Study Design. Survey study. Objective. To assess a sample of spine surgeons' current practices of thromboembolic prophylaxis after high-risk surgery for tumors and trauma. Summary of Background Data. Although chemoprophylaxis for thromboembolic events is not routinely used after elective spinal surgery, it is more widely recommended in high-risk patients after spine surgery for trauma or tumors. In these high-risk cases, surgeons must decide what method(s) of prophylaxis to use and when it can be safely initiated. Unfortunately, there are limited data evaluating the efficacy or safety of different prophylaxis protocols after high-risk spinal surgery; as a result there are no accepted treatment guidelines concerning this issue. To the authors' knowledge, no previous study examining practices of thromboembolic prophylaxis after high-risk spinal surgery has been published. Methods. One hundred ninety-three orthopaedic and neurosurgical spine surgeons with established clinical interest and volume in spine trauma and/or spine tumor surgery were invited by email to complete an on-line questionnaire. Ten questions focused on varying issues that included the perceived risk of deep venous thrombosis (DVT), pulmonary embolism (PE), postoperative epidural hematoma, preferred chemoprophylactic agents, the safe time point for initiation of chemoprophylaxis, and use of inferior vena cava (IVC) filters. Results. Ninety-four surgeons completed the questionnaire, which represented a 49% response rate. Regarding a safe time point to start chemoprophylaxis, the most common response was 48 hours after surgery (21 of 94, 22%). However, individual responses varied widely: 15% chose 24 hours, 13% chose 72 hours, 12% chose less than 24 hours, and 10% chose 96 hours. Some indicated they would start chemoprophylaxis before surgery, whereas others responded they would never use it. Sixty-three percent (59 of 94) stated that they based this decision on personal experience over evidence-based review of the literature. A majority of surgeons selected low-molecular-weight heparin as their agent of choice (54 of 94, 58%). Respondents most commonly (44 of 93, 47%) felt that the risk of clinically relevant postoperative epidural hematoma was between 1% and 5%; 29% (27 of 93) felt the risk was less than 1%; and 17% (16 of 93) felt it was as high as 5% to 10%. Those who felt the risk of epidural hematoma to be lower than 5% tended to initiate chemoprophylaxis earlier than those who estimated the risk to be higher than 5%. Thirty-seven percent (34 of 93) felt the perceived risk for a DVT was 1% to 5%; 25% (23 of 94) felt it was 5% to 10%; and 16% (15 of 93) felt it was less than 1%. Those who estimated the risk of DVT to be higher tended to initiate therapy earlier than groups that estimated the risk to be lower. Although the decision to use an IVC filter varied considerably, there was a clear trend towards having the filter placed before surgery (60 of 78, 77%). Conclusion. These data are the first to demonstrate the wide variability of surgeons' practices regarding thromboembolic prophylaxis in high-risk spine surgery patients. This variability is likely a symptom of the glaring paucity of scientific evidence concerning the risk for symptomatic epidural hematoma, DVT, and PE and the efficacy and safety of specific chemoprophylactic protocols after spine surgery. This study highlights the need for more rigorous prospective evaluation of thromboembolic risk after spinal surgery and, subsequently, the efficacy and safety of currently available thromboembolic prophylaxis protocols.
