170 – Is aspirin a viable chemoprophylaxis for VTE in patients undergoing spine surgery?

Nicholas Siegel, Mark Lambrechts, Chadi Tannoury, Alexander R. Vaccaro.

Response/Recommendation: While aspirin (ASA) may reduce venous thromboembolism (VTE) after orthopaedic procedures, there are no high-quality studies addressing this issue in patients undergoing spine surgery. We recommend surgeons weigh the potential benefits of chemoprophylaxis with known risks of increased bleeding.

Strength of Recommendation: Consensus.

Rationale: VTE following orthopaedic procedures is a feared complication as it may lead to fatal pulmonary embolism (PE). The incidence of VTE following spine surgery is not well established with published rates varying from 0.3 – 31%1-7. Currently, no specific protocol exists for VTE prophylaxis in patients undergoing spine surgery likely due to the heterogeneity of cases performed by spine surgeons. Another reason is that VTE chemoprophylaxis in spine surgery may increase the risk of bleeding and hematoma formation, which can result in cord impingement and paralysis8. Although the efficacy of ASA chemoprophylaxis following hip and knee joint arthroplasty is robust9-13, evidence in spine surgery is extremely limited. Previous studies are heterogeneous to allow drawing strong conclusions regarding the use of ASA for VTE prevention.

The only prospective deep venous thrombosis (DVT) chemoprophylaxis study in spine surgery found no incidence of acute DVT in 117 patients who underwent posterior lumbar spine fusion and were treated with 600 mg ASA twice a day (bis in die [BID]14.

Another study, retrospective, evaluated two cohorts consisting of no prophylaxis vs. 150 mg ASA daily for VTE prophylaxis in patients undergoing spine surgery. The no prophylaxis group consisted of 697 procedures, 554 of these were described as laminotomies, decompressions, or disc enucleations, and the remaining 143 were posterolateral spinal fusions. This group has two cases of DVT and no PE for an overall VTE rate of 0.29%. The ASA prophylaxis group consisted of 414 procedures, 272 of these were non-fusion, as described previously and the remaining 142 were fusions. This group had one case of DVT and no cases of PE for a VTE occurrence of 0.24%. Thus, no difference was observed in the rates of VTE when prophylactic ASA was used15.

A retrospective study of 637 patients who underwent surgery for spinal metastasis were given various VTE chemoprophylaxis starting 48 hours after surgery including low-molecular-weight heparin (LMWH), subcutaneous heparin, ASA, and warfarin. Symptomatic VTE developed in 11% of the patients that used any chemoprophylaxis and in 11% who received no chemoprophylaxis16.

A retrospective review of a prospectively collected data on 200 patients who underwent anterior lumbar interbody fusion (ALIF) were given LMWH and tinzaparin the evening before surgery and then daily for 3 to 5 days while inpatient, and then ASA daily for 4 weeks on an outpatient basis. No VTE or bleeding occurred in any of these 200 patients17.

Lastly, a retrospective study of 83,839 patients who underwent anterior cervical discectomy and fusion (ACDF), or posterior lumbar fusion (PLF) were given either ASA, regular heparin, or LMWH on the day of surgery. About 1,872 patients (2.23%) received ASA. No difference was found in the incidence of VTE between these groups. However, patients receiving ASA had increased odds of requiring a blood transfusion (1.48 [1.17 – 1.86])18.

Conclusion: There is a dearth of studies investigating the use of ASA as a VTE prophylaxis in patients undergoing spine surgery. The studies that exist are low in quality and are not conclusive. Although ASA has been shown to be effective for prevention of VTE following other orthopaedic procedures, its efficacy as a VTE prophylaxis in patients undergoing spine surgery remains unproven.


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