title: Prophylactic inferior vena cava filters prevent pulmonary embolisms in high-risk patients undergoing major spinal surgery.
abstract: METHODS
  Clinical case series.
  
  
  OBJECTIVE
  To show the efficacy of prophylactic inferior vena cava (IVC) filters in preventing venous thromboembolic event (VTE) in high-risk patients undergoing major spinal surgery.
  
  
  BACKGROUND
  Patients undergoing major spinal surgery are at increased risk for VTEs. Recent studies have shown IVC filters are effective in preventing clinically significant pulmonary embolism (PE), but have not documented the frequency of all emboli prevented.
  
  
  METHODS
  Patients undergoing major spinal surgery from 2006 to 2009, having IVC filters placed for VTE prophylaxis, were reviewed. Patients with 2 or more risk factors for VTE were included and their perioperative courses were reviewed for PE and device-related complications. Cavograms obtained at the time of attempted filter retrieval identified intercepted emboli. The rates of intercepted emboli and clinical PEs were compared with those of similar populations undergoing similar procedures.
  
  
  RESULTS
  Approximately 17% of patients had entrapped thrombus present at attempted filter retrieval. An additional 17% of filters were unable to be retrieved due to change in position within the IVC. No patients experienced symptomatic PE. One patient developed a deep vein thrombus requiring pharmacologic treatment and another patient developed superficial phlebitis. There were no complications related to IVC filter use.
  
  
  CONCLUSIONS
  These findings show that the decreased rate of PE observed in this and other series is likely because of the use of IVC filters, rather than sampling bias inherent when studying a relatively rare problem. The safety of IVC filters in this population is also confirmed. The observed rate of clinical PE is consistent with other published series. Emboli intercepted by filters may more accurately estimate clinically significant emboli prevented. Therefore, cavograms may prove to be a valuable method of assessing the efficacy of these devices in future studies.
authors.affiliation: Department of Orthopaedics, Stony Brook University Hospital, NY, USA.
authors.forename: Justin M
authors.initials: JM
authors.lastname: Dazley
authors.forename: Reese
authors.initials: R
authors.lastname: Wain
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Vellinga
authors.forename: Benjamin
authors.initials: B
authors.lastname: Cohen
authors.forename: Marc A
authors.initials: MA
authors.lastname: Agulnick
mesh_terms: D000328:Adult; D004869:Equipment Safety; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000517:prevention & control*; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D016896:Treatment Outcome; D016306:Vena Cava Filters