GREATER SUPERFICIAL PETROSAL NERVE DISSECTION: BACK TO FRONT OR FRONT TO BACK?

Abstract OBJECTIVE To introduce a novel surgical technique for the dissection of the greater superficial petrosal nerve (GSPN) in the middle fossa approach. METHODS Interdural temporal elevation was performed with a front-to-back technique to preserve the GSPN in 12 sides of 6 injected cadaveric heads dissected through a middle fossa approach. RESULTS The GSPN emerged from the facial hiatus in a shallow bony groove proximally, ran into a deeper sphenopetrosal groove, and eventually reached the mandibular nerve. With front-to-back dissection, this nerve was easily identified at the posterior border of the mandibular nerve. Dissection from front to back minimized the retraction force applied to the proximal part of the GSPN, which was preserved in all specimens. CONCLUSION The temporal dura can be elevated safely with a front-to-back technique to preserve the GSPN and to help maintain the physiological integrity of the facial nerve.

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Middle Fossa Approach for Resection of an Intracanalicular Vestibular Schwannoma

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0039-1677859 ◽

2019 ◽

Vol 80 (S 03) ◽

pp. S287-S287

Author(s):

Walter C. Jean ◽

Kyle Mueller ◽

H. Jeffrey Kim

Keyword(s):

Facial Nerve ◽

Vestibular Schwannoma ◽

Middle Cranial Fossa ◽

Petrous Bone ◽

Middle Fossa ◽

Middle Fossa Approach ◽

Nerve Preservation ◽

Greater Superficial Petrosal Nerve ◽

Cranial Fossa ◽

Video Case Report

Objective This video was aimed to demonstrate the middle fossa approach for the resection of an intracanalicular vestibular schwannoma. Design Present study is a video case report. Setting The operative video is showing a microsurgical resection. Participant The patient was a 59-year-old man who presented with worsening headache and right-side hearing loss. He was found to have a right intracanalicular vestibular schwannoma. After weighing risks and benefits, he chose surgery to remove his tumor. Since his hearing remained “serviceable,” a middle fossa approach was chosen. Main Outcome Measures Pre- and postoperative patient photographs evaluated the muscles of facial expression as a marker for facial nerve preservation. Results A right middle fossa craniotomy was performed which allowed access to the floor of the middle cranial fossa. The greater superficial petrosal nerve (GSPN) and arcuate eminence were identified. Using these two landmarks, the internal acoustic canal (IAC) was localized. After drilling the petrous bone, the IAC was unroofed. The facial nerve was identified by stimulation and visual inspection and the tumor was separated from it with microsurgical dissection. In the end, the tumor was fully resected. Both the facial and cochlear nerves were preserved. Postoperatively, the patient experienced no facial palsy and his hearing is at baseline. Conclusion With radiosurgery gaining increasing popularity, patients with intracanalicular vestibular schwannomas are frequently treated with it, or are managed with observation. The middle fossa approach is therefore becoming a “lost art,” but as demonstrated in this video, remains an effective technique for tumor removal and nerve preservation.The link to the video can be found at: https://youtu.be/MD6o3DF6jYg.

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Schwannoma of the greater superficial petrosal nerve

Otolaryngology ◽

10.1016/s0194-5998(00)70260-9 ◽

2000 ◽

Vol 122 (2) ◽

pp. 302-303 ◽

Cited By ~ 9

Author(s):

Eugene N. Myers ◽

Olaf Michel ◽

Mathias Wagner ◽

Orlando Guntinas-Lichius

Keyword(s):

Facial Nerve ◽

Geniculate Ganglion ◽

Nerve Function ◽

Middle Fossa ◽

Facial Nerve Function ◽

Progressive Hearing Loss ◽

Middle Fossa Approach ◽

Greater Superficial Petrosal Nerve ◽

Intracranial Schwannoma ◽

Ct And Mri

A case of an intracranial schwannoma originating from the greater superficial petrosal nerve with wide extension into the pterygopalatine fossa in a 20-year-old woman without neurofibromatosis is reported. The motor facial nerve including the geniculate ganglion was not affected. At presentation the patient had vertigo, progressive hearing loss, and mild facial nerve synkinesis without lacrimation deficit. The tumor was detected by CT and MRI. The tumor was completely removed with an intracranial, extradural middle fossa approach with complete preservation of the motor facial nerve function. To our knowledge, this is the first reported case of an isolated schwannoma of the greater superficial petrosal nerve without involvement of the motor facial nerve.

