title: Spinal cord arteriovenous fistulas involving the conus medullaris: presentation, management, and embryologic considerations.
abstract: BACKGROUND
  Spinal cord arteriovenous fistulas (SCAVF) are uncommon congenital lesions that usually involve the most caudal aspects of the cord. We present three cases of SCAVF that illustrate the clinical manifestations and possible management options. The characteristic involvement of the conus medullaris and an associated tethered spinal cord in one of our patient suggests that a disorder of secondary neurulation may be involved in the formation of these arteriovenous shunt lesions.
  
  
  METHODS
  Review of records and radiologic studies in three consecutive patients with SCAVF's treated at this institution.
  
  
  RESULTS
  All three patients had SCAVF involving the lower lumbar spinal cord segments or the conus. One of the conus lesions was associated with tethering of the spinal cord. One small lesion (Type A) was treated surgically, whereas the two larger lesions (Type B) were treated using interventional neuroradiologic techniques.
  
  
  CONCLUSIONS
  Both surgical and endovascular method have a role in management of these unusual spinal cord vascular malformations. The association with tethered cord suggests that the propensity for SCAVM to occur in the most caudal portions of the spinal cord may result from failure of secondary neurulation to properly develop the unique and complex vascular anatomy of the region.
authors.affiliation: Department of Radiology-Neuroradiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Hurst
authors.forename: L J
authors.initials: LJ
authors.lastname: Bagley
authors.forename: P
authors.initials: P
authors.lastname: Marcotte
authors.forename: L
authors.initials: L
authors.lastname: Schut
authors.forename: E S
authors.initials: ES
authors.lastname: Flamm
mesh_terms: D000328:Adult; D001164:Arteriovenous Fistula / Q000175:diagnosis / Q000196:embryology / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008499:Medical Records; D012189:Retrospective Studies; D013116:Spinal Cord / Q000098:blood supply*; D016896:Treatment Outcome