Does ultrasound guidance improve the efficacy of dorsal penile nerve block in children?

BACKGROUND: Penile nerve block (PNB) is a well-established technique used for circumcision; it requires the injection of local anesthetics close to the dorsal nerve of the penis. The goal of this study was to compare the efficacy of ultrasound-guided PNB versus the classical landmark-based technique (LBT) in children undergoing circumcision.

METHODS: Forty boys, aged 1-14 years old that were scheduled for circumcision were randomly assigned to ultrasound-guided and landmark-based groups. All patients were placed under standard anesthesia with sevoflurane. In each group, patients received the penile block with ropivacaine, 0.75 mg·kg(-1) per side, and 0.05 mg·kg(-1) at the penis base. Groups were compared for intraoperative failure rate of the block, anesthesia time, postoperative pain scale, time of first required dose of paracetamol, time to first micturition, and average duration of stay in the postanesthesia care unit.

RESULTS:   The failure rate of dorsal PNB was not statistically different between groups (P = 0.5). Ultrasound guidance improved the efficacy of the PNB compared to the LBT in terms of postoperative pain scores on arrival in the PACU (P < 0.01) and after 30 min (P < 0.01). The ultrasound-guided technique also delayed the time to the first paracetamol dose administration (P < 0.0001), but the duration of the procedure, defined as the time between anesthesia induction and the end of surgery, was increased by 10 min in the US-guided group (P = 0.001).

CONCLUSION:   Ultrasound-guided PNB improved the efficacy of the block compared with the LBT in terms of the postoperative pain during the first postoperative hour and the time to the first requirement for postoperative analgesia.