scholarly journals Value of intraoperative monitoring of the trigeminal nerve in detection of a superiorly displaced facial nerve during surgery for large vestibular schwannomas

2021 ◽  
Author(s):  
Yasmine A. Ashram ◽  
Youssef M. Zohdy ◽  
Tarek A. Rayan ◽  
Mohamed M. K. Badr-El-Dine
Keyword(s):  
Facial Nerve ◽  
Trigeminal Nerve ◽  
Intraoperative Monitoring ◽  
Vestibular Schwannomas

scholarly journals Dosimetric Analysis of Neural and Vascular Structures in Skull Base Tumors Treated with Stereotactic Radiosurgery

2017 ◽  
Vol 156 (5) ◽  
pp. 857-862
Author(s):  
Yarah M. Haidar ◽  
Jay M. Bhatt ◽  
Yaser Ghavami ◽  
Omid Moshtaghi ◽  
Amanda Schwer ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Facial Nerve ◽  
Stereotactic Radiosurgery ◽  
Trigeminal Nerve ◽  
Tumor Volume ◽  
Case Series ◽  
Vestibular Schwannomas ◽  
Anterior Inferior Cerebellar Artery ◽  
Cerebellar Artery ◽  
Neurovascular Structures

Objective To examine the relationship between the prescribed target dose and the dose to healthy neurovascular structures in patients with vestibular schwannomas treated with stereotactic radiosurgery (SRS). Study Design Case series with chart review. Setting SRS center from 2011 to 2013. Subjects Twenty patients with vestibular schwannomas treated at the center from 2011 to 2013. Methods Twenty patients with vestibular schwannomas were included. The average radiation dose delivered to healthy neurovascular structures (eg, carotid artery, basilar artery, facial nerve, trigeminal nerve, and cochlea) was analyzed. Results Twenty patients with vestibular schwannomas who were treated with fused computed tomography/magnetic resonance imaging–guided SRS were included in the study. The prescribed dose ranged from 10.58 to 17.40 Gy over 1 to 3 hypofractions to cover 95% of the target tumor volume. The mean dose to the carotid artery was 5.66 Gy (95% confidence interval [CI], 4.53-6.80 Gy), anterior inferior cerebellar artery was 8.70 Gy (95% CI, 4.54-12.86 Gy), intratemporal facial nerve was 3.76 Gy (95% CI, 3.04-4.08 Gy), trigeminal nerve was 5.21 Gy (95% CI, 3.31-7.11 Gy), and the cochlea was 8.70 Gy (95% CI, 7.81-9.59 Gy). Conclusions SRS for certain vestibular schwannomas can expose the anterior inferior cerebellar artery (AICA) and carotid artery to radiation doses that can potentially initiate atherosclerotic processes. The higher doses to the AICA and carotid artery correlated with increasing tumor volume. The dose delivered to other structures such as the cochlea and intratemporal facial nerve appears to be lower and much less likely to cause immediate complications when shielded.

scholarly journals Value of Intraoperative Monitoring of the Trigeminal Nerve in Detection of a Superiorly Displaced Facial Nerve During Surgery for Large Vestibular Schwannomas

2021 ◽  
Author(s):  
Yasmine A. Ashram ◽  
Youssef M. Zohdy ◽  
Tarek A. Rayan ◽  
Mohamed M.K. Badr-El-Dine
Keyword(s):  
Facial Nerve ◽  
Trigeminal Nerve ◽  
Compound Muscle Action Potential ◽  
Vestibular Schwannomas ◽  
Facial Emg ◽  
Trigeminal Nerve Stimulation ◽  
Muscle Action Potential ◽  
Facial Nerve Monitoring ◽  
Facial Nerves ◽  
Superior Surface

