Comparison of sciatic nerve block quality achieved using the anterior and posterior approaches: a randomised trial

Abstract Background The co-administration of sciatic and femoral nerve blocks can provide anaesthesia and analgesia in patients undergoing lower extremity surgeries. Several approaches to achieve sciatic nerve block have been described, including anterior and posterior approaches. Methods In total, 58 study patients were randomly assigned to receive either anterior (group A, n = 29) or posterior (group P, n = 29) sciatic nerve block. Thereafter, the following parameters were determined: sensory and motor block start and end times, time to first fentanyl requirement after blockade but before the start of the operation, time to first fentanyl requirement after the start of the operation, mean fentanyl dose administered after blockade but before the start of the operation, mean fentanyl dose after the start of the operation, time to first diclofenac sodium dose, and total dose of diclofenac sodium required. The trial was retrospectively registered on 11 July 2018. Results The time to initiation of sensory block was significantly shorter in group P than in group A (7.70 ± 2.05 min and 12.88 ± 4.87 min, respectively; p = 0.01). Group P also had a significantly shorter time to first fentanyl requirement after block but before the start of the operation (00.00 ± 00.00 min for group P and 4.05 ± 7.47 min for group A; p