Risk Factors for Postoperative Venous Thromboembolic Events in Patients Undergoing Lumbar Spine Surgery

STUDY DESIGN: Retrospective, database study. OBJECTIVES: The aim of this study was to investigate incidence and risk factors associated with venous thromboembolic events (VTEs) after lumbar spine surgery. METHODS: Patients who underwent lumbar surgery between 2007 and 2014 were identified using the Humana within PearlDiver database. ICD-9 (International Classification of Diseases Ninth Revision) diagnosis codes were used to search for the incidence of VTEs among surgery types, patient demographics and comorbidities. Complications including DVT and PE were queried each day from the day of surgery to postoperative day 7 and for periods 0 to 1 week, 0 to 1 month, 0 to 2 months, and 0 to 3 months postoperatively. RESULTS: A total of 64 892 patients within the Humana insurance database received lumbar surgery between 2007 and 2014. Overall VTE rate was 0.9% at 1 week, 1.8% at 1 month, and 2.6% at 3 months postoperatively. Among patients that developed a VTE within 1 week postoperatively, 45.3% had a VTE on the day of surgery. Patients with 1 or more identified risk factors had a VTE incidence of 2.73%, compared with 0.95% for patients without risk factors (P < .001). Risk factors associated with the highest VTE incidence and odds ratios (ORs) were primary coagulation disorder (10.01%, OR 4.33), extremity paralysis (7.49%, OR 2.96), central venous line (6.70%, OR 2.87), and varicose veins (6.51%, OR 2.58). CONCLUSIONS: This study identified several patient comorbidities that were independent predictors of postoperative VTE occurrence after lumbar surgery. Clinical VTE risk assessment may improve with increased focus toward patient comorbidities rather than surgery type or patient demographics.