10.14639/0392-100X-suppl.1-41-2021-05
Historically considered as a nobody’s land, craniovertebral junction (CVJ) surgery or specialty recently gained high consideration as symbol of challenging surgery as well as selective top level qualifying surgery. The alliance between Neurosurgeons and Otorhinolaringologists has become stronger in the time. CVJ has unique anatomical bone and neurovascular structures architecture. It not only separates from the subaxial cervical spine but it also provides a special cranial flexion, extension, and axial rotation pattern. Stability is provided by a complex combination of osseous and ligamentous supports which allows a large degree of motion. The perfect knowledge of CVJ anatomy and physiology allow to better understand surgical procedures of the occiput, atlas and axis and the specific diseases that affect the region. Although many years passed since the beginning of this pioneering surgery, managing lesions situated in the anterior aspect of the CVJ still remains a challenging neurosurgical problem. Many studies are available in the literature so far aiming to examine the microsurgical anatomy of both the anterior and posterior extradural and intradural aspects of the CVJ as well as the differences in all the possible surgical exposures obtained by 360° approach philosophy. Herein we provide a short but quite complete at glance tour across the personal experience and publications and the more recent literature available in order to highlight where this alliance between Neurosurgeon and Otorhinolaringologist is mandatory, strongly advisable or unnecessary.
application/xml
1827-675X
1686
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Mario Rigante
https://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
craniovertebral junction
Multidisciplinary approach to the craniovertebral junction. Historical insights, current and future perspectives in the neurosurgical and otorhinolaryngological alliance
Text.Serial.Journal
https://www.actaitalica.it/
41
Annual congress report
2021-05-14
2021-05-10
2021-05-14
2021-05-14
51-58
1
Mario Rigante
2021/05/14
10.14639/0392-100X-suppl.1-41-2021-05
51
Otorhinolaryngology, Head and Neck Surgery, “A. Gemelli” Hospital Foundation IRCCS, Catholic University of the Sacred Heart, Rome, Italy; Craniovertebral Junction Operative Unit, Master II Degree, Cadaver Lab and Research Center on Craniocervical Junction Surgery, Catholic University School of Medicine, Rome, Italy
1827-675X
craniovertebral junction
58
Multidisciplinary approach to the craniovertebral junction. Historical insights, current and future perspectives in the neurosurgical and otorhinolaryngological alliance
https://www.actaitalica.it/article/download/1686/559
41
ACTA OTORHINOLARYNGOLOGICA ITALICA 2021;41(SUPPL.1):S51-S58; doi: 10.14639/0392-100X-suppl.1-41-2021-05




Multidisciplinary approach to the craniovertebral
junction. Historical insights, current
and future perspectives in the neurosurgical
and otorhinolaryngological alliance
Approccio multidisciplinare alla giunzione cranio vertebrale. Cenni storici, attuali
orientamenti e prospettive future nell’alleanza tra neurochirurgia ed otorinolaringoiatria
Massimiliano Visocchi1,2,4, Francesco Signorelli1, Claudio Parrilla3, Gaetano Paludetti3,4, Mario Rigante3,4
1
  Institute of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; 2 Institute of Neurosurgery, Catholic
University School of Medicine, Rome, Italy; 3 Otorhinolaryngology, Head and Neck Surgery, “A. Gemelli” Hospital Foundation IRCCS,
Catholic University of the Sacred Heart, Rome, Italy; 4 Craniovertebral Junction Operative Unit, Master II Degree, Cadaver Lab and
Research Center on Craniocervical Junction Surgery, Catholic University School of Medicine, Rome, Italy


SUMMARY
Historically considered as a nobody’s land, craniovertebral junction (CVJ) surgery or
specialty recently gained high consideration as symbol of challenging surgery as well as
selective top level qualifying surgery. The alliance between Neurosurgeons and Otorhi-
nolaringologists has become stronger in the time. CVJ has unique anatomical bone and               Received: November 19, 2020
neurovascular structures architecture. It not only separates from the subaxial cervical spine      Accepted: January 22, 2021
but it also provides a special cranial flexion, extension, and axial rotation pattern. Stability
is provided by a complex combination of osseous and ligamentous supports which allows a            Correspondence
large degree of motion. The perfect knowledge of CVJ anatomy and physiology allows to              Francesco Signorelli
better understand surgical procedures of the occiput, atlas and axis and the specific diseases     Institute of Neurosurgery, Fondazione Policlinico
                                                                                                   Universitario A. Gemelli IRCCS,
that affect the region. Although many years passed since the beginning of this pioneering
                                                                                                   largo F. Vito 1, 00168 Rome, Italy
surgery, managing lesions situated in the anterior aspect of the CVJ still remains a chal-         E-mail: francesco.signorelli@policlinicogemelli.it
lenging neurosurgical problem. Many studies are available in the literature so far aiming to
examine the microsurgical anatomy of both the anterior and posterior extradural and intra-         Funding
dural aspects of the CVJ as well as the differences in all the possible surgical exposures ob-     None.
tained by 360° approach philosophy. Herein we provide a short but quite complete at glance
tour across the personal experience and publications and the more recent literature available      Conflict of interest
in order to highlight where this alliance between Neurosurgeon and Otorhinolaringologist           The Authors declare no conflict of interest.
is mandatory, strongly advisable or unnecessary.
KEY WORDS: instrumentation and fusion, endoscopy, transnasal approach, transoral                     How to cite this article: Visocchi M, Signorelli F,
approach, extreme lateral approach, far lateral approach, submandibular retropharyngeal              Parrilla C, et al. Multidisciplinary approach to the
approach, craniovertebral junction                                                                   craniovertebral junction. Historical insights, cur-
                                                                                                     rent and future perspectives in the neurosurgical
                                                                                                     and otorhinolaryngological alliance. Acta Otorhi-
RIASSUNTO                                                                                            nolaryngol Ital 2021;41(SUPPL.1):S51-S58.
Storicamente considerata “terra di nessuno”, la regione della giunzione cranio-vertebrale,           https://doi.org/10.14639/0392-100X-sup-
così come la chirurgia di questa sede, hanno guadagnato altissima considerazione negli               pl.1-41-2021-05
anni recenti per la complessità anatomica, funzionale e tecnica. La gestione multidisci-
plinare e l’alleanza tra neurochirurghi e otorinolaringoiatri anche in questo ambito è di-         © Società Italiana di Otorinolaringoiatria
ventata sempre più forte negli anni. La giunzione cranio-vertebrale ha una architettura            e Chirurgia Cervico-Facciale
anatomica ossea, neurovascolare e muscolare unica e complessa in quanto non solo separa
e congiunge il cranio con il rachide cervicale, ma presenta pattern speciali di flessione,                        OPEN ACCESS
estensione e rotazione assiale. La stabilità è garantita da una complessa combinazione             This is an open access article distributed in accordance with
di supporti ossei e ligamentosi, che consentono ampi gradi di motilità. La conoscenza              the CC-BY-NC-ND (Creative Commons Attribution-Non-
dell’anatomia e della fisiologia della giunzione cranio-vertebrale consente di comprendere         Commercial-NoDerivatives 4.0 International) license. The
                                                                                                   article can be used by giving appropriate credit and mentio-
meglio le procedure chirurgiche e le patologie specifiche che interessano questa regione           ning the license, but only for non-commercial purposes and
anatomica. Sebbene siano passati anni dell’inizio della chirurgia pioneristica di questa           only in the original version. For further information: https://
regione, le lesioni situate nella porzione anteriore della giunzione cranio-vertebrale riman-      creativecommons.org/licenses/by-nc-nd/4.0/deed.en




