Abstract No.: ABS1180: A randomised comparative evaluation of ultrasound guided classical vs parasacral parallel shift (PSPS) technique of sciatic nerve block combined with femoral nerve block as a sole anaesthetic modality for orthopaedic lower limb surgeries

Abstract

Background and Aims:Sciatic nerve can be blocked in the gluteal region via anterior, posterior and a newly developed lateral/parasacral approach. Primary objective of the study was to compare success of sciatic nerve block using classical versus parasacral parallel shift approach (PSPS).Methods:This study was conducted in a tertiary medical college hospital from October 2020 to October 2021 after approval of Institutional Ethics Committee and written informed patient consent. Total 160 patients (80 in each group) aged 18-80 years with American Society of Anesthesiologists physical status I-III ,undergoing traumatic lower limb orthopaedic surgery were assessed for eligibility based on the inclusion and exclusion criteria. Ultrasonography was used for the blocks.Results:Successful block was administered in 98.61%(n=71) subjects via PSPS approach, compared to 90.27%(n=57) via classical approach(table1). Time between ultrasound localisation of nerve to drug administration was significantly higher with classical as compared to PSPS approach. Successful first needle pass was seen in 90.27%(n=65) of PSPS group compared to 45.54%(n=27) of classical group. Time to motor blockade was found to be 17.33+/-3.6 minutes with PSPS approach, significantly lower than classical (22+/-3.53 minutes) approach.Conclusion:Parasacral sciatic nerve block via PSPS approach is superior to classical approach in terms of time to administration of block, success of block, requirements of sedation intraoperatively, time to motor blockade and time to sensory blockadeTable 1Block performance characteristicsClassical groupPSPS groupPSuccessful blockn=65 (90.27%)n=71 (98.61%)0.029Successful first needle passn=32 (44%)n=65 (90.27%)0.000Time from ultrasound localisation to drug administration (min)9.51±2.163.28±1.190.000Time to motor blockade (min)21.94±3.1917.32±2.490.000Time to sensory blockade (min)20.00±2.7716.21±3.080.000