Preoperative Opioid Weaning in Adult Spinal Deformity Surgery: Who Can Do It and Does It Predict Outcomes?

BACKGROUND AND OBJECTIVES: Although half of patients undergoing adult spinal deformity (ASD) surgery use chronic opioids preoperatively, few studies have investigated how preoperative opioid weaning affects outcomes. In this study, we sought to (1) identify predictors of successful preoperative opioid weaning, (2) evaluate the association between weaning and postoperative opioid freedom, and (3) determine whether weaning is associated with mechanical complications. METHODS: A retrospective cohort study (2017-2023) of ASD patients with minimum 2-year follow-up was performed. The primary exposure variable was preoperative weaning, classified as: (1) partial weaning: minimum reduction of 33% of preoperative morphine milligram equivalents, (2) complete weaning: off all opioids, and (3) any weaning: either group. Outcomes included predictors of successful weaning, postoperative opioid use, and mechanical complications. Mechanical complications were assessed using multivariable logistic regression adjusting for diabetes and postoperative alignment. RESULTS: Of 152 ASD surgical patients, 67 (44.1%) were preoperative opioid users. The mean age was 62.5 ± 10.1 years, and 71.6% were female. Nineteen patients (28.4%) completely weaned, 10 (14.9%) partially weaned, and 38 (56.7%) failed to wean. Shorter preoperative opioid duration (adjusted odds ratio 0.97 per month, P = .028) and Schedule II opioid type (adjusted odds ratio 5.52, P = .018) independently predicted complete discontinuation. Patients with any preoperative weaning had significantly higher 12-month opioid freedom rates (71.4% vs 22.9%, P < .001). After adjusting for opioid duration, complete weaning was associated with a nearly 5-fold acceleration in time to opioid freedom (adjusted hazard ratio 4.54, P < .001), while any weaning demonstrated a nearly 3-fold acceleration (adjusted hazard ratio 2.92, P = .011). A dose-response gradient was observed for reoperation for mechanical complication (trend P = .043). Weaned patients demonstrated 91.7% reoperation-free survival at 24 months vs 74.4% among no-weaning (P = .058). CONCLUSION: Preoperative opioid weaning independently predicted sustained postoperative opioid freedom and was associated with trends toward lower reoperation rates for mechanical complications. Opioid duration was the key barrier to successful weaning, reinforcing the urgency of early surgical referral.