                                                                                                                                                           S51
M. Visocchi et al.




gono ancora una stimolante sfida per il neurochirurgo. Molti studi sono presenti in letteratura con l’intento di esaminare l’anatomia microchi-
rurgica delle porzioni anteriori, posteriori, extra e intradurali della giunzione cranio-vertebrale, così come le differenze e tutte le possibili vie
di approccio a 360° per esporre al meglio e trattare patologie di questa regione. In questa revisione verrà effettuata una disamina sullo stato
dell’arte in tale chirurgia, partendo dall’esperienza personale, dalle pubblicazioni e dalla letteratura più recente, al fine di sottolineare quando
la collaborazione multidisciplinare sia fondamentale, altamente consigliata o non strettamente necessaria nella gestione delle patologie della
regione cranio-vertebrale.
PAROLE CHIAVE: fusione e procedure strumentate, endoscopia, approccio endoscopic transanasali, approcci transorali, approcci laterali al
basicranio, approccio sottomandibolare retrofaringeo, giunzione cranio-vertebrale



Introduction                                                                sion procedures, we herein outline the experience matured
                                                                            in our department including an equipped Cranio-Vertebral
Despite the continuous evolution and refinements of op-                     Junction Laboratory for anatomical dissection 8-10, a II De-
erating techniques, the disposability of dedicated surgical                 gree Master Course on Surgical Approaches on CVJ and a
instruments along with the growing awareness and experi-                    University Research Center on CVJ, all mastered and di-
ence of the dedicated surgeons, treatment of craniovertebral                rected by the Senior Authors (MV and GP) along with the
junction (CVJ) pathologies still is a complex challenge.                    Junior Authors (MR and FS) and referring to the Surgical
The tricky combination of bony, muscular and neurovas-                      Department / Pole of Medical Interest of our Catholic Uni-
cular vital structures crowded in a deep and narrow space                   versity of Rome Medical School.
makes surgical approaches to the CVJ hard and risky. De-                    In this review we will try to identify and objectivate the
pending on the location of the lesion, surgical approaches                  coworking potential of Neurosurgeons and Othorhinolarin-
have traditionally been directed toward ventral, dorsal and                 gologists in the common CVJ surgery field of interest.
lateral aspect of the cervico-medullary junction. The an-
terior aspect of CVJ can be approached by the transoral
approach (TOA), simple or extended, the endoscopic en-                      Where alliance between neurosurgeons and
donasal approach (EEA), introduced by Kassam 1, and the                     otorhinolaringologists is mandatory?
submandibular approach (SMA), i.e. retropharyngeal ap-                      Submandibular anterior Approach (SMA)
proach, which is indicated only in selected cases.                          Terms like anterolateral 11, submandibular 12, anterior high
Posterior suboccipital approach (SOA) intra-extradural ap-                  cervical 13, and retropharyngeal pre-vascular 14 have been
proaches along with instrumentation procedures has been                     used to describe a surgical approach between carotid sheath
traditionally considered for inferior craniectomy with or                   laterally and pharyngeal constrictor muscles medially to
without C1-C2 laminectomy for CVJ lesions. Through the                      high cervical spine. Cloward 15 and Robinson and Smith 16
same route it is possible to perform C0-C1-C2 instrumen-                    are generally acknowledged as establishing the anterior ap-
tation procedures with titanium cables, wires, screws and                   proach to the cervical spine for the management of disk
rods in order to fix and stabilize the CVJ.                                 herniation. McAfee et al. 14 described the retropharyn-
Intradural lesions located at the ventrolateral aspect of                   geal pre-vascular approach using the same fascial plane
CVJ can be approached by means of a postero-lateral or                      described by Southwick and Robinson 17. Submandibular
far lateral approach (FLA), an extension of the suboccipital                retropharyngeal approach provides a direct, perpendicular
approach with removal of a variable amount of occipital                     trajectory to the C2-3 interspace through a “natural” cor-
bone. Extradural lesions of the same region may require                     ridor above the superior laryngeal nerve (SLN) and below
an antero-lateral or extreme lateral approach (ELA), which                  the hypoglossal nerve. The approach requires a very little
allows a better control of the entire length of the vertebral               retraction and, comparing to other approaches (especially
artery (VA), the jugular foramen, the lowest cranial nerves,                ELA) is associated with a lower risk of hypoglossal, glos-
and the jugular-sigmoid complex. Finally, the posterior                     sopharyngeal and superior laryngeal nerves injury. These
midline approach is the most popular in the neurosurgical                   risks can be further limited using an endoscope-assisted
culture both for extra and intradural surgical control of the               retropharyngeal approach, mainly indicated for lesions in-
CVJ and mainly for instrumentation and fusion techniques.                   volving the clivus. Nevertheless, care must be taken when
Moving from a comparative analysis of the CVJ approach-                     using the approach in the setting of prior neck dissection.
es, and in the wake of our surgical experience 2-7 consist-                 On the other hand, this route can be burdened by some
ing of more than 40 anterior surgical procedures including                  complications as respiratory dysfunctions; pharyngeal fis-
TOA and EEA, more than ten comprising ELA, FLA, SMA                         tula; transient hoarseness and dysphagia; dural leakage;
and more than hundred posterior instrumentation and fu-                     hypoglossal and facial nerves paresis and salivary fistula.



