EFFECT OF PIEZOELECTRIC ENERGY ON PORCINE KIDNEYS USING THE EDAP LT.02

EDAP International (Cambridge, Massachusetts) has developed a new piez oelectric lithotripter (LT.02) that differs from their earlier model ( LT.01) in two important respects: method of stone visualization and av ailable power. The LT.02 provides both in-line fluoroscopy as well as real time ultrasound. The maximum energy is 1400 Bar (compared with 11 00 Bar in the LT.01). The purpose of this study was to determine wheth er treatment with the EDAP LT.02 piezoelectric lithotripter would caus e significant renal injury in minipigs. Accordingly, 18 minipigs were divided into 3 groups of 6. Each group received a treatment of 20, 40, or 60 minutes; the power level and shock wave frequency were kept at maximal levels throughout the treatment period. Three pigs from each g roup were sacrificed at 72 hours (acute). The remaining 9 pigs were sa crificed 1 month following LT.02 treatment (chronic). Histopathologic analysis of the treated kidney revealed that 33% of the 9 acute pigs d eveloped a small capsular hematoma, whereas 66% showed only a small pa renchymal contusion (less than or equal to 1% of total renal volume). Among the chronic pigs, 66% had a small cortical scar, whereas 33% had no macroscopic pathology. Despite the differences in the number of sh ock waves delivered, these changes were evenly distributed among the 3 groups. Histologic acute changes included circumscribed areas of hemo rrhagic infarction, vascular thrombosis with recanalization and focal tubular obstruction and damage. At 30 days, however, these acute injur ies had completely resolved in 3 pigs and were only notable as minute areas of focal tubular loss in 6 pigs.