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.

CONCLUSIONS

It appears that the Siemens Lithostar exerts a greater pressure on the renal capsule, which may account for the higher incidence of subcapsular hematoma.