Anterior Approach of Ultrasound Guided Sciatic Nerve Block for Knee and below Knee Surgeries:A Pilot Study

Background and Aims: Sciatic nerve block with femoral nerve block besides its advantages has been used to achieve complete anaesthesia for knee and below knee surgery. The anterior approach has been the most seldom used due to absence of reliable landmarks and technical difficulty. We evaluated the clinical application of the anterior approach to Sciatic nerve block under ultrasound guidance. Methods: This pilot study was conducted in 30 patients aged 18-59 yrs of ASA I-II who underwent knee and below knee surgery. With patient supine and knee externally rotated, sciatic nerve was approached under ultrasound guidance and 15 ml 0.5% bupivacaine along with 10 ml2% lignocaine with adrenaline was injected. Then 10 ml 0.5% bupivacaine&5 ml 2% lignocaine with adrenaline was injected at femoral nerve. Number of attempts, block execution time, onset of complete sensory and motor block, patient satisfaction was measured. Results: Surgical anaesthesia was achieved in 22 patients. 8 patients needed SAB wereas this was a pilot study no comparisons could be made and hence there was no p valueconsidered as failure of procedure. We observed themean number of attempts required to place the needle at site 3.50 ± 1.106; mean block execution time 9.66 ± 3.63 min; mean onset time of sensory block&motor block was 17.83 ± 7.552 min&24.97 ± 3.479 min respectively. 12 (40%) patients were satisfied with the technique used and reported it as excellent. Conclusion: Results of this study show promising outcome in terms of the number of attempts, block execution time, onset of sensory&motor block and patient satisfaction and indicate the need to conduct this study on a larger scale. We conclude that anterior approach is an excellent alternative approach to other approaches for sciatic nerve block especially in patients with multiple injuries.