ORIGINAL ARTICLE

Endoscope-assisted microsurgical transoral approachto the anterior craniovertebral junctioncompressive pathologies

Massimiliano Visocchi bull Francesco Doglietto bull Giuseppe Maria Della Pepa bull

Giuseppe Esposito bull Giuseppe La Rocca bull Concezio Di Rocco bull

Giulio Maira bull Eduardo Fernandez

Received 22 September 2010 Revised 25 January 2011 Accepted 7 March 2011 Published online 10 May 2011

Springer-Verlag 2011

Abstract At the present time an update to the classical

microsurgical transoral decompression is strongly provided

by the most recent literature dealing with the introduction of

the endoscopy in spine surgery In this paper we present our

experience on the endoscope-assisted microsurgical trans-

oral approach to anterior craniovertebral junction (CVJ)

compressive pathology We analysed seven patients (3

paediatrics and 4 adults ranging from 6 to 78 years) oper-

ated on for CVJ decompressive procedures using an open

access microsurgical technique neuronavigation and

endoscopy All techniques mentioned were simultaneously

employed Among the endoscopic routes described in the

literature we have preferred the transoral using 30 endo-

scopes In all the cases endoscopy allowed a radical

decompression compared to the microsurgical technique

alone as confirmed intraoperatively with contrast medium

fluoroscopy In conclusion endoscopy represents a useful

complement to the standard microsurgical approach to the

anterior CVJ it provides information for a better decom-

pression with no need for soft palate splitting hard palate

resection or extended maxillotomy Moreover intraopera-

tive fluoroscopy helps to recognize residual compression

Virtually in normal anatomic conditions no surgical limi-

tations exist for endoscopically assisted transoral approach

compared with the pure endonasal and transcervical endo-

scopic approaches In our opinion the endoscope deserves a

role as lsquolsquosupportrsquorsquo to the standard transoral microsurgical

approach since 30 angulated endoscopy significantly

increases the surgical area exposed at the level of the

anterior CVJ

Keywords Transoral Craniovertebral junction Endoscope-assisted Microsurgical

Introduction

In the modern armamentarium of surgical approaches for

anterior craniovertebral junction (CVJ) compressive

pathology the transoral approach is gaining increasing

acceptance because of a better knowledge of the biome-

chanics the pre- and intra-operative dynamic procedures

and the diffusion of endoscopy and new instrumentation

devices for this complex anatomic hinge Neuronavigation

and robotics open further perspectives to the future

developments of this challenging surgery [1]

The following factors have been claimed to influence the

specific treatment of anterior CVJ compressions (1)

reducibility ie whether anatomic alignment can be

restored alleviating the compression (2) direction and

mechanics of the compression (3) aetiology of the com-

pression and (4) presence of ossification centres [2] The

approach to the lesion is dictated by the location and nature

of the compression [2] When preoperative dynamic neu-

roradiological examinations demonstrate that the anterior

CVJ compression is reducible neural decompression may

be obtained by simply reducing the dislocation and by

stabilizing the CVJ with a posterior instrumentation either

with wires claws or screws (lsquolsquofunctional decompressionrsquorsquo)

[3 4] Conversely when the anterior CVJ compression is

irreducible surgical removal of the compression is strongly

suggested by the transoral route [5 6]

M Visocchi (amp) F Doglietto G M Della Pepa G Esposito G La Rocca C Di Rocco G Maira E Fernandez

Istituto di Neurochirurgia Catholic University School

of Medicine Policlinico lsquolsquoA Gemellirsquorsquo

Largo A Gemelli 8 00168 Rome Italy

e-mail mvisocchihotmailcom

123

Eur Spine J (2011) 201518ndash1525

DOI 101007s00586-011-1769-7

Endoscope-assisted and lsquolsquopurersquorsquo endoscopic procedures

for CVJ decompression have been developed as a result of

the experience with the use of the endoscope in trans-

sphenoidal pituitary surgery and approaches to the cervical

spine At the present time an update to the classical

microsurgical transoral decompression is strongly provided

by the most recent literature dealing with the introduction

of the endoscopy in spine surgery

In this paper we present our experience on the micro-

surgical endoscope-assisted transoral approach to anterior

CVJ compressive pathology

Materials and methods

In the last 4 years among 30 patients ranging from 6 to

78 years and operated on for CVJ decompressive proce-

dures seven patients (3 paediatrics and 4 adults) were

treated transorally using an open access microsurgical

technique (OPMI Pentero Carl Zeiss) neuronavigation

(Medtronic StealthStation) and endoscopy (Karl Storz)

(Table 1) All patients underwent magnetic resonance

(MR) computerized tomography (CT) scan and standard

and dynamic X-ray evaluation of the CVJ

The patients were intubated nasally with a fiberoptic

system One patient (1) needed a tracheostomy because of

a huge prevertebral extension of the lesion which occupied

the rinopharynx In supine position the head was placed in

a three-point skull fixation system (Mayfield headrest)

and the neck slightly extended

Surgical procedure

The tubercle of C1 was identified in all but one patient (who

had a huge destructive tumour) with the aid of a neuro-

navigation system Using conventional microsurgery a

midline longitudinal incision on the posterior pharyngeal

wall was performed and the longus colli longus capitis

muscles were mobilized laterally and held in place with

tooth-bladed lateral pharyngeal retractors (CrockardTM

Transoral Instrument Set) to expose the inferior clivus

anterior arch of C1 and C2 vertebral body The anterior

arch of C1 and the odontoid process were removed using a

high-speed drill and Ultrasonic Surgical Aspirator (Sono-

pet Ultrasonic Aspirator) The transverse ligament tecto-

rial membrane any residual ligaments and tumoral tissue

were removed decompressing the CVJ dura mater ade-

quately Contrast injection of Metrizamide into the epidural

space and fluoroscopy as well as endoscopy served to verify

and to complete decompression (Figs 1 2) Then a second

fluoroscopy was performed Closure was obtained by

approximating the mucosal layers with 3-0 vicryl inter-

rupted sutures Prophylactic antibiotics were administered

intraoperatively and postoperatively (Cefazoline 2 gday)

Patients fixed in Halo Vest were transferred to the Intensive

Care Unit where they stayed usually for 48ndash72 h A naso-

gastric tube was held for 1 week to allow healing of the

pharyngeal wound

After 2 weeks all the patients but one (patient no 6 had

a previous internal fixation system) underwent a posterior

screwed instrumentation operation One week later they

were discharged with a soft collar A complete postoper-

ative radiological set (MR imaging CT scan and X-ray

assessment) was obtained before discharge and every

3 months up to the complete bone fusion assessment

which required not more than 6 months X-rays every

month checked the stability of the construct

Results

All the patients harbouring preoperative neurological def-

icits improved after surgery (see Table 1)

The Metrizamide fluoroscopy (Fig 2) and 30 endo-

scope allowed identifying and eliminating any residual

compression not clearly visible using the microscope alone

In all cases a complete CVJ decompression and a good

bone fusion was accomplished as demonstrated by post-

operative X-rays CT scan and MR imaging (Figs 3 4 5)

No dysphagia dysphonia and nasal regurgitation of

fluids were present at the latest follow up

Discussion

The transoral approach to the posterior pharyngeal wall has

been used for years to drain retropharyngeal abscesses but

only in the 1930s such approach was used to treat spinal

abnormalities [7] In 1962 Fang and Ong [8] published the

first series of patients with irreducible atlantoaxial abnor-

malities treated with transoral decompression The high

morbidity and mortality caused poor acceptance of this

approach to treat CVJ abnormalities

The microsurgical anterior approach to the CVJ after

being popularized by Crockard et al [9] has been widely

described for decompression of irreducible extradural

pathology The shortest and most direct route to the ante-

rior aspect of the CVJ is indeed represented by an anterior

approach through the oral cavity The use of the operating

microscope high-speed drill self-retaining mouth retrac-

tors flexible oral endotracheal tubes intraoperative fluo-

roscopy and electrophysiological monitoring has made this

procedure much safer [10] However there are still tech-

nical difficulties with the operating microscope as working

through a narrow opening in a deep cavity To improve

visualization splitting of the soft palate and even resection

Eur Spine J (2011) 201518ndash1525 1519

123

Ta

ble

1S

um

mar

yo

fth

ep

rese

nt

seri

esp

atie

nts

Pat

ien

t

init

ials

Cas

en

o

Ag

e

(sex

)

Pri

mar

yd

isea

seR

adio

log

yP

re-o

pC

1ndash

C2

shif

t(X

-ray

s)

Tre

atm

ent

Po

sto

p

shif

t

(X-r

ays)

Fra

nk

elsc

ale

and

Di

Lo

ren

zo

gra

de

chan

ges

Ex

tern

al

ort

ho

sis

Fo

llo

w-u

p

(mo

nth

s)

SO

12

6(F

)C

VJ

cho

rdo

ma

C0

ndashC

2an

teri

or

com

pre

ssio

nC

VJ

inst

abil

ity

Vir

tual

1

Tra

nso

ral

dec

om

pre

ssio

n

2C

0ndash

C3

red

uct

ion

la

tera

lm

asse

ssc

rew

s

inst

rum

enta

tio

nan

dh

eter

olo

go

us

bo

ne

fusi

on

No

EE

II

Ph

ilad

elp

hia

(1m

on

th)

52

FF

23

3(M

)C

VJ

cho

rdo

ma

C0

ndashC

2an

teri

or

com

pre

ssio

nC

VJ

inst

abil

ity

Vir

tual

1

Tra

nso

ral

dec

om

pre

ssio

n

2

C0

ndashC

3re

du

ctio

n

C2

ped

icle

san

dC

3

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

and

het

ero

log

ou

sb

on

efu

sio

n

No

EE

II

Ph

ilad

elp

hia

(1m

on

th)