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Endoscopic Endonasal Interdural Middle Fossa Approach to the Maxillary Nerve: Anatomic Considerations and Surgical Relevance

Operative Neurosurgery ◽

10.1093/ons/opx010 ◽

2017 ◽

Vol 13 (4) ◽

pp. 522-528 ◽

Cited By ~ 3

Author(s):

Kumar Abhinav ◽

David Panczykowski ◽

Wei-Hsin Wang ◽

Carl H. Synderman ◽

Paul A. Gardner ◽

...

Keyword(s):

Average Length ◽

Tumor Resection ◽

Human Head ◽

Proximal Part ◽

Gasserian Ganglion ◽

Middle Fossa ◽

Perineural Spread ◽

Endoscopic Endonasal ◽

Middle Fossa Approach ◽

Maxillary Nerve

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.

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Resection of a Dumbbell-Shaped Facial Nerve Schwannoma With Preservation of Facial Nerve Function Through the Extended Middle Fossa Approach: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opab335 ◽

2021 ◽

Author(s):

Kaith K Almefty ◽

Wenya Linda Bi ◽

Walid Ibn Essayed ◽

Ossama Al-Mefty

Keyword(s):

Facial Nerve ◽

Cerebellopontine Angle ◽

Internal Auditory Canal ◽

Growth Patterns ◽

Geniculate Ganglion ◽

Nerve Function ◽

Middle Fossa ◽

Facial Nerve Function ◽

Large Tumor ◽

Middle Fossa Approach

Abstract Facial nerve schwannomas are rare and can arise from any segment along the course of the facial nerve.1 Their location and growth patterns present as distinct groups that warrant specific surgical management and approaches.2 The management challenge arises when the facial nerve maintains good function (House-Brackmann grade I-II).3 Hence, a prime goal of management is to maintain good facial animation. In large tumors, however, resection with facial nerve function preservation should be sought and is achievable.4,5 While tumors originating from the geniculate ganglion grow extradural on the floor of the middle fossa, they may extend via an isthmus through the internal auditory canal to the cerebellopontine angle forming a dumbbell-shaped tumor. Despite the large size, they may present with good facial nerve function. These tumors may be resected through an extended middle fossa approach with preservation of facial and vestibulocochlear nerve function. The patient is a 62-yr-old man who presented with mixed sensorineural and conductive hearing loss and normal facial nerve function. Magnetic resonance imaging (MRI) revealed a large tumor involving the middle fossa, internal auditory meatus, and cerebellopontine angle. The tumor was resected through an extended middle fossa approach with a zygomatic osteotomy and anterior petrosectomy.6 A small residual was left at the geniculate ganglion to preserve facial function. The patient did well with hearing preservation and intact facial nerve function. He consented to the procedure and publication of images. Image at 1:30 © Ossama Al-Mefty, used with permission. Images at 2:03 reprinted from Kadri and Al-Mefty,6 with permission from JNSPG.

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Hearing Preservation Using the Middle Fossa Approach for the Treatment of Vestibular Schwannoma

Neurosurgery ◽

10.1227/neu.0b013e31823110f1 ◽

2011 ◽

Vol 70 (2) ◽

pp. 334-341 ◽

Cited By ~ 26

Author(s):

Joe Walter Kutz ◽

Tyler Scoresby ◽

Brandon Isaacson ◽

Bruce E. Mickey ◽

Christopher J. Madden ◽

...

