Kroczak T et al, 2017: Shockwave lithotripsy: techniques for improving outcomes.
Kroczak T, Scotland KB, Chew B, Pace KT.
Division of Urology, Department of Surgery, St. Michael's Hospital, University of Toronto, Toronto, Canada.
Department of Urology, Vancouver General Hospital, University of British Columbia, Vancouver, Canada.
Kroczak T, Scotland KB, Chew B, Pace KT.
Division of Urology, Department of Surgery, St. Michael's Hospital, University of Toronto, Toronto, Canada.
Department of Urology, Vancouver General Hospital, University of British Columbia, Vancouver, Canada.
Abstract
OBJECTIVES: Shock wave lithotripsy (SWL) remains the only effective truly non-invasive treatment for nephrolithiasis. While single-treatment success rates may not equal those of ureteroscopy and percutaneous nephrolithotomy, it has an important role to play in the management of stones. In this paper, we outline the latest evidence-based recommendations for maximizing SWL outcomes, while minimizing complications.
MATERIALS AND METHODS: A comprehensive review of the current literature was performed regarding maximizing SWL outcomes.
RESULTS: Several different considerations need to be made regarding patient selection with respect to body habitus, body mass index, anatomical location and underlying urologic abnormalities. Stone composition and stone density (Hounsfield Units) are important prognostic variables. Patient positioning is critical to allow for adequate stone localization with either fluoroscopy or ultrasound. Coupling should be optimized with a low viscosity gel applied to the therapy head first and patient movement should be limited. SWL energy should be increased slowly and shockwave rates of 60 or 90 Hz should be used. Medical expulsive therapy with alpha-blockers after SWL treatment has shown benefit, particularly with stones greater than 10 mm.
CONCLUSION: While single-treatment success rates may not equal those of ureteroscopy or percutaneous nephrolithotomy, with proper patient selection, optimization of SWL technique, and use of adjunctive treatment after SWL, success rates can be maximized while further reducing the already low rate of serious complications. SWL remains an excellent treatment option for calculi even in 2017.
World J Urol. 2017 Jun 12. doi: 10.1007/s00345-017-2056-y. [Epub ahead of print]
Comments 1
This is a nice and comprehensive summary of requirements and recommendation for successful SWL. The text is indeed valuable reading for all persons (urologists, nurses, technicians) who more or less are involved in this kind of treatment. The final sentence is of note, emphasizing that provided patients are appropriately selected and the treatment carried out in a careful way: “SWL remains an excellent treatment option for calculi even in 2017”.
One aspect that deserves to be commented is that although pulsed fluoroscopy generally is recommended in order to reduce the dose of radiation, this method is not always optimal. When the stone moves as a result of respiration, one single image might indicate a perfect position. But this information might be false and in order to make sure that the shockwave really has a perfect stone hit, short-time continuous fluoroscopy will often be superior. It should be observed that when continuous fluoroscopy is used, radiation time should be of short duration and always combined with optimal collimation!