Comparative Analysis of Surgical Exposure among Endoscopic Endonasal Approaches to Petrosectomy: An Experimental Study in Cadavers

Author(s):  
Thanapong Loymak ◽  
Evgenii Belykh ◽  
Irakliy Abramov ◽  
Somkanya Tungsanga ◽  
Christina E. Sarris ◽  
...  

Abstract Objectives Endoscopic endonasal approaches (EEAs) for petrosectomies are evolving to reduce perioperative brain injuries and complications. Surgical terminology, techniques, landmarks, advantages, and limitations of these approaches remain ill defined. We quantitatively analyzed the anatomical relationships and differences between EEA exposures for medial, inferior, and inferomedial petrosectomies. Design This study presents anatomical dissection and quantitative analysis. Setting Cadaveric heads were used for dissection. EEAs were performed using the medial petrosectomy (MP), the inferior petrosectomy (IP), and the inferomedial petrosectomy (IMP) techniques. Participants Six cadaver heads (12 sides, total) were dissected; each technique was performed on four sides. Main Outcomes and Measures Outcomes included the area of exposure, visible distances, angles of attack, and bone resection volume. Results The IMP technique provided a greater area of exposure (p < 0.01) and bone resection volume (p < 0.01) when compared with the MP and IP techniques. The IMP technique had a longer working length of the abducens nerve (cranial nerve [CN] VI) than the MP technique (p < 0.01). The IMP technique demonstrated higher angles of attack to specific neurovascular structures when compared with the MP (midpons [p = 0.04], anterior inferior cerebellar artery [p < 0.01], proximal part of the cisternal CN VI segment [p = 0.02]) and IP (flocculus [p = 0.02] and the proximal [p = 0.02] and distal parts [p = 0.02] of the CN VII/VIII complex) techniques. Conclusion Each of these approaches offers varying degrees of access to the petroclival region, and the surgical approach should be appropriately tailored to the pathology. Overall, the IMP technique provides greater EEA surgical exposure to vital neurovascular structures than the MP and the IP techniques.

2007 ◽  
Vol 61 (suppl_3) ◽  
pp. ONS-7-ONS-14 ◽  
Author(s):  
Giorgio Iaconetta ◽  
Mario Fusco ◽  
Luigi M. Cavallo ◽  
Paolo Cappabianca ◽  
Madjid Samii ◽  
...  

Abstract Objective: Only a few anatomic studies concerning the intra- or extracranial course of the abducens nerve (Cranial Nerve VI) have been reported. This is likely because the nerve passes through anatomically intricate areas, making its neurovascular relationships complex. Here we provide an anatomically and surgically oriented classification of the abducens nerve, analyze the microanatomy of the nerve and the surrounding connective and/or neurovascular structures, and provide measurements and anatomic topography. Patients and Methods: A microsurgical anatomic dissection of 55 cadaveric human heads was performed using different skull base approaches to explore the entire course of the VIth cranial nerve, from its origin at the pontomedullary sulcus to the lateral rectus muscle. We then approached the same areas via an endoscopic endonasal transsphenoidal route, analyzed the neurovascular relationships from an anteromedial perspective, and made comparisons with the microsurgical views. Results: The abducens nerve is divided into five segments, of which three are intracranial (cisternal, gulfar, and cavernous) and two are orbital (fissural and intraconal). Using two opposing surgical routes (microsurgical transcranial and endoscopic endonasal approaches) allows us to clearly reveal the spatial relationships of the abducens nerve with other neurovascular structures on the different nerve segments. Conclusion: The classification of five segments for the abducens nerve seems anatomically valid and is surgically oriented with respect to both the microscopic and endonasal endoscopic approaches. It would be useful to explain, segment by segment, the pathogenic mechanism(s) for nerve injuries that are evidenced by lesions that exist along the entire intra- and extracranial course.


2009 ◽  
Vol 65 (suppl_6) ◽  
pp. ons42-ons52 ◽  
Author(s):  
Matteo de Notaris ◽  
Luigi Maria Cavallo ◽  
Alberto Prats-Galino ◽  
Isabella Esposito ◽  
Arnau Benet ◽  
...  

