Comparative study of anterior and posterior approaches for sciatic nerve block for lower limb and foot surgery in diabetic patients

Abstract

Introduction: Sciatic nerve block (SNB) is an established technique of anaesthesia for lower limb and foot surgeries. Although several approaches to SNB have been described not a single one is ideal in all respect. We aimed to compare commonly used two approaches to SNB to fin d out which one is better with regard to efficacy and patient satisfaction. Materials and Methods: Consented 60 diabetic patients of ASA grade II,III posted for foot and /or lower limb surgery were randomly allocated to receive SNB by either anterior (n=30) or posterior (n=30) approach. Blocks were performed utilizing peripheral nerve stimulator (PNS), with 25 ml of local anaesthetic mixture (10 ml of 2% lignocaine with adrenaline and 15 ml of 0.5% bupivacaine). Time taken to perform block with number of attempts required, onset of sensory and motor block, duration of analgesia were record ed and compared. We also had compared comfort level of the patients. Observations and Results: Out of 60 patients, 1of anterior and 2 of posterior approach es had failed block. Time taken to perform anterior approach was significantly less (p approach. Patients were comfortable with anterior approach than that of posterior. Faster onset of sensory and motor block, and more duration of analgesia was observed with the posterior group but the difference was not statistically significant. Conclusion: Our study concluded that though efficacy of both the anterior and posterior approaches to block sciatic nerve was same, anterior approach is easier than posterior approach as it requires lesser time to perform and gives far better patient comfort. Keywords: Anterior sciatic nerve block, Diabetic foot surgery.