title: Delayed cranial nerve palsy after microvascular decompression for hemifacial spasm.
abstract: OBJECTIVE
  Microvascular decompression (MVD) for hemifacial spasm (HFS) is a safe and effective treatment with favorable outcomes. The purpose of this study was to evaluate the incidence of delayed cranirve ( VI, VII, and VIII ) palsy following MVD and its clinical courses.
  
  
  METHODS
  Between January 1998 and December 2009, 1354 patients underwent MVD for HFS at our institution. Of them, 100 patients (7.4%) experienced delayed facial palsy (DFP), one developed sixth nerve palsy, and one patient had delayed hearing loss.
  
  
  RESULTS
  DFP occurred between postoperative day number 2 and 23 (average 11 days). Ninety-two patients (92%) completely recovered; however, House-Brackmann grade II facial weakness remained in eight other patients (8%). The time to recovery averaged 64 days (range, 16 days to 9 months). Delayed isolated sixth nerve palsy recovered spontaneously without any medical or surgical treatment after 8 weeks, while delayed hearing loss did not improve.
  
  
  CONCLUSIONS
  Delayed cranial nerve (VI, VII, and VIII) palsies can occur following uncomplicated MVD for HFS. DFP is not an unusual complication after MVD, and prognosis is fairly good. Delayed sixth nerve palsy and delayed hearing loss are extremely rare complications after MVD for HFS. We should consider the possibility of development of these complications during the follow up for MVD.
authors.affiliation: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jae-Suk
authors.initials: JS
authors.lastname: Han
authors.forename: Jeong-Ah
authors.initials: JA
authors.lastname: Lee
authors.forename: Doo-Sik
authors.initials: DS
authors.lastname: Kong
authors.forename: Kwan
authors.initials: K
authors.lastname: Park
keywords: Delayed abducens palsy; Delayed cranial palsy; Delayed facial palsy; Delayed hearing loss; Microvascular decompression