Authors: Corey Walker, MD; Arpan Patel, BS; Virginia Prendergast; Jakub Godzik, MD; Alexander Whiting, MD; Udaya Kakarla, MD; Juan Uribe, MD; Jay Turner, MD, PhD (Phoenix, AZ)

Introduction: Optimal post-operative pain control is critical after lumbar fusion surgery. However, there is significant variability in the use of intravenous opioid patient-controlled analgesia (PCA) and little data evaluating its utility compared to multimodal nurse-controlled analgesia (NCA) in this patient population. Methods: A single institution retrospective review was conducted in patients receiving posterior lumbar fusion for degenerative pathology. Baseline demographics, treatment data, and clinical outcomes were collected. Patients were divided into two cohorts: those treated postoperatively with PCA and NCA. Post-operative numerical rating scale (NRS) pain scores, length of stay, and total opioid consumption were collected. Patients were stratified according to pre-operative opioid consumption as naïve, low (<60 morphine milligram equivalents (MME) daily), high (61-90 MME) or very high (>90 MME). Results: 240 patients were identified: 62 and 178 in PCA and NCA groups, respectively. PCA patients had higher mean pre-operative opioid consumption compared to the NCA patients (49.2 vs 24.3 MME, p=0.009). After stratifying by preoperative opioid consumption, PCA patients had higher 72-hour opioid consumption in all groups. With opioid naïve patients, PCA was associated with higher post-operative NRS scores at 24 and 24-72 hours (p=0.046 and 0.023, respectively) despite greater opioid intake. In the Very High opioid consumption group (>90MME), PCA had increased maximal reported pain scores between 24-72 hours (p=0.014) and a greater rate of opioid-related adverse events per patient (0.86 vs 0.43, p=0.046). Pain control and adverse event rates were comparable between PCA and NCA in the middle groups (1-90 MME). Conclusion: Postoperative PCA utilization is associated with significantly more opioid consumption and equal or worse post-operative pain scores compared to NCA after lumbar spinal fusion surgery, particularly in opioid naïve patients. The increased opioid consumption with PCA may also lead to higher rates of opioid-related adverse events in subsets of patients.