46

CO

36

8(F

)R

heu

mat

oid

arth

riti

sA

nte

rio

rC

1ndash

C2

com

pre

ssio

nC

1ndash

C2

inst

abil

ity

[5

mm

1

Tra

nso

ral

dec

om

pre

ssio

n

2

C0

ndashC

2p

edic

les

and

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

29

CL

41

5(M

)D

evel

op

men

tal

ano

mal

yC

0ndash

Cl

C0

ndashC

1an

teri

or

com

pre

ssio

nC

1ndash

C2

inst

abil

ity

[5

mm

1

Tra

nso

ral

dec

om

pre

ssio

n

2

CI

lam

inec

tom

y

C0

do

ub

lev

erti

cal

scre

ws

C2

ped

icle

san

dC

3la

tera

l

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

24

CA

57

8(M

)C

ho

rdo

ma

(ch

on

dro

id)

CV

Jin

stab

ilit

yC

0ndash

C2

ante

rio

rco

mp

ress

ion

Vir

tual

Tra

nso

ral

C1

-od

on

toid

eco

tmy

and

cliv

ecto

my

C0

do

ub

lev

erti

cal

scre

ws

C2

C3

C4

C5

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

11

EA

61

1(M

)Im

pre

ssio

bas

ilar

is

Os

od

on

toid

eum

(Do

wn

s)

C1

ndashC

2an

teri

or

com

pre

ssio

n

Vir

tual

pre

vio

usl

y

do

cum

ente

d

Tra

nso

ral

C1

-od

on

toid

eco

tmy

and

cliv

ecto

my

inC

0ndash

C2

ndashC

3sc

rew

ing

inst

rum

enta

tio

nan

dh

eter

olo

go

us

bo

ne

fusi

on

(pre

vio

usl

yim

pla

nte

d)

No

DE

III

So

ftco

llar

(1m

on

th)

10

RR

71

4(M

)C

2fr

actu

rean

d

dis

loca

tio

n

C2

frac

ture

and

C1

ndashC

2

dis

loca

tio

nw

ith

cerv

ico

med

ull

ary

con

tusi

on

[7

mm

1

Tra

nso

ral

C1

ndashC

2d

eco

mp

ress

ion

2

C0

ndashC

3C

5sc

rew

ing

inst

rum

enta

tio

n

and

het

ero

log

ou

sb

on

efu

sio

n

No

DE

III

So

ftco

llar

(1m

on

th)

7

1520 Eur Spine J (2011) 201518ndash1525

123

of the hard palate with extended maxillotomy are occa-

sionally required These procedures increase operating time

and may result in significant postoperative morbidities such

as velo-pharyngeal incompetence [11]

Menezes et al [12] started his experience on transoral-

transpalatine approach in 1977 and up to 2008 the number

of microsurgical procedures were 732 (280 children)

According to him the anterior transoral-transpalatine

approach has evolved into a safe rapid effective and

direct approach to the anterior irreducible pathology of

the CVJ with minimal morbidity and mortality Recent

attempts aiming to improve visualization with endoscopy

are not shared by Menezes In his opinion intra-operative

fluoroscopy or the use of lsquolsquoStealth technologyrsquorsquo has little

value Menezes concludes that the advantages of the

transoral-transpalatine approach to the CVJ in irreducible

pathology compared with other operative approaches are

that the impinging bony pathology and granulation tissue

Fig 3 Patient 5 a b Preoperative T2-weighted (a) and T1-

weighted after contrast administration MR (b) showing a cystic and

solid lesion with enhancement of the tectorial membrane impinging

the bulbo-cervical junction c Postoperative T2W image showing the

complete removal of the lesion

Fig 1 a Endoscopic view of

the transoral surgical field 1 the

Crockard distractor valves

(lingual pharingeal and soft

palate) 2 on the left the bone

ultrasonic surgical aspirator

(Sonopet) 3 on the right the

diamond burr drill b Higher

magnification showing 1 the

dura after removal of the

tectorial membrane 2 the bone

ultrasonic surgical aspirator

(Sonopet) while removing the

inferior border of the clivus

Fig 2 Patient 3

a Intraoperative fluoroscopy

with Metrizamide before

endoscopy showing a contrast

defect at the level of right upper

corner of the radiograph

b Intraoperative fluoroscopy

after endoscopy showing the

decompression of the right

upper corner

Eur Spine J (2011) 201518ndash1525 1521

123

that accompanies chronic instability is easily accessible

[2] the patient is placed in the extended position as

opposed to the flexed position thus decreasing the

angulation on the brain stem during surgery and surgery

is performed through the avascular median raphe and

through the clivus [12]

In contrary to Menezesrsquo experience some papers

claimed significant oropharyngeal morbidity from splitting

the soft palate associated with the transoral approach Jones

reported that oropharyngeal complications occurred in

154 of patients who did not undergo splitting of the soft

palate as compared with 75 in the split soft palate group

The author concluded that this procedure should be dis-

continued where it is not absolutely necessary [13]

Recently increased diffusion in the use of the endo-

scope for transsphenoidal pituitary surgery led some stud-

ies to explore the possibility of applying the endoscopic

approach in the surgical treatment of skull base lesions

other than pituitary tumours

Endoscopic-assisted procedures endonasal

In recent years some papers have reported anatomical

studies and surgical experience in the endoscopic endona-

sal approach to different areas of the midline skull base

from the olfactory groove to the CVJ [14]

In 2002 Alfieri et al [15] performed a cadaveric study on

totally transnasal endoscopic odontoidectomy through one

or two nostrils following Jhorsquos endonasal paraseptal tech-

nique Rodlens endoscopes 27 or 4 mm in diameter 18 cm

in length with 0 30 and 70 lenses were used The sur-

gical landmarks leading to the CVJ were the inferior margin

of the middle turbinate nasopharynx and the Eustachian

tubes The nasopharynx was readily identified following the

inferior margin of the middle turbinate The line drawn

between the Eustachian tubes indicated the juncture between

the clivus and atlas The author concluded that lsquolsquohellip contrary

to a conventional transoral approach this endoscopic en-

donasal approach provides unlimited access to the midline

Fig 4 Patient 3

a Preoperative T2-weighted MR

showing a lsquolsquoballoon likersquorsquo

rheumatoid inflammatory

pannus impinging the

bulbo-cervical junction

b Postoperative T2-weighted

MR showing the complete

neural decompression

Fig 5 Patient 2

a Preoperative T1-weighted MR

documenting a chordoma

extending from the oropharinx

to the posterior cranial fossa and

from the clivus to C2

b Postoperative T1-weighted

MR showing removal of the

lesion and decompression of the

brainstem

1522 Eur Spine J (2011) 201518ndash1525

123

clivus and a potential of carrying out surgical decompression

at the ventral craniocervical junction without adding C1-2

instabilityrsquorsquo [15] Three years later Cavallo et al [16] con-

firmed such an observation on cadaveric study

In 2005 Kassam et al [17] operated on a 73-year old

woman affected by rheumatoid arthritis resecting the

odontoid with a transnasal endoscopic approach Kassam

recommended the following equipment (1) navigation

system (2) a zero degree endoscope (3) long angled en-

donasal drill (4) ultrasonic aspirator (5) bayoneted hand-

held microinstrumentation On one side this author

recognized that lsquolsquothe transoral approach remains the lsquolsquogold

standardrsquorsquo but lsquolsquohellip the transnasal endoscopic approach

being above the level of soft palate should expose to a

lower degree of bacterial contaminationrsquorsquo

In 2007 Messina et al [14] concluded that the endo-

scopic endonasal approach like that transoral provides a

direct route to the CVJ but probably with less morbidity

In 2009 Kassam et al [18] published the concept of the

lsquolsquoNasopalatine linersquorsquo (NPL) that is the line connecting the

inferior margin of the nasal bone anteriorly and the border

of the hard palate posteriorly in the midsagittal plane The

intersection of this line with the vertebral column indicates

the inferior limit of the approach Therefore the maximal

extent of inferior dissection with an endoscopic endonasal

approach can be predicted with the NPL traced on the

preoperative radiological study In conclusion this

approach is recommended in selected cases as a valid

alternative to the transoral microscopic approach to resect

the odontoid process of C2 and should be performed by

surgeons very skilled in endoscopic endonasal surgery and

in endoscopic cadaver-dissections [14 17]

Endoscopic-assisted procedures transcervical

In 2007 Wolinsky et al [19 20] described the endoscopic

transcervical approach to the anterior CVJ as an alternative

to the transpharyngeal approaches to avoid risks like con-

tamination with oral flora and infection poor pharyngeal

healing and meningitis if the dura is transgressed More-

over the transcervical exposure is familiar to neurosur-

geons its trajectory allows treatment of deep-seated basilar

invaginations and the postoperative time of recovery is

shorter Patients are able to ingest food orally soon after

surgery Using this approach the anterior arch of C1 can be

spared but the removal of the odontoid process of C2

results too oblique and partial To gain access to the lower

clivus the anterior arch of C1 has to be removed but the

angle of attack makes this portion of dissection very dif-

ficult or impossible

In our opinion in cases of impressio basilaris or other

high pathologies this approach could be uncomfortable and

challenging

Endoscopic-assisted procedures transoral

The 30 endoscope has been proposed for transoral

approach to avoid splitting of the soft palate or further

extensions ie splitting of the hard palate and extended

maxilla-mandibulotomy [21] Using the endoscope the

operator is able to look in all directions with superior illu-

mination reaching abnormalities as high as the midclivus

In a cadaveric study the surgical volume gained by this

approach was quantified The surgical area exposed over the

posterior pharyngeal wall is significantly improved using

the endoscope (6065 plusmn 1274 mm3) compared with the

operating microscope (4257 plusmn 1008 mm3) without any

compromise of surgical freedom (P 005) The extent of

the clivus exposed is significantly improved with the

endoscope (95 plusmn 07 mm) compared with the operating

microscope (20 plusmn 04 mm) (P 005) [20] Then it was

well demonstrated that with an angled-lens endoscope is

possible to approach the anterior CVJ transorally improv-

ing also the exposure of the clivus without splitting the soft

palate and without compromise of surgical freedom

Tubular retractor-assisted microsurgical retropharyngeal

approach

Beside the classic transoral approach the use of an alter-

native anterior extraoral approach in upper cervical surgery

has been strongly advocated to avoid the previous descri-

bed complications A minimally invasive window below

the hypoglossal and the superior laryngeal nerves has been

proposed for the use of tubular retractor system (Metrx)

along with the microscope Better proximal exposure has

also made possible by angling an end-beveled tubular

retractor on the mandible without undue compression on

the hypoglossal and superior laryngeal nerves the marginal

mandibular branch of the facial nerve and the sub-

mandibular gland [22] Although only cadaveric study is

available in the indexed literature only anecdotal reports

are available in clinical practice so far

Image guidance

Image guidance is a useful tool to visually reconstruct the

magnified three-dimensional anatomy imaging allowing

inspection of the anatomic images in multiple recon-

structed views permitting a better orientation during the

surgical procedure [23] Although the error associated with

spinal shift is not completely eliminated the calculated

accuracy is less than 1 mm [24]