Abstract ObjectiveTo investigate the role of trigeminal and facial nerve monitoring in the early identification of a superiorly displaced facial nerve.Patients and MethodsThis prospective study included 24 patients operated for removal of large vestibular schwannomas (VS). Electromyographic (EMG) events recorded after mapping the superior surface of the tumor were evaluated by analyzing the latencies of the responses from the masseter and facial nerve innervated muscles.ResultsThe latency of the recorded compound muscle action potential (CMAP) from the masseter muscle was 3.6 ±0.5 msec, and of the simultaneously recorded volume conducted responses from the frontalis, o.oculi, nasalis, o.oris and mentalis muscles were 4.6 ±0.9, 4.1 ±0.7, 3.9 ±0.4, 4.3 ±0.8 and 4.5 ±0.6 msec respectively after trigeminal nerve stimulation in 24 (100%) patients. In 6 (25%) patients, the mean latency of CMAP on the masseter was 3.6 ±0.5 msec, and the latencies of the CMAP from the frontalis, nasalis, o.oris and mentalis muscles were longer than those of the volume conduced responses (p=0.002; p=0.001; p< 0.001; and p=0.015 respectively) indicating stimulation of both nerves (trigemino-facial EMG response). All patients with this response were later confirmed anatomically to have an AS displaced facial nerve. ConclusionUnderstanding the trigemino-facial EMG response is of value in identifying an AS displaced facial nerve; in preventing electrophysiological confusion between the trigeminal and the facial nerves; and in detecting the presence of volume conducted contributions in the measured facial nerve CMAP at the end of surgery.

Cerebellopontine Angle Surgery Assisted by Continuous Mapping of the Facial Nerve Via the Ultrasonic Aspirator

2020 ◽  
Author(s):  
Marco Cenzato ◽  
Roberto Stefini ◽  
Francesco Zenga ◽  
Maurizio Piparo ◽  
Alberto Debernardi ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Facial Nerve ◽  
Cerebellopontine Angle ◽  
Continuous Mapping ◽  
Cost Effective ◽  
Current Intensity ◽  
Vestibular Schwannomas ◽  
Constant Current ◽  
Surgical Workflow ◽  
Ultrasonic Aspirator

Abstract Background Cerebellopontine angle (CPA) surgery carries the risk of lesioning the facial nerve. The goal of preserving the integrity of the facial nerve is usually pursued with intermittent electrical stimulation using a handheld probe that is alternated with the resection. We report our experience with continuous electrical stimulation delivered via the ultrasonic aspirator (UA) used for the resection of a series of vestibular schwannomas. Methods A total of 17 patients with vestibular schwannomas, operated on between 2010 and 2018, were included in this study. A constant-current stimulator was coupled to the UA used for the resection, delivering square-wave pulses throughout the resection. The muscle responses from upper and lower face muscles triggered by the electrical stimulation were displayed continuously on multichannel neurophysiologic equipment. The careful titration of the electrical stimulation delivered through the UA while tapering the current intensity with the progression of the resection was used as the main strategy. Results All operations were performed successfully, and facial nerve conduction was maintained in all patients except one, in whom a permanent lesion of the facial nerve followed a miscommunication to the neurosurgeon. Conclusion The coupling of the electrical stimulation to the UA provided the neurosurgeon with an efficient and cost-effective tool and allowed a safe resection. Positive responses were obtained from the facial muscles with low current intensity (lowest intensity: 0.1 mA). The availability of a resection tool paired with a stimulator allowed the surgeon to improve the surgical workflow because fewer interruptions were necessary to stimulate the facial nerve via a handheld probe.

scholarly journals Sensitivity and Negative Predictive Value of Motor Evoked Potentials of the Facial Nerve

2021 ◽  
Author(s):  
Nicolas Bovo ◽  
Shahan Momjian ◽  
Renato Gondar ◽  
Philippe Bijlenga ◽  
Karl Schaller ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Evoked Potentials ◽  
Negative Predictive Value ◽  
Patient Group ◽  
Vestibular Schwannoma ◽  
Predictive Value ◽  
Cerebellopontine Angle ◽  
Motor Evoked Potentials ◽  
Vestibular Schwannomas ◽  
Predictive Values

Abstract Objective The objective of this study was to determine the performance of the standard alarm criterion of motor evoked potentials (MEPs) of the facial nerve in surgeries performed for resections of vestibular schwannomas or of other lesions of the cerebellopontine angle. Methods This retrospective study included 33 patients (16 with vestibular schwannomas and 17 with other lesions) who underwent the resection surgery with transcranial MEPs of the facial nerve. A reproducible 50% decrease in MEP amplitude, resistant to a 10% increase in stimulation intensity, was applied as the alarm criterion during surgery. Facial muscular function was clinically evaluated with the House–Brackmann score (HBS), pre- and postsurgery at 3 months. Results In the patient group with vestibular schwannoma, postoperatively, the highest sensitivity and negative predictive values were found for a 30% decrease in MEP amplitude, that is, a criterion stricter than the 50% decrease in MEP amplitude criterion, prone to trigger more warnings, used intraoperatively. With this new criterion, the sensitivity would be 88.9% and the negative predictive value would be 85.7%. In the patient group with other lesions of the cerebellopontine angle, the highest sensitivity and negative predictive values were found equally for 50, 60, or 70% decrease in MEP amplitude. With these criteria, the sensitivities and the negative predictive values would be 100.0%. Conclusion Different alarm criteria were found for surgeries for vestibular schwannomas and for other lesions of the cerebellopontine angle. The study consolidates the stricter alarm criterion, that is, a criterion prone to trigger early warnings, as found previously by others for vestibular schwannoma surgeries (30% decrease in MEP amplitude).

