title: Gamma Knife radiosurgery for recurrent or residual seizures after anterior temporal lobectomy in mesial temporal lobe epilepsy patients with hippocampal sclerosis: long-term follow-up results of more than 4 years.
abstract: OBJECTIVE
  Gamma Knife radiosurgery (GKRS) has proven efficacy in the treatment of drug-resistant mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and is comparable to conventional resective surgery. It may be effective as an alternative treatment to reoperation after failed temporal lobe surgery in patients with MTLE-HS. The purpose of this study was to investigate the efficacy of GKRS in patients with unilateral MTLE-HS who did not achieve seizure control or had recurrent seizures after anterior temporal lobectomy (ATL).
  
  
  METHODS
  Twelve patients (8 males; mean age 35.50 ± 9.90 years) with MTLE-HS who underwent GKRS after failed ATL (Engel Classes III-IV) were included. GKRS targets included the remnant tissue or adjacent regions of the previously performed ATL with a marginal dose of 24-25 Gy at the 50% isodose line in all patients. Final seizure outcome was assessed using Engel's modified criteria during the final 2 years preceding data analysis. A comparison between signal changes on follow-up MRI and clinical outcome was performed.
  
  
  RESULTS
  All patients were followed up for at least 4 years with a mean duration of 6.18 ± 1.77 years (range 4-8.8 years) after GKRS. At the final assessment, 6 of 12 patients were classified as seizure free (Engel Class Ia, n = 3; Ic, n = 2; and Id, n = 1) and 6 patients were classified as not seizure free (Engel Class II, n = 1; III, n = 2; and IV, n = 3). Neither initial nor late MRI signal changes after GKRS statistically correlated with surgical outcome. Clinical seizure outcome did not differ significantly with initial or late MRI changes after GKRS.
  
  
  CONCLUSIONS
  GKRS can be considered an alternative option when the patients with MTLE-HS who had recurrent or residual seizures after ATL refuse a second operation.
authors.affiliation: Department of Neurology, Ulsan University Hospital, Ulsan; and 
authors.forename: Eun Mi
authors.initials: EM
authors.lastname: Lee
authors.affiliation: Departments of 2 Neurology.
authors.forename: Joong Koo
authors.initials: JK
authors.lastname: Kang
authors.affiliation: Radiology.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Neurosurgery.
authors.forename: Seok Ho
authors.initials: SH
authors.lastname: Hong
authors.affiliation: Pediatrics, and.
authors.forename: Tae Sung
authors.initials: TS
authors.lastname: Ko
authors.affiliation: Departments of 2 Neurology.
authors.forename: Sang Ahm
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Medical Physics Support Center, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
authors.forename: Do Heui
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Neurosurgery.
authors.forename: Jung Kyo
authors.initials: JK
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy; D004833:Epilepsy, Temporal Lobe / Q000473:pathology* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000295:instrumentation*; D012008:Recurrence; D012086:Reoperation; D012598:Sclerosis; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: AED = antiepileptic drug; ATL = anterior temporal lobectomy; ATL-AH = ATL with amygdalohippocampectomy; EEG = electroencephalography; GKRS = Gamma Knife radiosurgery; Gamma Knife radiosurgery; MTLE = mesial temporal lobe epilepsy; MTLE-HS = MTLE hippocampal sclerosis; TLE = temporal lobe epilepsy; anterior temporal lobectomy; mesial temporal lobe epilepsy; stereotactic radiosurgery; surgical failure