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Transclival Approach
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When access to the interpeduncular cistern and the retroinfundibular area is needed, we favor a combination of
a transtuberculum and transclival approach, named the
“above and below” approach.
22,23
With this technique, the
corridor above and below the pituitary gland offers surgeons the opportunity to gain access to the whole retrosellar area and to the superior third of the clival. In case more
space is required, the sellar floor can be removed up to the
dorsum sellae, together with posterior clinoids.24 Additionally, the transposition of the gland could tremendously increase the view over the retrosellar space, but it is always
time-consuming—being a very complex procedure—and exposes the patient to a high risk of hypopituitarism. It stands
clear that such a maneuver is better used in those patients in
whom the lesion has already led to a panhypopituitarism.
25
A major limitation of the endoscopic endonasal transclival approach is the lateral extension of the tumor, laterally to the internal carotid artery or toward the occipital
condyle. In this case, the transclival approach must be
combined with an endoscopic endonasal infrapetrous or
transcondylar transjugular approach. The complexity of
the technique would then significantly increase.
16,21,26–29
References
1. Cobb WS, Makosch G, Anand VK, Schwartz TH. Endoscopic transsphenoidal, transclival resection of an enterogenous cyst located
ventral to the brainstem: case report. Neurosurgery 2010;67(2,
Suppl Operative):522–526
2. Drazin D, Zhuang L, Schievink WI, Mamelak AN. Expanded endonasal approach for the clipping of a ruptured basilar aneurysm and
feeding artery to a cerebellar arteriovenous malformation. J Clin
Neurosci 2012;19(1):144–148
3. Enseñat J, Alobid I, de Notaris M, et al. Endoscopic endonasal clipping of a ruptured vertebral-posterior inferior cerebellar artery
aneurysm: technical case report. Neurosurgery 2011;69(1, Suppl
Operative):E121–E127, discussion E127–E128
4. Frank G, Sciarretta V, Calbucci F, Farneti G, Mazzatenta D, Pasquini
E. The endoscopic transnasal transsphenoidal approach for the treatment of cranial base chordomas and chondrosarcomas. Neurosurgery 2006;59(1, Suppl 1):ONS50–ONS57, discussion ONS50–ONS57
5. Fraser JF, Nyquist GG, Moore N, Anand VK, Schwartz TH. Endoscopic endonasal transclival resection of chordomas: operative
technique, clinical outcome, and review of the literature. J Neurosurg 2010;112(5):1061–1069
6. Kassam AB, Mintz AH, Gardner PA, Horowitz MB, Carrau RL, Snyderman CH. The expanded endonasal approach for an endoscopic
transnasal clipping and aneurysmorrhaphy of a large vertebral
artery aneurysm: technical case report. Neurosurgery 2006;59(1,
Suppl 1):E162–E165, discussion E162–E165
7. Paluzzi A, Gardner P, Fernandez-Miranda JC, et al. Endoscopic endonasal approach to cholesterol granulomas of the petrous apex: a series of 17 patients: clinical article. J Neurosurg
