Identification of perineural cysts during ultrasound-guided caudal anaesthesia

An 8-year-old boy was scheduled for urethral fistula correction under general anaesthesia with an ultrasound-guided caudal block. During scanning of the caudal area, we noticed two cystic structures in the caudal space in the region of the intended needle endpoint so we decided against performing the caudal block. Surgery was conducted uneventfully and a penile block was administered as an alternative for analgesia postoperatively. Radiological evaluation of the child 3 weeks later revealed the presence of perineural cysts in the sacral region. Routine use of ultrasound for caudal anaesthesia procedures may reveal unexpected anomalies in the sacral area, which could have implications for optimal patient management.