title: Facial nerve preservation with preoperative identification and intraoperative monitoring in large vestibular schwannoma surgery.
abstract: BACKGROUND
  Microsurgery is an option of choice for large vestibular schwannomas (VSs). Anatomical and functional preservation of facial nerve (FN) is still a challenge in these surgeries. FNs are often displaced and morphologically changed by large VSs. Preoperative identification of FN with magnetic resonance (MR) diffusion tensor tracking (DTT) and intraoperative identification with facial electromyography (EMG) may be desirable for improving functional results of FN.
  
  
  METHODS
  In this retrospective study, eight consecutive cases with large VS (≥30 mm in maximal extrameatal diameter) were retrospectively studied. FN DTT was performed in each case preoperatively. All the cases underwent microsurgical resection of the tumor with intraoperative FN EMG monitoring. Correctness of prediction for FN location by DTT was verified by the surgeon's inspection. Postoperative FN function of each patient was followed up.
  
  
  RESULTS
  Preoperative identification of FN was possible in 7 of 8 (87.5 %) cases. FN location predicted by preoperative DTT agreed to surgical finding in all the 7 cases. FN EMG was helpful to locate and protect the FN. Total resection was achieved in 7 of 8 (87.5 %). All FNs were anatomically preserved. All cases had excellent facial nerve function (House-Brackmann Grade I-II).
  
  
  CONCLUSIONS
  FN DTT is a powerful technique in preoperatively identification of FN in large VS cases. Continuous intraoperative FN EMG monitoring is contributive to locating and protecting FNs. Radical resection of large VSs as well as favorable postoperative FN outcome is available with application of these techniques.
authors.affiliation: Department of Neurosurgery, Nanjing Medical University, Nanjing Brain Hospital, Nanjing, 210029, Jiangsu, China.
authors.forename: YuHai
authors.initials: Y
authors.lastname: Zhang
authors.forename: YiJun
authors.initials: Y
authors.lastname: Chen
authors.forename: YuanJie
authors.initials: Y
authors.lastname: Zou
authors.forename: WenBin
authors.initials: W
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.forename: Zhuhai
authors.initials: Z
authors.lastname: Lv
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.forename: Xinhua
authors.initials: X
authors.lastname: Hu
authors.forename: ChaoYong
authors.initials: C
authors.lastname: Xiao
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.forename: HongYi
authors.initials: H
authors.lastname: Liu
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery*; D005154:Facial Nerve / Q000473:pathology / Q000601:surgery*; D020220:Facial Nerve Injuries / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications / Q000473:pathology; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies; D016896:Treatment Outcome