Dimethyl sulfoxide with lignocaine versus eutectic mixture of local anesthetics: prospective randomized study to compare the efficacy of cutaneous anesthesia in shock wave lithotripsy.

The objective of the study was to compare the efficacy of dimethyl sulfoxide (DMSO) mixed with lignocaine and eutectic mixture of local anesthetics (EMLA) cream as topically applied surface anesthetics in relieving pain during shock wave lithotripsy (SWL) in a prospective randomized study. Of the 160 patients, 80 patients received DMSO with lignocaine and 80 patients received EMLA cream, applied to the skin of the flank at the area of entry of shock waves. SWL was done with Seimens lithostar multiline lithotripter. The pain during the procedure was assessed using visual analog and verbal rating scores. The mean visual analog scale scores for the two groups were 3.03 for DMSO group and 4.43 for EMLA group. The difference of pain score on visual analog scale was statistically significant (p < 0.05). Similarly, the pain scores as rated on the verbal rating scale were also evaluated; the mean score on verbal rating scale were 2.34 for DMSO group and 3.00 for the EMLA group. The difference between the pain score on verbal rating scale was also found to be statistically significant (p < 0.05). Our study showed that DMSO with lignocaine is a better local anesthetic agent for SWL than EMLA cream. The stone fragmentation and clearance rates are also better in the DMSO group.