Abstract Objective: The removal of clival lesions, mainly those located intradurally and with a limited lateral extension, may be challenging because of the lack of a surgical corridor that would allow exposure of the entire lesion surface. In this anatomic study, we explored the clival/petroclival area and the cerebellopontine angle via both the endonasal and retrosigmoid endoscopic routes, aiming to describe the respective degree of exposure and visual limitations. Methods: Twelve fresh cadaver heads were positioned to simulate a semisitting position, thus enabling the use of both endonasal and retrosigmoid routes, which were explored using a 4-mm rigid endoscope as the sole visualizing tool. Results: The comparison of the 2 endoscopic surgical views (endonasal and retrosigmoid) allowed us to define 3 subregions over the clival area (cranial, middle, and caudal levels) when explored via the endonasal route. The definition of these subregions was based on the identification of some anatomic landmarks (the internal carotid artery from the lacerum to the intradural segment, the abducens nerve, and the hypoglossal canal) that limit the bone opening via the endonasal route and the natural well-established corridors via the retrosigmoid route. Conclusion: Different endoscopic surgical corridors can be delineated with the endonasal transclival and retrosigmoid approaches to the clival/petroclival area. Some relevant neurovascular structures may limit the extension of the approach and the view via both routes. The combination of the 2 approaches may improve the visualization in this challenging area.


Author(s):  
Markus Wiedmann ◽  
Aslan Lashkarivand ◽  
Jon Berg-Johnsen ◽  
Daniel Dahlberg

Abstract Background Tuberculum sellae meningiomas (TSMs) adherent to neurovascular structures are particularly challenging lesions requiring delicate and precise microneurosurgery. There is an ongoing debate about the optimal surgical approach. Method We describe technical nuances and challenges in TSM resection using the endoscopic endonasal approach (EEA) in two cases of fibrous tumors with adherence to neurovascular structures. The cases are illustrated with a video (case 1) and figures (cases 1 and 2). Conclusion A dedicated team approach and precise microsurgical technique facilitate safe resection of complex TSMs through the EEA.


2017 ◽  
Vol 13 (4) ◽  
pp. 522-528 ◽  
Author(s):  
Kumar Abhinav ◽  
David Panczykowski ◽  
Wei-Hsin Wang ◽  
Carl H. Synderman ◽  
Paul A. Gardner ◽  
...  

Abstract BACKGROUND: The maxillary nerve (V2) can be approached via the open middle fossa approach. OBJECTIVE: To delineate the anatomy of V2 and its specific segments with respect to the endonasal landmarks. We present the endoscopic endonasal interdural middle fossa approach to V2 and its potential application for the treatment of perineural spread in sinonasal/skull base tumors. METHODS: Five human head silicon-injected specimens underwent bilateral endoscopic endonasal transpterygoid approaches. V2 prominence and the maxillary strut were identified in the lateral recess along with paraclival carotid protruberance. The regions superior and inferior to V2 corresponding to the anteromedial and anterolateral triangles of the middle fossa were exposed. RESULTS: V2 can be classified into 3 segments: interdural (from the Gasserian ganglion to the proximal part of the maxillary strut), intracanalicular (corresponding to the anteroposterior length of the maxillary strut), and pterygopalatine (distal to the maxillary strut and the site of its divisions). Endonasally, the average length of the interdural and the intracanalicular segments were approximately 9 and 4.4 mm, respectively. V2, following its division distal to the maxillary strut, was successfully dissected off the middle fossa dura and transected just distal to the Gasserian ganglion. CONCLUSION: Endonasally, the interdural segment can be safely mobilized between the periosteal and meningeal dural layers while ensuring the integrity of the middle fossa dura. This allows transection of infiltrated V2 to facilitate tumor resection without entering the intradural/arachnoidal space. Posteriorly, this is limited by the Gasserian ganglion and superomedially by the dural envelope surrounding the cavernous sinus and the paraclival carotid artery.


2020 ◽  
Vol 19 (4) ◽  
pp. E413-E413
Author(s):  
Dennis London ◽  
Seth Lieberman ◽  
Omar Tanweer ◽  
Donato Pacione

