title: Gamma Knife surgery used as primary and repeated treatment for idiopathic trigeminal neuralgia.
abstract: OBJECTIVE
  The purpose of this study was to assess the outcome of idiopathic trigeminal neuralgia (TN) treated with Gamma Knife surgery (GKS) as a primary and repeated treatment modality with a mean follow-up of 5.7 years.
  
  
  METHODS
  Between July 1999 and September 2005, a total of 89 patients with idiopathic TN underwent GKS as a primary treatment. The entry zone of the TN was targeted with a 4-mm collimator and treated with a maximal dose of 60-90 Gy (mean 79 Gy). The dose to the pontine margin was always kept < 15 Gy. Twenty patients received repeated GKS for recurrent or residual pain with a maximal dose of 40-76 Gy (mean 52 Gy). For the second procedure, the target was positioned at the same location as the first treatment.
  
  
  RESULTS
  The mean follow-up period was 68 months (range 32-104 months). Sixty-nine (77.5%) of the 89 patients experienced a favorable response, as follows: 50 (56%) had excellent, 12 (13.5%) had good, and 7 (7.8%) had fair outcomes. The mean time to pain relief was 1.1 months (range 2 days-6 months). No significant correlation, but more likely a tendency, was found between the dose and pain relief (p = 0.08). Also, no correlation was noted for facial numbness (p = 0.77). The mean follow-up period after repeated GKS was 60 months (range 32-87 months). Outcomes after repeated GKS were excellent in 11 patients (55%) and good in 1 (5%). Seven patients experienced facial numbness. No correlation was found between the additive dose and pain relief (p = 0.24) or facial numbness (p = 0.15). Final outcomes of primary and repeated GKS were excellent in 61 (68.5%), good in 13 (14.6%), and fair in 7 (7.9%). In total, 91% of the patients were successfully treated with this method. There was no statistical significance for efficacy between primary and repeated GKS (p = 0.65), but there was a significant difference for facial numbness (p = 0.007).
  
  
  CONCLUSIONS
  Gamma Knife surgery established durable pain relief when used as a primary and repeated surgery. Treatment was successful for a total of 91% of patients at a mean follow-up of 5.7 years, but facial numbness was also relatively higher.
authors.affiliation: Department of Neurosurgery, Chung-Shan Medical University, Taichung, Taiwan. gk@csh.org.tw
authors.forename: Chuan-Fu
authors.initials: CF
authors.lastname: Huang
authors.forename: Hsien-Tang
authors.initials: HT
authors.lastname: Tu
authors.forename: Wen-Shan
authors.initials: WS
authors.lastname: Liu
authors.forename: Shyh-Ying
authors.initials: SY
authors.lastname: Chiou
authors.forename: Long-Yau
authors.initials: LY
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D012008:Recurrence; D019233:Retreatment; D012189:Retrospective Studies; D019051:Rhizotomy; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000209:etiology / Q000601:surgery*