As far as we know the present paper is the first and only

paper on the simultaneous use of all the techniques men-

tioned ie endoscope microscope neuronavigation Obvi-

ously a longer follow-up does not exist so far

Eur Spine J (2011) 201518ndash1525 1523

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

Endoscope-assisted and lsquolsquopurersquorsquo endoscopic procedures

for CVJ decompression have been developed as a result of

the experience with the use of the endoscope in trans-

sphenoidal pituitary surgery and approaches to the cervical

spine At the present time an update to the classical

microsurgical transoral decompression is strongly provided

by the most recent literature dealing with the introduction

of the endoscopy in spine surgery

In this paper we present our experience on the micro-

surgical endoscope-assisted transoral approach to anterior

CVJ compressive pathology

Materials and methods

In the last 4 years among 30 patients ranging from 6 to

78 years and operated on for CVJ decompressive proce-

dures seven patients (3 paediatrics and 4 adults) were

treated transorally using an open access microsurgical

technique (OPMI Pentero Carl Zeiss) neuronavigation

(Medtronic StealthStation) and endoscopy (Karl Storz)

(Table 1) All patients underwent magnetic resonance

(MR) computerized tomography (CT) scan and standard

and dynamic X-ray evaluation of the CVJ

The patients were intubated nasally with a fiberoptic

system One patient (1) needed a tracheostomy because of

a huge prevertebral extension of the lesion which occupied

the rinopharynx In supine position the head was placed in

a three-point skull fixation system (Mayfield headrest)

and the neck slightly extended

Surgical procedure

The tubercle of C1 was identified in all but one patient (who

had a huge destructive tumour) with the aid of a neuro-

navigation system Using conventional microsurgery a

midline longitudinal incision on the posterior pharyngeal

wall was performed and the longus colli longus capitis

muscles were mobilized laterally and held in place with

tooth-bladed lateral pharyngeal retractors (CrockardTM

Transoral Instrument Set) to expose the inferior clivus

anterior arch of C1 and C2 vertebral body The anterior

arch of C1 and the odontoid process were removed using a

high-speed drill and Ultrasonic Surgical Aspirator (Sono-

pet Ultrasonic Aspirator) The transverse ligament tecto-

rial membrane any residual ligaments and tumoral tissue

were removed decompressing the CVJ dura mater ade-

quately Contrast injection of Metrizamide into the epidural

space and fluoroscopy as well as endoscopy served to verify

and to complete decompression (Figs 1 2) Then a second

fluoroscopy was performed Closure was obtained by

approximating the mucosal layers with 3-0 vicryl inter-

rupted sutures Prophylactic antibiotics were administered

intraoperatively and postoperatively (Cefazoline 2 gday)

Patients fixed in Halo Vest were transferred to the Intensive

Care Unit where they stayed usually for 48ndash72 h A naso-

gastric tube was held for 1 week to allow healing of the

pharyngeal wound

After 2 weeks all the patients but one (patient no 6 had

a previous internal fixation system) underwent a posterior

screwed instrumentation operation One week later they

were discharged with a soft collar A complete postoper-

ative radiological set (MR imaging CT scan and X-ray

assessment) was obtained before discharge and every

3 months up to the complete bone fusion assessment

which required not more than 6 months X-rays every

month checked the stability of the construct

Results

All the patients harbouring preoperative neurological def-

icits improved after surgery (see Table 1)

The Metrizamide fluoroscopy (Fig 2) and 30 endo-

scope allowed identifying and eliminating any residual

compression not clearly visible using the microscope alone

In all cases a complete CVJ decompression and a good

bone fusion was accomplished as demonstrated by post-

operative X-rays CT scan and MR imaging (Figs 3 4 5)

No dysphagia dysphonia and nasal regurgitation of

fluids were present at the latest follow up

Discussion

The transoral approach to the posterior pharyngeal wall has

been used for years to drain retropharyngeal abscesses but

only in the 1930s such approach was used to treat spinal

abnormalities [7] In 1962 Fang and Ong [8] published the

first series of patients with irreducible atlantoaxial abnor-

malities treated with transoral decompression The high

morbidity and mortality caused poor acceptance of this

approach to treat CVJ abnormalities

The microsurgical anterior approach to the CVJ after

being popularized by Crockard et al [9] has been widely

described for decompression of irreducible extradural

pathology The shortest and most direct route to the ante-

rior aspect of the CVJ is indeed represented by an anterior

approach through the oral cavity The use of the operating

microscope high-speed drill self-retaining mouth retrac-

tors flexible oral endotracheal tubes intraoperative fluo-

roscopy and electrophysiological monitoring has made this

procedure much safer [10] However there are still tech-

nical difficulties with the operating microscope as working

through a narrow opening in a deep cavity To improve

visualization splitting of the soft palate and even resection

Eur Spine J (2011) 201518ndash1525 1519

123

Ta

ble

1S

um

mar

yo

fth

ep

rese

nt

seri

esp

atie

nts

Pat

ien

t

init

ials

Cas

en

o

Ag

e

(sex

)

Pri

mar

yd

isea

seR

adio

log

yP

re-o

pC

1ndash

C2

shif

t(X

-ray

s)

Tre

atm

ent

Po

sto

p

shif

t

(X-r

ays)

Fra

nk

elsc

ale

and

Di

Lo

ren

zo

gra

de

chan

ges

Ex

tern

al

ort

ho

sis

Fo

llo

w-u

p

(mo

nth

s)

SO

12

6(F

)C

VJ

cho

rdo

ma

C0

ndashC

2an

teri

or

com

pre

ssio

nC

VJ

inst

abil

ity

Vir

tual

1

Tra

nso

ral

dec

om

pre

ssio

n

2C

0ndash

C3

red

uct

ion

la

tera

lm

asse

ssc

rew

s

inst

rum

enta

tio

nan

dh

eter

olo

go

us

bo

ne

fusi

on

No

EE

II

Ph

ilad

elp

hia

(1m

on

th)

52

FF

23

3(M

)C

VJ

cho

rdo

ma

C0

ndashC

2an

teri

or

com

pre

ssio

nC

VJ

inst

abil

ity

Vir

tual

1

Tra

nso

ral

dec

om

pre

ssio

n

2

C0

ndashC

3re

du

ctio

n

C2

ped

icle

san

dC

3

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

and

het

ero

log

ou

sb

on

efu

sio

n

No

EE

II

Ph

ilad

elp

hia

(1m

on

th)

46

CO

36

8(F

)R

heu

mat

oid

arth

riti

sA

nte

rio

rC

1ndash

C2

com

pre

ssio

nC

1ndash

C2

inst

abil

ity

[5

mm

1

Tra

nso

ral

dec

om

pre

ssio

n

2

C0

ndashC

2p

edic

les

and

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

29

CL

41

5(M

)D

evel

op

men

tal

ano

mal

yC

0ndash

Cl

C0

ndashC

1an

teri

or

com

pre

ssio

nC

1ndash

C2

inst

abil

ity

[5

mm

1

Tra

nso

ral

dec

om

pre

ssio

n

2

CI

lam

inec

tom

y

C0

do

ub

lev

erti

cal

scre

ws

C2

ped

icle

san

dC

3la

tera

l

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

24

CA

57

8(M

)C

ho

rdo

ma

(ch

on

dro

id)

CV

Jin

stab

ilit

yC

0ndash

C2

ante

rio

rco

mp

ress

ion

Vir

tual

Tra

nso

ral

C1

-od

on

toid

eco

tmy

and

cliv

ecto

my

C0

do

ub

lev

erti

cal

scre

ws

C2

C3

C4

C5

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

11

EA

61

1(M

)Im

pre

ssio

bas

ilar

is

Os

od

on

toid

eum

(Do

wn

s)

C1

ndashC

2an

teri

or

com

pre

ssio

n

Vir

tual

pre

vio

usl

y

do

cum

ente

d

Tra

nso

ral

C1

-od

on

toid

eco

tmy

and

cliv

ecto

my

inC

0ndash

C2

ndashC

3sc

rew

ing

inst

rum

enta

tio

nan

dh

eter

olo

go

us

bo

ne

fusi

on

(pre

vio

usl

yim

pla

nte

d)

No

DE

III

So

ftco

llar

(1m

on

th)

10

RR

71

4(M

)C

2fr

actu

rean

d

dis

loca

tio

n

C2

frac

ture

and

C1

ndashC

2

dis

loca

tio

nw

ith

cerv

ico

med

ull

ary

con

tusi

on

[7

mm

1

Tra

nso

ral

C1

ndashC

2d

eco

mp

ress

ion

2

C0

ndashC

3C

5sc

rew

ing

inst

rum

enta

tio

n

and

het

ero

log

ou

sb

on

efu

sio

n

No

DE

III

So

ftco

llar

(1m

on

th)

7

1520 Eur Spine J (2011) 201518ndash1525

123

of the hard palate with extended maxillotomy are occa-

sionally required These procedures increase operating time

and may result in significant postoperative morbidities such

as velo-pharyngeal incompetence [11]

Menezes et al [12] started his experience on transoral-

transpalatine approach in 1977 and up to 2008 the number

of microsurgical procedures were 732 (280 children)

