Efficacy of Eutectic Mixture of Local Anesthetics on Pain Control During Extracorporeal Shock Wave Lithotripsy: A Systematic Review and Meta-Analysis

BACKGROUND: The efficacy of a eutectic mixture of local anesthetics (EMLA) for pain control in extracorporeal shock wave lithotripsy is unclear. The aim of this study was to assess the effect of EMLA cream on pain control during extracorporeal shock wave lithotripsy. MATERIAL/METHODS: We searched Medline, EMBASE, and the Cochrane Central Register of Controlled Trials to identify relevant randomized controlled trials that compared the pain control efficacies of EMLA vs. placebo. Study eligibility criteria, participants, and interventions: Randomized controlled trials that compared the effect of EMLA with placebo cream for patients underwent extracorporeal shock wave lithotripsy. Study appraisal and synthesis methods: Two review authors extracted data independently using a designed data extraction form and risk of bias by Cochrane Collaboration’s tool. RESULTS: Nine studies, including 10 randomized controlled trials with 1167 patients, were eligible. The EMLA group experienced less pain (mean difference, −0.47; 95% confidence interval, −0.78 to −0.16; p=0.003) and shorter duration of lithotripsy (mean difference, −1.70, 95% confidence interval: −2.31 to −1.10, p<0.0001) than the placebo group. There were no significant differences in the number of patients who needed extra intravenous medication (p=0.610), number of patients with insufficient extracorporeal shock wave lithotripsy pain control (p=0.530), and number of patients with opioid adverse effects (p=0.320). Limitations: Long interval between the studies, different kinds of lithotripters. CONCLUSIONS: EMLA can reduce pain during the ESWL procedure.