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                                                                                                                  360° approach to the craniovertebral junction




A                         B                         C
                                                                                A                                               B

                                                                                Figure 2. Importance of accurate preoperative radiological evaluation in or-
                                                                                der to choose the best corridor of approach. (A) CT scan of children with im-
                                                                                pression basilaris in which we preferred a transnasal corridor. (B) Angio CT
D                         E                         F                           showing an internal carotid kinking in the pharyngeal wall that exclude the
                                                                                anterior route to the CVJ.
Figure 1. Anatomical studies comparing the exposure of transoral (A) and
endoscopic transnasal approach (B, C) followed by exposure of the anterior
arch of C1 (D), odontoid (E) and its removal (F) through a combined transoral
transnasal approach.                                                            with the aid of Neuronavigation (Fig. 3), the upper and
                                                                                lower limits of the endoscopic transoral approach 34.
                                                                                This approach appears more consistent with the global
This surgical field appear more consistent with the onco-                       rhinological endoscopic experience of the Othorhinolarin-
logic Otorhinolaringological background up to the ante-                         gologist up to C1-C2.
rior profile of C1 and C2.
                                                                                TOA is a ventrally directed approach from the inferior third
Where alliance between neurosurgeons and                                        of clivus to C2-C3 interspace. It allows the shortest, wider
otorhinolaringologists is strongly advisable?                                   and most direct access to the CVJ, among the other ap-
                                                                                proaches to the CVJ 35. Extensions of the approach, some-
TOA and EEA                                                                     times necessary to expose more rostrally located patholo-
TOA still represents the “gold standard” for the surgi-                         gies, carry the risk of numerous permanent comorbidities
cal treatment of several conditions resulting in anterior                       expecially on the soft palate and the need for temporary
CVJ compression and myelopathy 18. Refinements of the                           tracheostomy and nasogastric feeding tube 20. The need to
approach have been introduced during the late 1970s by                          overcome the impact and significance of these comorbidi-
Menezes who outlined several issues that now represent                          ties has led to the development of potentially less invasive
pivotal steps of the approach 19. Nevertheless, some con-                       techniques, such as the EEA. As widely demonstrated by
cerns, such as the need of temporary tracheostomy and                           numerous comparative anatomic and clinical studies, the
postoperative nasogastric tube 20, soft palate morbility,
overall led in 2005 to the introduction by Kassam et al. 1
of the EEA (Fig. 1).

EEA
Although this approach, conceived in order to overcome
these surgical complications, rapidly gained wide attention,
a clear predominance over the TOA in the treatment of CVJ
                                                                                 A                                B                     C
pathologies, is still matter of discussion. In recent years,
several papers have reported anatomical studies and surgi-
cal experiences in EEA to target different areas of the mid-
line skull base, including the CVJ 20-28. Starting from these
preliminary experiences, further anatomical studies defined
the theoretical (radiological) and practical (surgical) cranio-
caudal limits of the endonasal route (Fig. 2) 29-31. Our group,
on the basis of the clinical experience gained after 30 ante-                   D                             E                          F
rior procedures, both transoral and transnasal, did the same
                                                                                Figure 3. Use of navigation system to perform a biopsy of a lesion (arrow)
for the transoral approach 32,33 and compared the reliability
                                                                                of the odontoid on sagittal and axial MRI (A, B, C). Intraoperative view with CT
of the radiological and surgical lines of the two different                     scan (D, E, F) The cross-air revealed a correct target reached through a mini-
approaches. Very recently, a cadaveric study tried to define,                   mally invasive EEA. The biopsy revealed a localization of myeloma.



