The effect of cannabis use on postoperative complications in patients undergoing spine surgery: A national database study.

Background: With the increased use of cannabis in the US, there is a significant need to understand the medical complications associated with its use in relationship to a surgical population. Cannabis has mainly been studied with respect to its qualities of pain treatment, yet few studies have investigated post-surgical complications associated with its use. Therefore, the purpose of this study was to explore the effect of cannabis use on complications in spine surgery, and compare these complications rates to opioid-related complications. Methods: This was a retrospective study conducted using the PearlDiver Database. Using ICD codes 40,989 patients that underwent lumbar spine fusion between January 2010 and October 2020 were identified and divided into 3 study groups (i.e., control, patients with known opioid use disorder, and patients identified as cannabis users). Differences in the incidence of complications within 30 days of the index procedure and pseudarthrosis rates at 18 months postindex procedure were assessed among study groups using a multivariate logistic regression. Results: Of 12.4% study population used cannabis and 38.8% had a known opioid use disorder. Results indicated increased odds of experiencing a VTE, hypoxia, myocardial infarction, and arrhythmia for both opioid and cannabis users compared to controls; however, when controlling for tobacco use there were no increased odds of complications within the cannabis group. The pseudarthrosis rate was greater in cannabis users (2.4%) than in controls (1.1%). Conclusions: The pseudarthrosis rate was significantly greater in patients using cannabis and opioids compared to the control group. However, when controlling for tobacco use, results suggested a possible negative synergistic between cannabis use and concomitant tobacco use that may influence bone fusion.