title: Transvenous balloon-protected embolization of a scalp arteriovenous fistula using Onyx liquid embolic.
abstract: BACKGROUND
  Scalp arteriovenous fistulas (AVFs) are rare and potentially complex lesions that can be treated in a multimodal fashion. We present here the first successful treatment of a Stage Ib scalp AVF using a balloon-protected, retrograde transvenous embolization with the liquid embolic Onyx.
  
  
  METHODS
  We describe the case of a 60-year-old man with a scalp AVF that had a fine, diffuse, serpiginous arterial supply, precluding a transarterial approach, and multiple venous drainage paths, including the external jugular vein (EJV). The lesion was successfully embolized exclusively via a femoral transvenous retrograde approach using Onyx with balloon-protection of the EJV to simultaneously prevent pulmonary embolism and enable improved retrograde casting of the fistula-outflow zone.
  
  
  RESULTS
  The combined use of Onyx with proximal balloon-protection in a transvenous retrograde femoral approach is a novel method that can be used to definitively treat scalp AVFs with a defined catheter-accessible venous outflow.
  
  
  CONCLUSIONS
  This technique may be useful when transarterial embolization, direct puncture, or surgical excision are not practical or possible.
authors.affiliation: Cerebrovascular and Endovascular Division, Department of Neurosurgery Tufts Medical Center, Tufts University School of Medicine, 800 Washington Street, Proger 7, Boston, MA, 02111, USA.
authors.forename: Richard T Z
authors.initials: RT
authors.lastname: Dalyai
authors.forename: Clemens M
authors.initials: CM
authors.lastname: Schirmer
authors.forename: Adel M
authors.initials: AM
authors.lastname: Malek
mesh_terms: D015901:Angiography, Digital Subtraction; D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging / Q000628:therapy*; D002404:Catheterization / Q000379:methods*; D004121:Dimethyl Sulfoxide / Q000008:administration & dosage*; D004621:Embolization, Therapeutic / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011145:Polyvinyls / Q000008:administration & dosage*; D012535:Scalp / Q000098:blood supply*; D014057:Tomography, X-Ray Computed
chemical_list: C450660:Onyx copolymer; D011145:Polyvinyls; D004121:Dimethyl Sulfoxide