                                                                                                                                                          S53
M. Visocchi et al.




endoscope provides also an improved rostral exposure,
brighter illumination and closer visualization of the surgi-
cal target 35 and can be also used during a TOA, as a valid
complement tool in a combined procedure. Nevertheless, a
recent systematic review and meta-analysis 37, while dem-
onstrating a statistically significant increased risk of post-
                                                                                 A                         B                         C
operative tracheostomy after TOA comparing with EEA,
showed a slight, although not statistically significant, ten-
dency toward a morbidity/mortality prevalence of EEA on
TOA (Fig. 4).
In order to clearly define the limits of the TOA, our re-
search group devised a radiologic “theoretical” line, the                        D                         E                         F
Palatine Inferior dental Arch line (PIA), as a reliable pre-
dictor of the maximal superior extension of the transoral                        Figure 5. CT scan (A) and T2 (B) and T1(C) weighted MRI of a case of im-
                                                                                 pressio basilaris and platybasia + bulbo-medullar compression (rounded area)
approach and then compared the reliability of the radio-                         This lesion was treated with transoral approach that allowed a wide exposure
logical and surgical lines of the two different approaches 33.                   and resection from clivus to C1(⎨) and decompression (arrow) as showed in
Very recently, a cadaveric study tried to define, with the                       postoperative CT (D) and T2 (E) and T1(F) MRI, in which you can observe the
                                                                                 presence of tracheostomy (*).
aid of Neuronavigation, the upper and lower limits of the
endoscopic TOA 34. Starting from our previous experimen-
tal volumetric studies 32,33 and other recent contributions,                     detachment of the ligaments (Fig. 5). On the other hand,
we tried to experimentally exploit the accuracy provided by                      excluding some well-known disadvantages and predictable
Neuronavigation, to further compare operative sagittal and                       complications appreciable only in clinical setting, such as
axial extensions of the transnasal and transoral corridors.                      working in a contaminated field, CSF leak management,
Our observations were consistent with a relevant advantage                       the airway swelling, the upper airway obstruction and the
of TOA over EEA in all the specimens. According to other                         velopharyngeal insufficiency, our study confirms the rel-
clinical and experimental studies reported in literature, we                     evance of fixed obstacles to the required retraction as the
found several advantages of TOA over EEA: wide work-                             tongue and the teeth.
ing area in terms of both craniocaudal and lateral exten-                        The management of TOA requires the role of the Otorhi-
sion, a more familial anatomy for neurosurgeons, a safer                         nolaryngologist for performing tracheostomy, cooperate in
top-down drilling of the clivus and odontoid with a better                       the surgical exposure and final reconstruction of the phar-
                                                                                 yngeal opening.

                                                                                 ELA
                                                                                 Starting from the 1970s, many surgeons developed and in-
                                                                                 troduced new skull base approaches to the lesions of the
                                                                                 anterolateral CVJ introducing several variations and modi-
                                                                                 fications. Hammon in 1972 and thereafter Heros in 1986
A                                         B
                                                                                 described a true lateral suboccipital approach for verte-
                                                                                 bral and vertebrobasilar aneurysms 38,39. Heros described
                                                                                 the combination of a lateral suboccipital craniotomy, C1
                                                                                 laminectomy and drilling of the occipital condyle (OC).
                                                                                 George described a VA medial mobilization from C2 to its
                                                                                 dural entrance point, with ligation of the sigmoid sinus and
                                                                                 without condyle drilling. Spetzler, Bertalanffy, and Seeger
C                                         D                                      mobilized the VA from C1 to dural entrance point, by drill-
Figure 4. Axial CT scan (A) and T2 weighted MRI (B) of platybasia and im-        ing C1 facet, posterior C1 arch and posterior lateral third
pressio basilaris with bulbo-medullar compression (rounded area) treated         of the OC 39-43. In recent years, extensive use of tools like
through a pure transnasal endoscopic approach. In the inferior line post-oper-   neuroendoscope and neuronavigation, greatly implemented
ative CT scan (C) and MRI (D) showing a decompression of the bulbopontine
(arrow) angle and the posterior stabilization (*) the absence of tracheostomy    safety and efficacy of this and other skull base approaches,
can be also observed.                                                            as demonstrated by several cadaveric studies 44-46. ELA is



S54
                                                                                         360° approach to the craniovertebral junction




