title: Effective Surgical Management of Competitive Venous Outflow Restriction After Radiosurgery for Cerebral AVMs: Report of 2 Cases.
abstract: BACKGROUND
  Intracranial arteriovenous malformations (AVMs) are complex pathologies. For patients who do not present with hemorrhage, treatment strategies are often predicated on reducing the risk of hemorrhage and minimizing morbidity. Outcomes vary according to the efficacy of treatment selected. Radiosurgical treatment of certain AVMs can result in incomplete obliteration and may also have only a minimal effect on the presenting nonhemorrhagic symptoms.
  
  
  METHODS
  We present 2 cases of patients with AVMs who were initially treated with radiosurgery. Both patients' primary clinical symptoms were headaches, which persisted after radiosurgical treatment but abated after subsequent microsurgical resection with or without endovascular embolization.
  
  
  CONCLUSIONS
  Venous outflow obstruction is likely a sizable contributive factor in occipital AVMs among patients who present with headaches and symptoms of intracranial hypertension. Because these high-flow lesions may be suboptimally responsive to stereotactic radiosurgery, microsurgical resection, with or without adjunctive endovascular embolization, should be considered as an initial and definitive treatment strategy. Optimal outcomes may be achieved in patients with a visual deficit that is anatomically correlated to their AVMs.
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
authors.forename: Vernard S
authors.initials: VS
authors.lastname: Fennell
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA; Division of Neurosurgery, Department of Surgery, University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: Nikolay L
authors.initials: NL
authors.lastname: Martirosyan
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
authors.forename: Gursant S
authors.initials: GS
authors.lastname: Atwal
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
authors.forename: M Yashar S
authors.initials: MY
authors.lastname: Kalani
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA. Electronic address: Neuropub@dignityhealth.org.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spetzler
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: G Michael
authors.initials: GM
authors.lastname: Lemole
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: Travis
authors.initials: T
authors.lastname: Dumont
mesh_terms: D002533:Cerebral Angiography; D004621:Embolization, Therapeutic / Q000009:adverse effects*; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects*; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery*
keywords: Arteriovenous malformation; Radiosurgery; Venous outflow