Persistent postoperative opioid prescription fulfillment and peripheral nerve blocks for ambulatory shoulder surgery: a retrospective cohort study

Background — There is need to identify perioperative interventions that decrease chronic opioid use. The authors hypothesized that receipt of a peripheral nerve block would be associated with a lower incidence of persistent postoperative opioid prescription fulfillment.

Methods — This was a retrospective population-based cohort study examining ambulatory shoulder surgery patients in Ontario, Canada. The main outcome measure was persistent postoperative opioid prescription fulfillment. In opioid-naive patients (no opioid prescription fulfillment in 90 days preoperatively), this was present if an individual fulfilled an opioid prescription of at least a 60-day supply during postoperative days 90 to 365. In opioid-exposed (less than 60 mg oral morphine equivalent dose per day within 90 days preoperatively) or opioid-tolerant (60 mg oral morphine equivalent dose per day or above within 90 days preoperatively) patients, this was classified as present if an individual experienced any increase in opioid prescription fulfillment from postoperative day 90 to 365 relative to their baseline use before surgery. The authors' exposure was the receipt of a peripheral nerve block.

Results — The authors identified 48,523 people who underwent elective shoulder surgery from July 1, 2012, to December 31, 2017, at one of 118 Ontario hospitals. There were 8,229 (17%) patients who had persistent postoperative opioid prescription fulfillment. Of those who received a peripheral nerve block, 5,008 (16%) went on to persistent postoperative opioid prescription fulfillment compared to 3,221 (18%) patients who did not (adjusted odds ratio, 0.90; 95% CI, 0.83 to 0.97; P = 0.007). This statistically significant observation was not reproduced in a coarsened exact matching sensitivity analysis (adjusted odds ratio, 0.85; 95% CI, 0.71 to 1.02; P = 0.087) or several other subgroup and sensitivity analyses.

Conclusions — This retrospective analysis found no association between receipt of a peripheral nerve block and a lower incidence of persistent postoperative opioid prescription fulfillment in ambulatory shoulder surgery patients.