scholarly journals The Anatomical Location and Course of the Facial Nerve in Vestibular Schwannomas : A Study of 163 Surgically Treated Cases

2007 ◽  
Vol 42 (6) ◽  
pp. 450 ◽  
Author(s):  
Chae Wan Bae ◽  
Young Hyun Cho ◽  
Seok Ho Hong ◽  
Jeong Hoon Kim ◽  
Jung-kyo Lee ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannomas ◽  
Anatomical Location

scholarly journals Preservation of Hearing and Facial Nerve Function with the Microsurgical Excision of Large Vestibular Schwannomas: Experience with the Retrosigmoid Approach

Cureus ◽  
2018 ◽  
Author(s):  
Muhammad Shaheryar Ahmed Rajput ◽  
Ahmad Nawaz Ahmad ◽  
Asif Ali Arain ◽  
Mohammad Adeel ◽  
Saeed Akram ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Retrosigmoid Approach ◽  
Vestibular Schwannomas ◽  
Nerve Function ◽  
Facial Nerve Function

scholarly journals Translabyrinthine microsurgical resection of small vestibular schwannomas

2018 ◽  
Vol 129 (1) ◽  
pp. 128-136 ◽  
Author(s):  
Marc S. Schwartz ◽  
Gregory P. Lekovic ◽  
Mia E. Miller ◽  
William H. Slattery ◽  
Eric P. Wilkinson
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Sinus Thrombosis ◽  
Treatment Options ◽  
Previous Treatment ◽  
Cerebrospinal Fluid Leak ◽  
Neurofibromatosis Type ◽  
Additional Treatment ◽  
Vestibular Schwannomas ◽  
Tumor Control

OBJECTIVETranslabyrinthine resection is one of a number of treatment options available to patients with vestibular schwannomas. Though this procedure is hearing destructive, the authors have noted excellent clinical outcomes for patients with small tumors. The authors review their experience at a tertiary acoustic neuroma referral center in using the translabyrinthine approach to resect small vestibular schwannomas. All operations were performed by a surgical team consisting of a single neurosurgeon and 1 of 7 neurotologists.METHODSData from a prospectively maintained clinical database were extracted and reviewed. Consecutive patients with a preoperative diagnosis of vestibular schwannoma that had less than 1 cm of extension into the cerebellopontine angle, operated on between 2008 and 2013, were included. Patents with neurofibromatosis Type 2, previous treatment, or preexisting facial weakness were excluded. In total, 107 patients were identified, 74.7% of whom had poor hearing preoperatively.RESULTSPathologically, 6.5% of patients were found to have a tumor other than vestibular schwannoma. Excluding two malignancies, the tumor control rates were 98.7%, as defined by absence of radiographic disease, and 99.0%, as defined by no need for additional treatment. Facial nerve outcome was normal (House-Brackmann Grade I) in 97.2% of patients and good (House-Brackmann Grade I–II) in 99.1%. Complications were cerebrospinal fluid leak (4.7%) and sigmoid sinus thrombosis (0.9%), none of which led to long-term sequelae.CONCLUSIONSTranslabyrinthine resection of small vestibular schwannomas provides excellent results in terms of complication avoidance, tumor control, and facial nerve outcomes. This is a hearing-destructive operation that is advocated for selected patients.

Intracanalicular vestibular schwannomas presenting with facial nerve paralysis

2018 ◽  
Vol 160 (4) ◽  
pp. 689-693 ◽  
Author(s):  
Luciano Mastronardi ◽  
Guglielmo Cacciotti ◽  
Raffaele Roperto
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannomas ◽  
Facial Nerve Paralysis ◽  
Nerve Paralysis
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