2012;116(4):792–798
8. Sanborn MR, Kramarz MJ, Storm PB, Adappa ND, Palmer JN, Lee JY.
Endoscopic, endonasal, transclival resection of a pontine cavernoma:
case report. Neurosurgery 2012;71(1, Suppl Operative):198–203
9. Simal Julian JA, Sanromán Álvarez P, Miranda Lloret P, Plaza
Ramirez E, Pérez Borreda P, Botella Asunción C. Full endoscopic
endonasal transclival approach: meningioma attached to
the ventral surface of the brainstem. Neurocirugia (Astur)
2014;25(3):140–144
10. Stamm AC, Vellutini E, Harvey RJ, Nogeira JF Jr, Herman DR. Endoscopic transnasal craniotomy and the resection of craniopharyngioma. Laryngoscope 2008;118(7):1142–1148
11. Hadad G, Bassagasteguy L, Carrau RL, et al. A novel reconstructive
technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope 2006;116(10):1882–1886
12. Saito K, Toda M, Tomita T, Ogawa K, Yoshida K. Surgical results
of an endoscopic endonasal approach for clival chordomas. Acta
Neurochir (Wien) 2012;154(5):879–886
13. Valentine R, Wormald PJ. Controlling the surgical field during a large
endoscopic vascular injury. Laryngoscope 2011;121(3):562–566
14. Kassam AB, Prevedello DM, Carrau RL, et al. Endoscopic endonasal
skull base surgery: analysis of complications in the authors’ initial
800 patients. J Neurosurg 2011;114(6):1544–1568
15. Barges-Coll J, Fernandez-Miranda JC, Prevedello DM, et al. Avoiding injury to the abducens nerve during expanded endonasal
endoscopic surgery: anatomic and clinical case studies. Neurosurgery 2010;67(1):144–154, discussion 154
16. Cavallo LM, Cappabianca P, Messina A, et al. The extended endoscopic endonasal approach to the clivus and cranio-vertebral junction: anatomical study. Childs Nerv Syst 2007;23(6):665–671
17. Harvey RJ, Parmar P, Sacks R, Zanation AM. Endoscopic skull base
reconstruction of large dural defects: a systematic review of published evidence. Laryngoscope 2012;122(2):452–459
18. Leng LZ, Brown S, Anand VK, Schwartz TH. “Gasket-seal” watertight
closure in minimal-access endoscopic cranial base surgery. Neurosurgery 2008;62(5, Suppl 2):ONSE342–343, discussion ONSE343
19. Romero Adel C, Nora JE, Topczewski TE, Aguiar PH, Alobid
I, Rodriguéz EF. Cerebrospinal fluid fistula after endoscopic
transsphenoidal surgery: experience in a spanish center. Arq
Neuropsiquiatr 2010;68(3):414–417
20. Alobid I, Enseñat J, Rioja E, et al. Management of cerebrospinal
fluid leaks according to size. Our experience [in Spanish]. Acta
Otorrinolaringol Esp 2014;65(3):162–169
21. Kassam AB, Vescan AD, Carrau RL, et al. Expanded endonasal
approach: vidian canal as a landmark to the petrous internal
carotid artery. J Neurosurg 2008;108(1):177–183
TH. Endoscopic endonasal transsphenoidal “above and below”
approach to the retroinfundibular area and interpeduncular
cistern—cadaveric study and case illustrations. World Neurosurg
2014;81(2):374–384
23. Cavallo LM, Solari D. The above-and-below endonasal transsphenoidal corridor to the retroinfundibular area: how to spin around
the pituitary gland. World Neurosurg 2014;81(2):271–272
24. Silva D, Attia M, Kandasamy J, Alimi M, Anand VK, Schwartz TH.
Endoscopic endonasal posterior clinoidectomy. Surg Neurol Int
2012;3:64
25. Kassam AB, Prevedello DM, Thomas A, et al. Endoscopic endonasal pituitary transposition for a transdorsum sellae approach to the
interpeduncular cistern. Neurosurgery 2008;62(3, Suppl 1):57–72,
discussion 72–74
26. d’Avella E, Angileri F, de Notaris M, et al. Extended endoscopic
endonasal transclival approach to the ventrolateral brainstem
and related cisternal spaces: anatomical study. Neurosurg Rev
2014;37(2):253–260, discussion 260
27. Fernandez-Miranda JC, Morera VA, Snyderman CH, Gardner P.
Endoscopic endonasal transclival approach to the jugular tubercle.
Neurosurgery 2012;71(1, Suppl Operative):146–158, discussion
158–159
28. Kassam AB, Gardner P, Snyderman C, Mintz A, Carrau R. Expanded
endonasal approach: fully endoscopic, completely transnasal
approach to the middle third of the clivus, petrous bone, middle cranial fossa, and infratemporal fossa. Neurosurg Focus 2005;19(1):E6
29. Morera VA, Fernandez-Miranda JC, Prevedello DM, et al. “Far-medial” expanded endonasal approach to the inferior third of the
clivus: the transcondylar and transjugular tubercle approaches.
Neurosurgery 2010;66(6, Suppl Operative):211–219, discussion
219–220
215
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Chapter 21
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21.1 Surgical Approaches 218
Endoscopic Approaches
to the Craniovertebral
Junction
21.2 Avoidance of Complications
during Endoscopic Surgery
of Craniovertebral Junction 224
21.3 Common Pathologies of
Craniovertebral Junction 225
21.4 Complications and Their
Avoidance 229
1
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21 Endoscopic Approaches to the
Craniovertebral Junction
Jau-Ching Wu, Tsung-Hsi Tu, Peng-Yuan Chang, Yu-Shu Yen
Introduction
The standard transoral approach for odontoidectomy has
been a widely accepted surgical procedure to decompress
the soft-tissue and osseous mass lesions at the anterior
craniovertebral junction (CVJ). There have been several
series published in the past two decades showing satisfactory clinical results of this transoral approach.
