title: Spontaneous spinal subarachnoid hematoma of unknown pathogenesis: case reports.
abstract: OBJECTIVE
  The occurrence of spontaneous spinal subarachnoid hematoma of unknown pathogenesis is extremely rare. In the cases reported to date, the hematoma, located dorsal to the spinal cord (dorsal type), has caused paraplegia and has required emergency surgical intervention.
  
  
  METHODS
  We examined two patients who sustained spontaneous spinal subarachnoid hematoma. Both experienced sudden back pain, but there were no symptoms of spinal cord compression. Magnetic resonance imaging revealed spinal subarachnoid hematoma located ventral to the spinal cord (ventral type).
  
  
  METHODS
  Both patients were treated conservatively, and follow-up examinations have revealed that they have remained neurologically normal for 7 years and 6 months, respectively.
  
  
  CONCLUSIONS
  We postulate that there are two types of spontaneous spinal subarachnoid hematoma of unknown pathogenesis (ventral and dorsal types), each of which presents a distinct clinical picture and prognosis. Ventral type hematoma may be one of the causes of acute back pain, and because of its benign prognosis, surgical treatment may not be necessary.
authors.affiliation: Department of Neurosurgery, Osaka City General Hospital, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Komiyama
authors.forename: T
authors.initials: T
authors.lastname: Yasui
authors.forename: T
authors.initials: T
authors.lastname: Sumimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Fu
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006406:Hematoma / Q000175:diagnosis / Q000209:etiology / Q000628:therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009460:Neurologic Examination; D013117:Spinal Cord Compression / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000209:etiology / Q000628:therapy*