Effect of pressure distribution of shockwave on renal hemorrhage after extracorporeal shockwave lithotripsy: comparison of EDAP LT-01 and Siemens Lithostar.

BACKGROUND: Renal hemorrhage is the most common adverse effect of SWL, and it has been speculated to be related to the type of lithotripter used.
METHODS: We investigated the incidence of renal hemorrhage in patients with urinary stones who underwent lithotripsy using either the EDAP LT-01 or the Siemens Lithostar. In addition, we performed in vitro experiments using pressure-sensitive paper in conjunction with gelatin, agar, or porcine tissue models of renal lithotripsy.
RESULTS: Thirty-one (16.6%) of 187 kidneys treated with the EDAP LT-01 and 44 (19.6%) of 225 kidneys treated with the Siemens Lithostar showed intrarenal or subcapsular hemorrhage or perinephric hematoma. In particular, the incidence of subcapsular hematoma was significantly higher in the Lithostar-treated patients (P < 0.0001). We discuss our results in light of the patterns of pressure distribution obtained from the two lithotripter units using in vitro models with colorometric, pressure-sensitive paper.
CONCLUSION: It appears that the Siemens Lithostar exerts a greater pressure on the renal capsule, which may account for the higher incidence of subcapsular hematoma.