Keyword(s):

Facial Nerve ◽

Vestibular Schwannoma ◽

Academic Medical Center ◽

Hearing Preservation ◽

Middle Fossa ◽

Middle Fossa Approach ◽

Class A ◽

Facial Function ◽

Grade Iii

Abstract BACKGROUND: The incidence of small vestibular schwannomas in patients with serviceable hearing is increasing because of the widespread use of MRI. The middle fossa approach provides the patient with an opportunity for tumor removal with hearing preservation. OBJECTIVE: To determine the rate of hearing preservation and facial nerve outcomes after removal of a vestibular schwannoma with the use of the middle fossa approach. METHODS: A retrospective case review at a tertiary, academic medical center was performed identifying patients from 1998 through 2008 that underwent removal of a vestibular schwannoma by the middle fossa approach. Preoperative and postoperative audiograms were compared to determine hearing preservation rates. In addition, facial nerve outcomes at last follow-up were recorded. RESULTS: Forty-six patients underwent a middle fossa craniotomy for the removal of a vestibular schwannoma. Of the 38 patients that had class A or class B hearing preoperatively, 24 (63.2%) retained class A or B hearing and 29 (76.3%) retained class A, B, or C hearing. When tumors were 10 mm or less in patients with class A or B preoperative hearing, 22 of 30 patients (73.3%) retained class A or B hearing. When the tumor size was greater than 10 mm in patients with class A or B preoperative hearing, 2 of 8 patients (25%) retained class A or B hearing. At most recent follow-up, 76.1% of patients had House-Brackmann grade I facial function, 13.0% had House-Brackmann grade II facial function, and 10.9% had House-Brackmann grade III facial function. CONCLUSION: Hearing preservation rates are excellent using the middle fossa approach, especially for smaller tumors. No patient experienced long-term facial nerve function worse than House-Brackmann grade III.

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Intraspinosum Middle Meningeal Artery Ligation: A Simple Technique to Control Bleeding in the Middle Fossa During the Anterior Transpetrosal Approach

Operative Neurosurgery ◽

10.1093/ons/opw013 ◽

2017 ◽

Vol 13 (2) ◽

pp. 163-172

Author(s):

Shunsuke Shibao ◽

Hamid Borghei-Razavi ◽

Kazunari Yoshida

Keyword(s):

Facial Nerve ◽

Histological Study ◽

Middle Meningeal Artery ◽

Mandibular Nerve ◽

Petrous Apex ◽

Middle Fossa ◽

Foramen Ovale ◽

Anterior Transpetrosal Approach ◽

Nerve Paresis ◽

Meningeal Artery

Abstract BACKGROUND: Although the greater superficial petrosal nerve (GSPN) is an important landmark of the anterior transpetrosal approach (ATPA), bleeding from the interdural space around the foramen spinosum (FS), the GSPN, and the foramen ovale impedes the identification of the GSPN, during epidural dissection in the ATPA. OBJECTIVE: To describe the technique of intraspinosum middle meningeal artery (MMA) ligation, which enables us to control bleeding from the interdural space. METHODS: During epidural dissection, we identified the FS and partially drilled the lateral side of the FS. Next, we cut the convergence site of the neurovascular structures such as the MMA, middle meningeal vein, and the meningeal branch of the mandibular nerve with the periosteal dura within the FS and continued dural detachment epidurally to expose the petrous apex. Bleeding control around the FS and postoperative facial nerve paresis were assessed for 96 patients treated with the ATPA. Additionally, histological study was performed around the FS using Masson's trichrome stain. RESULTS: In all cases, in which this technique was used, bleeding from the interdural space was well controlled and no persistent facial nerve paresis was identified. In the histological study, we confirmed that the MMA, the middle meningeal vein, and the meningeal branch of the mandibular nerve converged into the FS and many venous channels existed in the interdural space around the FS and the foramen ovale. CONCLUSION: Intra-FS MMA ligation is an effective method for control of bleeding from the interdural space of the middle fossa during the ATPA.

