Regional anesthesia is now recommended as an adjunct to general anesthesia whenever feasible for its opioid and anesthetic sparing effect. Caudal epidural block (CEB) is one of the most routinely practiced regional anesthetic procedures for intra and post-operative analgesia in paediatric patients. Although complications are rare, adverse effects reported include intravascular, subarachnoid or intraosseous space injection, hypotension (more common in adults), epidural hematoma as well as urinary retention.  USG-guided ESPB is now a common regional anesthetic technique used in clinical practice for a variety of indications including breast reconstruction surgeries, lumbar spine fusion surgeries, post thoracotomy surgeries and hemorrhoidectomy surgeries. In paediatric patients it has shown effective pain control in hypospadias surgery, lower abdominal surgeries, hip surgeries and spine surgeries. It is considered a very safe block and very few adverse effects have been reported till date because the target area that is the vertebral transverse process is an avascular space and is away from all major vital structures and the neuraxis. The various approaches to the ESPB include thoracic, lumbar and sacral depending on the level of the target dermatomes. Sacral ESPB blocks lumbo-sacral dermatomes and is useful for lower abdominal and lower limb surgeries.

On extensive literature review, we could not find any study directly comparing sacral ESPB and caudal epidural block in pediatric patients undergoing lower limb surgery. Therefore, this study to compare sacral ESPB with caudal epidural block has been planned.