Detailed surgical techniques and nuance of transoral surgery have been described in detail by multiple authors
in the literature.
anterior or lateral CVJ with wider exposures, which often
involve more aggressive osteotomies along the surgical
corridor, have been reported. For example, such extensive surgical approaches include palate splitting, mandibulotomy, or trespassing the maxillary sinus, and even a
zygomatic process or other extensive craniotomies. Under
microscopes or loupe with head lights, these extensive
approaches allow magnification and illumination of the
deeply seated anterior CVJ and surgical maneuver of the
neural tissue. However, as these microscopic approaches
require wide exposures, they inevitably carry problems of
reconstruction, including both cosmetic and functional.
Endoscopic approaches have emerged and prevailed in
the past decade for many skull base cases.
doscope, magnification and illumination can be achieved
easily. Moreover, the endoscope provides a remarkably more
panoramic view of the deeply seated CVJ than microscopes.
Around the CVJ, which usually requires a working corridor
of length 8 to 10 cm, the viewing angle and working space
are inherently limited through the microscopes. In contrast,
the endoscope can move the surgeons’ eyes closer to the
target of pathology and thus gain a greater panoramic view
of surrounding structures. Moreover, by introducing the
endoscope at an angled view (e.g., the 30-, 45-, and 70-degree-angled endoscopes), significantly greater and wider
visualization can be achieved. Surgical manipulation of the
structures seen under the endoscope often also requires
specialized instruments, which have a bayonet-shaped
long shaft, or mechanisms that could convert the direction
of force. The endoscopic approaches to the anterior CVJ are
less invasive than traditional microscopic surgery because
they require less exposure and thus less compromise to the
normal anatomic structures and physiologic functions. For
example, an endoscopic transnasal transclival odontoidectomy can achieve similar decompression at the anterior
CVJ while allowing less velopharyngeal insufficiency and
earlier oral intake than the traditional transoral odontoidectomy performed under microscopes.
1,3–7
In addition, other approaches to the
8–11
Using the en-
8,10,11
1–4
21.1 Surgical Approaches
Endoscopic approaches provide a panoramic view
through a deep working channel with sufficient magnification and illumination. Together with specialized instruments and image guidance, which can be fluoroscopy or
a navigation system if required, surgery of the anterior
CVJ can be performed with a few comorbidities. Over the
past 15 years, approximately 100 patients with pathologies around the CVJ were treated in our institute using
endoscopic approaches. Among them, the most common
pathologies were (in frequency) chordoma, compression
related to odontoid process, pituitary macroadenoma
with skull base involvement, chondrosarcoma, meningioma, metastatic carcinoma, sarcoma of the skull-base,
epidermoid tumor, and others (Table 21.1).
Endoscopic surgery to address pathologies of the anterior CVJ can be categorized into two types, namely,
transnasal and transoral, according to high- or low-lying
pathologies in relation to the palate.
scopic approaches can be combined during the same
operation, but the palatal line is an important anatomic
consideration in the selection of the surgical approach.
9
These two endo-
21.1.1 Endoscopic Transnasal
Approach
The transnasal endoscopic approach is best used when
the target pathology of the CVJ lies higher than the palate.
There are various kinds of pathologies, including both
extradural and intradural, at the ventral CVJ that can
be dealt with using the endoscopic transnasal corridor.
Accordingly, the transnasal endoscopic approach involves
two modifications: transnasal transsphenoidal and transnasal transclival approaches, respectively.
A: Endoscopic Transnasal
Transsphenoidal Approach
This approach targets lesions at the upper and middle
clivus. Laterally, this endoscopic approach is limited
by the eustachian tubes and medial pterygoid plates.
