Study design:

Retrospective cohort study.

Objective:

The purpose of this study was to evaluate safety in lumbar spinal fusion with tranexamic acid (TXA) utilization in patients using marijuana.

Methods:

This was a retrospective cohort study involving a single surgeon’s cases of 1 to 4 level lumbar fusion procedures. Two hundred and ninety-four patients were followed for ninety days post-operatively. Consecutive patients were self-reported for daily marijuana use (n = 146) and compared to a similar cohort of patients who denied usage of marijuana (n = 146). Outcomes were collected, which included length of stay (LOS), estimated blood loss (EBL), post-operative myocardial infarction, seizures, deep venous thrombosis, pulmonary embolus, death, readmission, need for further surgery, infection, anaphylaxis, acute renal injury, and need for blood product transfusion.

Results:

Patients in the marijuana usage cohort had similar age (58.9 years ±12.9 vs 58.7 years ±14.8, P = .903) and distribution of levels fused (P = .431) compared to the non-usage cohort. Thromboembolic events were rare in both groups (marijuana usage: 1 vs non-usage: 2). Compared to the non-usage cohort, the marijuana usage cohort had a similar average EBL (329.9 ± 298.5 mL vs 374.5 ± 363.8 mL; P = .254). Multivariate regression modeling demonstrated that neither EBL (OR 1.27, 95% CI 0.64-2.49) nor need for transfusion (OR 1.56, 95% CI 0.43-5.72) varied between cohorts. The non-usage cohort had twice the risk of prolonged LOS compared to the marijuana usage cohort (OR 2.05, 95% CI 1.15-3.63).

Conclusion:

Marijuana use should not be considered a contraindication for TXA utilization in lumbar spine surgery.