According to him the anterior transoral-transpalatine

approach has evolved into a safe rapid effective and

direct approach to the anterior irreducible pathology of

the CVJ with minimal morbidity and mortality Recent

attempts aiming to improve visualization with endoscopy

are not shared by Menezes In his opinion intra-operative

fluoroscopy or the use of lsquolsquoStealth technologyrsquorsquo has little

value Menezes concludes that the advantages of the

transoral-transpalatine approach to the CVJ in irreducible

pathology compared with other operative approaches are

that the impinging bony pathology and granulation tissue

Fig 3 Patient 5 a b Preoperative T2-weighted (a) and T1-

weighted after contrast administration MR (b) showing a cystic and

solid lesion with enhancement of the tectorial membrane impinging

the bulbo-cervical junction c Postoperative T2W image showing the

complete removal of the lesion

Fig 1 a Endoscopic view of

the transoral surgical field 1 the

Crockard distractor valves

(lingual pharingeal and soft

palate) 2 on the left the bone

ultrasonic surgical aspirator

(Sonopet) 3 on the right the

diamond burr drill b Higher

magnification showing 1 the

dura after removal of the

tectorial membrane 2 the bone

ultrasonic surgical aspirator

(Sonopet) while removing the

inferior border of the clivus

Fig 2 Patient 3

a Intraoperative fluoroscopy

with Metrizamide before

endoscopy showing a contrast

defect at the level of right upper

corner of the radiograph

b Intraoperative fluoroscopy

after endoscopy showing the

decompression of the right

upper corner

Eur Spine J (2011) 201518ndash1525 1521

123

that accompanies chronic instability is easily accessible

[2] the patient is placed in the extended position as

opposed to the flexed position thus decreasing the

angulation on the brain stem during surgery and surgery

is performed through the avascular median raphe and

through the clivus [12]

In contrary to Menezesrsquo experience some papers

claimed significant oropharyngeal morbidity from splitting

the soft palate associated with the transoral approach Jones

reported that oropharyngeal complications occurred in

154 of patients who did not undergo splitting of the soft

palate as compared with 75 in the split soft palate group

The author concluded that this procedure should be dis-

continued where it is not absolutely necessary [13]

Recently increased diffusion in the use of the endo-

scope for transsphenoidal pituitary surgery led some stud-

ies to explore the possibility of applying the endoscopic

approach in the surgical treatment of skull base lesions

other than pituitary tumours

Endoscopic-assisted procedures endonasal

In recent years some papers have reported anatomical

studies and surgical experience in the endoscopic endona-

sal approach to different areas of the midline skull base

from the olfactory groove to the CVJ [14]

In 2002 Alfieri et al [15] performed a cadaveric study on

totally transnasal endoscopic odontoidectomy through one

or two nostrils following Jhorsquos endonasal paraseptal tech-

nique Rodlens endoscopes 27 or 4 mm in diameter 18 cm

in length with 0 30 and 70 lenses were used The sur-

gical landmarks leading to the CVJ were the inferior margin

of the middle turbinate nasopharynx and the Eustachian

tubes The nasopharynx was readily identified following the

inferior margin of the middle turbinate The line drawn

between the Eustachian tubes indicated the juncture between

the clivus and atlas The author concluded that lsquolsquohellip contrary

to a conventional transoral approach this endoscopic en-

donasal approach provides unlimited access to the midline

Fig 4 Patient 3

a Preoperative T2-weighted MR

showing a lsquolsquoballoon likersquorsquo

rheumatoid inflammatory

pannus impinging the

bulbo-cervical junction

b Postoperative T2-weighted

MR showing the complete

neural decompression

Fig 5 Patient 2

a Preoperative T1-weighted MR

documenting a chordoma

extending from the oropharinx

to the posterior cranial fossa and

from the clivus to C2

b Postoperative T1-weighted

MR showing removal of the

lesion and decompression of the

brainstem

1522 Eur Spine J (2011) 201518ndash1525

123

clivus and a potential of carrying out surgical decompression

at the ventral craniocervical junction without adding C1-2

instabilityrsquorsquo [15] Three years later Cavallo et al [16] con-

firmed such an observation on cadaveric study

In 2005 Kassam et al [17] operated on a 73-year old

woman affected by rheumatoid arthritis resecting the

odontoid with a transnasal endoscopic approach Kassam

recommended the following equipment (1) navigation

system (2) a zero degree endoscope (3) long angled en-

donasal drill (4) ultrasonic aspirator (5) bayoneted hand-

held microinstrumentation On one side this author

recognized that lsquolsquothe transoral approach remains the lsquolsquogold

standardrsquorsquo but lsquolsquohellip the transnasal endoscopic approach

being above the level of soft palate should expose to a

lower degree of bacterial contaminationrsquorsquo

In 2007 Messina et al [14] concluded that the endo-

scopic endonasal approach like that transoral provides a

direct route to the CVJ but probably with less morbidity

In 2009 Kassam et al [18] published the concept of the

lsquolsquoNasopalatine linersquorsquo (NPL) that is the line connecting the

inferior margin of the nasal bone anteriorly and the border

of the hard palate posteriorly in the midsagittal plane The

intersection of this line with the vertebral column indicates

the inferior limit of the approach Therefore the maximal

extent of inferior dissection with an endoscopic endonasal

approach can be predicted with the NPL traced on the

preoperative radiological study In conclusion this

approach is recommended in selected cases as a valid

alternative to the transoral microscopic approach to resect

the odontoid process of C2 and should be performed by

surgeons very skilled in endoscopic endonasal surgery and

in endoscopic cadaver-dissections [14 17]

Endoscopic-assisted procedures transcervical

In 2007 Wolinsky et al [19 20] described the endoscopic

transcervical approach to the anterior CVJ as an alternative

to the transpharyngeal approaches to avoid risks like con-

tamination with oral flora and infection poor pharyngeal

healing and meningitis if the dura is transgressed More-

over the transcervical exposure is familiar to neurosur-

geons its trajectory allows treatment of deep-seated basilar

invaginations and the postoperative time of recovery is

shorter Patients are able to ingest food orally soon after

surgery Using this approach the anterior arch of C1 can be

spared but the removal of the odontoid process of C2

results too oblique and partial To gain access to the lower

clivus the anterior arch of C1 has to be removed but the

angle of attack makes this portion of dissection very dif-

ficult or impossible

In our opinion in cases of impressio basilaris or other

high pathologies this approach could be uncomfortable and

challenging

Endoscopic-assisted procedures transoral

The 30 endoscope has been proposed for transoral

approach to avoid splitting of the soft palate or further

extensions ie splitting of the hard palate and extended

maxilla-mandibulotomy [21] Using the endoscope the

operator is able to look in all directions with superior illu-

mination reaching abnormalities as high as the midclivus

In a cadaveric study the surgical volume gained by this

approach was quantified The surgical area exposed over the

posterior pharyngeal wall is significantly improved using

the endoscope (6065 plusmn 1274 mm3) compared with the

operating microscope (4257 plusmn 1008 mm3) without any

compromise of surgical freedom (P 005) The extent of

the clivus exposed is significantly improved with the

endoscope (95 plusmn 07 mm) compared with the operating

microscope (20 plusmn 04 mm) (P 005) [20] Then it was

well demonstrated that with an angled-lens endoscope is

possible to approach the anterior CVJ transorally improv-

ing also the exposure of the clivus without splitting the soft

palate and without compromise of surgical freedom

Tubular retractor-assisted microsurgical retropharyngeal

approach

Beside the classic transoral approach the use of an alter-

native anterior extraoral approach in upper cervical surgery

has been strongly advocated to avoid the previous descri-

bed complications A minimally invasive window below

the hypoglossal and the superior laryngeal nerves has been

proposed for the use of tubular retractor system (Metrx)

along with the microscope Better proximal exposure has

also made possible by angling an end-beveled tubular

retractor on the mandible without undue compression on

the hypoglossal and superior laryngeal nerves the marginal

mandibular branch of the facial nerve and the sub-

mandibular gland [22] Although only cadaveric study is

available in the indexed literature only anecdotal reports

are available in clinical practice so far

Image guidance

Image guidance is a useful tool to visually reconstruct the

magnified three-dimensional anatomy imaging allowing

inspection of the anatomic images in multiple recon-

structed views permitting a better orientation during the

surgical procedure [23] Although the error associated with

spinal shift is not completely eliminated the calculated

accuracy is less than 1 mm [24]

As far as we know the present paper is the first and only

paper on the simultaneous use of all the techniques men-

tioned ie endoscope microscope neuronavigation Obvi-

ously a longer follow-up does not exist so far

Eur Spine J (2011) 201518ndash1525 1523

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

Ta

ble

1S

um

mar

yo

fth

ep

rese

nt

seri

esp

atie

nts

Pat

ien

t

init

ials

Cas

en

o

Ag

e

(sex

)

Pri

mar

yd

isea

seR

adio

log

yP

re-o

pC

1ndash

C2

shif

t(X

-ray

s)

Tre

atm

ent

Po

sto

p

shif

t

(X-r

ays)

Fra

nk

elsc

ale

and

Di

Lo

ren

zo

gra

de

chan

ges

Ex

tern

al

ort

ho

sis

Fo

llo

w-u

p

(mo

nth

s)

SO

12

6(F

)C

VJ

cho

rdo

ma

C0

ndashC

2an

teri

or

com

pre

ssio

nC

VJ

inst

abil

ity

Vir

tual

1

Tra

nso

ral

dec

om

pre

ssio

n

2C

0ndash

C3

red

uct

ion

la

tera

lm

asse

ssc

rew

s

inst

rum

enta

tio

nan

dh

eter

olo

go

us

bo

ne

fusi

on

No

EE

II

Ph

ilad

elp

hia

(1m

on

th)

52

FF

23

3(M

)C

VJ

cho

rdo

ma

C0

ndashC

2an

teri

or

com

pre

ssio

nC

VJ

inst

abil

ity

Vir

tual

1

Tra

nso

ral

dec

om

pre

ssio

n

2

C0

ndashC

3re

du

ctio

n

C2

ped

icle

san

dC

3

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

and

het

ero

log

ou

sb

on

efu

sio

n

No

EE

II

Ph

ilad

elp

hia

(1m

on

th)