Abstract Cerebral cavernous malformations are common vascular anomalies consisting of a cluster of capillaries without intervening brain tissue.1 A variety of approaches for resection have been undertaken,2 and a handful of case reports have described the endoscopic, endonasal, transclival approach.3 We present a case of a 51-yr-old woman with lupus and hepatitis B-associated cirrhosis who presented with diplopia, dysphagia, and ataxia. She had a left abducens nerve palsy and magnetic resonance imaging (MRI) showed a left pontine cavernous malformation. After a repeat hemorrhage, she consented to surgical resection. The lesion appeared to come to the medial pontine pial surface. Tractography indicated a rightward displacement of the left corticospinal tract. Therefore, an endoscopic, transnasal, transclival approach was chosen. A lumbar drain was placed preoperatively. The clivus and ventral petrous bone were drilled using the vidian canal to help identify the anterior genu of the petrous carotid artery. The clival dura was opened, revealing the abducens nerve exiting the ventral pons. The cavernoma was visible on the surface lateral to the nerve. It was removed using blunt dissection and the remaining cavity inspected. The skull base was reconstructed using an abdominal dermal-fat graft and Alloderm covered by a nasoseptal flap. Postoperatively she had transient swallowing difficulty. The lumbar drain was kept open for 5 d. Cerebrospinal fluid (CSF) leak was ruled out using an intrathecal fluorescein injection. She was discharged home, but presented 2 wk postoperatively with aseptic meningitis, which was treated supportively. Postoperative imaging did not show residual cavernoma.


2018 ◽  
Vol 80 (S 03) ◽  
pp. S323-S324
Author(s):  
Carlos Candanedo ◽  
Sergey Spektor

Intracranial epidermoid cysts are considered benign tumors with a good general prognosis; however, their radical removal, including tumor capsule, is associated with significant morbidity, especially when the capsule is attached to neurovascular structures. We show an operative video describing main steps and surgical nuances in the resection of a large right cerebellopontine angle (CPA) epidermoid cyst in a 42-year-old male patient who presented with intractable trigeminal neuralgia. Craniectomy was performed to exposure the transverse-sigmoid sinus junction. A mold for a polymethylmethacrylate (PMMA) bone flap was built before opening the dura to avoid potentially neurotoxic effects on the cerebellum. The video illustrates the management of the rare anatomical variant of the anterior inferior cerebellar artery (AICA). Its loop was embedded in the dura, covering the subarcuate fossa where it gives off the subarcuate artery. Near total removal of the epidermoid cyst was achieved, leaving only a tiny capsule remnant adhering to the abducens nerve. Postoperatively the patient's trigeminal neuralgia was fully relieved and medications were discontinued. The patient's hearing was preserved per audiometry at the preoperative level (Gardner–Robertson II). Postoperative magnetic resonance imaging (MRI) revealed no signs of residual tumor. In this case, it was not possible to obtain optimal surgical exposure of the CPA without handling a rare anatomical anomaly of the AICA in the dura of the subarcuate fossa, which demanded coagulation and transection of the subarcuate artery and transposition of AICA with the dural cuff. This manipulation enabled optimal surgical removal of the epidermoid and didn't cause any neurological deficit.The link to the video can be found at: https://youtu.be/lLZqBHlu-uA.


2016 ◽  
Vol 36 (01) ◽  
pp. 58-61 ◽  
Author(s):  
Arquimedes Cardoso ◽  
Luiz Lemos ◽  
Marcos Marques Júnior

Anterior inferior cerebellar artery (AICA) aneurysms are extremely rare, accounting for only 0.75% of all intracranial aneurysms. The average age of patients suffering from those aneurysms found in the literature was 44 years, with no significant difference between the sexes. These aneurysms can manifest clinically through expansive symptoms in cerebellopontine angle or through signs and symptoms of subarachnoid hemorrhage, such as nausea, vomiting, headache, nystagmus and paresis. The gold standard exam for diagnosis is cerebral angiography. The treatment of these lesions is controversial. The main difficulty of the surgical treatment of these aneurysms is the location of the AICA, which lies close to critical neurovascular structures. In this article, we describe a proximal AICA aneurysm embolization without occlusion of the parent artery, with excellent results in the postoperative period.


2019 ◽  
Vol 126 (6) ◽  
pp. 820
Author(s):  
Л.П. Сафонова ◽  
В.Г. Орлова ◽  
А.Н. Шкарубо

The possibility of using phase modulation spectrophotometry for the detection and recognition of large blood vessels and nerves in the biological tissues volume in the tasks of neurosurgery with endoscopic endonasal access while removing the skull base tumors has been investigated. Optical and dynamic characteristics of various neurovascular structures types were studied. Informative independent parameters and their corresponding criteria for the detection and recognition of neurovascular structures in the tissue volume, based on the difference in the optical properties of the blood, nerves and their surrounding tissues, was proposed and experimentally investigated in vivo and in situ. The obtained preliminary results indicate the promise of applying the method of phase modulation spectrophotometry in endoscopic neurosurgery and can be used in spectrophotometry with the impulse time-domain approach.


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