title: Preoperative Embolization of Spinal Tumors: A Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  Spinal tumors are referred for preoperative embolization to minimize intraoperative blood loss and facilitate surgical resection.
  
  
  OBJECTIVE
  To perform a systematic review and meta-analysis and provide comprehensive data on embolization technique, efficacy, and complications.
  
  
  METHODS
  A systematic review of PubMed articles was performed with the following inclusion criteria: original studies, studies of ≥ 10 patients (except Onyx because of the scarcity of available data), embolization through vascular access, and reporting of the embolic agent used. In addition, the manuscript needed to contain at least 1 of the following variables: demographics, tumor type, location, vascularity, degree of devascularization, complications, time to operation, type of operation, estimated blood loss (EBL), and use of blood transfusion.
  
  
  RESULTS
  Thirty-seven studies with a total of 1305 patients met inclusion criteria. Renal cell carcinoma was the most commonly embolized tumor, comprising 47.4% (95% confidence interval [95% CI] 39.4-55.4) of all tumor embolizations. The rate of complete devascularization for all tumor types was 68.3% (95% CI 60.0-76.6). There was a significant decrease in operative EBL in more recently published studies compared with earlier studies; however, the rate of complete embolization remained stable. Polyvinyl alcohol and Onyx were associated with similar EBL and rates of complete embolization. The overall complication rate was 3.1% (95% CI 1.2-4.9).
  
  
  CONCLUSIONS
  The rapid evolution of neurointervention and spinal tumor embolization has made scientific inquiry and definitive conclusion on the safety and efficacy of the practice difficult. The data supporting the procedure are fragmented and largely based on a multitude of retrospective studies that use varying techniques. Review of the available literature support embolization of spinal tumors as a safe and efficacious treatment adjunct before surgery.
authors.affiliation: Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA. Electronic address: christoph.griessenauer@gmail.com.
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Griessenauer
authors.affiliation: Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salem
authors.affiliation: Department of Neurosurgery, Saarland University Hospital, Homburg/Saar, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hendrix
authors.affiliation: Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Foreman
authors.affiliation: Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ogilvy
authors.affiliation: Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Ajith J
authors.initials: AJ
authors.lastname: Thomas
mesh_terms: D016063:Blood Loss, Surgical; D004621:Embolization, Therapeutic / Q000379:methods*; D006801:Humans; D019635:Neurosurgical Procedures / Q000379:methods*; D013125:Spinal Neoplasms / Q000601:surgery* / Q000628:therapy*
keywords: Embolization; Meta-analysis; Spine; Systematic review; Tumor