The acute and long-term adverse effects of shock wave lithotripsy

Abstract

Shock wave lithotripsy (SWL) has proven to be a highly effective treatment for the removal of kidney stones. Shock waves (SWs) can be used to break most stone types, and because lithotripsy is the only noninvasive treatment for urinary stones, SWL is particularly attractive. On the downside SWL can cause vascular trauma to the kidney and surrounding organs. This acute SW damage can be severe, can lead to scarring with a permanent loss of functional renal volume, and has been linked to potentially serious long-term adverse effects. A recent retrospective study linking lithotripsy to the development of diabetes mellitus has further focused attention on the possibility that SWL may lead to life-altering chronic effects. Thus, it appears that what was once considered to be an entirely safe means to eliminate renal stones can elicit potentially severe unintended consequences. The purpose of this review is to put these findings in perspective. The goal is to explain the factors that influence the severity of SWL injury, update current understanding of the long-term consequences of SW damage, describe the physical mechanisms thought to cause SWL injury, and introduce treatment protocols to improve stone breakage and reduce tissue damage.

Figure 1

Exacerbation of stone disease may be a consequence of SWL treatment. These images illustrate the morphological features of the renal papilla from a patient with brushite kidney stone disease. This patient received five SWL sessions prior to the onset of brushite stones. (A) Endoscopic view of a renal papilla showing three dilated openings (arrows) to the ducts of Bellini, one of which has a plug of apatite protruding from its lumen (asterisk). In addition, sites of Randall’s plaque appear as irregular whitish areas (arrowheads) next to sites of yellow plaque (double arrows) representing crystalline deposits in the lumen of inner medullary collecting ducts. (B) Tissue section of papillary biopsy stained by the Yasue method for calcium showing blockage of a duct of Bellini (arrows) with a surrounding cuff of interstitial fibrosis. (C) At higher magnification, sites of Yasue positive material (arrows) are seen embedded within fibrotic/atrophic tissue.

Figure 2

Demonstration that proper treatment strategies can protect against kidney injury in SWL. Top row shows exterior kidney surface, and bottom row shows macroscopic images of sections through three pig kidneys following different treatment protocols using the Dornier HM3 lithotripter (24 kV). Circles indicate approximate location of the focal zone targeted to the lower pole. Tissue sections depict morphometric segmentation of regions showing parenchymal hemorrhage (digitally colored red). (Left) Standard treatment protocol in which pig received 2000 SW’s at 120 SW/min. Kidneys typically developed subcapsular hematomas (arrows). The hemorrhagic lesion in this kidney, determined from serial sections, measured ~5% FRV. (Middle) Protective effect of voltage ramping at standard rate. This pig received a priming dose of 500 SW’s at low energy (12 kV) followed by 2000 SW’s (24 kV) all at 120 SW/min. The lesion, limited to the tips of renal papillae (arrowhead), is dramatically reduced (~0.3% FRV) compared to the injury seen with the standard protocol. (Right) The protective effect of slow SW-rate. This animal was treated with 2000 SW’s delivered at 30 SW/min. No lesion is visible in this section. Injury at slow rate as determined from serial sections measured <0.1% FRV.