Split facial nerve course in vestibular schwannomas

2006 ◽  
Vol 105 (5) ◽  
pp. 698-705 ◽  
Author(s):  
Christian Strauss ◽  
Julian Prell ◽  
Stefan Rampp ◽  
Johann Romstöck
Keyword(s):  
Facial Nerve ◽  
Internal Auditory Canal ◽  
Nerve Fibers ◽  
Vestibular Schwannomas ◽  
Major Portion ◽  
Neurophysiological Monitoring ◽  
Nerve Preservation ◽  
Root Exit Zone ◽  
Trigeminal Root ◽  
Orbicularis Oris Muscle

Object The facial nerve in vestibular schwannomas (VSs) is located on the ventral tumor surface in more than 90% of cases; other courses are rare. A split facial nerve course with two distinct bundles has thus far been described exclusively for medial extrameatal tumors. Methods Between 1996 and 2005, 16 consecutive cases of 241 surgically treated VSs were observed to have distinct splitting of the facial nerve. The mean tumor size measured 27 mm. In one third of the cases, intrameatal tumor extension with obliteration of the fundus was documented. All patients underwent extensive intraoperative neurophysiological monitoring using multichannel electromyography recordings. Patients were reevaluated 12 months after surgery. In all 16 patients, distinct splitting of the facial nerve was demonstrated. The major portion of the facial nerve followed a typical course on the ventral tumor surface. The smaller nerve portion in all cases ran parallel to the brainstem up to the level of the trigeminal root exit zone and crossed on the cranial tumor pole to the internal auditory canal. The two nerve portions rejoined at the level of the porus acusticus. The smaller portion carried fibers exclusively to the orbicularis oris muscle, whereas the major portion supplied all three branches of the facial nerve. Conclusions In VSs, an aberrant course with distinct splitting of the facial nerve adds considerably to the surgical challenge. Long-term facial nerve results are excellent with extensive neurophysiological monitoring, which allows the differentiation and identification of aberrant facial nerve fibers and avoids additional risks to facial nerve preservation.

Effects of Facial Nerve Compression on the Stapedial Nerve

1984 ◽  
Vol 93 (3_suppl) ◽  
pp. 7-11 ◽  
Author(s):  
Yasushi Matsumoto ◽  
Shingo Murakami ◽  
Naoaki Yanagihara ◽  
Hiroshi Fujita
Keyword(s):  
Facial Nerve ◽  
Functional Recovery ◽  
Histological Finding ◽  
Average Diameter ◽  
Nerve Fibers ◽  
Factors Influencing ◽  
Stapedius Muscle ◽  
Orbicularis Oris Muscle ◽  
Stapedial Reflex ◽  
Series Of Experiments

A series of experiments on guinea pigs was conducted to determine the prognostic dependability of the stapedial reflex measurement in Bell's palsy. Comparison of the threshold of evoked electromyographic response of the stapedius muscle with that of the orbicularis oris muscle revealed that the stapedial nerve had a lower excitability than did the nerve innervating the orbicularis oris muscle. This lower excitability correlates with the histological finding that the stapedial nerve fibers have a smaller average diameter. The results indicate the resistance of the stapedial nerve to injury of the facial nerve. Functional recovery after cramping of the facial nerve tended to occur later in the stapedial nerve than in the nerve innervating the orbicularis oris muscle. The resistance of the stapedial nerve and the longer period required to recover function in this nerve were factors influencing the prognostic ambiguity of this test.

scholarly journals Facial Nerve Schwannomas Mimicking as Vestibular Schwannomas

2017 ◽  
Vol 78 (04) ◽  
pp. 283-287
Author(s):  
Sean Wise ◽  
David Cohen ◽  
Jason Bell ◽  
Dennis Bojrab ◽  
Michael LaRouere ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Outcome Measures ◽  
Action Potentials ◽  
Internal Auditory Canal ◽  
Vestibular Schwannomas ◽  
Tumor Capsule ◽  
Spontaneous Action ◽  
The Mean ◽  
Spontaneous Action Potentials ◽  
Stimulation Of

Objective The objective of this study was to identify preoperative and intraoperative findings that may aid in distinguishing facial nerve schwannomas (FNS) from vestibular schwannomas (VSs), particularly in cases limited to the internal auditory canal (IAC) and cerebellopontine angle (CPA). Study Design This was a retrospective study. Setting This study was set at a Tertiary Referral Center. Patients Seventeen cases from October 2002 to July 2015 with an IAC/CPA mass presumed to be a VS who were found to have a FNS intraoperatively. Main Outcome Measures The main outcome measures included preoperative presentation, intraoperative findings, and subsequent intervention. Results Preoperative hearing loss and imbalance were seen in 70.5 and 64.7%, respectively. Suspicious intraoperative findings included: facial nerve incorporated intimately with the tumor capsule in 12 cases; spontaneous action potentials noted while drilling the bony IAC in 3 cases; and action potentials noted on stimulation of the entire tumor capsule in 10 cases. The mean long-term facial function was House–Brackmann grade II and the mean length of follow-up was 4.86 years. Conclusion FNSs are rare and may be difficult to distinguish from VS preoperatively. Surgical findings that should raise concern include spontaneous action potentials during drilling the bony IAC, absence of a plane of dissection between the facial nerve and tumor, or stimulation of the tumor capsule.

