The Impact of Tobacco and Marijuana Use on Spinal Fusion: A Systematic Review and Meta-Analysis

Introduction: Spinal fusion is one of the most common procedures performed in the United States. Surgery can be impacted by a number of risk factors with smoking being one of the most well-documented of these. While current literature has extensively reported the harmful effects of smoking on bone healing, less is known regarding the impact of marijuana use on postsurgical healing.

Methods: A systematic review of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included manuscripts were methodically scrutinized for quality, and follow-up duration. Factors evaluated were tobacco use, vaping history, and marijuana use. Outcomes were compared via the random-effects analysis.

Results: A total of 57 studies were included with a total of 183,801 patients undergoing spinal fusion. There were 68,241 patients using tobacco and 115 marijuana users with 115,445 control-matched patients total. For tobacco users, the rate of pseudarthrosis was 20.7% (1727/14189 patients; 95% CI 17.9 – 23.9%) while the rate of surgical site infection was 4.4% (446/19826 patients; 95% CI 2.6 – 6.1%). Control-matched participants demonstrated a rate of pseudarthrosis of 12.9% (1009/27135 patients; 95% CI 10.6 – 15.3%) and a rate of surgical site infection of 3% (4/115 patients; 95% CI 1.0 – 6.0%). Amongst marijuana users, the rate of pseudarthrosis was 35.7% (45/101 patients; 23.7 – 95.1%) while the rate of surgical site infection was 3.0% (4/115 patients; 95% CI 0.1 – 6.0%). Control-matched patients demonstrated a rate of pseudarthrosis of 1.1% (3/244 patients; 95% CI 0.2 – 2.5%) and a rate of surgical site infection of 1.6% (4/246 patients; 0.1 – 3.2%). In total, tobacco and marijuana users had a total postsurgical complication rate of 29.2% (2361/36339 patients; 95% CI 16.0 – 74.3).

Conclusion : The available data demonstrates that marijuana affects postsurgical healing and may lead to higher rates of pseudarthrosis compared to tobacco users. However, tobacco users had similarly higher rates of complications as marijuana users when compared to their control-matched counterparts.