P019: THE IMPACT OF A SINGLE DOSE OF INTRAOPERATIVE METHADONE ON POSTOPERATIVE PAIN MANAGEMENT: A RETROSPECTIVE COHORT STUDY
Grace DeSena, BA; Karly Landvay, BS; Shahrukh Bengali; Basma Mohamed, MDChB; University of Florida
Introduction / Background: Acute postoperative pain is associated with increased morbidity, length of stay, and readmission rates, and may contribute to persistent postoperative pain which all have an impact on healthcare cost and utilization.1,2,3 Major spine surgery ranked 2nd, 3rd, and 6th in a study comparing pain intensity across 179 various surgical procedures.4 Methadone is a long-acting μ-opioid receptor agonist with N-methyl-D-aspartate (NMDA) receptor antagonism which may play a role in the development of hyperalgesia and opioid tolerance.5,6 There is some evidence to suggest that a single intraoperative dose of methadone administered at the beginning of complex spine surgery decreased postoperative opioid requirements, pain scores, and improved patient satisfaction up to postoperative day (POD) 3.7,8 Our institution implemented the use of 0.1 – 0.2 mg/kg of ideal body weight intravenous methadone for patients undergoing complex spine surgery in 2018. The objective of this study is to evaluate the postoperative analgesic effect of a single intraoperative dose of methadone in patients undergoing lumbar spine surgery.
Methods: A single-center retrospective study was performed at a tertiary care teaching hospital in patients who underwent multilevel lumbar spinal fusion surgeries between 2015 to 2022. Patients were split into two groups based on administration of intraoperative methadone: pre-intervention (no methadone prior to 2018) and post-intervention (methadone after 2018). Primary outcomes were pain scores and postoperative opioid consumption. Secondary outcomes included length of stay and complication rates. Statistical analysis was completed using independent t-tests and chi-square tests. Baseline characteristics were assessed between both groups. The exclusion criteria were patients younger than 18, emergency or trauma spine surgery, simple laminectomy or discectomy without instrumentation or fusion, history of opioid or alcohol abuse, acute liver failure or cirrhosis, and end-stage renal disease or dialysis. Ethical approval was obtained (IRB#: IRB201902613).
Results: Sixty patients were included in the analysis with thirty patients in each group. Baseline characteristics and comorbidities for both groups were similar. Total opioid consumption was significantly lower in the post-intervention group on POD 0 (mean MME 362 vs. 88.7; P < 0.0001) and had a lower 72-hour total MME (mean MME 743 vs. 347; P = 0.0061). Patient-controlled analgesia use was decreased in the post-intervention group (27 vs. 6, P < 0.0001). There was no statistically significant difference in DVPRS pain scores and secondary outcomes including length of stay and complication rate between the groups.
Discussion / Conclusion: Our study findings suggest that a single dose of intravenous methadone is associated with decreased postoperative opioid consumption without impacting overall pain scores for patients undergoing multilevel lumbar spine surgery. Furthermore, intraoperative methadone may be associated with decreased opioid PCA use postoperatively which may present a cheaper alternative. Finally, there was no increase in postoperative complication rates with administration of intravenous methadone. Limitations of this study include small sample size and lack of blinding to providers.