MECHANISMS OF SHOCKWAVE ACTION IN THE HUMAN KIDNEY

The effects on the human kidney parenchyma of high-energy shockwaves ( HESW) with different energy densities were examined, Kidneys of patien ts treated by radical nephrectomy for renal cell carcinoma were perfus ed with cold HTK solution immediately after nephrectomy and kept in hy pothermia (8 degrees C) for a maximum of 4 hours, The tumor-free paren chyma was treated with 2000 shocks at energy outputs of 15 kV (16 MPa, 0.15 mJ/mm(2)), 17 kV (32 MPa, 0.25 mJ/mm(2)), 19 kV (50 MPa, 0.4 mJ/ mm(2)), and 21 kV (65 MPa, 0.6 mJ/mm(2)) in an experimental electromag netic shockwave system (Siemens Co., Erlanger, Germany), Resulting tis sue effects were analyzed by histologic and immunohistochemical examin ations and confocal laser scanning microscopy, Different sensitivities of cell components, blood vessels, and tubules were found. Laser scan ning microscopy revealed nuclear alterations in the vicinity of the fo cus up to a distance of approximately 10 mm, Severe histologic changes were found in a smaller zone, while immunohistochemistry studies reve aled negative collagen IV staining in an area of approximately 4 x 4 m m (all distances measured within the plane perpendicular to the acoust ic axis), From these results, it can be concluded that HESW directly d amage the tubules and the vascular system, which might explain the cli nical changes after extracorporeal shockwave lithotripsy in human pati ents, The extent of these effects seems to be dependent on the applied energy.