title: Regression of dural arteriovenous fistulae after venous flow reconstructive surgery in a case with hemangiopericytoma at the confluence of sinuses.
abstract: BACKGROUND
  The mechanism by which acquired dural arteriovenous fistula (dAVF) develops is still unclear. Few cases have been reported with both dAVF and intracranial tumors, and in these few cases the authors have proposed that induced venous hypertension may lead to the pathogenesis of dAVF. We experienced a case of intrasinusoidal hemangiopericytoma (HPC) with dAVF development. In addition to its rare pathology and tumor location, this case showed regression of dAVF immediately after tumor removal.
  
  
  METHODS
  The patient was a 23-year-old man who developed progressively worse headaches and papilledema. The HPC was located entirely inside the confluence of the sinuses (CoS) and resulted in venous sinus occlusion. Cerebral angiography demonstrated a dAVF located in the straight sinus, upstream of the occluded CoS, which was fed by the dural branch of the posterior cerebral artery. After the endovascular embolization of the tumor feeders, subsequent surgery included venous reconstruction in addition to tumor excision. Although the dAVF was not treated with an endovascular procedure or surgery, postoperative angiography revealed complete disappearance of the dAVF.
  
  
  CONCLUSIONS
  We conclude that venous reconstructive surgery greatly contributed to the immediate regression of the dAVF. When planning the treatment strategy for such cases, it should be remembered that acquired dAVF may regress due to the normalization of venous hypertension.
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Kurisu
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Motegi
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Osanai
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Terasaka
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Houkin
keywords: Confluence of sinuses; Dural arteriovenous fistula; Hemangiopericytoma; Sinus occlusion; Venous hypertension; Venous reconstructive surgery