title: Cerebral arteriovenous malformations and seizures: differential impact on the time to seizure-free state according to the treatment modalities.
abstract: BACKGROUND
  To determine the prognostic factors for the incidence and the outcome of seizure in patients with cerebral arteriovenous malformation (AVM) and to identify the time to seizure-free state according to the treatment modalities.
  
  
  METHODS
  Between 1995 and 2008, the multidisciplinary team at our institution treated 399 patients with cerebral AVMs. Treatment consisted of surgical resection, radiosurgery, and embolization, either alone or in combination. The median follow-up period was 6.0 years (range, 3.0-16.2 years). Eighty-six patients (21.5 %) experienced seizures before treatment. We investigated the variables associated with seizure incidence and seizure outcome and analyzed the outcomes of seizure among each treatment modality.
  
  
  RESULTS
  After treatment, 60 (70 %) patients were seizure-free. Compared with 313 patients who did not experience seizures, we found that younger age (≤ 35 years), size ≥ 3 cm, and location of temporal lobe were associated with seizures (p < 0.05). Short seizure history, accompanying intracerebral hemorrhage, generalized tonic-clonic type seizure, deep-seated or infratentorial AVM, complete obliteration of AVM, and a favorable neurological outcome at 12 months were closely associated with Engel Class I outcomes (p < 0.05). Seizure-free outcomes after microsurgery, radiosurgery, or embolization were 78 %, 66 %, and 50 %, respectively. The overall annual bleeding rate was 1.0 % and 2.2 % in microsurgery-treated and radiosurgery-treated AVMs, respectively. In the surgery group, the median time to seizure-free status was 1.1 months (95 % CI, 0.7-1.2 months), whereas the radiosurgery group and embolization-alone group showed 20.5 months (95 % CI, 18.3-23.8 months), and 8.1 months (95 % CI, 6.0-13.5 months), respectively.
  
  
  CONCLUSIONS
  A multidisciplinary team approach for cerebral AVMs achieved satisfactory seizure control results. Microsurgery led to the highest percentage of seizure-free outcomes and had the lowest annual bleeding rate, whereas radiosurgery had a higher bleeding rate. Median time to seizure-free status in surgically treated patients was shorter than in patients who underwent radiosurgical or endovascular treatment.
authors.affiliation: Department of Neurosurgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Hyun
authors.forename: Doo-Sik
authors.initials: DS
authors.lastname: Kong
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Lee
authors.forename: Jong-Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Seung-Chyul
authors.initials: SC
authors.lastname: Hong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D004833:Epilepsy, Temporal Lobe / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D002538:Intracranial Arteriovenous Malformations / Q000453:epidemiology* / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods; D012640:Seizures / Q000453:epidemiology* / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D055815:Young Adult