Risk Factors For Prolonged Opioid Use and Effects of Opioid Tolerance on Clinical Outcomes after ACDF Surgery.

Study Design. Retrospective study. Objective. The aim of this study was to determine risk factors for prolonged opioid use and to investigate whether opioid-tolerance affects patient-reported outcomes following anterior cervical discectomy and fusion (ACDF) surgery. Summary of Background Data. There is a lack of consensus on risk factors that can affect continued opioid use after cervical spine surgery and the influence of opioid use on patient-reported outcomes. Methods. Ninety-two patients who underwent ACDF for degenerative cervical pathologies were retrospectively identified and their opioid usage before surgery was investigated using a state-sponsored prescription drug monitoring registry. Opioid-naive and opioid tolerant groups were defined using criteria most consistent with the Federal Drug Administration (FDA) definition. Patient-reported outcomes were then collected, including the Short Form-12 (SF-12) Physical Component (PCS-12) and Mental Component (MCS-12), the Neck Disability Index (NDI), the Visual Analogue Scale Neck (VAS neck) and the Visual Analogue Scale Arm (VAS Arm) pain scores. Logistic regression was used to determine predictors for prolonged opioid use following ACDF. Univariate and multivariate analyses were conducted to compare change in outcomes over time between the two groups. Results. Logistic regression analysis demonstrated that opioid tolerance was a significant predictor for prolonged opioid use after ACDF (odds ratio [OR]: 18.2 [1.46, 226.4],P = 0.02). Duration of usage was also found to be a significant predictor for continued opioid use after surgery (OR: 1.10 [1.0, 1.03],P = 0.03). No other risk factors were found to be significant predictors. Both groups overall experienced improvements in patient-reported outcomes after surgery. Multiple linear regression analysis, controlling for patient demographics, demonstrated that opioid-tolerant user status positively affected change in outcomes over time for NDI (beta = -13.7 [-21.8,-5.55],P = 0.002) and PCS-12 (beta = 6.99 [2.59, 11.4],P = 0.003) but no other outcomes measured. Conclusion. Opioid tolerance was found to be a significant predictor for prolonged opioid use after ACDF. Additionally, opioid-naive and opioid-tolerant users experienced overall improvements across PROMs following ACDF. Opioid-tolerance was associated with NDI and PCS-12 improvements over time compared to opioid-naive users.