guest speakers lectures, oral presentations, clinical case presentations
TRANSCRIPT
© 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
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).
© 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
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
© 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. �
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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-
© 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 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-
© 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 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.
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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.
© 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 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. �
© 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 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).
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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.
© 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 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.
© 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 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. �
© 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 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
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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).
© 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 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.
© 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 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
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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. �
© 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 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. �
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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! �
© 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 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.
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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.
© 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 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.
Vol. 24 - N°3-4 - quarterly december 2012 - ArgoSpine NEWS&JOURNAL - © Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6
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.
© 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 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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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).
© 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
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