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Middle Fossa Approach for Facial Nerve Schwannoma Aiming for Functional Improvement: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opz178 ◽

2019 ◽

Vol 18 (5) ◽

pp. E167-E168

Author(s):

Ken Matsushima ◽

Michihiro Kohno ◽

Hitoshi Izawa ◽

Yujiro Tanaka

Keyword(s):

Facial Nerve ◽

Facial Palsy ◽

Tumor Resection ◽

Nerve Fibers ◽

Middle Fossa ◽

Tumor Removal ◽

Middle Fossa Approach ◽

Brainstem Response ◽

Facial Nerve Schwannoma

Abstract The treatment paradigm of skull base surgery has been changed from radical tumor resection to maximal tumor removal while giving priority to functional preservation. Facial nerve schwannoma is one of the representative disorders of this type of paradigm shift.1 This video demonstrates facial nerve schwannoma surgery through the middle fossa approach, aiming for improvement of facial function. A 33-yr-old woman presented with gradually worsening facial palsy (House-Brackmann grade IV), dizziness, and nausea. Neuroimaging revealed a growing tumor involving the geniculate ganglion, and extending to the middle fossa, internal acoustic meatus, and cerebellopontine angle. The nerve-sparing surgery through the left middle fossa approach was performed under detailed neuromonitoring including the evoked facial electromyograms and auditory brainstem response. The facial nerve fibers were involved within the tumor mass and the plane between the tumor and facial nerve could not be identified as seen in most cases of such large facial nerve schwannomas. But sufficient tumor removal with facial nerve preservation was achieved owing to continuous facial monitoring.2 The patient had no new neurological deficits. Her facial palsy has been gradually improving, now at grade III, without any signs of tumor regrowth during the 10 mo of follow up after the operation. Careful follow up is being continued to survey the possible tumor recurrence. The video was reproduced after informed consent of the patient.

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Preservation of Facial, Cochlear, and other Nerve Functions in Acoustic Neuroma Treatment

Otolaryngology ◽

10.1177/019459989411000202 ◽

1994 ◽

Vol 110 (2) ◽

pp. 146-155 ◽

Cited By ~ 82

Author(s):

Jean-Marc Sterkers ◽

Gavin A. J. Morrison ◽

Olivier Sterkers ◽

Mohamed M. K. Badr El-Dine

Keyword(s):

Facial Nerve ◽

Cranial Nerves ◽

Surgical Excision ◽

Hearing Preservation ◽

Middle Fossa ◽

Middle Fossa Approach ◽

Translabyrinthine Approach ◽

Number Of Patients ◽

Facial Nerve Monitoring ◽

Facial Function

Between March 1966 and September 1992, 1400 acoustic neuromas were treated in Paris, France, by surgical excision. The findings over the last 7 years are presented. The translabyrinthine approach has been used in more than 85% of cases. Where hearing preservation is attempted, the middle fossa approach has been adopted for intracanilicular tumors and the retrosigmoid approach for small tumors extending into the cerebellopontine angle, in which the fundus of the internal meatus is free of tumor. The main goal is to achieve a grade I or II result in facial function within 1 month of surgery. Results improved during 1991 after the introduction of continuous facial nerve monitoring and the use of the Beaver mini-blade for dissection of tumor from nerve. With these techniques, facial function at grade I or II at 1 month improved from 20% to 52% for large tumors (larger than 3 cm), from 42% to 81% for medium tumors (2 to 3 cm), and from 70% to 92% for small tumors (up to and including 2 cm extracanalicular). The facial nerve was at greater risk using the retrosigmoid or middle fossa approaches than by the translabyrinthine route. Since 1985, success in hearing preservation has changed little, with useful hearing being preserved in 38.2% of cases operated on by means of the retrosigmoid route and 36.4% of cases after the middle fossa approach. In older patients with good hearing and small tumors, observation with periodic MRI scanning is recommended. Despite earlier diagnosis, the number of patients suitable for hearing preservation surgery remains very limited and careful selection is required. Trigeminal nerve signs were present in 20% of cases preoperativey, in 10% postoperatively, and recovered spontaneously. Palsies of the other cranial nerves after surgery were much rarer and were as follows: sixth nerve (abducens), 0.5%; ninth nerve (glossopharyngeal), 1.4%; and tenth nerve (vagus), 0.7%. The importance of preservation of function of the nervus intermedius of Wrisberg is stressed. These results emphasize the advantages of the translabyrinthine approach, offering greater security to the facial nerve and lower morbidity.

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