scholarly journals Intraoperative neurophysiological monitoring in vestibular schwannoma surgery: advances and clinical implications

2009 ◽  
Vol 27 (4) ◽  
pp. E9 ◽  
Author(s):  
A. Samy Youssef ◽  
Angela E. Downes
Keyword(s):  
Facial Nerve ◽  
Functional Outcome ◽  
Vestibular Schwannoma ◽  
Cranial Nerve ◽  
Evoked Potential ◽  
Hearing Preservation ◽  
Auditory Evoked Potential ◽  
Intraoperative Neurophysiological Monitoring ◽  
Neurophysiological Monitoring ◽  
Clinical Series

Object Intraoperative neurophysiological monitoring has become an integral part of vestibular schwannoma surgery. The aim of this article was to review the different techniques of intraoperative neurophysiological monitoring in vestibular schwannoma surgery, identify the clinical impact of certain pathognomonic patterns on postoperative outcomes of facial nerve function and hearing preservation, and highlight the role of postoperative medications in improving delayed cranial nerve dysfunction in the different reported series. Methods The authors performed a review of the literature regarding intraoperative monitoring in acoustic/vestibular schwannoma surgery. The different clinical series representing different monitoring techniques were reviewed. All the data from clinical series were analyzed in a comprehensive and comparative model. Results Intraoperative brainstem auditory evoked potential monitoring, direct cochlear nerve action potential monitoring, and facial nerve electromyography are the main tools used to assess the functional integrity of an anatomically intact cranial nerve. The identification of pathognomonic brainstem auditory evoked potential and electromyography patterns has been correlated with postoperative functional outcome. Recently, perioperative administration of intravenous hydroxyethyl starch and nimodipine as vasoactive and neuroprotective agents was shown to improve vestibular schwannoma functional outcome in few reported studies. Conclusions Recent advances in electrophysiological technology have considerably contributed to improvement in functional outcome of vestibular neuroma surgery in terms of hearing preservation and facial nerve paresis. Perioperative intravenous nimodipine and hydroxyethyl starch may be valuable additions to surgery.

Hearing Preservation Surgery in the Sitting Position for Grade 3B Hannover Classification Vestibular Schwannoma: 3-Dimensional Operative Video

2021 ◽  
Author(s):  
Devon O’Donnell ◽  
Amir R Dehdashti
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Treatment Options ◽  
Cranial Nerves ◽  
Hearing Preservation ◽  
Auditory Evoked Potential ◽  
Sitting Position ◽  
3 Dimensional ◽  
Facial Nerve Stimulation

Abstract Surgical treatment of large vestibular schwannomas is challenging. Both facial and cochlear nerves should be preserved in patients who have no neurological deficit preoperatively. In this 3-dimensional video, we present a 35-yr-old patient who presented with documented increase in the size of a known vestibular schwannoma over the span of 3 yr. Surgery was favored among all treatment options due to his young age and the tumor size. Informed consent was obtained. Semisitting surgery allowed for bimanual microdissection of the tumor capsule from the surrounding arachnoid and cranial nerves with 2 micro dissectors. The precision of microdissection is enhanced in the sitting position. Facial nerve stimulation remained stable at 0.05 mA. The auditory evoked potential remained unchanged during the surgery. Complete resection of the tumor and preservation of facial and cochlear nerves was achieved. The patient had a stable hearing grade B and a normal facial nerve function at 3-mo follow-up.

scholarly journals Impact of Motor-Evoked Potential Monitoring on Facial Nerve Outcomes after Vestibular Schwannoma Resection

2018 ◽  
Vol 128 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Kareem O. Tawfik ◽  
Zoe A. Walters ◽  
Gavriel D. Kohlberg ◽  
Noga Lipschitz ◽  
Joseph T. Breen ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Predictive Value ◽  
Evoked Potential ◽  
Amplitude Ratio ◽  
Motor Evoked Potential ◽  
Level Of Evidence ◽  
Facial Function

