CUTANEOUS ANESTHESIA WITH LIDOCAINE-PRILOCAINE CREAM - A USEFUL ADJUNCT DURING SHOCK-WAVE LITHOTRIPSY WITH ANALGESIC SEDATION

A comparative randomized double-blind study between 99 patients with (group 1) and 100 without (group 2) cutaneous anesthesia with a lidocaine-prilocaine cream during extracorporeal shock wave lithotripsy (ESWL*) with an unmodified Dornier HM3 lithotriptor was done. The application of the anesthetic cream or a placebo preparation was used in addition to premedication with meperidine hydrochloride and diazepam. In case of pain experience additional doses of analgesic sedation were administered. The requirement of additional analgesic sedation at a generator voltage of 14 kv. was significantly higher in group 2 than in group 1 (42 versus 26 patients, p <0.05). The ESWL treatment was completed with only premedication in 39% of the patients in group 2 compared with 50% in group 1. The pain experience at 14 kv. was significantly lower for male patients in group 1 (p <0.01). The most pronounced difference between groups 1 and 2 was recorded during treatment of stones in the upper calices, whereby 22% and 79%, respectively, required additional analgesic sedation at a generator voltage of 14 kv. (p <0.05). A less pronounced but still significant difference was also recorded at 14 kv. for patients with stones in the other parts of the kidney and ureter (p <0.05). The maximal median energy settings in groups 1 and 2 were 15.9 kv. and 15.4 kv., respectively. There were 27 patients in group 2 and 18 in group 1 who were treated with a maximum of 14 kv. The overall requirement of additional analgesic sedation was 62% in group 2 and 51% in group 1. Cutaneous anesthesia with lidocaine-prilocaine cream obviously has clinically significant effects on pain experience during ESWL. It cannot replace the need for analgesic sedation but it can be used advantageously to reduce the dosage of analgesic and sedative drugs during ESWL treatments performed without regional or general anesthesia in the unmodified Dornier HM3 lithotriptor.