title: Preoperative identification of facial nerve in vestibular schwannomas surgery using diffusion tensor tractography.
abstract: OBJECTIVE
  Facial nerve palsy is a common complication of treatment for vestibular schwannoma (VS), so preserving facial nerve function is important. The preoperative visualization of the course of facial nerve in relation to VS could help prevent injury to the nerve during the surgery. In this study, we evaluate the accuracy of diffusion tensor tractography (DTT) for preoperative identification of facial nerve.
  
  
  METHODS
  We prospectively collected data from 11 patients with VS, who underwent preoperative DTT for facial nerve. Imaging results were correlated with intraoperative findings. Postoperative DTT was performed at postoperative 3 month. Facial nerve function was clinically evaluated according to the House-Brackmann (HB) facial nerve grading system.
  
  
  RESULTS
  Facial nerve courses on preoperative tractography were entirely correlated with intraoperative findings in all patients. Facial nerve was located on the anterior of the tumor surface in 5 cases, on anteroinferior in 3 cases, on anterosuperior in 2 cases, and on posteroinferior in 1 case. In postoperative facial nerve tractography, preservation of facial nerve was confirmed in all patients. No patient had severe facial paralysis at postoperative one year.
  
  
  CONCLUSIONS
  This study shows that DTT for preoperative identification of facial nerve in VS surgery could be a very accurate and useful radiological method and could help to improve facial nerve preservation.
authors.affiliation: Department of Neurosurgery, College of Medicine, Yeungnam University, Deagu, Korea.
authors.forename: Kyung-Sik
authors.initials: KS
authors.lastname: Choi
authors.affiliation: Department of Neurosurgery, College of Medicine, Yeungnam University, Deagu, Korea.
authors.forename: Min-Su
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Deagu, Korea.
authors.forename: Hyeok-Gyu
authors.initials: HG
authors.lastname: Kwon
authors.affiliation: Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Deagu, Korea.
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Jang
authors.affiliation: Department of Neurosurgery, College of Medicine, Yeungnam University, Deagu, Korea.
authors.forename: Oh-Lyong
authors.initials: OL
authors.lastname: Kim
keywords: Diffusion tensor imaging; Facial nerve injury; Vestibular schwannomas