title: Prognostic value of the lateral spread response for intraoperative electromyography monitoring of the facial musculature during microvascular decompression for hemifacial spasm.
abstract: OBJECTIVE
  The authors conducted a large retrospective study in which they evaluated the efficacy of intraoperative electromyography (EMG) monitoring of facial musculature during microvascular decompression (MVD) and assessed the predictive value of the lateral spread response (LSR) as a prognostic indicator for the treatment outcome of hemifacial spasm (HFS).
  
  
  METHODS
  The authors undertook intraoperative monitoring during MVD in 300 consecutive patients with HFS. The patients were divided into two groups based on whether the LSR disappeared or persisted following decompression. The mean follow-up period was 35.8 months (range 12-55 months). In 263 (87.7%) of the 300 patients, the LSR was observed during intraoperative facial EMG monitoring. In 230 (87.4%) of these 263 patients, the LSR disappeared following decompression (Group I), and in the remaining 33 patients (12.5%) the LSR persisted despite decompression (Group II). At the postoperative 1-year follow-up visit, there was a significant difference in clinical outcomes between both groups (p < 0.05).
  
  
  CONCLUSIONS
  Facial EMG monitoring of the LSR is an effective tool to use when performing complete decompression, and it may be helpful in predicting outcomes.
authors: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors: Doo-Sik
authors: DS
authors: Kong
authors: Kwan
authors: K
authors: Park
authors: Byoung-Gook
authors: BG
authors: Shin
authors: Jeong Ah
authors: JA
authors: Lee
authors: Dong-Ok
authors: DO
authors: Eum
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical; D004576:Electromyography; D005152:Facial Muscles / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D019569:Hemifacial Spasm / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D016896:Treatment Outcome