46

CO

36

8(F

)R

heu

mat

oid

arth

riti

sA

nte

rio

rC

1ndash

C2

com

pre

ssio

nC

1ndash

C2

inst

abil

ity

[5

mm

1

Tra

nso

ral

dec

om

pre

ssio

n

2

C0

ndashC

2p

edic

les

and

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

29

CL

41

5(M

)D

evel

op

men

tal

ano

mal

yC

0ndash

Cl

C0

ndashC

1an

teri

or

com

pre

ssio

nC

1ndash

C2

inst

abil

ity

[5

mm

1

Tra

nso

ral

dec

om

pre

ssio

n

2

CI

lam

inec

tom

y

C0

do

ub

lev

erti

cal

scre

ws

C2

ped

icle

san

dC

3la

tera

l

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

24

CA

57

8(M

)C

ho

rdo

ma

(ch

on

dro

id)

CV

Jin

stab

ilit

yC

0ndash

C2

ante

rio

rco

mp

ress

ion

Vir

tual

Tra

nso

ral

C1

-od

on

toid

eco

tmy

and

cliv

ecto

my

C0

do

ub

lev

erti

cal

scre

ws

C2

C3

C4

C5

late

ral

mas

ses

scre

ws

inst

rum

enta

tio

n

No

DE

III

So

ftco

llar

(1m

on

th)

11

EA

61

1(M

)Im

pre

ssio

bas

ilar

is

Os

od

on

toid

eum

(Do

wn

s)

C1

ndashC

2an

teri

or

com

pre

ssio

n

Vir

tual

pre

vio

usl

y

do

cum

ente

d

Tra

nso

ral

C1

-od

on

toid

eco

tmy

and

cliv

ecto

my

inC

0ndash

C2

ndashC

3sc

rew

ing

inst

rum

enta

tio

nan

dh

eter

olo

go

us

bo

ne

fusi

on

(pre

vio

usl

yim

pla

nte

d)

No

DE

III

So

ftco

llar

(1m

on

th)

10

RR

71

4(M

)C

2fr

actu

rean

d

dis

loca

tio

n

C2

frac

ture

and

C1

ndashC

2

dis

loca

tio

nw

ith

cerv

ico

med

ull

ary

con

tusi

on

[7

mm

1

Tra

nso

ral

C1

ndashC

2d

eco

mp

ress

ion

2

C0

ndashC

3C

5sc

rew

ing

inst

rum

enta

tio

n

and

het

ero

log

ou

sb

on

efu

sio

n

No

DE

III

So

ftco

llar

(1m

on

th)

7

1520 Eur Spine J (2011) 201518ndash1525

123

of the hard palate with extended maxillotomy are occa-

sionally required These procedures increase operating time

and may result in significant postoperative morbidities such

as velo-pharyngeal incompetence [11]

Menezes et al [12] started his experience on transoral-

transpalatine approach in 1977 and up to 2008 the number

of microsurgical procedures were 732 (280 children)

According to him the anterior transoral-transpalatine

approach has evolved into a safe rapid effective and

direct approach to the anterior irreducible pathology of

the CVJ with minimal morbidity and mortality Recent

attempts aiming to improve visualization with endoscopy

are not shared by Menezes In his opinion intra-operative

fluoroscopy or the use of lsquolsquoStealth technologyrsquorsquo has little

value Menezes concludes that the advantages of the

transoral-transpalatine approach to the CVJ in irreducible

pathology compared with other operative approaches are

that the impinging bony pathology and granulation tissue

Fig 3 Patient 5 a b Preoperative T2-weighted (a) and T1-

weighted after contrast administration MR (b) showing a cystic and

solid lesion with enhancement of the tectorial membrane impinging

the bulbo-cervical junction c Postoperative T2W image showing the

complete removal of the lesion

Fig 1 a Endoscopic view of

the transoral surgical field 1 the

Crockard distractor valves

(lingual pharingeal and soft

palate) 2 on the left the bone

ultrasonic surgical aspirator

(Sonopet) 3 on the right the

diamond burr drill b Higher

magnification showing 1 the

dura after removal of the

tectorial membrane 2 the bone

ultrasonic surgical aspirator

(Sonopet) while removing the

inferior border of the clivus

Fig 2 Patient 3

a Intraoperative fluoroscopy

with Metrizamide before

endoscopy showing a contrast

defect at the level of right upper

corner of the radiograph

b Intraoperative fluoroscopy

after endoscopy showing the

decompression of the right

upper corner

Eur Spine J (2011) 201518ndash1525 1521

123

that accompanies chronic instability is easily accessible

[2] the patient is placed in the extended position as

opposed to the flexed position thus decreasing the

angulation on the brain stem during surgery and surgery

is performed through the avascular median raphe and

through the clivus [12]

In contrary to Menezesrsquo experience some papers

claimed significant oropharyngeal morbidity from splitting

the soft palate associated with the transoral approach Jones

reported that oropharyngeal complications occurred in

154 of patients who did not undergo splitting of the soft

palate as compared with 75 in the split soft palate group

The author concluded that this procedure should be dis-

continued where it is not absolutely necessary [13]

Recently increased diffusion in the use of the endo-

scope for transsphenoidal pituitary surgery led some stud-

ies to explore the possibility of applying the endoscopic

approach in the surgical treatment of skull base lesions

other than pituitary tumours

Endoscopic-assisted procedures endonasal

In recent years some papers have reported anatomical

studies and surgical experience in the endoscopic endona-

sal approach to different areas of the midline skull base

from the olfactory groove to the CVJ [14]

In 2002 Alfieri et al [15] performed a cadaveric study on

totally transnasal endoscopic odontoidectomy through one

or two nostrils following Jhorsquos endonasal paraseptal tech-

nique Rodlens endoscopes 27 or 4 mm in diameter 18 cm

in length with 0 30 and 70 lenses were used The sur-

gical landmarks leading to the CVJ were the inferior margin

of the middle turbinate nasopharynx and the Eustachian

tubes The nasopharynx was readily identified following the

inferior margin of the middle turbinate The line drawn

between the Eustachian tubes indicated the juncture between

the clivus and atlas The author concluded that lsquolsquohellip contrary

to a conventional transoral approach this endoscopic en-

donasal approach provides unlimited access to the midline

Fig 4 Patient 3

a Preoperative T2-weighted MR

showing a lsquolsquoballoon likersquorsquo

rheumatoid inflammatory

pannus impinging the

bulbo-cervical junction

b Postoperative T2-weighted

MR showing the complete

neural decompression

Fig 5 Patient 2

a Preoperative T1-weighted MR

documenting a chordoma

extending from the oropharinx

to the posterior cranial fossa and

from the clivus to C2

b Postoperative T1-weighted

MR showing removal of the

lesion and decompression of the

brainstem

1522 Eur Spine J (2011) 201518ndash1525

123

clivus and a potential of carrying out surgical decompression

at the ventral craniocervical junction without adding C1-2

instabilityrsquorsquo [15] Three years later Cavallo et al [16] con-

firmed such an observation on cadaveric study

In 2005 Kassam et al [17] operated on a 73-year old

woman affected by rheumatoid arthritis resecting the

odontoid with a transnasal endoscopic approach Kassam

recommended the following equipment (1) navigation

system (2) a zero degree endoscope (3) long angled en-

donasal drill (4) ultrasonic aspirator (5) bayoneted hand-

held microinstrumentation On one side this author

recognized that lsquolsquothe transoral approach remains the lsquolsquogold

standardrsquorsquo but lsquolsquohellip the transnasal endoscopic approach

being above the level of soft palate should expose to a

lower degree of bacterial contaminationrsquorsquo

In 2007 Messina et al [14] concluded that the endo-

scopic endonasal approach like that transoral provides a

direct route to the CVJ but probably with less morbidity

In 2009 Kassam et al [18] published the concept of the

lsquolsquoNasopalatine linersquorsquo (NPL) that is the line connecting the

inferior margin of the nasal bone anteriorly and the border

of the hard palate posteriorly in the midsagittal plane The

intersection of this line with the vertebral column indicates

the inferior limit of the approach Therefore the maximal

extent of inferior dissection with an endoscopic endonasal

approach can be predicted with the NPL traced on the

preoperative radiological study In conclusion this

approach is recommended in selected cases as a valid

alternative to the transoral microscopic approach to resect

the odontoid process of C2 and should be performed by

surgeons very skilled in endoscopic endonasal surgery and

in endoscopic cadaver-dissections [14 17]

Endoscopic-assisted procedures transcervical

In 2007 Wolinsky et al [19 20] described the endoscopic

transcervical approach to the anterior CVJ as an alternative

to the transpharyngeal approaches to avoid risks like con-

tamination with oral flora and infection poor pharyngeal

healing and meningitis if the dura is transgressed More-

over the transcervical exposure is familiar to neurosur-

geons its trajectory allows treatment of deep-seated basilar

invaginations and the postoperative time of recovery is

shorter Patients are able to ingest food orally soon after

surgery Using this approach the anterior arch of C1 can be

spared but the removal of the odontoid process of C2

results too oblique and partial To gain access to the lower

clivus the anterior arch of C1 has to be removed but the

angle of attack makes this portion of dissection very dif-

ficult or impossible

In our opinion in cases of impressio basilaris or other

high pathologies this approach could be uncomfortable and

challenging

Endoscopic-assisted procedures transoral

The 30 endoscope has been proposed for transoral

approach to avoid splitting of the soft palate or further

extensions ie splitting of the hard palate and extended

maxilla-mandibulotomy [21] Using the endoscope the

operator is able to look in all directions with superior illu-

mination reaching abnormalities as high as the midclivus

In a cadaveric study the surgical volume gained by this

approach was quantified The surgical area exposed over the

posterior pharyngeal wall is significantly improved using

the endoscope (6065 plusmn 1274 mm3) compared with the

operating microscope (4257 plusmn 1008 mm3) without any

compromise of surgical freedom (P 005) The extent of

the clivus exposed is significantly improved with the

endoscope (95 plusmn 07 mm) compared with the operating

microscope (20 plusmn 04 mm) (P 005) [20] Then it was

well demonstrated that with an angled-lens endoscope is

possible to approach the anterior CVJ transorally improv-

ing also the exposure of the clivus without splitting the soft

palate and without compromise of surgical freedom

Tubular retractor-assisted microsurgical retropharyngeal

approach

Beside the classic transoral approach the use of an alter-

native anterior extraoral approach in upper cervical surgery

has been strongly advocated to avoid the previous descri-

bed complications A minimally invasive window below

the hypoglossal and the superior laryngeal nerves has been

proposed for the use of tubular retractor system (Metrx)

along with the microscope Better proximal exposure has

also made possible by angling an end-beveled tubular

retractor on the mandible without undue compression on

the hypoglossal and superior laryngeal nerves the marginal

mandibular branch of the facial nerve and the sub-

mandibular gland [22] Although only cadaveric study is

available in the indexed literature only anecdotal reports

are available in clinical practice so far

Image guidance

Image guidance is a useful tool to visually reconstruct the

magnified three-dimensional anatomy imaging allowing

inspection of the anatomic images in multiple recon-

structed views permitting a better orientation during the

surgical procedure [23] Although the error associated with

spinal shift is not completely eliminated the calculated

accuracy is less than 1 mm [24]

