Open-label placebo treatment for acute postoperative pain (OLP-POP study): a randomized controlled trial

Introduction: Treatment options for acute postoperative pain are often limited and associated with side effects and negative consequences. Therefore, effective, accessible, and safe alternatives are needed to extend existing multimodal analgesia concepts. Open-label placebos (OLPs) are discussed as a means to do so in various experimental and clinical conditions. Objective: With this randomized controlled trial, we aimed to investigate whether OLPs have the potential to reduce opioid consumption in patients suffering from postoperative pain after dorsal lumbar interbody fusion (dLIF) surgery. Methods: In this study, 65 patients with acute postoperative pain after dLIF were randomly assigned to 2 groups. One group received treatment as usual (TAU) including a patient-controlled morphine pump, whereas the other group additionally received 2 daily OLP injections during the first 2 postoperative days. As an indirect measure of pain and desire for pain relief, the primary outcome was defined as the cumulative amount of morphine consumed during the intervention period of 48 hours. Results: In our elderly study population, an analysis of covariance showed no significant differences in morphine consumption between the OLP and TAU group (estimate = -6.94, SE = 5.75, t[60] = -1.21, P = 0.880, d = -0.15). Conclusion: These findings suggest that transferring the effects of OLPs from experimental studies with younger participants to clinical studies might not be feasible. Further research should confirm these results and explore additional methodological factors such as administration mode and observation time frame.