Comparing precision of ultrasonography assisted lumbar epidural space depth measurement against loss of resistance in sitting versus lateral position in lower limb surgeries - A randomised controlled trial

Central neuraxial block ( CNB ) is a widely used regional anesthesia technique, achieved by injecting local anesthetics into the sub arachnoid or epidural space to block spinal nerve roots. Traditionally, CNB relies on anatomical landmarks and the loss of resistance (LOR) technique, but this gold standard technique ia a blind approach which often requires multiple attempts, increasing complications.Ultrasonography (USG) has emerged as a valuable tool which is safe, non-invasive and provides real time image for visualizing spinal anatomy, improving first-pass success rates, and reducing needle redirection.This prospective, randomized, single-blind study aims to compare the precision of USG-assisted epidural space depth measurement against the LOR technique in sitting versus lateral position during lower limb surgeries and the study will help evaluate whether patient positioning affects the precision of epidural depth measurement and also to enhance the safety and accuracy of CNB in clinical practice.