As far as we know the present paper is the first and only

paper on the simultaneous use of all the techniques men-

tioned ie endoscope microscope neuronavigation Obvi-

ously a longer follow-up does not exist so far

Eur Spine J (2011) 201518ndash1525 1523

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

of the hard palate with extended maxillotomy are occa-

sionally required These procedures increase operating time

and may result in significant postoperative morbidities such

as velo-pharyngeal incompetence [11]

Menezes et al [12] started his experience on transoral-

transpalatine approach in 1977 and up to 2008 the number

of microsurgical procedures were 732 (280 children)

According to him the anterior transoral-transpalatine

approach has evolved into a safe rapid effective and

direct approach to the anterior irreducible pathology of

the CVJ with minimal morbidity and mortality Recent

attempts aiming to improve visualization with endoscopy

are not shared by Menezes In his opinion intra-operative

fluoroscopy or the use of lsquolsquoStealth technologyrsquorsquo has little

value Menezes concludes that the advantages of the

transoral-transpalatine approach to the CVJ in irreducible

pathology compared with other operative approaches are

that the impinging bony pathology and granulation tissue

Fig 3 Patient 5 a b Preoperative T2-weighted (a) and T1-

weighted after contrast administration MR (b) showing a cystic and

solid lesion with enhancement of the tectorial membrane impinging

the bulbo-cervical junction c Postoperative T2W image showing the

complete removal of the lesion

Fig 1 a Endoscopic view of

the transoral surgical field 1 the

Crockard distractor valves

(lingual pharingeal and soft

palate) 2 on the left the bone

ultrasonic surgical aspirator

(Sonopet) 3 on the right the

diamond burr drill b Higher

magnification showing 1 the

dura after removal of the

tectorial membrane 2 the bone

ultrasonic surgical aspirator

(Sonopet) while removing the

inferior border of the clivus

Fig 2 Patient 3

a Intraoperative fluoroscopy

with Metrizamide before

endoscopy showing a contrast

defect at the level of right upper

corner of the radiograph

b Intraoperative fluoroscopy

after endoscopy showing the

decompression of the right

upper corner

Eur Spine J (2011) 201518ndash1525 1521

123

that accompanies chronic instability is easily accessible

[2] the patient is placed in the extended position as

opposed to the flexed position thus decreasing the

angulation on the brain stem during surgery and surgery

is performed through the avascular median raphe and

through the clivus [12]

In contrary to Menezesrsquo experience some papers

claimed significant oropharyngeal morbidity from splitting

the soft palate associated with the transoral approach Jones

reported that oropharyngeal complications occurred in

154 of patients who did not undergo splitting of the soft

palate as compared with 75 in the split soft palate group

The author concluded that this procedure should be dis-

continued where it is not absolutely necessary [13]

Recently increased diffusion in the use of the endo-

scope for transsphenoidal pituitary surgery led some stud-

ies to explore the possibility of applying the endoscopic

approach in the surgical treatment of skull base lesions

other than pituitary tumours

Endoscopic-assisted procedures endonasal

In recent years some papers have reported anatomical

studies and surgical experience in the endoscopic endona-

sal approach to different areas of the midline skull base

from the olfactory groove to the CVJ [14]

In 2002 Alfieri et al [15] performed a cadaveric study on

totally transnasal endoscopic odontoidectomy through one

or two nostrils following Jhorsquos endonasal paraseptal tech-

nique Rodlens endoscopes 27 or 4 mm in diameter 18 cm

in length with 0 30 and 70 lenses were used The sur-

gical landmarks leading to the CVJ were the inferior margin

of the middle turbinate nasopharynx and the Eustachian

tubes The nasopharynx was readily identified following the

inferior margin of the middle turbinate The line drawn

between the Eustachian tubes indicated the juncture between

the clivus and atlas The author concluded that lsquolsquohellip contrary

to a conventional transoral approach this endoscopic en-

donasal approach provides unlimited access to the midline

Fig 4 Patient 3

a Preoperative T2-weighted MR

showing a lsquolsquoballoon likersquorsquo

rheumatoid inflammatory

pannus impinging the

bulbo-cervical junction

b Postoperative T2-weighted

MR showing the complete

neural decompression

Fig 5 Patient 2

a Preoperative T1-weighted MR

documenting a chordoma

extending from the oropharinx

to the posterior cranial fossa and

from the clivus to C2

b Postoperative T1-weighted

MR showing removal of the

lesion and decompression of the

brainstem

1522 Eur Spine J (2011) 201518ndash1525

123

clivus and a potential of carrying out surgical decompression

at the ventral craniocervical junction without adding C1-2

instabilityrsquorsquo [15] Three years later Cavallo et al [16] con-

firmed such an observation on cadaveric study

In 2005 Kassam et al [17] operated on a 73-year old

woman affected by rheumatoid arthritis resecting the

odontoid with a transnasal endoscopic approach Kassam

recommended the following equipment (1) navigation

system (2) a zero degree endoscope (3) long angled en-

donasal drill (4) ultrasonic aspirator (5) bayoneted hand-

held microinstrumentation On one side this author

recognized that lsquolsquothe transoral approach remains the lsquolsquogold

standardrsquorsquo but lsquolsquohellip the transnasal endoscopic approach

being above the level of soft palate should expose to a

lower degree of bacterial contaminationrsquorsquo

In 2007 Messina et al [14] concluded that the endo-

scopic endonasal approach like that transoral provides a

direct route to the CVJ but probably with less morbidity

In 2009 Kassam et al [18] published the concept of the

lsquolsquoNasopalatine linersquorsquo (NPL) that is the line connecting the

inferior margin of the nasal bone anteriorly and the border

of the hard palate posteriorly in the midsagittal plane The

intersection of this line with the vertebral column indicates

the inferior limit of the approach Therefore the maximal

extent of inferior dissection with an endoscopic endonasal

approach can be predicted with the NPL traced on the

preoperative radiological study In conclusion this

approach is recommended in selected cases as a valid

alternative to the transoral microscopic approach to resect

the odontoid process of C2 and should be performed by

surgeons very skilled in endoscopic endonasal surgery and

in endoscopic cadaver-dissections [14 17]

Endoscopic-assisted procedures transcervical

In 2007 Wolinsky et al [19 20] described the endoscopic

transcervical approach to the anterior CVJ as an alternative

to the transpharyngeal approaches to avoid risks like con-

tamination with oral flora and infection poor pharyngeal

healing and meningitis if the dura is transgressed More-

over the transcervical exposure is familiar to neurosur-

geons its trajectory allows treatment of deep-seated basilar

invaginations and the postoperative time of recovery is

shorter Patients are able to ingest food orally soon after

surgery Using this approach the anterior arch of C1 can be

spared but the removal of the odontoid process of C2

results too oblique and partial To gain access to the lower

clivus the anterior arch of C1 has to be removed but the

angle of attack makes this portion of dissection very dif-

ficult or impossible

In our opinion in cases of impressio basilaris or other

high pathologies this approach could be uncomfortable and

challenging

Endoscopic-assisted procedures transoral

The 30 endoscope has been proposed for transoral

approach to avoid splitting of the soft palate or further

extensions ie splitting of the hard palate and extended

maxilla-mandibulotomy [21] Using the endoscope the

operator is able to look in all directions with superior illu-

mination reaching abnormalities as high as the midclivus

In a cadaveric study the surgical volume gained by this

approach was quantified The surgical area exposed over the

posterior pharyngeal wall is significantly improved using

the endoscope (6065 plusmn 1274 mm3) compared with the

operating microscope (4257 plusmn 1008 mm3) without any

compromise of surgical freedom (P 005) The extent of

the clivus exposed is significantly improved with the

endoscope (95 plusmn 07 mm) compared with the operating

microscope (20 plusmn 04 mm) (P 005) [20] Then it was

well demonstrated that with an angled-lens endoscope is

possible to approach the anterior CVJ transorally improv-

ing also the exposure of the clivus without splitting the soft

palate and without compromise of surgical freedom

Tubular retractor-assisted microsurgical retropharyngeal

approach

Beside the classic transoral approach the use of an alter-

native anterior extraoral approach in upper cervical surgery

has been strongly advocated to avoid the previous descri-

bed complications A minimally invasive window below

the hypoglossal and the superior laryngeal nerves has been

proposed for the use of tubular retractor system (Metrx)

along with the microscope Better proximal exposure has

also made possible by angling an end-beveled tubular

retractor on the mandible without undue compression on

the hypoglossal and superior laryngeal nerves the marginal

mandibular branch of the facial nerve and the sub-

mandibular gland [22] Although only cadaveric study is

available in the indexed literature only anecdotal reports

are available in clinical practice so far

Image guidance

Image guidance is a useful tool to visually reconstruct the

magnified three-dimensional anatomy imaging allowing

inspection of the anatomic images in multiple recon-

structed views permitting a better orientation during the

surgical procedure [23] Although the error associated with

spinal shift is not completely eliminated the calculated

accuracy is less than 1 mm [24]