Table 21.1 Types of diseases operated
Pathology Case number (%)
Chordoma 34 (33.7%)
Odontoid compression 15 (14.9%)
Pituitary adenoma 11 (10.9%)
Chondrosarcoma 8 (7.9%)
Meningioma 8 (7.9%)
Carcinoma (metastatic) 5 (5%)
Sarcoma 4 (4%)
Epidermoid tumor 4 4%)
Fibrous dysplasia 3 (3%)
Craniopharyngioma 2 (2%)
Giant cell tumor 2 (2%)
Abscess 1 (1%)
Anaplastic ependymoma 1 (1%)
Cerebrospinal leakage 1 (1%)
Infl ammatory pseudotumor 1 (1%)
Multiple myeloma 1 (1%)
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Typically, the nasal turbinates are pushed and out-fractured but not resected during this approach. The surgery
can be performed via one nostril, and frequently it is
convenient to use a nasal speculum to maintain an appropriate working space and to keep the endoscopic lens
uncontaminated. The endoscope can be held either with
a pneumatic-controlled scope-holder or by an assistant
surgeon.
first made and the nasal septum is pushed toward the
contralateral side after submucosal dissection. The sphenoid rostrum is removed widely, as low as possible, and
the clivus bone is then drilled to expose the anterior
CVJ. Extradural pathologies of this region can thus be
addressed easily. For intradural targets, there is an inevitable problem of cerebrospinal fluid (CSF) leakage, which
requires reconstruction. In our earlier experiences,
multilayered repair of a skull base bony defect using
facia, autologous fat, and bone grafts was performed to
prevent postoperative CSF leakage for intradural pathologies. However, approximately 7 years ago we adapted
the pedicled nasoseptal flap plus multilayered reconstruction. Since then we have experienced a very high
success rate in repairing the dural defect for intradural
and intra-arachnoid lesions such as meningioma, craniopharyngioma, and epidermoid tumor, using the following procedure.
10–13
In this approach, a “rescue flap” mucosal incision is
Surgical Steps
• The patient was put in a supine position under gener-
al anesthesia. The neuronavigation and/or fluoroscopy
was set. The nasal cavity and the right low abdomen
were disinfected and draped (to harvest fascia or fat
graft whenever necessary).
• The rigid-rod straight 0-degree endoscope was used to
identify the inferior, middle and superior turbinates,
and the choana. The one-side middle turbinate was
out-fractured or removed for better exposure. The superior arm of the pedicled nasoseptal flap was incised
(“rescue flap” incision) and submucosal dissection was
done. The nasal septum could then be pushed contralaterally to expose the sphenoidal rostrum.
• The sphenoidal rostrum was widely opened as low as
possible using Kerrison’s rongeurs or drills.
• The clivus bone, sella turcica, bilateral clival protuber-
ances of internal carotid artery (ICA), and lower clivus
were subsequently identified.
• These bony structures were drilled and punched su-
periorly to the pituitary fossa (including dorsum sellae
and the posterior clinoid process if needed), bilaterally
to both ICA margins, and inferiorly to the lower clivus
bone as needed. The ICA flow could be detected with
the micro-Doppler and its location verified with neuronavigation. Venous oozing from the clival dura or venous plexus was managed with packing of Gelfoam or
other hemostatic agents.
• Epidural lesions could be removed at this stage. The
wound w
sealed by tissue glue.
• For intradural lesions, the dura matter had to be
opened. The intradural maneuver of the pathology required more caution and was repaired in multilayers
by Gelfoam, fascia, fat, and bone grafts. The pedicled
nasoseptal flap was then raised to cover the operative
wound to ensure closure.
as repaired with Gelfoam or fat graft, and then
Case Examples
Case A: A 14-year-old girl had rapidly progressive double vision 1 week prior to admission. Her diplopia was associated
with severe headache, dizziness, nausea, and vomiting. The
CSF examination from lumbar puncture was negative for
evidence of meningitis. The magnetic resonance imaging
(MRI) demonstrated a 2.7-cm chordoma involving upper,
middle, and lower clivus, retrosellar area, dorsum sellae
and medial posterior clinoid process, left Dorello’s canal,
and left posterior cavernous sinus. An endoscopic transnasal transsphenoidal surgery without resection of the nasal
turbinates was performed to remove this tumor, which
involved bone (clivus, sella, and dorsum sellae, part of the
posterior clinoid process). The wound was impacted with a
small piece of fat tissue without a nasoseptal flap. This girl
experienced a full recovery of preoperative abducent palsy
within 2 weeks after surgery. The postoperative MRI confirmed complete removal of the chordoma. Her hormonal
functions were all normal. She has remained disease-free
since then. There was no tumor recurrence as demonstrated by MRI taken 4 years post-peration (Figs. 21.1 and 21.2).
Case B: A 61-year-old woman had suffered from dizziness
and unsteady gait for 2 years. She also had difficulty in
swallowing and had hoarseness of voice for half a year.