Objectives: Assess the utility of intraoperative transcranial facial motor-evoked potential (FMEP) monitoring in predicting and improving facial function after vestibular schwannoma (VS) resection. Study Design: Retrospective chart review. Methods: Data were obtained from 82 consecutive VS resections meeting inclusion criteria. Sixty-two cases were performed without FMEP and 20 with FMEP. Degradation of FMEP response was defined as a final-to-baseline amplitude ratio of 0.5 or less. House-Brackmann (HB) grade was assessed preoperatively, postoperatively, at follow-up assessments, and it was compared between pre- and post-FMEP cohorts. Positive predictive value (PPV) and negative predictive value (NPV), sensitivity, and specificity of FMEP degradation in predicting facial weakness were calculated. Results: In the pre-FMEP group, at length of follow-up (LOF) ⩾9 months, 83.9% (52/62) of patients exhibited HB 1-2 outcome. In the post-FMEP cohort, 75.0% (15/20) exhibited HB 1-2 function at LOF ⩾9 months. There was no difference in rates of HB 1-2 outcomes between groups in the immediate postoperative period ( P = .35) or at long-term follow-up ( P = 1.0). With respect to predicting immediate postoperative facial function, FMEP demonstrated high specificity (88.9%) and moderate sensitivity (54.5%). The PPV and NPV for immediate postoperative facial function were 85.7% and 61.5%, respectively. With respect to long-term (⩾9 months LOF) facial function, intraoperative FMEP was moderately sensitive (71.4%) and highly specific (84.6%); PPV was moderate (71.4%), and NPV was high (84.6%). Conclusions: Intraoperative FMEP is highly specific and moderately sensitive in predicting postoperative facial function for patients undergoing VS resection, but its use may not be associated with improved facial nerve outcomes. Level of Evidence: 4

Role of Facial Nerve Motor-Evoked Potential Ratio in Predicting Facial Nerve Function in Vestibular Schwannoma Surgery Both Immediate and at 1 Year

2016 ◽  
Vol 37 (8) ◽  
pp. 1162-1167 ◽  
Author(s):  
Sanjiv K. Bhimrao ◽  
Trung N. Le ◽  
Charles C. Dong ◽  
Serge Makarenko ◽  
Sarin Wongprasartsuk ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Nerve Function ◽  
Facial Nerve Function

Hearing Preservation After Translabyrinthine Vestibular Schwannoma Excision: Audiometry and Electrocochleography Results

2018 ◽  
Vol 127 (8) ◽  
pp. 563-567 ◽  
Author(s):  
Kenneth Akakpo ◽  
William J. Riggs ◽  
Michael S. Harris ◽  
Edward E Dodson
Keyword(s):  
Hair Cell ◽  
Vestibular Schwannoma ◽  
Cranial Nerve ◽  
Cell Activity ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Healthy Patient ◽  
Cochlear Hair Cell ◽  
Translabyrinthine Approach ◽  
Cranial Nerve Viii

Objectives: To describe a case of inadvertent hearing preservation following a classical translabyrinthine resection of a vestibular schwannoma of the internal auditory canal in an otherwise healthy patient. Methods: Herein, we describe the case of an otherwise healthy patient who underwent resection of an intracanalicular vestibular schwannoma via a translabyrinthine approach. Furthermore, as part of an ongoing study aimed at characterizing hearing changes due to intraoperative events, cochlear hair cell and nerve activity were monitored using electrocochleography throughout surgery. Unexpectedly, the patient maintained serviceable hearing following surgery. As a result, we are able to provide electrophysiologic evidence of cochlear hair cell activity at various stages of this surgery. Results: Hair cell responses across tested frequencies were detectable prior to and following completion of the translabyrinthine procedure. Neural integrity of the auditory division of cranial nerve VIII was maintained throughout. Lastly, postoperative audiometric testing supported the patient’s subjective assertion of serviceable hearing in the surgical ear. Conclusion: Our results suggest that some degree of hair cell and neural integrity can be maintained throughout the course of the translabyrinthine approach, and if preservation of the auditory division of cranial nerve VIII is feasible, a functional amount of hearing preservation is attainable.

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