title: Preoperative embolization of intracranial arteriovenous malformations with Onyx.
abstract: OBJECTIVE
  Preoperative embolization in accordance with multimodal therapies for cerebral arteriovenous malformations (AVMs) is generally the first step in treatment and may result in complete obliteration. The Onyx liquid embolic system (Micro Therapeutics, Inc., Irvine, CA) may offer advantages for intranidal targeted embolization and microsurgical resection. We present our experience in the combined treatment of intracranial AVMs using Onyx embolization and neurosurgical resection.
  
  
  METHODS
  We treated a total of 47 patients for compact intracranial AVMs that were located in the frontal or frontoparietal area (16 patients); temporal, temporoparietal, or temporo-occipital regions (12 patients); parietal or parieto-occipital areas (8 patients); occipital regions (8 patients); had basal ganglia involvement (2 patients); and was cerebellar (1 patient). The Spetzler-Martin grading scale values were as follows: 25 patients were Grades I or II, 10 patients were Grade III, and 12 patients were Grades IV or V. Twenty-three AVMs were located in eloquent brain regions.
  
  
  RESULTS
  After we performed final embolizations, the mean nidus reduction was 84%. Seven patients had new, nondisabling neurological deficits, and four patients had new, disabling neurological deficits after embolization. Periprocedurally, five vessel perforations and four stuck microcatheters were encountered without clinical deficits. In two patients, delayed hemorrhage after embolization occurred with good clinical outcome. We completely resected 46 AVMs; in one patient, we detected an AVM on postoperative angiography. The mean operative time was 4.7 hours, and the mean blood loss was 455 mL. Clinical status worsened postoperatively in 14 patients. Angiographic and clinical follow-up examinations were available for 42 patients (89%); the average follow-up period was 13 months. We found no relapse of arteriovenous shunt. Fourteen patients improved clinically after discharge. Of the 42 patients followed up, 23 individuals had no neurological deficit, 16 had a nondisabling deficit, and three had a disabling deficit.
  
  
  CONCLUSIONS
  Preoperative use of the Onyx liquid embolic system in cerebral AVM treatment allows profound occlusion by targeted embolization and provides a basis for safe neurosurgical resection.
authors.affiliation: Department of Radiology and Neuroradiology, Alfried Krupp Hospital, Essen, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Weber
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kis
authors.forename: Ralf
authors.initials: R
authors.lastname: Siekmann
authors.forename: Paul
authors.initials: P
authors.lastname: Jans
authors.forename: Rudolf
authors.initials: R
authors.lastname: Laumer
authors.forename: Dietmar
authors.initials: D
authors.lastname: Kühne
mesh_terms: D000293:Adolescent; D000328:Adult; D002533:Cerebral Angiography; D002648:Child; D003131:Combined Modality Therapy; D004121:Dimethyl Sulfoxide; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D011145:Polyvinyls; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011300:Preoperative Care; D016896:Treatment Outcome
chemical_list: C450660:Onyx copolymer; D011145:Polyvinyls; D004121:Dimethyl Sulfoxide