a direct lateral approach to the deep anterior portion of the   first description of Heros and George 53, extensive discus-
SCM, behind the internal jugular vein and anterior to the       sion and modifications of this approach have been reported
VA. It is generally considered a more aggressive exten-         in the literature. Several cadaver studies have demonstrat-
sion of far lateral approach. This term comes from 1990         ed the use and benefits of the endoscope in the FLA. A
when Sen and Sekhar described an alternative way to deal        study 54 has divided the surgical corridors for inserting the
with meningiomas and schwannomas located anteriorly at          endoscope into upper, middle and lower. The cranial nerves
the CVJ 47. The rationale behind this procedure is to al-       VII and VIII, IX and X, and XII are respectively roof and
low gross total resection of lesions with significant lateral   floor of the three corridors and provide access and observa-
extensions that would be otherwise inaccessible via ante-       tion of the aspects of brainstem and posterior circulation
rior or classic FLA. ELA involves a greater extent of bony      by means of 0° lens (upper and middle corridor) and 30°
removal, skeletization of the jugular bulb along with the       lens (inferior corridor). Another cadaver study compared
sigmoid sinus (in the transjugular variant), and more often     3D endoscopic and microscopic vision in FLA after partial
VA transposition. These technical nuances overall widen         condilectomy and resection of jugular tubercle. The study
the surgical corridor, but inherently are associated with a     concluded that the 3D endoscopic probe is too large and the
higher rate of morbidity and mortality 48,49.                   surgical maneuverability is significantly hampered. Several
ELA provides good access to the bone and extradural ante-       authors have stated similar benefits of endoscope use in
rior and lateral space. It can be easily extended caudally to   clinical series. These studies report a significant benefit in
the cervical spine and it offers simultaneous control of the    the endoscope’s ability to identify any tumor adherent to
VA, cervical segment of the ICA, the lower cranial nerves,      brainstem or clivus amenable to resection 55.
and the sigmoid-jugular complex 50.                             For this approach the Neurosurgeon appears to be quite
In ELA, muscles are detached from their insertion on the        confident, since it can be considered an extension of the
transverse process of atlas. Great attention should be paid     classic well known PIFP but in park bench position.
to avoid damage of VA, internal jugular vein, and spinal
nerves, which are under these muscles. The key point for        SOA Occipitocervical fusion (OCF) as well as C1-C2 is
dissection and control of the VA is to preserve the peri-       indicated for instability at the CVJ. Numerous surgical
osteal sheath surrounding it. Our study further confirms        techniques, which evolved over 90 years, as well as unique
that ELA allows exposure of the whole odontoid process,         anatomic and kinematic relationships of this region pre-
the inferior clivus, and the medial surface of the contralat-   sent a challenge to the neurosurgeon. The current stand-
eral atlanto-occipital joint.                                   ard involves internal rigid fixation by polyaxial screws in
In this surgery the more confident knowledge of Otorhi-         cervical spine, contoured rods and, eventually, occipital
nolaryngologists of the superficial and middle and deep plane   plate. Such approach precludes the need of postoperative
layers of the neck make this alliance absolutely advisable.     external stabilization, lesser number of involved spinal seg-
                                                                ments, and provides 95-100% fusion rates. New surgical
Where alliance between neurosurgeons                            techniques such as occipital condyle screw or transarticular
                                                                occipito-condylar screws address limitations of occipital
and otorhinolaringologists is unnecessary?                      fixation such as variable lateral occipital bone thickness
                                                                and dural sinus anatomy. As the C0-C1-C2 complex is the
Transcervical Anterior Approach (TCA)                           most mobile portion of the cervical spine (40% of flexion-
Wolinsky described an endoscopic transcervical approach         extension, 60% of rotation and 10% of lateral bending)
in order to perform odontoidectomy without traversing the       stabilization leads to substantial reduction of neck move-
oral cavity 51. A recent cadaveric study exploited the feasi-   ments. Preoperative assessment of vertebral artery ana-
bility of an endoscope-assisted retropharyngeal approach        tomical variations and feasibility of screw insertion as well
to the CVJ and clivus following submandibular gland re-         as visualization with intraoperative fluoroscopy are neces-
section 52.                                                     sary. Placement of structural and supplemental bone graft
The knowledge of the Neurosurgeons of this region gained by     around the decorticated bony elements is an essential step
cervical spine surgery along with the skill obtained in spine   of every OCF procedure as the ultimate goal of stabiliza-
traumatology aimed to screwing the odontoid fractures with      tion with implants is to provide immobilization until bony
biplanar fluoroscopy, make him confident and no surgical al-    fusion can develop.
liance seems to be required for this infrequent surgery.        This historical neurosurgical approach makes the Neuro-
FLA nowadays represents a mainstay for the surgical treat-      surgeon absolutely confident, since it is required for con-
ment of intradural pathologies at the ventral CVJ. Since the    ventional posterior cranial lesions approaches.



                                                                                                                                S55
M. Visocchi et al.




