1457. A Double-Blind, Randomized, Placebo-Controlled Trial of Naloxegol for Prevention of Post-Operative Constipation in Spinal Fusion Patients

Authors: Pankaj Kumar Agarwalla, MD; Benjamin Grannan; Casey Silvernale; Christine Lee; Christopher Curtis; Vijay Yanamadala; Lawrence Borges; Jean-Valery Coumans; John Shin; Ziv Williams; Kyle Staller, MD (Tampa, FL)

Introduction: Spinal fusion surgery patients require significant opioid medications in the perioperative period, with constipation a common complication of opioid use for non-cancer pain. Naloxegol is a peripherally acting mu-opioid receptor antagonist that is FDA approved for opioid-induced constipation. We sought to assess whether naloxegol prophylaxis improves constipation among inpatients after posterior spinal fusion surgery. Methods: Adult patients undergoing non-urgent, elective posterior spinal fusions by the neurosurgical service at the Massachusetts General Hospial were eligible. Enrolled patients were randomized to daily oral naloxegol (25 mg) or placebo starting in the recovery room in a double-blind fashion. All patients also received daily docusate plus rescue laxatives as needed. The primary outcome was time to first bowel movement. Complete protocol details are available at ClinicalTrials.Gov (NCT02946580). Results: A total of 52 patients were enrolled and randomized (28 to naloxegol and 24 to placebo). All subjects completed the study except for one patient who was discharged prior to bowel movement and was unable to be contacted afterward. The median time to first post-operative bowel movement in the naloxegol group was 91 hours vs. 94 hours in the placebo group. Cox proportional hazard analyses adjusted for age, sex, race, pre-operative laxative use, pre-operative opioid use, surgeon, and surgical time demonstrated no significant difference in time to first bowel movement between the study groups (p = 0.85). Only one patient in the placebo group had a gastrointestinal adverse event (diarrhea). In total, 38 subjects (73%) did not have a bowel movement within first 72 hours post-operatively. Conclusion: There was no significant difference in time to first bowel movement between posterior spinal fusion surgery patients given prophylactic naloxegol vs. placebo in the postoperative period. Our data suggest that there is significant post-operative constipation in this population and additional studies are needed to optimize peri-operative constipation management.