The MRI demonstrated a 4-cm meningioma at the middle and lower clivus, causing compression to the pons
and medulla as well. The endoscopic transnasal transsphenoidal transclival approach was used to resect this
tumor. Postoperative CSF leakage with resultant meningitis was noticed 2 weeks after surgery, and she received
a second endoscopic transnasal surgery with continuous
lumbar drainage to repair the CSF rhinorrhea. A ventriculoperitoneal shunt was placed later for meningitis- related
hydrocephalus. The patient maintained her neurologic
functions as per preoperation. Serial MRI follow-ups (the
last at 7 years after surgery) showed a 1.5-cm residual
tumor without progression (Figs. 21.3 and 21.4).
B: Endoscopic Transnasal
Transpharyngeal Approach
The endoscopic transnasal transpharyngeal approach
targets the lower clivus, odontoid process, and upper C2
regions. The lateral limit of this approach is the eustachian
tube. Pathologies of this area include bony deformity of
CVJ with compression to the medulla, the spinal cord
at the medullo-cervical junction, and neoplasms. It is
worthwhile mentioning that it is extremely difficult to
tightly close the operative wound in this approach, owing
to the narrow surgical corridor and long distance of
reach. Therefore, we avoided as far as possible operating
on intradural lesions using this approach because of the
high risks of postoperative CSF leakage.
Surgical Steps
• The patient was put in a supine position under general
anesthesia. The neuronavigation and/or fluoroscopy
was set prior to the start of the surgery. The nasal cavity and the right lower abdomen were disinfected and
draped (for fascia or fat grafts as necessary).
• The endoscope, together with a suction instru-
ment, went into the right nostril, and the endoscope
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Fig. 21.1 MRI demonstrated a tumor
of clivus (arrow). (a) Preoperative
sagittal T1-weighted images
(T1WI) with contrast enhancement.
(b) Preoperative axial T2WI
demonstrated both the tumor and
the abducens nerve within Dorello’s
canal (arrow head). (c) Postoperative
sagittal T1WI demonstrated fat graft
(asterisk) after complete resection of
the tumor. (d) Postoperative T2WI
demonstrated well decompression of
the left abducens nerve (arrow head).
a
b
*
c
was subsequently fixed by a pneumatic-controlled
scope-holder or held by an assistant surgeon. Another
instrument (usually a drill, grasping forceps, or a dissector) went in through the other nostril. Note that there
was no need for a speculum retractor in this approach.
• A direct vertical mucosal incision, approximately 2.5 cm,
was made from the sphenoid floor to the soft palate level
in the midline. It was deepened and subperiosteal dissection was done to expose the lower clivus superiorly, the
anterior tubercle of C1, the odontoid process (if visible),
and the upper portion of the C2 vertebral body.
• Epidural soft-tissue lesions could be encountered im-
mediately at this level. They and other hard compressive lesions could be drilled out or punched away till
the ligaments and dura matter were exposed. The adequacy of decompression could be achieved as planned
preoperatively under image guidance and confirmed
intraoperatively by navigation or fluoroscopy.
• The operative cavity was filled with Gelfoam and fat
grafts, and was sealed with fibrin glue.
• Transoral sutures may be possible after the transnaso-
pharyngeal procedure is finished. It may be helpful to
fix the fat graft inside the operative space to enhance
wound healing.
d
Case Examples
Case C: Using MRI examination, a 30-year-old woman
was found to have a chordoma at the CVJ causing her
intractable headache. She underwent surgery using an
endoscopic transnasal transpharyngeal approach to remove the tumor. Although the tumor and involved bone
were resected in piecemeal, grossly complete resection
was confirmed by postoperative MRI. This woman had
complete relief of her headache after the surgery and had
no evidence of tumor recurrence at postoperative 5-year
follow-up (Figs. 21.5 and 21.6).
Case D: A 19-year-old boy suffered from progressive
weakness of all four limbs for 6 months. He was a patient of os odontoideum with reducible atlantoaxial subluxation and twice received posterior fixation
surgery 3 and 2.5 years previously in other hospitals.
His MRI and computed tomography (CT) scan demonstrated severe spinal cord compression caused by
bony deformity at the CVJ. The bony deformity was
not reducible even after halo-ring retraction up to 30
pounds. Therefore, endoscopic transnasal transpharyngeal resection of the soft-tissue or bony odontoid
compression was done via a vertical mucosal incision.
