Effectiveness of Liposomal Bupivacaine With Bupivacaine Hydrochloride vs Bupivacaine Hydrochloride Alone as a Local Anesthetic for Children Undergoing Ambulatory Urologic Surgery: The Baby ORIOLES Randomized Clinical Trial.

Purpose: We sought to determine if the addition of liposomal bupivacaine to bupivacaine hydrochloride improves opioid-free rate and postoperative pain scores among children undergoing ambulatory urologic surgery.

Materials And Methods: A prospective, phase 3, single-blinded, single-center randomized trial with superiority design was conducted in children 6 to 18 years undergoing ambulatory urologic procedures between October 2021 and April 2023. Patients were randomized 1:1 to receive dorsal penile nerve block (penile procedures) or incisional infiltration with spermatic cord block (inguinal/scrotal procedures) with weight-based liposomal bupivacaine plus bupivacaine hydrochloride or bupivacaine hydrochloride alone. The primary outcome was opioid-free rate at 48 hours. Secondary outcomes included parents' postoperative pain measure scores, numerical pain scale scores, and weight-based opioid utilization at 48 hours and 10 to 14 days.

Results: We randomized 104 participants, with > 98% (102/104) with complete follow-up data at 48 hours and 10 to 14 days. At interim analysis, there was no significant difference in opioid-free rate at 48 hours between arms (60% in the intervention vs 62% in the control group; estimated difference in proportion -1.9% [95% CI, -20%-16%]; = .8). We observed no increased odds of patients being opioid-free at 48 hours with the intervention compared to the control group (OR 0.96 [95% CI 0.41-2.3]; = .9). The trial met the predetermined futility threshold for early stopping. There was no difference in parents' postoperative pain measure scores, numerical pain scale scores, or opioid utilization at 48 hours or 10 to 14 days. No difference in adverse events was observed.

Conclusions: The addition of liposomal bupivacaine to bupivacaine hydrochloride did not significantly improve opioid-sparing effect or postoperative pain compared with bupivacaine hydrochloride alone among children ≥ 6 years undergoing ambulatory urologic surgery.