Comparison of ring block, dorsal penile nerve block, and topical anesthesia for neonatal circumcision: a randomized controlled trial

CONTEXT: Beliefs about the safety and effectiveness of current anesthetics have resulted in many newborns being circumcised without the benefit of anesthesia. OBJECTIVE: To compare ring block, dorsal penile nerve block, a topical eutectic mixture of local anesthetics (EMLA), and topical placebo when used for neonatal circumcision. The placebo represented current practice, with no anesthetic for neonatal circumcision. DESIGN: A randomized controlled trial. SETTING: Antenatal units in 2 tertiary care hospitals in Edmonton, Alberta. PARTICIPANTS: A consecutive sample of 52 healthy, full-term, male newborns, aged 1 to 3 days. INTERVENTIONS: Physiological and behavioral monitoring occurred in a series of trials: baseline, drug application, preparation, circumcision, and postcircumcision. Surgical procedures defined the following 4 stages of the circumcision: cleansing, separation, clamp on, and clamp off. Methemoglobin level was assessed 6 hours after surgery. MAIN OUTCOME MEASURES: Heart rate, cry, and methemoglobin level. RESULTS: Newborns in the untreated placebo group exhibited homogeneous responses that consisted of sustained elevation of heart rate and high-pitched cry throughout the circumcision and following. Two newborns in the placebo group became ill following circumcision (choking and apnea). The 3 treatment groups all had significantly less crying and lower heart rates during and following circumcision compared with the untreated group. The ring block was equally effective through all stages of the circumcision, whereas the dorsal penile nerve block and EMLA were not effective during foreskin separation and incision. Methemoglobin levels were highest in the EMLA group, although no newborn required treatment. CONCLUSIONS: The most effective anesthetic is the ring block; EMLA is the least effective. It is our recommendation that an anesthetic should be administered to newborns prior to undergoing circumcision.