The anterior tubercle of C1 and odontoid tip were
identified and were removed with drilling and Kerrison rongeurs. The odontoid process was drilled until
pulsatile dural expansion was seen. The decompression
was made as low as the C2 vertebral body. The operative cavity was filled with Gelfoam and a piece of fat
tissue, and was sealed with fibrin glue. A stitch suture
was made in the oral route to secure the fat tissue. The
patient was extubated after recovery from anesthesia
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*
*
Clivus
a
d
SP
b
Sella
IC
Dura
AS
e
MT
NS
IT
c
Dura
f
MT
NS
g
Fig. 21.2 Serial intraoperative endoscopic photographs. (a) Direct visualization of the sphenoid sinus after wide opening of sphenoid
rostrum. The clivus was eroded by tumor (arrow), and bilateral carotid protuberances (asterisks) were identifi ed. (b–d) Clivus and
involved bones were drilled and removed. Tumor was dissected away from the dura matter and removed in piecemeal. (e) Dissection
of the intracavernous right internal carotid (IC) artery and dorsum sellae region with angled suction (AS) device. (f) Direct visualization
of the dural matter after removal of tumor. (g) The operative cavity were packed with Gelfoam and a piece of fat graft, and then
sealed with dural sealant (blue color material). SP, nasal speculum. (h) Final endonasal view after surgery demonstrated intact
inferior turbinate (IT), middle turbinate (MT), and nasal septum (NS). (i) Endoscopic examination of the nasal mucosa at 2-month
postoperation.
and was allowed to have oral intake by himself on the
same day. There was no velopharyngeal insufficiency
and the muscle powers improved from grade 2 to grade
3 in the left limbs and from grade 3 to grade 4 in the
right. A posterior revision surgery of prior fixation was
performed after several days (Figs. 21.7 and 21.8).
h
i
21.1.2 Endoscopic Transoral
Approach
The transoral endoscopic approach is best used when the
target pathology of the CVJ lies lower than the palate.
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ab
Fig. 21.3 T1-weighted (T1W)
MRI with contrast enhancement:
Preoperative sagittal (a), axial
(b), postoperative sagittal (c), and
axial (d) T1W MRI demonstrated
removal of the majority portion
of the tumor.
c d
The endoscopic transoral approach targets pathologies
between the lower clivus and the C3 vertebral body. Its
lateral limits are the bilateral carotid arteries. With the
uvula and soft palate being retracted upwards, the angled
endoscope provides clear visualization to the odontoid
process. In contrast to conventional microscopic transoral
surgery, which often requires splitting of the soft or hard
palates, endoscopic transoral surgery requires limited tissue damage of the surrounding oral pharynx. Furthermore,
the midline pharyngeal mucosal incision can be shortened
to approximately 2.5 cm. A suture stitch can be easily
placed on the upmost portion of the incision, which can
be difficult to close under microscope, under an angled
(e.g., 30-degree) endoscope (Figs. 21.9 and 21.10).
Surgical Steps
• The patient was put in a supine position under gener-
al anesthesia. The neuronavigation and/or fluoroscopy
was set prior to the start of surgery. The oral cavity and
the right low abdomen were disinfected and draped
(for harvest of fascia and fat grafts when necessary).
• The uvula and soft palate were retracted superiorly
with 2 Nélaton catheters or 14 French nasogastric tubes
for exposure of the nasopharyngeal area. The tongue
was retracted inferiorly and bilateral buccal soft tissues
were retracted laterally to expose the oral-pharyngeal
region.
• A midline vertical incision, approximately 2.5 cm, was
made by e
Subperiosteal dissection was made for exposure of the
underlying bony structures, including the anterior tubercle of C1, odontoid tip, and upper portion of the C2
vertebral body. The lower part of this approach can be
undertaken with a microscope, but the upmost pharyngeal wall can only be visualized well with an angled
endoscope.
• The anterior tubercle of C1, odontoid process, and
upper part of the C2 vertebral body were drilled or
punched away for decompression. Full expansion of
the previously indented dural sac could gradually be
appreciated under endoscopic visualization. Complete
decompression could also be confirmed by neuronavigation or intraoperative fluoroscopy.
• The operation wound was then subsequently sutured
in two layers (both the muscle and mucosal layers) under the microscope with endoscopic assistance.
lectrocautery and deepened by dissectors.
