Comparing Two Local Anesthesia Techniques for Extracorporeal Shock Wave Lithotripsy

ObjectivesTo evaluate the efficacy of a eutectic mixture of local anesthetics (EMLA) cream compared with dimethyl sulfoxide (DMSO) with lidocaine during extracorporeal shock wave lithotripsy (ESWL) in a prospective randomized study.MethodsOf 167 patients, 85 received 10 g of EMLA cream (EMLA group) and 82 received 10 g of 40% DMSO (DMSO group) with an amount of lidocaine equal to that in the lidocaine gel, applied to the skin of the flank at the area of entry of the shock wave marked by the urologist. A second-generation lithotriptor Siemens Lithostar was used. The degree of pain was rated by the patients using a 10-point visual analog scale.ResultsIn 80 patients in the EMLA group (94%), the entire procedure was performed with no, minor, or tolerable pain after the application of EMLA cream (pain score 5.2 ± 1.3). In 5 EMLA patients (6%), EWSL was interrupted because of intolerable pain. Of the 82 DMSO patients, 80 (98%) underwent the entire procedure with no, minor, or tolerable pain after the application of DMSO with lidocaine (pain score 3.7 ± 1.1). In 2 DMSO patients (2%), EWSL was interrupted because of intolerable pain. The pain scores were significantly lower for the DMSO group than for the EMLA group (P = 0.011).ConclusionsOur findings have indicated that the pain scores were significantly lower for the DMSO group than for the EMLA group. In addition to the local anesthetic effect of DMSO, diuretic, anti-inflammatory, muscle relaxant, and hydroxyl radical scavenger effects can be important for patients undergoing ESWL. These effects should be evaluated with new studies of patients undergoing ESWL.