title: Delayed complication after Gamma Knife surgery for mesial temporal lobe epilepsy.
abstract: OBJECTIVE
  Despite the controversy over the clinical significance of Gamma Knife surgery (GKS) for refractory mesial temporal lobe epilepsy (MTLE), the modality has attracted attention because it is less invasive than resection. The authors report long-term outcomes for 7 patients, focusing in particular on the long-term complications.
  
  
  METHODS
  Between 1996 and 1999, 7 patients with MTLE underwent GKS. The 50% marginal dose covering the medial temporal structures was 18 Gy in 2 patients and 25 Gy in the remaining 5 patients.
  
  
  RESULTS
  High-dose treatment abolished the seizures in 2 patients and significantly reduced them in 2 others. One patient in this group was lost to follow-up. However, 2 patients presented with symptomatic radiation necrosis (SRN) necessitating resection after 5 and 10 years. One patient who did not need necrotomy continued to show radiation necrosis on MRI after 10 years. One patient died of drowning while swimming in the sea 1 year after GKS, before seizures had disappeared completely.
  
  
  CONCLUSIONS
  High-dose treatment resulted in sufficient seizure control but carried a significant risk of SRN after several years. Excessive target volume was considered as a reason for delayed necrosis. Drawbacks such as a delay in seizure control and the risk of SRN should be considered when the clinical significance of this treatment is evaluated.
authors.affiliation: Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan. usaken-tky@umin.ac.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Usami
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kawai
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Koga
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shin
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurita
authors.forename: Ichiro
authors.initials: I
authors.lastname: Suzuki
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saito
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology / Q000528:radiation effects; D002423:Cause of Death; D004833:Epilepsy, Temporal Lobe / Q000401:mortality / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009336:Necrosis; D011183:Postoperative Complications / Q000209:etiology*; D011832:Radiation Injuries / Q000175:diagnosis / Q000601:surgery; D016634:Radiosurgery; D012086:Reoperation; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult