title: Comprehensive assessment of prophylactic preoperative inferior vena cava filters for major spinal reconstruction in adults.
abstract: METHODS
  A retrospective data analysis.
  
  
  OBJECTIVE
  To report a comprehensive assessment of preoperative prophylactic inferior vena cava (IVC) filter placement in spine surgery.
  
  
  BACKGROUND
  Venous thromboembolism (VTE) is a serious complication after major spinal reconstructive surgery in adults. Specifically, pulmonary embolism (PE) can result in significant morbidity and mortality, and it has been reported in up to 13% of patients. Prophylactic IVC filter placement was initiated for all "high-risk" spinal surgery patients after a pilot study demonstrated decreased VTE-related morbidity and mortality.
  
  
  METHODS
  After institutional review board approval, the medical records of all patients receiving an IVC filter at a single institution from 2000 to 2007 were reviewed. Age, sex, surgical approach, postoperative deep vein thrombosis (DVT), postoperative superficial thrombus, presence of pulmonary or paradoxical embolus, mortality, and IVC filter complications were all evaluated. Indications for IVC filter placement included history of DVT or PE, malignancy, hypercoagulability, prolonged immobilization, staged procedures of longer than 5 segment levels, combined anterior-posterior approaches, iliocaval manipulation during exposure, and anesthetic time of more than 8 hours. Descriptive statistics were used for the analysis of patient characteristics. Nonparametric frequency statistics (odds ratios [OR], χ) were used for analysis of main outcomes.
  
  
  RESULTS
  A total of 219 patients (150 women, 69 men) with a mean age of 58.8 (range, 17-86) years, were analyzed. There were 2 complications from IVC filter placement (66 Greenfield filters; 157 retrievable filters). The incidence of lower extremity DVT was 18.7% (41/219) in 36 patients. PE incidence was 3.7% (8/219 patients), and the paradoxical embolus rate was 0.5% (1 patient). Prophylactic IVC filter use reduced the odds of developing a pulmonary embolus (OR = 3.7, P < 0.05) compared with population controls. Patients receiving Greenfield filters had significantly higher VTE incidence than those receiving retrievable filters (OR = 2.8, P = 0.008). Anesthesia duration of more than 8 hours significantly increases VTE incidence (P = 0.029). No statistical significance (P < 0.05) was noted with combined anterior-posterior approach (118 patients) versus posterior-only approach (101 patients) and the incidence of DVT (24/118, 20.3% for former; 17/101, 16.8% for latter). There were a total of 14 deaths; none related to PE or paradoxical embolism during an 8-year period. Mean and median follow-up was 2.8 and 2.4 years, respectively, with 126 achieving 2 or more years of follow-up.
  
  
  CONCLUSIONS
  VTE-related morbidity and mortality have heightened the awareness within the spine community to the perioperative management of patients undergoing major spinal reconstruction. Prophylactic IVC filter placement significantly lowers VTE-related events, including PE development, than population controls.
authors.affiliation: Department of Surgery, Northwestern Memorial Hospital, Chicago, IL 60611, USA. jamal-jr@md.northwestern.edu
authors.forename: Jamal
authors.initials: J
authors.lastname: McClendon
authors.forename: Brian A
authors.initials: BA
authors.lastname: Oʼshaughnessy
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Smith
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Sugrue
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Halpin
authors.forename: Mark
authors.initials: M
authors.lastname: Morasch
authors.forename: Tyler
authors.initials: T
authors.lastname: Koski
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Ondra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D002641:Chicago; D019320:Embolism, Paradoxical / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000401:mortality; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D011655:Pulmonary Embolism / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D016306:Vena Cava Filters; D054556:Venous Thromboembolism / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D020246:Venous Thrombosis / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D055815:Young Adult