title: Microsurgical Resection for Persistent Arteriovenous Malformations Following Gamma Knife Radiosurgery: A Case-Control Study.
abstract: OBJECTIVE
  To explore outcomes after microsurgery of brain arteriovenous malformations (AVMs) that failed to be obliterated by Gamma Knife radiosurgery (GKRS).
  
  
  METHODS
  From January 2000 to January 2014, 42 consecutive patients underwent surgical resection of persistent AVMs after GKRS. These 42 patients with AVMs who underwent radiosurgery (radiosurgery group) were individually matched with 42 patients with AVMs who did not undergo radiosurgery (no radiosurgery group) based on patient and AVM characteristics. The modified Rankin Scale was used to assess neurologic status of patients. The effects of GKRS on AVM resection and surgical outcomes were analyzed.
  
  
  RESULTS
  After GKRS, the mean AVM volume was significantly reduced by 76.8% (P < 0.01), the size was reduced by 41% (P < 0.01), and the Spetzler-Martin grade was reduced in 61.9% of the patients (P < 0.01). During the time interval from radiosurgery to surgical resection, subsequent hemorrhages led to significant neurologic deterioration (P = 0.046). Compared with the control group, the frequency of preoperative embolization, operative time, and blood loss were significantly lower in the radiosurgery group (all P < 0.05). The no radiosurgery group had a significantly higher rate of worsening in mRS scores at 6 months after surgery (40.5% vs. 16.7%, P = 0.029). Good neurologic status (mRS score <3) was achieved in 81% of the radiosurgery group and 83% of the no radiosurgery group at the final follow-up evaluation.
  
  
  CONCLUSIONS
  GKRS performed several years before microsurgical resection can facilitate resectability of AVMs and decrease the rate of postoperative neurologic deterioration. For patients with persistent AVMs several years after GKRS, microsurgical resection is recommended to achieve good clinical outcomes.
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China.
authors.forename: Xianzeng
authors.initials: X
authors.lastname: Tong
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Gamma Knife Center, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Pan
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China.
authors.forename: Fuxin
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China.
authors.forename: Yuanli
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China. Electronic address: captain9858@vip.sina.com.
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China.
authors.forename: Jizong
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000328:Adult; D002548:Cerebral Revascularization / Q000379:methods*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis* / Q000601:surgery*; D008297:Male; D016634:Radiosurgery / Q000379:methods*; D012008:Recurrence; D017211:Treatment Failure
keywords: Gamma Knife radiosurgery; Microsurgical resection; Persistent arteriovenous malformations