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The Anatomically Intact but Electrically Unresponsive Facial Nerve in Vestibular Schwannoma Surgery

Carlson, Matthew L. MD*; Van Abel, Kathryn M. MD*; Schmitt, William R. MD*; Driscoll, Colin L. MD*,‡; Neff, Brian A. MD*; Link, Michael J. MD*,‡

doi: 10.1227/NEU.0b013e318271bce3
Research-Human-Clinical Studies
CNS University of Neurosurgery

BACKGROUND: Permanent facial nerve (FN) paresis after vestibular schwannoma surgery is distressing to both the patient and surgeon. Intraoperative electrophysiological testing has proven invaluable in reducing the incidence of FN injury and may assist in prognosticating long-term function.

OBJECTIVE: To report definitive FN outcomes among a cohort of patients with an unevokable but anatomically intact seventh nerve after microsurgical vestibular schwannoma resection.

METHODS: All patients undergoing vestibular schwannoma surgery between 2000 and 2010 at a single tertiary academic referral center were identified. Intraoperative FN monitoring data and definitive FN outcomes were reviewed, and all patients with an anatomically intact but electrically unresponsive FN were included.

RESULTS: Eleven patients met the inclusion criteria. The median preoperative and definitive postoperative FN scores were House-Brackmann grades 1 and 3, respectively. The median time to definitive FN recovery was 9.4 months.

CONCLUSION: These data demonstrate that even among this extreme subset, modern electroprognostic testing strategies are incapable of reliably predicting poor outcomes. Therefore, if FN continuity is maintained, attempts at same-surgery FN repair should not be pursued.

ABBREVIATIONS: EMG, electromyographic

FN, facial nerve

HBG, House-Brackmann grade

VS, vestibular schwannoma

Department of *Otolaryngology Head and Neck Surgery

Neurologic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota

Correspondence: Michael J. Link, MD, Department of Neurologic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905. E-mail: link.michael@mayo.edu

Received April 30, 2012

Accepted August 16, 2012

Copyright © by the Congress of Neurological Surgeons