Comparison of 22G vs 25G needle for ultrasound guided popliteal nerve block distal to sciatic bifurcation, randomized prospective study

Background and purpose: The goal of the study was to evaluate whether 25G spinal needles can successfully be applied for ultrasound guided popliteal nerve block distal to sciatic bifurcation compared to standard 22G needles. Patients and methods: A prospective, randomized study was conducted during 8 months. 50 patients were included in the study, randomized to either 22G or 25G group. Ultrasound guided popliteal nerve block distal to sciatic bifurcation was performed using 20 mL 0, 5% levobupivacaine. The parameters recorded were ease of needle handle evaluated by the performing anesthesiologist, block success rates, need for intra-operative sedation, incidence of conversion to general anesthesia, incidence of side-effects and general patient satisfaction. Results and conclusion: The success rates were similar in both groups (22G vs 25G : 92% vs 96%, p=0, 55), as were need for intra-operative sedation (22G vs 25G : 12% vs 12%) and conversion to general anesthesia (8% vs 4%, p=0, 637). 25G spinal needles can be applied with equal success to standard 22G needles for ultrasound guided popliteal nerve block distal to sciatic bifurcation.