Combined Betamethasone and Ropivacaine for Scalp Nerve Block for Patients Undergoing Elective Craniotomy: A Prospective, Randomized, Controlled Clinical Study

BACKGROUND: Scalp nerve block (SNB) enhances neurosurgical recovery, but local anesthetics alone provide short-term analgesia. This study aimed to ascertain if a betamethasone and ropivacaine combination (betamethasone plus ropivacaine) prolongs analgesia relative to ropivacaine alone. METHOD: This prospective, single-center, randomized controlled clinical trial was conducted from August 16, 2022, to December 19, 2024. Eligible patients for elective craniotomy were randomly allocated in a 1:1 ratio to the betamethasone group (n=45), which received SNB with 0.5% ropivacaine combined with betamethasone, or the control group (n=45), which received SNB with 0.5% ropivacaine alone. The primary outcome was the Numerical Rating Scale (NRS) pain score at 48 hours postoperatively. The secondary outcomes were NRS pain score within 48 hours postoperatively and plasma concentrations of interleukin-6, interleukin-10, and interferon-γ. RESULTS: The baseline data of the groups showed no significant differences. The betamethasone group had significantly lower NRS scores at 48 hours postoperatively (1 [0 to 2] vs 2 [2 to 3], P<0.001). Betamethasone plus 0.5% ropivacaine improved the NRS scores within 24 hours postoperatively. The betamethasone group had significantly lower interleukin-6 (3.3 [2.5 to 5.6] vs 11.6 [4.5 to 21.5] pg/ml, P=0.001) and interferon-gamma (3.4 [2.4 to 8.3] vs 5.3 [3.6 to 9.1] pg/ml, P=0.042) concentrations than the control group. Their interleukin-10 concentrations were not different (P=0.582). CONCLUSION: Betamethasone plus 0.5% ropivacaine SNB significantly decreased postoperative pain intensity within and at 48 hours postoperatively, likely due to prolonged analgesia and reduced inflammatory responses. CLINICAL TRIAL REGISTRATION: No. ChiCTR2200062670.