Antithrombotic Effects of Aspirin on 1- or 2-Level Lumbar Spinal Fusion Surgery

STUDY DESIGN: Retrospective clinical analysis. OBJECTIVE: To study proper discontinuation date of aspirin in spinal fusion surgery. SUMMARY OF BACKGROUND DATA: It is thought that excess bleeding can be normalized if aspirin intake is discontinued approximately 7 days before surgery; however, the average life span of a platelet is generally regarded to be 7 to 10 days. METHODS: From January 2004 to December 2009, a single surgeon performed 182 cases of 1- or 2-level lumbar fusion surgical procedures. Patients who were aspirin users (n = 86) were divided into 2 groups according to the number of days prior to surgery that they discontinued their aspirin use: the aspirin 1 group discontinued their aspirin use 3 to 7 days before surgery and the aspirin 2 group discontinued their aspirin use 7 to 10 days before surgery. Ninety-six patients who did not use aspirin before surgery were selected for the control group. We retrospectively compared the several hematological parameters among the 2 aspirin groups and the control group. RESULTS: Both the total amount of drained blood and the duration of indwelling of the drainage catheter were significantly less in the control group than in the aspirin 1 group in patients who underwent either type of 1-level fusion surgery. However, those were not significantly different between aspirin 2 group and control group in patients who underwent either type of 1-level fusion surgery. Only drainage catheter was significantly less in the control group than in the aspirin 1 group in patients who underwent 2-level fusion surgery. CONCLUSION: Only the aspirin 1 group, wherein patients discontinued aspirin use 3 to 7 days before surgery, showed a greater drained blood and drainage catheter than the control group. If aspirin was discontinued 7 days or longer before surgery, there was no difference in the study parameters, compared with the control group. LEVEL OF EVIDENCE: 3.