Future perspectives                                               able for the surgeon (also in the presence of EX) and the
                                                                  need of complex, time consuming and uneffective surgical
In recent years, the surgical armamentarium has been en-
                                                                  manouvres required.
riched with high-definition 4 K endoscope 56 as well as exo-
                                                                  The spreading diffusion of such technologies seems to be-
scope 57 systems, which potentially provide a wide viewing
                                                                  long to the personal and institutional skill of both Neuro-
angle as well as high-resolution image quality available with
                                                                  surgeons and Otorhinolaryngologists, always more devoted
an endoscope with an optic resolution power equal or su-
                                                                  to share common objectives, operative tools for a common
perior to the conventional Operating Microscope (OM) 57.
                                                                  clinical and experimental final strategy.
In particular, the exoscope is a new surgical tool recently
conceived in order to overcome some limitations of OM and
endoscope. Limitations of the first are mainly ergonomics:        Conclusions
the size and weight, the ocular-dependent visualization, the      The present paper confirms the irreplaceable role of in-
continuous need of refocus because of the short field depth at    terdisciplinary coworking in order to improve the difficult
high magnification and of continuously readjusting the OM         knowledge of the CVJ. Anatomical dissections in the train-
and the body position in order to preserve a perfect stereo-      ing of surgeons, especially when approaching an anatomi-
scopic picture. Limitations of the endoscope include a short      cal region among the most complex such as the CVJ, is
focal distance and a limited field of view that requires an en-   possible only with sharing experience and traditions and it
doscope placement in the surgical field with the shaft reduc-     is of paramount importance when dealing with this region.
ing the available working space. Overall, these limitations       Accurate and multidisciplinary preoperative evaluation of
are even more evident in complex and narrow anatomical            the best corridor of approach, taking care also of all the
corridors as those of the CVJ. Besides to the classic neuro-      possible intra, perioperative and postoperative problems
navigation with preoperative neuroradiological assessment         are nowadays the mainstays for the best treatment of the
it’s worth mentioning also OArm neuronavigation and intra-        patients affected of pathologies of CVJ.
operatory System. Intraoperative imaging represents another
important upgrade in neurosurgery.
For spinal surgery in particular, the introduction of the         References
OArm system has made it possible to implement the safety          1
                                                                      Kassam AB, Snyderman C, Gardner P, et al. The expanded endonasal
of instrumentation procedures on the one hand, allowing               approach: a fully endoscopic transnasal approach and resection of the
                                                                      odontoid process: technical case report. Neurosurgery 2005;57:E213.
much more accurate intraoperative neuronavigation than                https://doi.org/10.1227/01.neu.0000163687.64774.e4
traditional techniques; secondly the setting with intraop-        2
                                                                      Visocchi M, Trevisi G, Iacopino DG, et al. Odontoid process and
erative imaging allows a real-time verification of the effec-         clival regeneration with Chiari malformation worsening after tran-
tiveness of the procedure, such as in cases of medullary              soral decompression: an unexpected and previously unreported cause
                                                                      of “accordion phenomenon”. Eur Spine J 2015;24 (Suppl 4):S564-
decompression or the correct positioning of arthrodesis               568. https://doi.org/10.1007/s00586-014-3720-1
systems 58.                                                       3
                                                                      Visocchi M, Di Martino A, Maugeri R, et al. Videoassisted anterior
OArm acquisition, comparing to fluoroscopy, not only                  surgical approaches to the craniocervical junction: rationale and clini-
should have the obvious advantage of a better definition              cal results. Eur Spine J 2015;24:2713-2723. https://doi.org/10.1007/
with a resulting easier screws insertion, but, for sure, it           s00586-015-3873-6
permits an intraoperative direct and indirect assessment
                                                                  4
                                                                      Visocchi M. Transnasal and transoral approach to the clivus and the
                                                                      craniovertebral junction. J Neurosurg Sci 2019;63:498-500. https://
of bony and legamentous CVJ anterior decompression. In                doi.org/10.23736/S0390-5616.16.03114-3
two of five cases, after OArm acquisition the cranio-caudal       5
                                                                      Visocchi M. Considerations on “endoscopic endonasal approach
decompression was augmented because it proved to be                   to the craniovertebnral junction: the importance of the anterior C1
suboptimal in an absolutely reliable and anatomically de-             arch preservation or its reconstruction”. Acta Otorhinolaryngol Ital
                                                                      2016;36:228-230. https://doi.org/10.14639/0392-100X-927
tailed way. Otherwise in our previous experience concern-         6
                                                                      Visocchi M, Iacopino G, Signorelli F, et al. Walk the line, the surgical
ing fluoroscopic monitoring of TOA, the use of Iopamire,              hightways to the craniovertebral junction in endoscopic approaches.
as contrast filler of the surgical cavity, allowed in a quite         A historical perspective. World Neurosurg 2018;110:544-57. https://
fair way to, indirectly, evaluate possible residual compres-          doi.org/10.1016/j.wneu.2017.06.125
sion at the CVJ. Otherwise, it does not provide a real time       7
                                                                      Visocchi M, Signorelli F, Liao C, et al. Transoral versus transnasal
visualization.                                                        approach for craniovertebral junction pathologies: never say never.
                                                                      World Neurosurg 2018;110:592-603. https://doi.org/10.1016/j.
Finally, the possibility to convert the intraoperative neuro-         wneu.2017.05.125
navigated 3D modality into 2 D real time OArm monitoring          8
                                                                      Signorelli F, Stumpo V, Oliva A, et al. Mastering craniovertebral junc-
is very unconfortable due to the poor volume space avail-             tion surgical approaches: the dissection laboratory experience at the




S56
                                                                                                                360° approach to the craniovertebral junction