Internal Auditory Canal Variability and Facial Nerve Outcome after Translabyrinthine Resection of Vestibular Schwannomas

2020 ◽  
Author(s):  
Michael A. Cohen ◽  
Forrest Hammrick ◽  
Austin S. Gamblin ◽  
Michael Karsy ◽  
Richard Gurgel ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Internal Auditory Canal ◽  
Vestibular Schwannomas

scholarly journals Anterior Extension of Tumor is as Important as Tumor Size to Facial Nerve Outcome and Extent of Resection for Vestibular Schwannomas

2017 ◽  
Vol 78 (06) ◽  
pp. 473-480 ◽  
Author(s):  
Ricky Wong ◽  
William Copeland ◽  
Jeffrey Jacob ◽  
Sananthan Sivakanthan ◽  
Jamie Van Gompel ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Tumor Size ◽  
Internal Auditory Canal ◽  
Extent Of Resection ◽  
Vestibular Schwannomas ◽  
Brainstem Compression ◽  
Anterior Extension ◽  
Preoperative Magnetic Resonance ◽  
Ac Measurement ◽  
Anterior Posterior

Objectives We examined vestibular schwannoma tumor dimension and direction of growth to determine whether these correlate with facial nerve outcome as well as extent of resection (EOR). Design Retrospective review of prospectively maintained databases. Participants 206 patients were a part of this study. Main Outcome Measures Tumor dimensions were measured using preoperative magnetic resonance imaging, and a series of ratios were then calculated to further characterize tumor dimension. Regression analyses were performed to investigate correlation with facial nerve outcome and EOR. Results Patients with tumor extending >1.5 cm anterior to the internal auditory canal (IAC) (AB measurement) were three times more likely to have postoperative House-Brackman grades of 3 or worse. We also found that an EB/BF ratio (representing elongated growth parallel to the IAC axis) ≥1.1 was associated with half the risk of poor facial nerve outcome. Tumors with anterior-posterior diameter (AC measurement) >1.9 cm were five times less likely to undergo gross total resection (GTR). Furthermore, an increased degree of tumor extension into the IAC (DE measurement >2.4 cm) or an increased amount of brainstem compression (EB measurement >1.1 cm) were each associated with a nearly 3-fold decrease in the likelihood of GTR. Conclusion Our study demonstrates that anterior extent of the tumor is as important as tumor size to facial nerve outcome and degree of resection for vestibular schwannomas.

scholarly journals Keyhole retrosigmoid approach for large vestibular schwannomas: strategies to improve outcomes

2018 ◽  
Vol 44 (3) ◽  
pp. E2 ◽  
Author(s):  
Reid Hoshide ◽  
Harrison Faulkner ◽  
Mario Teo ◽  
Charles Teo
Keyword(s):  
Minimally Invasive ◽  
Facial Nerve ◽  
Chart Review ◽  
Retrospective Chart Review ◽  
Retrosigmoid Approach ◽  
Vestibular Schwannomas ◽  
Tumor Diameter ◽  
Nerve Preservation ◽  
Facial Nerve Preservation

OBJECTIVEThere are numerous treatment strategies in the management for large vestibular schwannomas, including resection only, staged resections, resections followed by radiosurgery, and radiosurgery only. Recent evidence has pointed toward maximal resection as being the optimum strategy to prevent tumor recurrence; however, durable tumor control through aggressive resection has been shown to occur at the expense of facial nerve function and to risk other approach-related complications. Through a retrospective analysis of their single-institution series of keyhole neurosurgical approaches for large vestibular schwannomas, the authors aim to report and justify key techniques to maximize tumor resection and reduce surgical morbidity.METHODSA retrospective chart review was performed at the Centre for Minimally Invasive Neurosurgery. All patients who had undergone a keyhole retrosigmoid approach for the resection of large vestibular schwannomas, defined as having a tumor diameter of ≥ 3.0 cm, were included in this review. Patient demographics, preoperative cranial nerve status, perioperative data, and postoperative follow-up were obtained. A review of the literature for resections of large vestibular schwannomas was also performed. The authors’ institutional data were compared with the historical data from the literature.RESULTSBetween 2004 and 2017, 45 patients met the inclusion criteria for this retrospective chart review. When compared with findings in a historical cohort in the literature, the authors’ minimally invasive, keyhole retrosigmoid technique for the resection of large vestibular schwannomas achieved higher rates of gross-total or near-total resection (100% vs 83%). Moreover, these results compare favorably with the literature in facial nerve preservation (House-Brackmann I–II) at follow-up after gross-total resections (81% vs 47%, p < 0.001) and near-total resections (88% vs 75%, p = 0.028). There were no approach-related complications in this series.CONCLUSIONSIt is the experience of the senior author that complete or near-complete resection of large vestibular schwannomas can be successfully achieved via a keyhole approach. In this series of 45 large vestibular schwannomas, a greater extent of resection was achieved while demonstrating high rates of facial nerve preservation and low approach-related and postoperative complications compared with the literature.

