Ultrasound guided two-in-one technique for sciatic and femoral nerve block in below knee surgery: Comparison between two entry points

BackgroundAnesthesia for lower limb surgery requires the combination of femoral and sciatic nerve blocks. Although the anterior approach to the sciatic nerve block has rarely been performed, ultrasound guidance may make performance of this approach easier. This prospective, randomized, double blind study was designed to evaluate the success rate, the clinical use and complications of performing ultrasound-guided combined sciatic and femoral nerve block with one needle entry technique in adult patients scheduled for below knee surgery using two different anterior approaches.Patients and methodsFifty-one patients ASA1 and 11 (25–49 years) were randomly divided into two groups according to the method used for identification of the puncture point: (Para n = 26) using the parafemoral approach, (Aysun n = 25) using Aysun et al. approach for anterior sciatic nerve block using 0.5% bupivacaine 20 ml for each block. Measurements included block execution time, needle and nerve depth, onset time of sensory and motor block, duration of the block, the degree and the quality of block.ResultsThe sciatic nerve was located significantly deeper and the needle depth was significantly greater in Para group compared with Aysun group. The execution time of the sciatic nerve block and for the combined sciatic and femoral nerve block were statistically significant longer in Para group than Aysun group. There were no statistically significant differences in success rate, onset time or duration of blockade between the two groups. In 24 cases of each group, complete sensory and motor block (successful block) were obtained. No patient in both groups had a failed block. For patients with complete block, there was no statistical difference regarding the quality of block in both groups, No side effects or complication were recorded in both groups.ConclusionCombined sciatic and femoral block guided with US could be performed easily, successfully and safely in adult patients using single needle/one puncture point technique through two different anterior approaches.