A randomized comparison of caudal block by sacral hiatus injection under ultrasound guidance with traditional sacral canal injection in children

Abstract

There is a risk of inadvertent dural or vascular puncture for the traditional single-shot caudal block performed by inserting the needle into the sacral canal through the sacral hiatus. This prospective, randomized study was to evaluate the clinical feasibility of the hiatus injection under ultrasound guidance for caudal block in children. 140 ASA I-II children undergoing inguinal hernia repair were randomly allocated to one of two groups (Group C or Group H, n=70). 1ml·kg(-1) of 0.25% ropivacaine was injected after the needle was inserted into the sacral canal in Group C, or after the needle pierced the sacrococcygeal ligament under a transverse ultrasound view in Group H. Success rate of block, puncture frequency, complications, and durations of block were recorded. The success rate of block was similar between two groups (95.7% in Group C vs 92.8% in Group H, P>0.05). The first puncture success rate was higher, and the durations of block were shorter in Group H than in Group C (92.8% vs 60% and 145±23s vs 164±31s, respectively P<0.05). Bloody puncture had an incidence of 18.6% in Group C and 5.7% in Group H (P<0.05). Subcutaneous bulging occurred in six patients (7.1%) in Group C but none in Group H (P<0.05). Sacral hiatus injection offers a reliable caudal block for pediatric inguinal hernia repair with the advantages of easier performance and fewer complications compared with traditional sacral canal injection.