Beware the rebound effect: regional anesthesia increases opioid utilization after humerus fracture surgery.

INTRODUCTION

Regional anesthesia (RA) is used reduce pain in proximal humerus and humeral shaft fracture surgery. The study hypothesis was that RA would decrease opioid demand in patients undergoing fracture surgery.

MATERIALS AND METHODS

Opioid demand was recorded in all patients ages 18 and older undergoing proximal humerus or humeral shaft fracture surgery at a single, Level I trauma center from 7/2013 - 7/2018 (n = 380 patients). Inpatient opioid consumption from 0-24, 24-48, and 48-72 h and outpatient opioid demand from 1-month pre-operative to 90-days post-operative were converted to oxycodone 5-mg equivalents (OE's). Unadjusted and adjusted models were constructed to evaluate the impact of RA and other factors on opioid utilization.

RESULTS

Adjusted models demonstrated increases in inpatient opioid consumption in patients with RA (6.8 estimated OE's without RA vs 8.8 estimated OE's with RA from 0-24 h post-op; 10 vs 13.7 from 24-48 h post-op; and 8.7 vs 11.6 from 48-72 h post-op; all  < 0.05). Estimated cumulative outpatient opioid demand was significantly higher in patients with RA at all timepoints.

DISCUSSION

In proximal humerus and humeral shaft fracture surgery, RA was associated with increased inpatient and outpatient opioid demand after adjusting for baseline patient and treatment characteristics.