Introduction: At this time, there is a paucity of literature on the optimal timing for initiation of post-operative chemoprophylaxis for venous thromboembolism. As such, there is great variability in current practices.1 We sought to examine potential outcomes differences between timing strategies in a single institutional series of patients at high risk for postoperative deep venous thrombosis.

Methods: A consecutive series of patients was identified who underwent thoracolumbar surgery for either degenerative or idiopathic scoliosis between January 1, 2009 and December 31, 2010. Patients were characterized by demographics, surgical characteristics, and past medical history, and separated into three chemoprophylaxis groups – none (mechanical prophylaxis only), early (initiation 12-24 hours post-operatively), and late (initiation >24 hours post-operatively). All patients receiving chemoprophylaxis received enoxaparin, 40mg subcutaneously on a daily basis. Cohorts were compared using multivariate logistic regression in terms of rates of venous thromboembolism (deep vein thrombosis or pulmonary embolism), and bleeding complications (spinal epidural hematoma or post-operative coagulopathy requiring blood product transfusion with fresh frozen plasma or platelets).

Results: 279 patients were identified, with an average age of 62.4 +/- 14.5 years, 5.4 +/- 3.2 average levels fused, and an average estimated blood loss of 1051 +/- 1155cc. 40(14.3%) received no chemoprophylaxis, 204(73.1%) received early prophylaxis, and 35(12.5%) received late prophylaxis. Across all patients, only 2(0.7%) experienced a thromboembolic event. 19(6.8%) patients developed a bleeding complication (2 with spinal epidural hematomas, 17 with post-operative coagulopathy requiring blood products). In multivariate logistic regression, there was no significant differences between those patients receiving early and late chemoprophylaxis (OR: 2.12, 95%CI: 0.55-7.11, p=0.2461) in terms of bleeding complication rate.

Conclusions: Early chemoprophylaxis in scoliosis surgery patients did not significantly increase the rate of bleeding complications in our cohort of patients. More research is needed to establish effective protocols for timing anticoagulant therapy in spinal surgery patients.

Patient Care: This research will help surgeons better manage their patients’ anticoagulant regimens following spinal surgery.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the current state of the literature regarding prophylaxis for venous thromboembolism in spinal surgery patients, 2) discuss the implications of early chemoprophylaxis in scoliosis surgery patients, and 3) establish more effective timing protocols for venous thromboembolism chemoprophylaxis in spinal surgery patients.

References: 1) Glotzbecker MP, Bono CM, Harris MB, et al. “Surgeon Practices Regarding Postoperative Thromboembolic Prophylaxis After High-Risk Spinal Surgery” Spine 2008; 33(26):2915-2921.