     Catholic University of Rome. Acta Neurochir Suppl 2019;125:13-15.               sion. Eur Spine J 2012;21(Suppl 1):S55-60. https://doi.org/10.1007/
     https://doi.org/10.1007/978-3-319-62515-7_3                                     s00586-012-2220-4
9
     Signorelli F, Costantini A, Stumpo V, et al. Transoral ap-                 26
                                                                                     Duntze J, Eap C, Kleiber JC, et al. Advantages and limitations of endo-
     proach to the craniovertebral junction: a neuronavigated ca-                    scopic endonasal odontoidectomy. A series of nine cases. Orthopaed
     daver Study. Acta Neurochir Suppl 2019;125:51-55. https://doi.                  Traumatol Surg Res 2014;100:775-778. https://doi.org/10.1016/j.
     org/10.1007/978-3-319-62515-7_8                                                 otsr.2014.07.017
10
     Signorelli F, Pace M, Stumpo V, et al. Endoscope-assisted far lateral      27
                                                                                     Alfieri A, Jho HD, Tschabitscher M. Endoscopic endonasal approach
     approach to the craniovertebral junction with neuronavigation: a ca-            to the ventral cranio-cervical junction: anatomical study. Acta Neuro-
     daver laboratory experience. Acta Neurochir Suppl 2019;125:165-                 chir 2002;144:219-225. https://doi.org/10.1007/s007010200029
     169. https://doi.org/10.1007/978-3-319-62515-7_24                          28
                                                                                     Messina A, Bruno MC, Decq P, et al. Pure endoscopic endonasal od-
11
     Song Y, Tharin S, Divi V, et al. Anterolateral approach to the up-              ontoidectomy: anatomical study. Neurosurg Rev 2007;30:189-194.
     per cervical spine: case report and operative technique. Head Neck              https://doi.org/10.1007/s10143-007-0084-6
     2015;37:E115-119. https://doi.org/10.1002/hed.23951                        29
                                                                                     de Almeida JR, Zanation AM, Snyderman CH, et al. Defining the na-
12
     Russo A, Albanese E, Quiroga M, et al. Submandibular approach to                sopalatine line: the limit for endonasal surgery of the spine. Laryngo-
     the C2-3 disc level: microsurgical anatomy with clinical application. J         scope 2009;119:239-244. https://doi.org/10.1002/lary.20108
     Neurosurg Spine 2009;10:380-389. https://doi.org/10.3171/2008.12.          30
                                                                                     Aldana PR, Naseri I, La Corte E. The naso-axial line: a new meth-
     SPINE08281                                                                      od of accurately predicting the inferior limit of the endoscopic en-
13
     Fard SA, Patel A, Avila MJ, et al. Anatomic considerations of the               donasal approach to the craniovertebral junction. Neurosurgery
     anterior upper cervical spine during decompression and instrumen-               2012;71(2 Suppl Operative):ons308-14;discussion ons314. https://
     tation: a cadaveric based study. J Clin Neurosc 2015;22:1810-1815.              doi.org/10.1227/NEU.0b013e318266e4
     https://doi.org/10.1016/j.jocn.2015.05.012                                 31
                                                                                     La Corte E, Aldana PR, Ferroli P, et al. The rhinopalatine line
14
     McAfee PC, Bohlman HH, Riley LH, et al. The anterior retropharyn-               as a reliable predictor of the inferior extent of endonasal od-
     geal approach to the upper part of the cervical spine. J Bone Joint Surg        ontoidectomies. Neurosurg Focus 2015;38:e16. https://doi.
     1987;69:1371-1383. PMID: 2450093                                                org/10.3171/2015.1.FOCUS14777
15
     Cloward RB. The anterior approach for removal of ruptured cervical         32
                                                                                     Visocchi M, La Rocca G, Della Pepa GM, et al. Anterior video-assist-
     disks. J Neurosurg Spine 1958;15:602-617. https://doi.org/10.3171/              ed approach to the craniovertebral junction: transnasal or transoral?
     jns.1958.15.6.0602                                                              A cadaver study. Acta Neurochir 2014.156:285-292. https://doi.
16
     Robinson RA, Smith GW. Anterolateral cervical disc removal and in-              org/10.1007/s00701-013-1910-y
     terbody fusion for cervical disc syndrome. Bull John Hopkins Hosp          33
                                                                                     Visocchi M, Pappalardo G, Pileggi M, et al. Experimental endoscopic
     1955;96:223-224. PMID: 13539086                                                 angular domains of transnasal and transoral routes to the craniover-
17
     Southwick WO, Robinson RA. Surgical approaches to the vertebral                 tebral junction light and shade. Spine 2016;41:669-677. https://doi:
     bodies in the cervical and lumbar regions. J Bone Joint Surg Am                 10.1097/BRS.0000000000001288.
     1957;39-A:631-644. PMID: 13428808                                          34
                                                                                     La Corte E, Aldana PR. Endoscopic approach to the upper cervi-
18
     Menezes AH, VanGilder JC. Transoral-transpharyngeal approach                    cal spine and clivus: an anatomical study of the upper limits of the
     to the anterior craniocervical junction. Ten-year experience with 72            transoral corridor. Acta Neurochir 2017;159:633-639. https://doi.
     patients. J Neurosurg 1988;M69:895-903. https://doi.org/10.3171/                org/10.1007/s00701-017-3103-6
     jns.1988.69.6.0895                                                         35
                                                                                     Visocchi M, Della Pepa GM, Doglietto F, et al Video-assisted micro-
19
     Visocchi M, Signorelli F, Liao C, et al. Endoscopic endonasal approach          surgical transoral approach to the craniovertebral junction: personal
     for craniovertebral junction pathologies: myth and truth in clinical se-        experience in childhood. Childs Nerv Syst 2011;27:825-831. https://
     ries and personal experience. World Neurosurg 2017;101:122-129.                 doi.org/10.1007/s00381-010-1386-5
     https://doi.org/10.1007/978-3-319-62515-7_31                               36
                                                                                     Pillai P, Baig MN, Karas CS, et al. Endoscopic image-guided
20
     Menezes AH. Surgical approaches: postoperative care and compli-                 transoral approach to the craniovertebral junction: an anatomic
     cations “transoral-transpalatopharyngeal approach to the craniocer-             study comparing surgical exposure and surgical freedom ob-
     vical junction”. Childs Nerv Syst 2008;24:1187-1193. https://doi.               tained with the endoscope and the operating microscope. Neuro-
     org/10.1007/s00381-008-0597-5                                                   surgery 2009;64(5 Suppl 2):437-442. https://doi.org/10.1227/01.
21
     Ponce-Gomez JA, Ortega-Porcayo LA, Soriano-Baron HE, et al.                     NEU.0000334050.45750.C9
     Evolution from microscopic transoral to endoscopic endonasal               37
                                                                                     Shriver MF, Kshettry VR, Sindwani R, et al. Transoral and transna-
     odontoidectomy. Neurosurgical Focus 2014;37:e15. https://doi.                   sal odontoidectomy complications: a systematic review and meta –
     org/10.3171/2014.7.FOCUS14301                                                   analysis. Clin Neurol Neurosurg 2016;148:121-129. https://doi.
22
     Mazzatenta D, Zoli M, Mascari C, et al. Endoscopic endonasal od-                org/10.1016/j.clineuro.2016.07.019
     ontoidectomy: clinical series. Spine 2014;39:846-853. https://doi.         38
                                                                                     Hammon WM, Kempe LG. The posterior fossa approach to aneu-
     org/10.1097/BRS.0000000000000271                                                rysms of the vertebral and basilar arteries. J Neurosurg 1972;37:339-
23
     Lee A, Sommer D, Reddy K, et al. Endoscopic transnasal approach to              347. https://doi.org/10.3171/jns.1972.37.3.0339
     the craniocervical junction. Skull Base 2010;20:199-205. https://doi.      39
                                                                                     Heros RC. Lateral suboccipital approach for vertebral and verte-
     org/10.1055/s-0029-1246220                                                      brobasilar artery lesions. J Neurosurg 1986;64:559-562 https://doi.
24
     Goldschlager T, Hartl R, Greenfield JP, et al. The endoscopic en-               org/10.3171/jns.1986.64.4.0559
     donasal approach to the odontoid and its impact on early extu-             40
                                                                                     Bian LG, Sun QF, Tirakotai W, et al. Surgical management of PICA
     bation and feeding. J Neurosurg 2015;122:511-518. https://doi.                  aneurysm and incidental facial nerve schwannoma: case report. Skull
     org/10.3171/2014.9.JNS14733                                                     Base 2007;17:145-150. https://doi.org/10.1055/s-2006-953515
25
     Gladi M, Iacoangeli M, Specchia N, et al. Endoscopic transnasal            41
                                                                                     Flores BC, Boudreaux BP, Klinger DR, et al. The far-lateral approach
     odontoid resection to decompress the bulbo-medullary junction: a                for foramen magnum meningiomas. Neurosurg Focus 2013;35:e12
     reliable anterior minimally invasive technique without posterior fu-            https://doi.org/10.3171/2013.10.FOCUS13332




