Is high diuresis an important prerequisite for successful SWL-disintegration of ureteral stones?

Furosemide improves the stone clearance rate of extracorporeal shockwave lithotripsy for kidney stones but not ureteral stones: a systematic review and meta-analysis

Introduction

We conducted a meta-analysis (MA) to investigate the effects of furosemide on the prognosis of extracorporeal shockwave lithotripsy (SWL) therapy to remove renal (RS) and ureteric stones (US).

Methods

We screened scientific databases including PubMed, Clinicalkey, Google Scholar, Medline, Embase, and Cochrane, from the date of establishment until March 2022, to search for randomized controlled trials evaluating SWL, in combination with furosemide (experimental group) or with SWL alone (control group), in treating RS or US. Our search terms included furosemide, extracorporeal SWL, and urolithiasis. For this MA, we employed the Cochrane Collaboration's RevMan version 5.3.0.

Results

Six trials, involving 1344 participants, with RS (n = 1097) and/or US (n = 247), met our predefined criteria. This included 137 proximal ureteral stones (PUSs), 35 mid-ureteral stones (MUS), and 75 distal ureteral stones (DUS). In case of RS, the experimental group exhibited significantly enhanced clearance, relative to controls (risk ratio [RR] = 1.16, 95% confidence interval [CI] = 1.07-1.25, p = 0.0002), yet there was no obvious difference in the PUS, MUS, and DUS (RR = 1.14, 95% CI = 0.97-1.33, p = 0.10; odds ratio [OR] = 1.26, 95% CI = 1.40-3.95, p = 0.69; RR = 1.21, 95% CI = 0.99-1.49, p = 0.06). There was also no marked difference between fragmentations in either group. Only reports of SWL treatment of RS provided adequate data on shocks, sessions, and complications for our analysis. Unfortunately, there was no significant alteration between the two groups.

Conclusion

According to our analysis, furosemide strongly accelerates the clearance rate of SWL-treated RS. However, it does not enhance the fragmentation rate. Given this evidence, we propose that furosemide does not significantly improve the efficacy of SWL therapy in removing US.

Registration

Our work is registered with PROSPERO (CRD42020204780).

How can and should we optimize extracorporeal shockwave lithotripsy?

It is well recognized that the popularity of extracorporeal shock wave lithotripsy (SWL), despite its non-invasive character, has decreased during recent years. This is partly explained by the technological achievements in endoscopy and urologists’ enthusiasm for such procedures. Another explanation is that many urologists have been insufficiently successful with SWL. The latter effect might to some extent be a result of the performance of the lithotripter used, but in too many cases, it is evident that the principles of how shock wave lithotripsy should be carried out are poorly applied. The purpose of this article is to emphasize some important aspects on how SWL best should be used. Based on decades of experience, it stands to reason that success with SWL does not come automatically and attention has to be paid to all details of this technique.

Shockwave lithotripsy: techniques for improving outcomes

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.