Rebound Pain and Patient Satisfaction With Dexamethasone as an Adjunct for Peripheral Nerve Blocks. A Substudy Based on Two Randomised Clinical Trials

BACKGROUND: Peripheral nerve blocks (PNBs) are a cornerstone in postoperative pain management, reducing pain, opioid consumption, and opioid-related adverse effects. However, the duration of PNBs is limited and might result in rebound pain after block cessation. Dexamethasone, a synthetic glucocorticoid, when administered in addition to PNBs, prolongs block duration and might mitigate rebound pain. We assessed the effect of adjunct dexamethasone on pain after block cessation and rebound pain. METHODS: This is a substudy pooling data from two randomised, placebo-controlled three-arm clinical trials conducted between June 9, 2022 and May 17, 2023. Participants underwent osseous surgery of either the lower or upper limb under peripheral nerve block. Participants were allocated to dexamethasone (12 mg oral, 24 mg oral, or 12 mg intravenous) or placebo (oral or intravenous). The primary outcome was pain immediately after block cessation (Numerical Rating Scale, NRS, 0 to 10) and rebound pain (NRS ≥ 7 immediately after block cessation). RESULTS: Data from 159 participants were included. Fifty-six participants received placebo and 103 participants received dexamethasone. The median pain score after block cessation was 5.0 points (IQR 3.0 to 8.0) in the placebo group and 3.0 points (IQR 1.0 to 6.0) in the dexamethasone group. Rebound pain occurred in 20 of 56 participants (35.7%) in the placebo group and in 19 out of 103 participants (18.4%) in the dexamethasone group. Dexamethasone significantly reduced pain after block cessation (mean difference: -1.7 points, 95% CI: -2.6 to -0.8, p < 0.001) and the risk of rebound pain (risk ratio: 0.51, 95% CI: 0.30 to 0.88, p = 0.014) when compared to placebo. We found no association between patient satisfaction and rebound pain. However, the satisfaction measure exhibited a ceiling effect with most participants reporting maximum satisfaction and therefore the ability to detect a difference may have been limited. CONCLUSIONS: Dexamethasone reduced pain after block cessation and the risk of rebound pain when compared with placebo. EDITORIAL COMMENT: This study combined data from two randomised controlled trials, which included patients who underwent osseous surgery on either the upper or lower limb under peripheral nerve block. The trials investigated rebound pain and patient satisfaction. When administered intravenously or orally, dexamethasone reduces pain after block cessation and the occurrence of rebound pain. No significant difference in satisfaction scores was found between patients who received systemic dexamethasone and those who received a placebo.