Case series of elective instrumented posterior lumbar spinal fusions demonstrating a low incidence of venous thromboembolism

Abstract

BACKGROUND: Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in orthopaedic surgery. While specific guidelines exist for hip and knee arthroplasty, there is wide variation in VTE prophylaxis in complex spinal surgery. This study sought to determine the incidence of VTE, and risk factors associated with VTE, in patients undergoing elective instrumented posterior lumbar spinal fusion. METHODS: In a single-centre case series study, 107 consecutive patients undergoing elective lumbar spinal fusion were evaluated for VTE by lower limb duplex ultrasonography and/or clinical observation, and where indicated, computed tomography pulmonary angiogram. The Caprini model for thrombosis risk factor assessment was retrospectively applied to grade levels of VTE risk, which were compared with overall VTE incidence. RESULTS: All patients were operated on a spinal frame and received mechanical prophylaxis (thromboembolic deterrent stockings and sequential calf-compression devices). Thirty-seven per cent also received chemoprophylaxis with low-molecular-weight heparin (LMWH). There was no significant relationship between LMWH use and protection from VTE. Risk scores ≥3 (high/highest risk categories) were observed in 96.2% of patients. Four (3.7%) patients encountered a VTE complication (all with no chemoprophylaxis), either deep vein thrombosis (1.9%) or pulmonary embolism (1.9%). No patients sustained an epidural haematoma. CONCLUSION: Although patients undergoing elective instrumental posterior lumbar spinal fusion are at high risk of developing VTE, the actual incidence of VTE in these patients is low. Our data support the use of mechanical prophylaxis with thromboembolic deterrent stockings and sequential calf-compression devices to prevent VTE in these patients.