As far as we know the present paper is the first and only

paper on the simultaneous use of all the techniques men-

tioned ie endoscope microscope neuronavigation Obvi-

ously a longer follow-up does not exist so far

Eur Spine J (2011) 201518ndash1525 1523

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

that accompanies chronic instability is easily accessible

[2] the patient is placed in the extended position as

opposed to the flexed position thus decreasing the

angulation on the brain stem during surgery and surgery

is performed through the avascular median raphe and

through the clivus [12]

In contrary to Menezesrsquo experience some papers

claimed significant oropharyngeal morbidity from splitting

the soft palate associated with the transoral approach Jones

reported that oropharyngeal complications occurred in

154 of patients who did not undergo splitting of the soft

palate as compared with 75 in the split soft palate group

The author concluded that this procedure should be dis-

continued where it is not absolutely necessary [13]

Recently increased diffusion in the use of the endo-

scope for transsphenoidal pituitary surgery led some stud-

ies to explore the possibility of applying the endoscopic

approach in the surgical treatment of skull base lesions

other than pituitary tumours

Endoscopic-assisted procedures endonasal

In recent years some papers have reported anatomical

studies and surgical experience in the endoscopic endona-

sal approach to different areas of the midline skull base

from the olfactory groove to the CVJ [14]

In 2002 Alfieri et al [15] performed a cadaveric study on

totally transnasal endoscopic odontoidectomy through one

or two nostrils following Jhorsquos endonasal paraseptal tech-

nique Rodlens endoscopes 27 or 4 mm in diameter 18 cm

in length with 0 30 and 70 lenses were used The sur-

gical landmarks leading to the CVJ were the inferior margin

of the middle turbinate nasopharynx and the Eustachian

tubes The nasopharynx was readily identified following the

inferior margin of the middle turbinate The line drawn

between the Eustachian tubes indicated the juncture between

the clivus and atlas The author concluded that lsquolsquohellip contrary

to a conventional transoral approach this endoscopic en-

donasal approach provides unlimited access to the midline

Fig 4 Patient 3

a Preoperative T2-weighted MR

showing a lsquolsquoballoon likersquorsquo

rheumatoid inflammatory

pannus impinging the

bulbo-cervical junction

b Postoperative T2-weighted

MR showing the complete

neural decompression

Fig 5 Patient 2

a Preoperative T1-weighted MR

documenting a chordoma

extending from the oropharinx

to the posterior cranial fossa and

from the clivus to C2

b Postoperative T1-weighted

MR showing removal of the

lesion and decompression of the

brainstem

1522 Eur Spine J (2011) 201518ndash1525

123

clivus and a potential of carrying out surgical decompression

at the ventral craniocervical junction without adding C1-2

instabilityrsquorsquo [15] Three years later Cavallo et al [16] con-

firmed such an observation on cadaveric study

In 2005 Kassam et al [17] operated on a 73-year old

woman affected by rheumatoid arthritis resecting the

odontoid with a transnasal endoscopic approach Kassam

recommended the following equipment (1) navigation

system (2) a zero degree endoscope (3) long angled en-

donasal drill (4) ultrasonic aspirator (5) bayoneted hand-

held microinstrumentation On one side this author

recognized that lsquolsquothe transoral approach remains the lsquolsquogold

standardrsquorsquo but lsquolsquohellip the transnasal endoscopic approach

being above the level of soft palate should expose to a

lower degree of bacterial contaminationrsquorsquo

In 2007 Messina et al [14] concluded that the endo-

scopic endonasal approach like that transoral provides a

direct route to the CVJ but probably with less morbidity

In 2009 Kassam et al [18] published the concept of the

lsquolsquoNasopalatine linersquorsquo (NPL) that is the line connecting the

inferior margin of the nasal bone anteriorly and the border

of the hard palate posteriorly in the midsagittal plane The

intersection of this line with the vertebral column indicates

the inferior limit of the approach Therefore the maximal

extent of inferior dissection with an endoscopic endonasal

approach can be predicted with the NPL traced on the

preoperative radiological study In conclusion this

approach is recommended in selected cases as a valid

alternative to the transoral microscopic approach to resect

the odontoid process of C2 and should be performed by

surgeons very skilled in endoscopic endonasal surgery and

in endoscopic cadaver-dissections [14 17]

Endoscopic-assisted procedures transcervical

In 2007 Wolinsky et al [19 20] described the endoscopic

transcervical approach to the anterior CVJ as an alternative

to the transpharyngeal approaches to avoid risks like con-

tamination with oral flora and infection poor pharyngeal

healing and meningitis if the dura is transgressed More-

over the transcervical exposure is familiar to neurosur-

geons its trajectory allows treatment of deep-seated basilar

invaginations and the postoperative time of recovery is

shorter Patients are able to ingest food orally soon after

surgery Using this approach the anterior arch of C1 can be

spared but the removal of the odontoid process of C2

results too oblique and partial To gain access to the lower

clivus the anterior arch of C1 has to be removed but the

angle of attack makes this portion of dissection very dif-

ficult or impossible

In our opinion in cases of impressio basilaris or other

high pathologies this approach could be uncomfortable and

challenging

Endoscopic-assisted procedures transoral

The 30 endoscope has been proposed for transoral

approach to avoid splitting of the soft palate or further

extensions ie splitting of the hard palate and extended

maxilla-mandibulotomy [21] Using the endoscope the

operator is able to look in all directions with superior illu-

mination reaching abnormalities as high as the midclivus

In a cadaveric study the surgical volume gained by this

approach was quantified The surgical area exposed over the

posterior pharyngeal wall is significantly improved using

the endoscope (6065 plusmn 1274 mm3) compared with the

operating microscope (4257 plusmn 1008 mm3) without any

compromise of surgical freedom (P 005) The extent of

the clivus exposed is significantly improved with the

endoscope (95 plusmn 07 mm) compared with the operating

microscope (20 plusmn 04 mm) (P 005) [20] Then it was

well demonstrated that with an angled-lens endoscope is

possible to approach the anterior CVJ transorally improv-

ing also the exposure of the clivus without splitting the soft

palate and without compromise of surgical freedom

Tubular retractor-assisted microsurgical retropharyngeal

approach

Beside the classic transoral approach the use of an alter-

native anterior extraoral approach in upper cervical surgery

has been strongly advocated to avoid the previous descri-

bed complications A minimally invasive window below

the hypoglossal and the superior laryngeal nerves has been

proposed for the use of tubular retractor system (Metrx)

along with the microscope Better proximal exposure has

also made possible by angling an end-beveled tubular

retractor on the mandible without undue compression on

the hypoglossal and superior laryngeal nerves the marginal

mandibular branch of the facial nerve and the sub-

mandibular gland [22] Although only cadaveric study is

available in the indexed literature only anecdotal reports

are available in clinical practice so far

Image guidance

Image guidance is a useful tool to visually reconstruct the

magnified three-dimensional anatomy imaging allowing

inspection of the anatomic images in multiple recon-

structed views permitting a better orientation during the

surgical procedure [23] Although the error associated with

spinal shift is not completely eliminated the calculated

accuracy is less than 1 mm [24]

As far as we know the present paper is the first and only

paper on the simultaneous use of all the techniques men-

tioned ie endoscope microscope neuronavigation Obvi-

ously a longer follow-up does not exist so far

Eur Spine J (2011) 201518ndash1525 1523

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

clivus and a potential of carrying out surgical decompression

at the ventral craniocervical junction without adding C1-2

instabilityrsquorsquo [15] Three years later Cavallo et al [16] con-

firmed such an observation on cadaveric study

In 2005 Kassam et al [17] operated on a 73-year old

woman affected by rheumatoid arthritis resecting the

odontoid with a transnasal endoscopic approach Kassam

recommended the following equipment (1) navigation

system (2) a zero degree endoscope (3) long angled en-

donasal drill (4) ultrasonic aspirator (5) bayoneted hand-

held microinstrumentation On one side this author

recognized that lsquolsquothe transoral approach remains the lsquolsquogold

standardrsquorsquo but lsquolsquohellip the transnasal endoscopic approach

being above the level of soft palate should expose to a

lower degree of bacterial contaminationrsquorsquo

In 2007 Messina et al [14] concluded that the endo-

scopic endonasal approach like that transoral provides a

direct route to the CVJ but probably with less morbidity

In 2009 Kassam et al [18] published the concept of the

lsquolsquoNasopalatine linersquorsquo (NPL) that is the line connecting the

inferior margin of the nasal bone anteriorly and the border

of the hard palate posteriorly in the midsagittal plane The

intersection of this line with the vertebral column indicates

the inferior limit of the approach Therefore the maximal

extent of inferior dissection with an endoscopic endonasal

approach can be predicted with the NPL traced on the

preoperative radiological study In conclusion this

approach is recommended in selected cases as a valid

alternative to the transoral microscopic approach to resect

the odontoid process of C2 and should be performed by

surgeons very skilled in endoscopic endonasal surgery and

in endoscopic cadaver-dissections [14 17]

