EMLA cream for renal extracorporeal shock wave lithotripsy in ambulatory patients.

The effectiveness of a Eutectic Mixture of Local Anaesthetics (EMLA cream) for pain control during renal extracorporeal shock wave lithotripsy (ESWL) was evaluated in a group of 20 patients who had not been able to tolerate a previous session without intravenous (i.v.) analgesia. EMLA cream (10 g) was applied on the skin over the area (64-100 cm2) where the shock waves were to be focussed. A second generation lithotriptor Siemens Lithostar was used. The following measurements were made: the shock wave (kV) maximum voltage, the number of successful stone fragmentations (SSF), the visual analogue scale score (0-10) for pain (VAS), and the tolerance scale score (1-4) for the tolerance for the procedure. Significantly higher voltage (17.9 +/- 0.6 kV vs. 16.2 +/- 0.8 kV), lower VAS scores (5.9 +/- 1.1 vs. 8.7 +/- 1.3), lower TS score (2.3 +/- 0.6 vs. 3.6 +/- 0.6) and a higher number of SSF (18 vs. 5) were found in those patients for whom EMLA cream was used. Intravenous analgesia was not needed in nine patients. Nine patients received fentanyl 0.05 mg, one 0.10 mg and another 0.15 mg. These favourable results were attributed both to the sequence of gradual voltage increments used and to the cutaneous analgesia produced by EMLA cream.