scholarly journals Chances of Improvement in Cases of Vestibular Schwannoma Presenting with Facial Nerve Weakness: Presentation of Two Cases and Literature Review

2018 ◽  
Vol 80 (01) ◽  
pp. 040-045
Author(s):  
Ahmed Rizk ◽  
Marcus Mehlitz ◽  
Martin Bettag
Keyword(s):  
Hearing Loss ◽  
Facial Nerve ◽  
Male Patient ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Retrosigmoid Approach ◽  
Neurophysiological Monitoring ◽  
Facial Weakness ◽  
First Case ◽  
The Brain

Background and Study Aim Facial nerve (FN) weakness as a presenting feature in vestibular schwannoma (VS) is extremely rare. We are presenting two different cases of VS with significant facial weakness and reviewed the literature for similar cases. Methods and Results We are presenting two cases of VS with significant facial weakness. The first case was a 63-year-old male patient presented with 3 weeks' history of severe left-sided facial weakness (House–Brackmann [HB] grade V) and hearing loss. Magnetic resonance imaging (MRI) of the brain showed a tumor in the left internal auditory canal. Gross total removal with anatomical and physiological FN preservation was performed through a retrosigmoid approach under neurophysiological monitoring. FN function improved postoperatively to HB grade II after 16 months. The other case was 83-year-old male patient presented with sudden left-sided hearing loss and severe facial weakness (HB grade V). MRI of the brain 2.5 years before showed a left-sided (Class-T3A) cystic VS. The tumor was asymptomatic; wait-and-scan strategy was advised by the treating neurologist. Recent MRI of the brain showed approximately three times enlargement of the tumor with brain stem compression, extensive cystic changes, and suspected intratumoral hemorrhage. Surgery was performed; the tumor was subtotally removed through a retrosigmoid approach with intraoperative FN monitoring. The FN was anatomically preserved; however, physiological preservation was not possible. Severe facial weakness with incomplete lid closure persisted postoperatively. Conclusion Surgical treatment could be offered to cases of suspected VS presenting with facial weakness, as these cases may still have a chance for improvement especially in laterally located tumors.

Suboccipital Retrosigmoid Approach for Removal of Vestibular Schwannomas: Facial Nerve Function and Hearing Preservation

Neurosurgery ◽  
2005 ◽  
Vol 56 (3) ◽  
pp. 560-570 ◽  
Author(s):  
Ivan Ciric ◽  
Jin-cheng Zhao ◽  
Sami Rosenblatt ◽  
Richard Wiet ◽  
Brian O'shaughnessy
Keyword(s):  
Prognostic Factors ◽  
Surgical Technique ◽  
Facial Nerve ◽  
Hearing Preservation ◽  
Vestibular Schwannomas ◽  
Neurophysiological Monitoring ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Tumor Removal ◽  
Neurovascular Anatomy

Abstract IN THIS REPORT, we discuss the pertinent bony, arachnoid, and neurovascular anatomy of vestibular schwannomas that has an impact on the surgical technique for removal of these tumors, with the goal of facial nerve and hearing preservation. The surgical technique is described in detail starting with anesthesia, positioning, and neurophysiological monitoring and continuing with the exposure, technical nuances of tumor removal, hemostasis, and closure. Positive prognostic factors for hearing preservation are also highlighted.