Endoscopic-assisted procedures transcervical

In 2007 Wolinsky et al [19 20] described the endoscopic

transcervical approach to the anterior CVJ as an alternative

to the transpharyngeal approaches to avoid risks like con-

tamination with oral flora and infection poor pharyngeal

healing and meningitis if the dura is transgressed More-

over the transcervical exposure is familiar to neurosur-

geons its trajectory allows treatment of deep-seated basilar

invaginations and the postoperative time of recovery is

shorter Patients are able to ingest food orally soon after

surgery Using this approach the anterior arch of C1 can be

spared but the removal of the odontoid process of C2

results too oblique and partial To gain access to the lower

clivus the anterior arch of C1 has to be removed but the

angle of attack makes this portion of dissection very dif-

ficult or impossible

In our opinion in cases of impressio basilaris or other

high pathologies this approach could be uncomfortable and

challenging

Endoscopic-assisted procedures transoral

The 30 endoscope has been proposed for transoral

approach to avoid splitting of the soft palate or further

extensions ie splitting of the hard palate and extended

maxilla-mandibulotomy [21] Using the endoscope the

operator is able to look in all directions with superior illu-

mination reaching abnormalities as high as the midclivus

In a cadaveric study the surgical volume gained by this

approach was quantified The surgical area exposed over the

posterior pharyngeal wall is significantly improved using

the endoscope (6065 plusmn 1274 mm3) compared with the

operating microscope (4257 plusmn 1008 mm3) without any

compromise of surgical freedom (P 005) The extent of

the clivus exposed is significantly improved with the

endoscope (95 plusmn 07 mm) compared with the operating

microscope (20 plusmn 04 mm) (P 005) [20] Then it was

well demonstrated that with an angled-lens endoscope is

possible to approach the anterior CVJ transorally improv-

ing also the exposure of the clivus without splitting the soft

palate and without compromise of surgical freedom

Tubular retractor-assisted microsurgical retropharyngeal

approach

Beside the classic transoral approach the use of an alter-

native anterior extraoral approach in upper cervical surgery

has been strongly advocated to avoid the previous descri-

bed complications A minimally invasive window below

the hypoglossal and the superior laryngeal nerves has been

proposed for the use of tubular retractor system (Metrx)

along with the microscope Better proximal exposure has

also made possible by angling an end-beveled tubular

retractor on the mandible without undue compression on

the hypoglossal and superior laryngeal nerves the marginal

mandibular branch of the facial nerve and the sub-

mandibular gland [22] Although only cadaveric study is

available in the indexed literature only anecdotal reports

are available in clinical practice so far

Image guidance

Image guidance is a useful tool to visually reconstruct the

magnified three-dimensional anatomy imaging allowing

inspection of the anatomic images in multiple recon-

structed views permitting a better orientation during the

surgical procedure [23] Although the error associated with

spinal shift is not completely eliminated the calculated

accuracy is less than 1 mm [24]

As far as we know the present paper is the first and only

paper on the simultaneous use of all the techniques men-

tioned ie endoscope microscope neuronavigation Obvi-

ously a longer follow-up does not exist so far

Eur Spine J (2011) 201518ndash1525 1523

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

It is apparently surprising the fact that there is not a

single adverse effect in such virtually high risk surgery In

our opinion two possible explanations can be claimed The

first is the association of all the facilities mentioned aimed

at reducing the adverse effect described for transoral sur-

gery the second is the small number of cases reported and

the consequent dilution of the percentage of complication

including the 15 morbidity related to the midline incision

of the pharynx [13]

Conclusions

The progressive worldwide blooming of transoral proce-

dures thanks to the intensive care and the intraoperative

neurophysiological monitoring techniques improvements

are spreading the expertise of this surgery to a new popu-

lation of surgeons New trends in technology drive from the

lsquolsquoclassicrsquorsquo microneurosurgeons to a new generation of

young spine surgeons more committed to video-assisted

and endoscopic procedures

Though the pure endonasal and cervical endoscopic

approach to the anterior CVJ deserve consideration some

limiting factors exist (1) the learning curve (2) the lack of

three-dimensional perception of the surgical field The 27-

mm endoscopes provide better manoeuvrability but worse

image quality than standard 4-mm endoscopes (3) a lim-

ited working channel according to the variability of the

nasopalatine line can render difficult the removal of huge

tumours as in case 1 (Fig 4)

Among the endoscopic routes we have preferred the

transoral one using 30 endoscopes Endoscopy represents

a useful complement to the standard microsurgical

approach to the anterior CVJ it provides information for a

better decompression with no need for soft palate splitting

hard palate resection or extended maxillotomy Intraop-

erative fluoroscopy helps to recognize residual compres-

sion Virtually in normal anatomic conditions no surgical

limitations exist for endoscopically assisted transoral

approach compared with the pure endonasal and trans-

cervical endoscopic approaches

So far the endoscope deserves an interesting role as

lsquolsquosupportrsquorsquo to the standard transoral microsurgical approach

since 30 angulated endoscopy strongly increase the sur-

gical area exposed over the posterior pharyngeal wall and

the extent of the clivus

In conclusion transoral video-assisted microsurgical

approach remains the gold standard compared to the

lsquolsquopurersquorsquo transnasal and transcervical approaches Further

experience is required with greater numbers of patients and

long-term follow-up to further validate this technique

Image guidance systems allow a correct and safe sur-

gical procedure However contrast medium fluoroscopy

lsquolsquoper sersquorsquo represents an lsquolsquoever greenrsquorsquo old fashion image

guidance system still effective

Conflict of interest None

References

1 Desai SC Sung CK Genden EM (2008) Transoral robotic

surgery using an image guidance system Laryngoscope

1182003ndash2005 doi101097MLG0b013e3181818784

2 Menezes A (1994) Occipito-cervical fusion indications tech-

nique and avoidance of complications In Hitchon P (ed) Tech-

niques of spinal fusion and stabilisation Thieme New York

pp 82ndash91

3 Visocchi M Di Rocco F Meglio M (2003) Craniocervical

junction instability instrumentation and fusion with titanium rods

and sublaminar wires Effectiveness and failures in personal

experience Acta Neurochir (Wien) 145265ndash272 (discussion

272) doi101007s00701-002-1067-6

4 Visocchi M Cabezas DC Rocco CD Meglio M (2001) Cranio-

cervical instability instrumentation and fusion personal experi-

ence with contoured titanium bar and sublaminar wires In

Culloch GM Reilly P (eds) World Federation of Neurosurgical

Societies 12th World Congress of Neurosurgery Sydney Aus-

tralia pp 279ndash283

5 Sonntag W Dickman C (1996) Posterior occipital C1ndashC2

instrumentation In Menezes A (ed) Principles of spinal surgery

McGraw Hill New York pp 1067ndash1079

6 Visocchi M Pietrini D Tufo T Fernandez E Di Rocco C (2009)

Pre-operative irreducible C1ndashC2 dislocations intra-operative

reduction and posterior fixation The lsquolsquoalways posterior strategyrsquorsquo

Acta Neurochir (Wien) 151551ndash559 (discussion 560) doi

101007s00701-009-0271-z

7 Symonds C Meadows S Julian T (1937) Compression of the

spinal cord in the neighbourhood of the foramen magnum with a

note on the surgical approach Brain 6052ndash84

8 Fang H Ong G (1962) Direct anterior approach to the upper

cervical spine J Bone Joint Surg Am 441588ndash1604

9 Crockard HA (1991) Ventral approaches to the upper cervical

spine Orthopade 20140ndash146

10 Pillai P Baig MN Karas CS Ammirati M (2009) Endoscopic

image-guided transoral approach to the craniovertebral junction

an anatomic study comparing surgical exposure and surgical

freedom obtained with the endoscope and the operating micro-

scope Neurosurgery 64437ndash442 (discussion 442ndash444) doi

10122701NEU000033405045750C9

11 Mummaneni PV Haid RW (2005) Transoral odontoidectomy

Neurosurgery 561045ndash1050 (discussion 1045ndash1050)

12 Menezes AH (2008) Surgical approaches postoperative care and

complications lsquolsquotransoral-transpalatopharyngeal approach to the

craniocervical junctionrsquorsquo Childs Nerv Syst 241187ndash1193 doi

101007s00381-008-0599-3

13 Jones DC Hayter JP Vaughan ED Findlay GF (1998) Oropha-

ryngeal morbidity following transoral approaches to the upper

cervical spine Int J Oral Maxillofac Surg 27295ndash298

14 Messina A Bruno MC Decq P Coste A Cavallo LM de Divittis

E Cappabianca P Tschabitscher M (2007) Pure endoscopic en-

donasal odontoidectomy anatomical study Neurosurg Rev

30189ndash194 (discussion 194) doi101007s10143-007-0084-6

15 Alfieri A Jho HD Tschabitscher M (2002) Endoscopic endonasal

approach to the ventral cranio-cervical junction anatomical

study Acta Neurochir (Wien) 144219ndash225 (discussion 225) doi

101007s007010200029

1524 Eur Spine J (2011) 201518ndash1525

123

16 Cavallo LM Messina A Cappabianca P Esposito F de Divitiis

E Gardner P Tschabitscher M (2005) Endoscopic endonasal

surgery of the midline skull base anatomical study and clinical

considerations Neurosurg Focus 19E2 doi190102[pii]

17 Kassam AB Snyderman C Gardner P Carrau R Spiro R (2005)

The expanded endonasal approach a fully endoscopic transnasal

approach and resection of the odontoid process technical case

report Neurosurgery 57E213 (discussion E213)

18 de Almeida JR Zanation AM Snyderman CH Carrau RL

Prevedello DM Gardner PA Kassam AB (2009) Defining the

nasopalatine line the limit for endonasal surgery of the spine

Laryngoscope 119239ndash244 doi101002lary20108

19 Wolinsky JP Sciubba DM Suk I Gokaslan ZL (2007) Endo-

scopic image-guided odontoidectomy for decompression of bas-

ilar invagination via a standard anterior cervical approach

Technical note J Neurosurg Spine 6184ndash191 doi103171spi

200762184

20 McGirt MJ Attenello FJ Sciubba DM Gokaslan ZL Wolinsky

JP (2008) Endoscopic transcervical odontoidectomy for pediatric

basilar invagination and cranial settling Report of 4 cases

J Neurosurg Pediatr 1337ndash342 doi103171PED200814337

21 Husain M Rastogi M Ojha BK Chandra A Jha DK (2006)

Endoscopic transoral surgery for craniovertebral junction anom-

alies Technical note J Neurosurg Spine 5367ndash373 doi

103171spi200654367

22 Fong S DuPlessis SJ (2005) Minimally invasive anterior

approach to upper cervical spine surgical technique J Spinal

Disord Tech 18(4)321ndash325

23 Pillai P Sammet S Ammirati M (2008) Application accuracy of

computed tomography-based image-guided navigation of tem-

poral bone Neurosurgery 63326ndash332 (discussion 332ndash333)

24 Vougioukas VI Hubbe U Schipper J Spetzger U (2003) Navigated

transoral approach to the cranial base and the craniocervical junc-

tion technical note Neurosurgery 52247ndash250 (discussion 251)

Eur Spine J (2011) 201518ndash1525 1525

123