P150. The impact of preoperative cannabis use on outcomes following thoracolumbar spinal fusion: a propensity score-matched analysis

Abstract

BACKGROUND CONTEXT Cannabis is the most commonly used illicit drug in the United States, and with changing state legislation, the use of cannabis is expected to expand. Although other literature has noted potentially medicinally beneficial effects of cannabis, there is limited literature evaluating the impact of cannabis on outcomes for patients following spinal surgery. With shifting public sentiment, expanding decriminalization, and a dearth of knowledge on the potential surgical implications of cannabis, it is imperative we take a closer, objective look at how cannabis dependence or abuse impacts the outcomes of common orthopedic procedures, such as thoracolumbar fusion. PURPOSE To determine if adverse outcomes would be comparable between baseline cannabis users and non-cannabis users undergoing thoracolumbar spinal fusion. We compared the rates of 90-day outcomes and complications and 2-year revisions between baseline cannabis users and non-users following thoracolumbar spinal fusion. STUDY DESIGN/SETTING Retrospective cohort study of a prospectively-collected database. PATIENT SAMPLE The New York State Statewide Planning and Research Cooperative System (SPARCS) was queried to identify all patients from January 2009 to September 2013 who underwent thoracolumbar spinal fusion. Patients were included if they had ≤90-day follow-up for complications and readmissions or ≥2-year follow-up for revisions. Patients with preoperative cannabis abuse/dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. OUTCOME MEASURES Demographic information, fusion approach, fusion levels, complications, readmissions, and revisions. METHODS The NYS SPARCS database was queried to identify all patients ≥18y who underwent thoracolumbar spinal fusion from 2009-13. Patients were included if they had ≤90D FU for complications and readmissions or 2Y FU for revisions. Patients with preoperative cannabis abuse/dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. Following patient identification in the SPARCS database, patients with ICD-9-CM diagnosed cannabis use were 1:1 propensity score-matched by age, gender, race, Deyo score, fusion levels and approach and tobacco use to non-cannabis users. These groups were compared for hospital-related parameters, rates of 90-day complications and readmissions and 2-year revisions. Multivariate binary stepwise logistic regression models identified independent predictors of outcomes. RESULTS A total of 628 patients (n=314 each) were identified and included; patients had comparable age, gender, fusion approaches and fusion levels distribution. More cannabis patients were African American (19.7 vs 7.6%) and primarily utilized Medicaid (24.2% vs 11.5%), all p≤0.001. Non-cannabis patients incurred lower 90-day overall and medical complication rates (5.1% vs 12.1%; 4.5% vs 9.9%), all p CONCLUSIONS Cannabis was a protective factor against postoperative anemia and any medical complication, and baseline cannabis use was not associated with increased surgical or overall 90-day complications and readmissions or 2-year revision rates. These findings underscore that baseline cannabis use in the absence of acute intoxication may not necessarily require delays in preoperative clearance. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.