title: Radiosurgery for temporal lobe arteriovenous malformations: effect of temporal location on seizure outcomes.
abstract: OBJECTIVE
  The temporal lobe is particularly susceptible to epileptogenesis. However, the routine use of anticonvulsant therapy is not implemented in temporal lobe AVM patients without seizures at presentation. The goals of this case-control study were to determine the radiosurgical outcomes for temporal lobe AVMs and to define the effect of temporal lobe location on postradiosurgery AVM seizure outcomes.
  
  
  METHODS
  From a database of approximately 1400 patients, the authors generated a case cohort from patients with temporal lobe AVMs with at least 2 years follow-up or obliteration. A control cohort with similar baseline AVM characteristics was generated, blinded to outcome, from patients with non-temporal, cortical AVMs. They evaluated the rates and predictors of seizure freedom or decreased seizure frequency in patients with seizures or de novo seizures in those without seizures.
  
  
  RESULTS
  A total of 175 temporal lobe AVMs were identified based on the inclusion criteria. Seizure was the presenting symptom in 38% of patients. The median AVM volume was 3.3 cm3, and the Spetzler-Martin grade was III or higher in 39% of cases. The median radiosurgical prescription dose was 22 Gy. At a median clinical follow-up of 73 months, the rates of seizure control and de novo seizures were 62% and 2%, respectively. Prior embolization (p = 0.023) and lower radiosurgical dose (p = 0.027) were significant predictors of seizure control. Neither temporal lobe location (p = 0.187) nor obliteration (p = 0.522) affected seizure outcomes. The cumulative obliteration rate was 63%, which was significantly higher in patients without seizures at presentation (p = 0.046). The rates of symptomatic and permanent radiation-induced changes were 3% and 1%, respectively. The annual risk of postradiosurgery hemorrhage was 1.3%.
  
  
  CONCLUSIONS
  Radiosurgery is an effective treatment for temporal lobe AVMs. Furthermore, radiosurgery is protective against seizure progression in patients with temporal lobe AVM-associated seizures. Temporal lobe location does not affect radiosurgery-induced seizure control. The low risk of new-onset seizures in patients with temporal or extratemporal AVMs does not seem to warrant prophylactic use of anticonvulsants.
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Dale
authors.initials: D
authors.lastname: Ding
authors.affiliation: Neurology, University of Virginia, Charlottesville, Virginia.
authors.forename: Mark
authors.initials: M
authors.lastname: Quigg
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Chun-Po
authors.initials: CP
authors.lastname: Yen
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Przybylowski
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Blair K
authors.initials: BK
authors.lastname: Dodson
authors.affiliation: Departments of 1 Neurological Surgery and.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D004833:Epilepsy, Temporal Lobe / Q000209:etiology / Q000601:surgery*; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000098:blood supply*; D016896:Treatment Outcome; D055815:Young Adult
keywords: AED = antiepileptic drug; AVM = arteriovenous malformation; Gamma Knife; MTLE = mesial temporal lobe epilepsy; RBAS = radiosurgery-based AVM score; RIC = radiation-induced change; VRAS = Virginia Radiosurgery AVM Scale; epilepsy; intracranial arteriovenous malformation; seizures; stereotactic radiosurgery; temporal lobe; vascular disorders; vascular malformations