitoring (MIOM) during spine surgery: a

prospective study of 1017 patients. Eur Spine J 16: S162-70

i Schwartz DM, Auerbach JD, Dormans JP et al. (2007)

Neurophysiological detection of impending spinal cord injury during

scoliosis surgery. J Bone Joint Surg Am 89A: 2440-9