With great interest we read the recent article by Zundel and colleagues,[1] which compared postoperative analgesic efficacy of caudal block and wound infiltration (WI) for inguinal procedures in young children. The primary outcome of this study was pain score within 24 hours postoperatively and a difference of 2 points in mean pain scores was considered as clinically relevant in sample size estimation. However, available literature indicates that a change of 1 point on the 10-point pain scale provided by analgesic interventions signifies a clinically important improvement or deterioration.[2] We argue that using a larger effect size of 2 points would have underestimated sample size of this study.

Importantly, we noted that compared to the WI group, pain scores in the caudal block group were lower within 2 hours postoperatively and then were higher within 4 to 18 hours postoperatively. Furthermore, the caudal block group received statistically significantly more doses of nonopioids and 8% of children with the WI received opioids in the recovery room. Unlike other works comparing efficacy of regional analgesia techniques in children undergoing inguinal procedures,[3] [4] this study did not provide indications of opioid or nonopioid use for postoperative pain control. We are concerned that the lack of a consistent pain control target in this study would have biased primary and secondary outcomes.

Finally, the authors did not report the time to first analgesic need during the study period, though this is a useful variable that evaluates analgesic duration of a regional block.[5] Especially, this study did not assess the patient/parental satisfaction with postoperative analgesia, which would provide valuable insights into clinical usefulness of two regional analgesic techniques for pediatric inguinal surgery.