title: Epidemiologic Survey of Dural Arteriovenous Fistulas in Japan: Clinical Frequency and Present Status of Treatment.
abstract: There are few reports describing the prevalence of dural arteriovenous fistulas (dAVFs). We conducted a nation-wide retrograde survey on the clinical frequency and the status of treatment of dAVFs in Japan.
  
  
  
  The first questionnaire was sent to 1,236 certified neurosurgery clinics in Japan to ask about the number of patients treated and the location of dAVF during the 5 years from 1998 to 2002. The second questionnaire was sent to 102 large-volume centers to ask the patients' ages, gender, location of the fistula, clinical presentation, treatment modalities, clinical and radiological results, and recurrence.
  
  
  
  In the first survey, 1,815 cases were chosen from 338 clinics, including 826 cavernous sinus, 514 transverse-sigmoid sinus, 105 spinal, and 370 lesions in other places. The estimated detection rate was 0.29 per 100,000 persons per year in Japan. In the second survey, there were 1,490 cases (mean age: 62.7 ; 628 men and 850 women) that were culled from 68 high-volume centers. The initial clinical presentation was ocular symptoms (45 % of the cases), tinnitus (20 %), intracranial hemorrhage (16 %), and non-hemorrhagic neurological deficits (20 %). Treatment modality was endovascular therapy (76 % of the patients), open surgery (13 %), irradiation (3.4 %), and conservative therapy (11 %). Angiographic results were total obliteration in 59 % of the patients and subtotal obliteration in 16 %. Clinical symptoms disappeared in 54 % of the patients, improved in 16 %, unchanged in 7 %, worsened in 1.5 %, and death occurred in 1.2 %. Recurrence was reported in 5.9 % of the patients.
  
  
  
  This survey delineated the clinical frequency and the epidemiologic features of dAVF in Japan.
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, Toyama University, 2630 Sugitani, Toyama, 930-0194, Japan. kuwayama@ms.toyama-mpu.ac.jp.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kuwayama
mesh_terms: D002426:Cavernous Sinus; D020785:Central Nervous System Vascular Malformations / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000628:therapy; D002533:Cerebral Angiography; D000072700:Conservative Treatment; D003392:Cranial Sinuses; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D000069471:Neurosurgeons; D019635:Neurosurgical Procedures; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D015995:Prevalence; D016634:Radiosurgery; D012008:Recurrence; D012189:Retrospective Studies; D054063:Superior Sagittal Sinus; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: Dural arteriovenous fistula; Endovascular treatment; Prevalence