Ultrasound Guided Transversus Abdominis Plane vs Surgeon Administered Intraoperative Regional Field Infiltration with Bupivacaine for Early Postoperative Pain Control in Children Undergoing Open Pyeloplasty

Purpose: Regional analgesic techniques are commonly used in pediatric urology. Ultrasound guided transversus abdominis plane block has recently gained popularity. However, there is a paucity of information supporting a benefit over regional field infiltration. We present a parallel group, randomized, controlled trial evaluating ultrasound guided transversus abdominis plane block superiority over surgeon delivered regional field infiltration for children undergoing open pyeloplasty at a tertiary referral center. Materials and Methods: Following ethics board approval and registration, children 0 to 6 years old were recruited and randomized to undergo perioperative transversus abdominis plane block or regional field infiltration for early post-pyeloplasty pain control. General anesthetic delivery, surgical technique and postoperative analgesics were standardized. A blinded assessor regularly captured pain scores in the recovery room using the FLACC (Face, Legs, Activity, Cry, Consolability) scale. The primary outcome was the need for rescue morphine administration based on a FLACC score of 3 or higher. Results: Two pediatric urologists performed 57 pyeloplasties during a 2.5-year period, enrolling 32 children (16 in each group, balanced for age and weight). There were statistically significant differences in the number of children requiring rescue morphine administration (13 of 16 receiving transversus abdominis plane block and 6 of 16 receiving regional field infiltration, p = 0.011), mean +/- SD total morphine consumption (0.066 +/- 0.051 vs 0.028 +/- 0.040 mg/kg, p = 0.021) and mean +/- SD pain scores (5 +/- 5 vs 2 +/- 3, p = 0.043) in the recovery room, in favor of surgeon administered regional field infiltration. No local anesthetic specific adverse events were noted. Conclusions: Ultrasound guided transversus abdominis plane block is not superior to regional field infiltration with bupivacaine as a strategy to minimize early opioid requirements following open pyeloplasty in children. Instead, our data suggest that surgeon delivered regional field infiltration provides better pain control.