661 Six-Month Spinal Surgery Outcomes in Marijuana and Opiate Users as Determined by Preoperative Urine Toxicology

INTRODUCTION: Despite their limited utility, diagnostic codes for substance use disorders and self-reported patient histories are often used to assess the impact of marijuana and opiate use on spinal surgery outcomes in the pre-operative setting. METHODS: Adult patients undergoing elective spinal surgery between August 2020 and May 2022 with a single neurosurgical provider were offered enrollment into the study. Participants completed urine toxicology screenings at preoperative baseline visits and reported Oswetry Disability Index (ODI), Neck Disability Index (NDI), and Visual Analogue Scale (VAS) at baseline and postoperative follow-up visits over a six-month period. Outcome measures for the marijuana and opiate use groups were analyzed using group-wise linear regression analyses (P<0.05). RESULTS: 67 participants (mean age 59 years, 66% female, 96% white) were included in this study. Participants commonly underwent lumbar decompression with laminectomy (47%), lumbar fusion (24%), and cervical fusion (12%). Preoperative urine toxicology screenings demonstrated that marijuana (28%) and opiate (19%) use were variably consistent with patient-reported frequencies (18% and 19%, respectively). Regression analyses revealed a statistically significant increase in NDI (P = 0.042) and VAS (P = 0.034) among marijuana users relative to non-users over a six-month period after spinal surgery. However, no significant changes were observed in ODI (P = 0.065) among marijuana users or ODI (P = 0.105), NDI (P = 0.241), and VAS (P = 0.125) among opiate users over the same time period. CONCLUSIONS: Preoperative marijuana use, as determined by urine toxicology, was associated with poorer postoperative neck disability and subjective pain outcomes, potentially due to decreased pain tolerance. The same effect was not seen with preoperative opiate use. Future analyses will evaluate marijuana and other substance use within a larger cohort.