Continuous Facial Nerve Stimulating Burr for Otologic Surgeries *†‡Daniele Bernardeschi, §Nawel Meskine, *Naif Al Otaibi, *Reka Ablonczy, kMichel Kalamarides, *†‡Alexis Bozorg Grayeli, and *†‡Olivier Sterkers *AP-HP, Hosp Beaujon, ENT Department, Clichy; ÞInserm; þUniv Paris Diderot, Sorbonne Paris Cite ´, Paris; and §Radiology Department, and kNeurosurgery Department, AP-HP, Hosp Beaujon, Clichy, France Objective: To evaluate a continuous facial nerve (FN) stimu- lating burr (the StimBurGard) during otologic/neurotologic pro- cedures in terms of safety and reliability when drilling in contact with the Fallopian canal (FC) of the mastoid segment of the FN. Study Design: Prospective clinical trial. Setting: Tertiary referral center. Patients: Thirty-five patients operated through translabyrin- thine (TL) approach for vestibular schwannoma removal were divided into 3 groups. Group 1 (5 patients): the stimulation cur- rent was set at 3 and then at 2 mA visualizing the localization of the burr when the first response at 100-KV threshold was obtained in the mastoid cavity. Group 2 (15 patients): exposure of the FC in the mastoid segment during TL approach was stopped when the first response was obtained at 1-mA stimu- lation; FC thickness in the second genu and mastoid segment of the FC was evaluated on a postoperative computed tomo- graphic (CT) scan, and FC dehiscence observed on CT scan was compared with surgical observation. Group 3 (15 patients), exposure of the FC was performed as routinely done during a TL approach and surgical observation of FC dehiscence; stim- ulation values in mA at the 100 KV threshold and FC thick- ness on postoperative CT scan were evaluated. In all cases, the stimulation value at the cerebellopontine angle root of the FN with a 100-KV response threshold was measured before tu- mor resection. Results: Group 1: stimulation at 3 mA occurred in aditus ad antrum and at 2 mA near the FC. Group 2: mean thickness of 1.09 T 0.69 mm with 2 cases of radiologic dehiscence of the FN. Group 3: the stimulation threshold was 0.6 T 0.37 mA, and the thickness was 0.41 T 0.56 mm with 9 cases of uncov- ered FN (p = 0.0082). In all patients, FN at brainstem was stim- ulated at 0.03 mA before VS dissection. Conclusion: Continuous FN stimulating burr by means of the StimBurGard system is a safe and effective tool for FN stim- ulation and identification. The integrity of FC is preserved in most cases when the stimulation intensity is 1 mA. Key Words: Facial nerveVIntraoperative monitoringVMastoidectomyV Vestibular schwannoma. Otol Neurotol 32:1347Y1351, 2011. Intraoperative facial nerve (FN) monitoring is a stan- dard of care during neurotologic procedures (1Y6). The systematic use of it reduces the incidence of facial palsy after a cerebellopontine angle (CPA) resection (7). Its role in middle ear surgery is less defined (8Y12) even if there is strong recommendation to use it in particular cases such as revisions, cholesteatomas, malformations, and cochlear implantations (13,14). The FN is at risk of injury during middle ear surgery, and the iatrogenic palsy can be facilitated by aberrant course of the FN and/or spontaneous or iatrogenic dehiscence of the Fallopian canal (FC); before the use of intraoperative FN monitor- ing (IOM), FN injuries represented up to 10% of com- plications in revision surgery, and it was the second cause of litigation in otologic surgery (15). This is why all ef- forts should be done to avoid this dreaded complication. The most important limitation in FN monitoring is that during drilling, the system does not alert the surgeon if he is drilling close to the FN, and the electromyographic (EMG) responses could be elicited when injury of the FN has already been done; furthermore, with a direct trauma or progressive heating, the IOM could fail to alert the sur- geon. The aim of this prospective study is to evaluate the continuous stimulating burr (StimBurGard [SBG]) during otologic/neurotologic procedures in terms of safety and reliability when drilling in contact with the mastoid seg- ment of FC during translabyrinthine (TL) approach for vestibular schwannoma (VS) removal. Localization and integrity of FC were analyzed at different stimulation Address correspondence and reprint requests to Daniele Bernardeschi, M.D., Ph.D., ENT Department, Beaujon Hospital, 100, Bd du Genaral LeclercY92100 Clichy, France; E-mail: daniele.bernardeschi@bjn.aphp.fr All authors do not receive any financial support that relates in any way to information contained in this article. All authors do not receive any support for the reported research, and they do not have other financial interests related to this study. Otology & Neurotology 32:1347Y1351 Ó 2011, Otology & Neurotology, Inc. 1347 Copyright © 2011 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.