Shock wave lithotripsy: advances in technology and technique

Abstract

Shock wave lithotripsy (SWL) is the only noninvasive method for stone removal. Once considered as a primary option for the treatment of virtually all stones, SWL is now recognized to have important limitations that restrict its use. In particular, the effectiveness of SWL is severely limited by stone burden, and treatment with shock waves carries the risk of acute injury with the potential for long-term adverse effects. Research aiming to characterize the renal response to shock waves and to determine the mechanisms of shock wave action in stone breakage and renal injury has begun to suggest new treatment strategies to improve success rates and safety. Urologists can achieve better outcomes by treating at slower shock wave rate using a step-wise protocol. The aim is to achieve stone comminution using as few shock waves and at as low a power level as possible. Important challenges remain, including the need to improve acoustic coupling, enhance stone targeting, better determine when stone breakage is complete, and minimize the occurrence of residual stone fragments. New technologies have begun to address many of these issues, and hold considerable promise for the future.

Prediction of far-field acoustic emissions from cavitation clouds during shock wave lithotripsy for development of a clinical device

“…Such a case is studied here, simulating the responses of bubbles subjected to shock waves generated by SWL [1,2]. The technique is however equally applicable to scenarios involving underwater explosions or industrial erosion, which might be undesirable [8] or required, as with ultrasonic cleaning [9,10].…”

“…During shock wave lithotripsy (SWL), thousands of shock waves are directed into the patient at a rate of about one per second in order to fragment kidney stones or reduce them to a size whereby they can subsequently be dissolved using drugs [1,2]. With current apparatus, the clinician is ill-equipped to determine in-theatre whether the treatment has been successful, with the result that 30-50% of patients need to return for re-treatment, and an unknown number receive a greater exposure to shock waves than is necessary for stone fragmentation [2].…”

The Effect of Pre-Procedure Anxiety on Pain Perception During First Session of Shock Wave Lithotripsy

“…SWL offers important advantages for the treatment of renal and ureteral stones. In particular, it is noninvasive, is readily performed on an out-patient basis and can be very effective in treating solitary uncomplicated stones (2). However, despite the advantages of SWL, pain resulting from shock wave treatment is still commonly bothersome to the patients.…”

The collapse of single bubbles and approximation of the far-field acoustic emissions for cavitation induced by shock wave lithotripsy

“…Shock wave lithotripsy (SWL; also known as extracorporeal shock wave lithotripsy) is a technique for fragmenting kidney or gall stones with shock waves (Lingeman et al 2009;Leighton & Cleveland 2010). It involves focusing thousands of shocks onto the stones to break them into small pieces that can be dissolved by drugs or passed in urine.…”