title: Prevalence of venous thromboembolic events after elective major thoracolumbar degenerative spine surgery.
abstract: METHODS
  A case-control study.
  
  
  OBJECTIVE
  The purposes of this study were to establish the prevalence of venous thromboembolic disease in patients undergoing elective major thoracolumbar degenerative spine surgery and identify risk factors.
  
  
  BACKGROUND
  Venous thromboembolic events (VTE) are a serious complication of orthopedic surgery, but the prevalence of VTE after elective thoracolumbar degenerative spine surgery is not well known.
  
  
  METHODS
  This was a case-control study of 5766 consecutive elective thoracolumbar degenerative spine surgeries. Symptomatic pulmonary emboli (PE) were diagnosed by spiral chest CT scans, nuclear scintigraphic ventilation-perfusion, and angiography. Deep vein thromboses (DVT) were diagnosed by venous duplex scans. The prevalence of VTE was analyzed according to patient demographic variables and type of surgery performed.
  
  
  RESULTS
  The prevalence of developing a VTE was 1.5% (89/5766), with a prevalence of symptomatic PE of 0.88% (51/5766) and DVT of 0.66% (38/5766). There were 47% males and 53% females with a mean age of 60.3 years. In patients undergoing 5-segment fusions the prevalence of PE was 3.1% (P=0.022). Patients who had ≥4 segments fused had a prevalence of PE of 1.7% (P=0.014). The odds of having a PE in those above 65 years at the time of surgery were 2.196 times as large as for those below 65 years. Noncontributory factors included sex, instrumentation, and revision surgery.
  
  
  CONCLUSIONS
  This case-control study of 5766 patients who underwent elective thoracolumbar degenerative spine surgery revealed a prevalence of VTE of 1.5%, with a prevalence of PE of 0.88% and DVT of 0.66%. Patients with increasingly extensive surgery had a higher risk of PE, specifically those undergoing fusion of ≥5 segments.
authors.affiliation: *Intermountain Spine Institute, Murray, UT †Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA ‡Vanderbilt Orthopaedics, Vanderbilt University, Nashville, TN.
authors.forename: Justin B
authors.initials: JB
authors.lastname: Hohl
authors.forename: Joon Y
authors.initials: JY
authors.lastname: Lee
authors.forename: Steven P
authors.initials: SP
authors.lastname: Rayappa
authors.forename: Colin E
authors.initials: CE
authors.lastname: Nabb
authors.forename: Clinton J
authors.initials: CJ
authors.lastname: Devin
authors.forename: James D
authors.initials: JD
authors.lastname: Kang
authors.forename: William Timothy
authors.initials: WT
authors.lastname: Ward
authors.forename: William F
authors.initials: WF
authors.lastname: Donaldson
mesh_terms: D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D002574:Cervical Vertebrae / Q000601:surgery*; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000453:epidemiology*; D015995:Prevalence; D011655:Pulmonary Embolism / Q000453:epidemiology / Q000209:etiology; D012307:Risk Factors; D013123:Spinal Fusion; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000209:etiology; D020246:Venous Thrombosis / Q000453:epidemiology