Caudal epidural block is the commonest modality used for pain relief during intra and post-operative periods, by decreasing the release of stress hormones. However, the presence of anatomic variations, spine abnormalities, or in older children wherein the ligamentum flavum gets calcified makes the placement of the caudal epidural difficult. Also, there is a potential risk of rare complications like block failure (1.9%), infection, epidural hematoma, intravascular injection, intrathecal injection, motor blockade, and urinary retention, as depicted by the Pediatric regional anesthesia network. In the past there have been reports suggesting an association of caudal block (CB) to urethrocutaneous fistula, strictures, and wound dehiscence following hypospadias surgery.

Recently there is a trend towards using peripheral nerve blocks for pediatric urological procedures; the pudendal nerve block (PNB) is one of those, used for effective pain relief. Pudendal nerve supplies the perineum with somatosensory input for the penile region and arises from anterior rami of sacral segments (S2-4), it is a field block, wherein the local anesthetic is deposited adjacent to the terminal branches (perineal and dorsal penile nerve) and provides effective analgesia. It has been traditionally used for male genitalia surgeries, vaginal deliveries, chronic pain management, and hemorrhoidectomies. Although used for pain management in pediatric urological procedures, still there is limited data on its effectiveness, which warrants more randomized studies. It has been shown to reduce post-operative pain scores, decrease post-operative stay, and provide better parental satisfaction. Pudendal nerve block can be done by various approaches such as transgluteal,  transrectal, and transvaginal either through Alcock’s canal or by interligamentous plane. With the advent of ultrasound, inherent risks with an inadvertent vascular or rectal injury can be mitigated, adding to the safety profile of pudendal nerve block with more consistent analgesic coverage.

We hypothesize that ultrasound(US)-guided PNB is not inferior to CB in terms of the Face Legs Activity Cry Consolability behavioral scale(FLACC) score at the 6th postoperative hour (with a non-inferiority margin (NIM) of 2), in children presenting for penile procedures under General Anesthesia.

The research question for this study is to determine the meaningful postoperative pain relief in children aged between 2 yrs. to 7 yrs. presenting for penile surgeries under general anesthesia and comparing the US-guided PNB with a caudal block by comparing the FLACC pain score at the 6^th postoperative hour (noninferiority of the pudendal block with a margin of difference of 2) to be conducted in the elective operation theatre in the advanced pediatric centre, PGIMER Chandigarh.