Intraoperative facial nerve electromyography parameters to optimize postoperative facial nerve outcome in patients with large unilateral vestibular schwannoma

Mohamed Elsayed, Huan Jia, Baptiste Hochet, Olivier Sterkers, Victor Renato Torres Lazo, Yann Nguyen, Isabelle Bernat, Ghizlene Lahlou, Michel Kalamarides

Research output: Contribution to journalArticlepeer-review


Background: Decision-making for large sporadic vestibular schwannomas (VS) resection guided by the intraoperative change in supramaximal facial nerve (FN) amplitude and latency response to optimize post-operative FN outcome. Methods: Prospectively study of 43 patients, from January to December 2018, of large sporadic VS with preoperative normal FN function at our center. Tumors were removed through retrosigmoid (81%) or translabyrinthine (19%) approaches with FN monitoring. Intraoperative pre- and post-VS resection supramaximal (2 mA) amplitude and latency responses at the proximal FN root were recorded. Results: Total, near-/subtotal VS resections (TR, NTR, STR) were achieved in 51%, 38%, and 11% of tumors, respectively, guided by no more than 40% decrease in supramaximal amplitude. Pre- and post-resection supramaximal amplitude and latency responses were lower and longer, respectively, in NTR+STR than in TR. At day 8, FN function was grade I–II in 77% of patients and grade III–V in 23%, and after 6 months, it was in grade I-II in 95% and grade III in 5%, and there was no significant difference between TR and NTR+STR. Facial palsy occurred in older patients and in the case of severe FN adhesion. At day 8, pre- and post-resection supramaximal amplitude but not latency responses were different between FN grade III-V and grade I-II. Serviceable hearing was preserved in 28% of large VS. Conclusions: Intraoperative FN monitoring guided VS resection in large VS so that 49% retained some residual tumor. Accordingly, 95% good postoperative FN function and significant hearing preservation were achieved after 6 months.

Original languageEnglish
JournalActa Neurochirurgica
StateAccepted/In press - 2021

Bibliographical note

Funding Information:
Mohamed Elsayed was provided financial support in the form of Ministry of Higher Education, Mission sector, Egypt ( ) and the Ministry of Scientific Research.

Funding Information:
Huan Jia was provided financial support in the form of Shanghai Scientific and Technological Innovation Action Plan (17441903600), and Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases. (14DZ2260300). The sponsor had no role in the design or conduct of this research.

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.


  • Electromyography
  • Facial nerve
  • Intraoperative monitoring
  • Tumor resection
  • Vestibular schwannoma


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