The Influence of Antiplatelet Drug Medication on Spine Surgery

BACKGROUND: The incidence of cardiovascular and neurovascular diseases has been increasing with the aging of the population, and antiplatelet drugs (APDs) are more frequently used than in the past. With the average age of spinal surgery patients also increasing, there has been a great concern on the adverse effects of APD on spine surgery. To our knowledge, though there have been many studies on this issue, their results are conflicting. In this study, we aimed to determine the influence of APDs on spine surgery in terms of intraoperative bleeding and postoperative spinal epidural hematoma complication. METHODS: Patients who underwent posterior thoracolumbar decompression and instrumentation at our institution were reviewed. There were 34 APD takers (APDT group). Seventy-nine non-APD takers (NAPDT group) were selected as a control group in consideration of demographic and surgical factors. There were two primary endpoints of this study: the amount of bleeding per 10 minutes and cauda equina compression by epidural hematoma measured at the cross-sectional area of the thecal sac in the maximal compression site on the axial T2 magnetic resonance imaging scans taken on day 7. RESULTS: Both groups were homogeneous regarding age and sex (demographic factors), the number of fused segments, operation time, and primary/revision operation (surgical factors), and the number of platelets, prothrombin time, and activated partial thromboplastin time (coagulation-related factors). However, the platelet function analysis-epinephrine was delayed in the APDT group than in the NAPDT group (203.6 seconds vs. 170.0 seconds, p = 0.050). Intraoperative bleeding per 10 minutes was 40.6 ± 12.8 mL in the APDT group and 43.9 ± 9.9 mL in the NAPDT group, showing no significant difference between the two groups (p = 0.154). The cross-sectional area of the thecal sac at the maximal compression site by epidural hematoma was 120.2 ± 48.2 mm2 in the APDT group and 123.2 ± 50.4 mm2 in the NAPDT group, showing no significant difference between the two groups (p = 0.766). CONCLUSIONS: APD medication did not increase intraoperative bleeding and postoperative spinal epidural hematoma. Therefore, it would be safer to perform spinal surgery without discontinuation of APD therapy in patients who are vulnerable to cardiovascular and neurovascular complications.

Postoperative Spinal Epidural Hematoma: The Danger Caused by the Misuse of Thrombin-Containing Local Hemostatics

STUDY DESIGN: Retrospective case-control study. PURPOSE: To examine the hypothesis that the misuse of thrombin-containing local hemostatics (TCLH) increases the risk of postoperative spinal epidural hematoma (POSEH). OVERVIEW OF LITERATURE: Many studies have focused on hypocoagulability as a risk factor for POSEH. However, there are no prior reports on the increased risk of POSEH in hypercoagulable states. METHODS: Posterior instrumented lumbar spine surgery cases over 2 consecutive years were divided into two groups: a study group (98 patients in whom TCLH was used) and a control group (176 patients in whom TCLH was not used). The excess TCLH matrix that was not associated with blood clot was not removed from the patients in the study group. The senior author decided whether to use TCLH or not. Suction drains were used in all patients. The demographics, coagulation-related factors, and intraoperative factors of the patients in the two groups were analyzed. The development of POSEH was compared between the two groups. RESULTS: The two groups were homogenous in demographics (age and sex), coagulation-related factors (platelet count, prothrombin time, activated partial thromboplastin time, and platelet function analysis), and surgical factors (total blood loss, operation time, blood loss/10 minutes, number of fusion segments, posterolateral fusion/posterior lumbar interbody fusion, and virgin or revision surgery). POSEH developed more frequently in the patients in the study group than in those in the control group (14/98 patients, 14.3% vs. 3/176 patients, 1.7%, respectively; p=0.001; odds ratio, 17.1). CONCLUSIONS: TCLH causes blood clot not only at the edge of damaged vessels but also at the site of extravascular blood. Excess TCLH matrix not associated with blood clot at the epidural space can enhance POSEH development because early clotted hematomas do not drain through suction drains.

Why Cannot Suction Drains Prevent Postoperative Spinal Epidural Hematoma?

BACKGROUND: Postoperative spinal epidural hematoma (POSEH) is different from spontaneous or post-spinal procedure hematoma because of the application of suction drains. However, it appeared that suction drains were not effective for prevention of POSEH in previous studies. The purpose of this study was to test our hypothesis that POSEH can be caused by hypercoagulability. METHODS: This was an experimental study. One hundred fifty milliliters of blood was donated from each of the 12 consecutive patients who underwent spine surgery and infused into 3 saline bags of 50 mL each. One of the 3 bags in each set contained 5,000 units of thrombin. All of them were connected to 120 ± 30 mmHg vacuum suctions: drainage was started 8 minutes after connection to the vacuum system for 12 normal blood bags (BV8) and 12 thrombin-containing blood bags (TBV8) and 15 minutes after connection for the remaining 12 normal blood bags (BV15). The amount of initial and remaining hematoma at 20 minutes, 120 minutes, and 24 hours after vacuum application were measured by their weight (g). The primary endpoint was the difference between BV8 and TBV8. The secondary end point was the difference between BV8 and BV15. RESULTS: The remaining hematoma in TBV8 was significantly greater than that in BV8 at all measurement points: 46.3 ± 12.4 vs. 17.0 ± 1.3 (p = 0.000) at 20 minutes; 33.0 ± 8.2 vs. 16.3 ± 1.2 (p = 0.000) at 120 minutes; and 26.1 ± 4.0 vs. 15.8 ± 1.6 (p = 0.000) at 24 hours after vacuum application. The remaining hematoma of BV15 was significantly greater than that of BV8 at all measurement points: 30.0 ± 12.0 vs. 17.0 ± 1.3 (p = 0.002) at 20 minutes; 24.2 ± 7.6 vs. 16.3 ± 1.2 at 120 minutes (p = 0.002); and 22.2 ± 6.6 vs. 15.8 ± 1.6 (p = 0.004) at 24 hours after vacuum application. CONCLUSIONS: With a suction drain in place, the amount of remaining hematoma could be affected by coagulability. Thrombin-containing local hemostatics and the length of time elapsed before the commencement of suction resulted in hypercoagulability, indicating these two factors could be causes of POSEH.