Transcranial translabyrinthine approach to vestibular schwannomas

1993 ◽  
Vol 107 (2) ◽  
pp. 111-114 ◽  
Author(s):  
Joseph G. Feghali ◽  
Allen B. Kantrowitz
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Endolymphatic Sac ◽  
Vestibular Schwannomas ◽  
Translabyrinthine Approach ◽  
Vestibular Aqueduct ◽  
Temporal Bones ◽  
Suboccipital Approach

Surgeons who utilize the suboccipital approach for the removal of large vestibular schwannomas, can perform a planned labyrinthectomy from within the intracranial cavity via the suboccipital exposure. This transcranial translabyrinthine approach provides one of the major advantages of the conventional transmastoid translabyrinthine approach, namely, unambiguous identification of the facial nerve as it exits the internal auditory canal, without the need for complete mastoidectomy and labyrinthectomy. The labyrinthectomy is best performed prior to the complete exposure of the internal auditory canal. The approach requires the surgeon to identify the endolymphatic sac intracranially, then drill the temporal bone and follow the vestibular aqueduct to the utricle. The lateral and superior semicircular canal ampullae, the superior vestibular nerve, Bill's bar, and the facial nerve at the lateral end of the internal auditory canal can then be identified. After testing on multiple cadaver temporal bones, this approach was used in patients with large tumours that extended far laterally in the internal auditory canal. The steps in the technique are described in detail.

scholarly journals Surgical Strategy in Large Vestibular Schwannoma

2018 ◽  
Vol 80 (S 03) ◽  
pp. S272-S273
Author(s):  
Georgios Klironomos ◽  
Amir Reza Dehdashti
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Air Embolism ◽  
Patient Positioning ◽  
Skin Incision ◽  
Surgical Strategy ◽  
Vestibular Schwannomas ◽  
Magnetic Resonance Imaging Mri ◽  
Large Vestibular Schwannoma

Particular care to facial nerve function preservation should be the ultimate goal in surgery for large vestibular schwannomas. We present a 60-year-old patient who presented with an enlarging right vestibular schwannoma and nonserviceable hearing. The patient was operated in the semisitting position after a patent foramen ovale was ruled out. During the positioning, the feet were positioned at the level of the heart. Precordial Doppler was used to monitor for air embolism. Straight skin incision and retrosigmoid craniotomy was performed. Specific attention to venous bleeding was made during the approach. Meticulous arachnoid dissection of the capsule preserving the arachnoid plane at the surface of the brain stem and the facial nerve can be achieved more efficiently with the patient in the semisiting position and with bimanual microdissection technique. After drilling of the internal auditory canal (IAC), we were able to achieve near total removal of the tumor, leaving a tiny tumor carpet due to extreme adherence to the nerve. Water-tight dura closure and replacement of the bone flap was performed. The patient woke up with a House–Brackmann grade III facial weakness which improved to grade I at 6 weeks postoperatively. Postoperative magnetic resonance imaging (MRI) showed a tiny residual at the surface of the facial nerve at the entrance of the IAC. Near total (> 98%) resection of large vestibular schwannomas is an acceptable surgical strategy with excellent facial nerve outcome. With appropriate patient positioning in semisitting and proper anesthesiological and surgical management, the risk of air embolism is negligible.The link to video can be found at: https://youtu.be/ErG9VexbiGw.

scholarly journals Extra-Arachnoidal Dissection for Excision of Giant Vestibular Schwannomas: Improved Facial Nerve Preservation

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Sunil K Gupta
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannomas ◽  
Nerve Function ◽  
Total Excision ◽  
Facial Nerve Function ◽  
Nerve Preservation ◽  
Group A ◽  
Grade 3 ◽  
Group B

Abstract INTRODUCTION Surgical excision of giant vestibular schwannomas with preservation of facial nerve function remains a challenge. A modified surgical technique using an extra-arachnoid plane of dissection and limited meatal drilling is described here with the goal of improving the rated of functional preservation of facial nerve. METHODS The clinical material was analyzed for two groups: Group A patients of giant vestibular schwannomas operated between 2002 and 2009 with the “standard” surgical technique, Group B- patients of giant vestibular schwannomas operated between 2009 and 2015 using the new technique of pure extra-arachnoid dissection and limited meatal drilling. RESULTS Group A: Of the 115 patients in this group, total excision was possible in 103 (89.5%), near total excision in 7 (6%) and partial excision in 5 (4.3%) patients. Anatomical preservation of 7th nerve was achieved in 87.8% of patients. House and Brackman grade 1 and grade 2 facial nerve function was present in 68 (59.1%) patients, grade 3 in 10 (8.7%), grades 4 and 5 in 11 (9.6%), and 26 (22.6%) had grade 6 facial nerve involvement. Group B: Of the 127 patients operated by this technique, details and long term follow-up was available for 98 patients. Total excision was achieved in 70 (71.4%) patients, near total excision in 9 (9.2%), and subtotal excision in 19 (19.4%) cases. Four patients had repeat surgery and 14 patients underwent gamma knife radiosurgery. At follow-up, 78 (79.5%) patients had grade 1 and 2 facial nerve involvement, while 20 (20.4%) patients continued to have a poor function (grade 3-5). CONCLUSION Extra-arachnoid dissection and limited meatal drilling resulted in an improved rate of functional facial nerve preservation.

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