Case Examples
Case E: A 15-year-old girl, with Down’s syndrome, fell down
and had quadriparesis (grade 4 of bilateral limbs). The
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Sella
Clivus bone
a
Clival dura
b
Fig. 21.4 Serial intraoperative
endoscopic photographs. (a, b)
The clivus bone, sella, and bilateral
carotid protuberances (asterisks)
were visualized after opening of the
sphenoid rostrum. The clivus was
then drilled under the endoscope.
(c, d) The tumor was debulked after
opening the clival dura, and was
dissected away from brain stem
and neighboring neurovascular
structures, including right abducens
nerve (arrow) and basilar artery
(asterisk). (e) Coagulating a bleeder
using a bipolar forceps. (f) The
operative cavity was packed with fat
graft and autologous bony fragments
harvested during the approach, and
was sealed with tissue glue.
*
Cottonoid
Tum or
c
d
e
f
preoperative MRI and CT scan demonstrated os odontoideum
with C1–C2 subluxation. She underwent posterior surgery
of the C1 laminectomy and suboccipital craniectomy for
decompression and was put into halo-vest immobilization
for 3 months. However, there was deterioration of her
muscle powers of all four limbs. She was then taken for
Sella
posterior C1–C2 fixation and placed in a supine position for
endoscopic transoral decompression for the ventral bony
deformity at CVJ. The transoral route was chosen because
of the lower lying target pathology in relation to the palate.
Nearly complete recovery of muscle power of all limbs was
achieved at 6-month postoperation (Figs. 21.9 and 21.10).
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Endoscopic Approaches to the Craniovertebral Junction
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a b c
d e f
Fig. 21.5 Comparison of pre- and postoperative images of a chordoma located at the lower tip of clivus and ventral craniovertebral
junction. (a) Preoperative sagittal MRI; tumor in circle. (b) Preoperative axial MRI; tumor (arrow). (c) Preoperative axial CT. (d) Postoperative
sagittal MRI; tumor was completely removed and replaced by a piece of fat graft (arrow). (e) Postoperative axial MRI. (f) Postoperative axial
CT demonstrated the extent of resection of bony structures, including lower clivus.
21.2 Avoidance of
Complications during
Endoscopic Surgery of
Craniovertebral Junction
There are many critical anatomic structures around the
CVJ, including vascular and neural tissues. Iatrogenic
injury of them could cause serious neurologic deficits
or functional impairment. For example, injury to the
brain stem, cranial nerves, or spinal cord could result in
quadriparesis, respiratory failure, and aspiration. Injury to
the vertebral artery, carotid artery, or basilar artery could
also be problematic and even fatal. This endoscopic surgery
per se is minimally invasive to the CVJ and rarely causes
velopharyngeal insufficiency or difficulty of phonation, as
there are little alterations to the surrounding musculatures
of nasopharynx and larynx. Persistent postoperative CSF
leakage might eventually cause meningitis or encephalitis,
although sometimes the CSF leakage would be selflimiting. Care must be taken to repair durotomy, which
often requires autologous fat and bone grafts, or use of a
nasoseptal mucosal flap.
diversion (i.e., lumbar drainage) could also be beneficiary
in cases of modest CSF leakage.
11
Postoperative bedrest or CSF
Surgical tips to avoid complications include thorough
preoperative evaluations, use of intraoperative image
guidance, meticulous dissection, and reconstruction.
Preoperative thin-cut CT scans is extremely useful for
depiction of the bony anatomy around CVJ. Moreover,
CT angiography provides good knowledge of the course
of major vessels of this neighborhood. During the
operation, identification of the midline is essential, and
can be assisted by navigation system. It is also a good
idea to have intraoperative fluoroscopy at hand for
real-time assessment of the cranial-caudal location as
well as the extent of surgical field. The deeply seated
target of surgery can be visualized under the endoscope,
and some lateral lesions can also be seen using angled
endoscopes. However, some of them are difficult to
reach by currently available instruments, even with
those specially designed endoscopic tools. Furthermore,
the endoscopic views are two-dimensional and there
is inevitably less tactile feedbacks when using the
long-shaft surgical instruments. Therefore, meticulous
dissection is warranted during surgery. Hemostasis
could be more difficult than traditional microsurgery,
which is performed under three-dimensional
microscopic visualization. Last but not least, efforts are
necessary for repair of durotomy to minimize the chance
to postoperative CSF leakage and subsequent infection
of the central nervous system.
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