The Effects of Cannabis Use on Postoperative Outcomes after Spinal Fusion for Adolescent Idiopathic Scoliosis.

Linden G.; Bosco A.; Cook D.; Tavabi N.; Kiapour A.; Birch C.; Hresko M.; Hedequist D.; Hogue G. · Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2026

**Background & Methods** This retrospective matched-cohort study examined 13 adolescent idiopathic scoliosis (AIS) patients with self-reported preoperative cannabis use matched to 65 control subjects without cannabis history undergoing spinal fusion surgery (2011-2019). Matching criteria included age, sex, initial curve magnitude, curve type, and number of levels fused, with primary outcomes assessed at 1-month postoperative follow-up including surgical time, pain scores, opioid use, and complication rates. **Key Findings** • Cannabis-using patients demonstrated a statistically significant increase in surgical time per level fused (33 minutes vs. 28 minutes, P = 0.03), though this difference became insignificant after propensity score adjustment (P = 0.08), suggesting potential confounding variables. • No significant differences were identified between cannabis and control groups across intraoperative outcomes, postoperative pain scores, pain medication use, discharge medication amounts, length of hospital stay, curve correction achievement, or postoperative complication rates. • Preoperative cannabis use was not associated with increased anesthesia risk, inpatient pain levels, or opioid consumption during the acute postoperative period through the first postoperative appointment. **Dosage & Administration** Not reported. The study documented self-reported cannabis use without specifying frequency, quantity, potency (THC concentration), route of administration, or timing relative to surgery. **Safety & Adverse Effects** Not reported. No adverse effects, complications, or safety concerns specific to cannabis use were identified in either group during the study period. Complication rates between groups were comparable. **Evidence Quality** This study represents low-to-moderate level evidence with significant limitations. The small cannabis-positive sample (n=13) limits statistical power and generalizability. The short 1-month follow-up window is insufficient to assess long-term surgical outcomes, fusion integration, or delayed complications. Being retrospective, the study is vulnerable to selection bias and incomplete documentation of cannabis use patterns. Propensity score adjustment for the surgical time difference suggests unmeasured confounding may exist. The authors acknowledge the need for prospective, controlled research with longer follow-up periods. Findings are preliminary and cannot definitively establish cannabis safety or harm in this population. Generalization is limited to a single surgical center and predominantly male adolescent cohort.

More recent cannabis research