Efficacy of ultrasound and nerve stimulation guidance in peripheral nerve block: A systematic review and meta-analysis.

Evidence was controversial about whether nerve stimulation (NS) can optimize ultrasound guidance (US)-guided nerve blockade for peripheral nerve block. This review aims to explore the effects of the two combined techniques. We searched EMBASE (from 1974 to March 2015), PubMed (from 1966 to Mar 2015), Medline (from 1966 to Mar 2015), the Cochrane Central Register of Controlled Trials and clinicaltrials.gov. Finally, 15 randomized trials were included into analysis involving 1,019 lower limb and 696 upper limb surgery cases. Meta-analysis indicated that, compared with US alone, USNS combination had favorable effects on overall block success rate (risk ratio [RR] 1.17; confidence interval [CI] 1.05 to 1.30, P = 0.004), sensory block success rate (RR 1.56; CI 1.29 to 1.89, P < 0.00001), and block onset time (mean difference [MD] -3.84; CI -5.59 to -2.08, P < 0.0001). USNS guidance had a longer procedure time in both upper and lower limb nerve block (MD 1.67; CI 1.32 to 2.02, P < 0.00001; MD 1.17; CI 0.95 to 1.39, P < 0.00001) and more patients with anesthesia supplementation (RR 2.5; CI 1.02 to 6.13, P = 0.05). USNS guidance trends to result in a shorter block onset time than US alone as well as higher block success rate, but no statistical difference was demonstrated, as more data are required. © 2017 IUBMB Life, 69(9):720-734, 2017.