Analgesic Drug Prescription After Carpal Tunnel Surgery: A Pharmacoepidemiological Study Investigating Postoperative Pain

Background and Objectives Carpal tunnel syndrome is a frequent cause of neuropathic pain of the upper limb. Surgery is often proposed in second-line treatment, leading to an expected decrease in analgesic drug consumption. The main objective of this study was to investigate the variations in analgesic drug prescriptions, with a special focus on constant or increasing prescription patterns, before and after surgery for carpal tunnel syndrome. Methods We designed a retrospective cohort study of French beneficiaries from the health insurance system in Midi-Pyrenees area. All patients undergoing carpel tunnel surgery during a specified period were identified and included. Definition of increased or constant prescription of analgesics was based on the comparison of the accumulated defined daily doses received by months and a difference between early preoperative (2 months before) and late postoperative period (2–12 months after surgery) superior to a −3.5 margin. We performed 4 multivariate logistic regression models to identify factors associated with increased or constant analgesic drug prescription patterns (for all analgesics, opioid, antineuropathic, nonopioid drugs). Results Among the 3665 patients included, 3255 (89%) received at least 1 analgesic drug during the late postoperative period (39% [n = 1426] for opioids and 15% [n = 563] for antineuropathic drugs). Prescription of analgesic, opioid, or antineuropathic drugs was maintained or increased in the late postoperative period in 11%, 5%, and 3% of the population, respectively. High levels of preoperative pain and female sex were associated with an increase in opioid use, whereas inpatient surgery (vs ambulatory surgery), high levels of preoperative pain, and psychiatric disorders were found to be associated with an increase in antineuropathic drug use. Conclusions This study revealed that approximately 3% to 5% of patients undergoing carpal tunnel surgery had persistent and even increased use of opioid or antineuropathic drugs more than 2 months after surgery, in relation with possible chronic postoperative pain. Considering the incidence of carpal tunnel syndrome, the risks associated with persistent opioid use in this population should be further monitored.