The Effects of Marijuana Use on Lumbar Spinal Fusion.

November 28, 2019

STUDY DESIGN:

A retrospective cohort study.

OBJECTIVE:

The purpose of this study was to evaluate marijuana usage and its effect on outcomes following transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA:

As marijuana becomes legalized throughout the United States, its medicinal and recreational usage is becoming more mainstream. Clinicians currently have little guidance regarding both short-term and long-term effects of marijuana usage on surgical interventions. While the rate of lumbar spinal fusion in the United States continues to grow, the effect of marijuana usage on fusion remains uncertain.

METHODS:

102 patients who underwent TLIF performed by the same surgeon were followed for 12 months. Patients were self-reported for marijuana usage (n = 36). Patient reported outcome measures included preoperative Oswestry Disability Index (ODI), 6-month ODI and 12-month ODI, as well as length of stay (LOS), complications, return to operating room (OR), revision surgery, and confirmed fusion. Continuous variables were compared using the independent two-sample t test or analysis of variance (ANOVA), whereas categorical variables were analyzed using the chi-square or Fischer exact tests. Adjusted analysis was performed using a multivariate logistic regression model.

RESULTS:

Marijuana usage was associated with a younger population (p < 0.001), but showed no difference regarding sex or BMI compared to the non-usage group. There was no statistically significant difference in complications, return to OR, or revision surgery between groups. When controlling for factors such as age and pre-operative ODI, multivariate analysis demonstrated that marijuana usage did not limit post-operative ODI reduction. The marijuana usage group demonstrated shorter LOS (2.42 vs. 3.00 days, p = 0.020). Fusion rates at 12 months were similar between groups (96% vs. 92.3%, p = 0.678). ODI was similar between groups at all time points.