A randomised comparative evaluation of ultrasound guided classical versus parasacral parallel shift (PSPS) technique of sciatic nerve block combined with femoral nerve block as a sole anaesthetic modality for orthopaedic lower limb surgeries

Combined femoral and sciatic nerve block were initially administered for post-operative analgesia after major lower limb surgery.6 They were administered either as a single injection technique or as a continuous catheter technique.7 Various studies exist regarding the safety of combined femoral and sciatic nerve block over general and central neuraxial blocks for lower limb surgeries. 8,9.It is the primary anaesthetic modality in critically ill patients where both GA and central neuraxial block carry a high risk of mortality.10 The primary aim of this study is to compare the success of the parasacral sciatic nerve block with the classical and PSPS approach when combined with the USG femoral nerve block and administered as a sole anaesthetic agent for OLLS. The secondary aim of the study will be to compare the time to onset and intensity of sensory and motor blockade, time to first rescue analgesia and average pain scores at 6,12 and 24 hours post-operatively.