                                                                                                                                                       S57
M. Visocchi et al.




42
     van Overbeeke JJ, Cornips E. General principles of cranial base           51
                                                                                    Wolinsky JP, Sciubba DM, Suk I, et al. Endoscopic image-guided od-
     surgery. In: Sekhar LN, Fessler RG, editors. Atlas Neurosurg Tech -            ontoidectomy for decompression of basilar invagination via a stand-
     Brain, Second Edition. New York: Thieme; 2015. pp. 199-208.                    ard anterior cervical approach. Technical note. J Neurosurg Spine
43
     Tirakotai W, Benes L, Kappus C, et al. Surgical management of dural            2007;6:184-191. https://doi.org/10.3171/spi.2007.6.2.184
     arteriovenous fistulas with transosseous arterial feeders involving the   52
                                                                                    Salle H, Cavalcanti Mendes GdA, Gantois C, et al. Endoscopic sub-
     jugular bulb. Neurosurg Rev 2007;30:40-48. https://doi.org/10.1007/            mandibular retropharyngeal approach to the craniocervical junction
     s10143-006-0056-2                                                              and clivus: an anatomical study. World Neurosurg 2017;106:266-276.
44
     Guan MW, Wang JY, Feng DX, et al. Anatomical study of endo-                    https://doi.org/10.1016/j.wneu.2017.06.162
     scope-assisted far lateral keyhole approach to the ventral crani-         53
                                                                                    George B, Dematons C, Cophignon J. Lateral approach to the ante-
     ocervical region with neuronavigational guidance. Chin Med J                   rior portion of the foramen magnum. Surg Neurol 1988;29:484-490.
     2013;126:1707-1710.                                                            https://doi.org/10.1016/0090-3019(88)90145-0
45
     Hayashi N, Cohen AR. Endoscope-assisted far-lateral transcondylar         54
                                                                                    Anichini G, Evins A, Santoro A, et al. 3D Endoscope-assisted anato-
     approach to the skull base. Minim Invasive Neurosurg 2002;45:132-
                                                                                    my of the foramen magnum and cranio-vertebral junction through a
     135. https://doi.org/10.1055/s-2002-34349
                                                                                    far lateral approach – a technical note. In: Congress of Neurological
46
     Chotai S, KShettry VR, Ammirati M. Endoscopic-assisted microsur-               Surgeons Annual Meeting, 2012.
     gical techniques at the craniovertebral junction: 4 illustrative cases
     and literature review. Clin Neurol Neurosurg 2014;121:1-9. https://
                                                                               55
                                                                                    Kshettry VR, Chotai S, Hou J, et al. Successful resection of anterior
     doi.org/10.1016/j.clineuro.2014.03.004                                         and anterolateral lesions at the craniovertebral junction using a simple
                                                                                    posterolateral approach. J Clin Neurosci 2013;4:616-622. https://doi.
47
     Sen CN, Sekhar LN. An extreme lateral approach to intradural lesions of
                                                                                    org/10.1016/j.jocn.2013.06.010
     the cervical spine and foramen magnum. Neurosurgery 1990;27:197-
     204. https://doi.org/10.1097/00006123-199008000-00004                     56
                                                                                    Rigante M, La Rocca G, Lauretti L, et al. Preliminary experience with
48
     Komotar RJ, Zacharia BE, McGovern RA, et al. Approaches                        4K ultra-high definition endoscope: analysis of pros and cons in skull
     to anterior and anterolateral foramen magnum lesions: a criti-                 base surgery. Acta Otorhinolaryngol Ital 2017;37:237-241. https://
     cal review. J Craniovert Junction Spine 2010;1:86-99. https://doi.             doi.org/10.14639/0392-100X-1684
     org/10.4103/0974-8237.77672                                               57
                                                                                    Herlan S, Marquardt JS, Hirt B, et al. 3D exoscope system in neu-
49
     Suhardja A, Agur AMR, Cusimano MD. Anatomical basis of ap-                     rosurgery-comparison of a standard operating microscope with a
     proaches to foramen magnum and lower clival meningiomas: com-                  new 3D exoscope in the cadaver lab. Oper Neurosurg (Hagerstown)
     parison of retrosigmoid and transcondylar approaches. Neurosurg                2019;17:518-524. https://doi.org/10.1093/ons/opz081
     Focus 2003;14:e9. https://doi.org/10.3171/foc.2003.14.6.9                 58
                                                                                    Farah K, Coudert P, Graillon T, et al. Prospective comparative study
50
     George B, Laurian C. Surgical approach to the whole length of the              in spine surgery between o-arm and airo systems: efficacy and ra-
     vertebral artery with special reference to the third portion. Acta Neu-        diation exposure. World Neurosurg 2018;118:e175-e184 https://doi.
     rochir (Wien) 1980;51:259-272. https://doi.org/10.1007/BF01406753              org/10.1016/j.wneu.2018.06.148




S58
