A new transportable shock-wave lithotripsy machine for managing urinary stones: a single-centre experience with a dual-focus lithotripter

[What is the current status of shock wave lithotripsy?]

BACKGROUND

Shock wave lithotripsy (SWL) became the therapy of choice for the majority of patients with urolithiasis early after its introduction in the early 1980s. Since then, SWL remains the only noninvasive therapy modality for the treatment of urinary stones. Although lithotripters became more versatile and affordable-making them available worldwide-indications for SWL have shifted as well. In most western countries, endoscopic techniques took the lead in stone therapy due to high (early) stone-free and better reimbursement rates. Notwithstanding SWL remains the first-line therapy for most intrarenal and many ureteral stones.

PURPOSE

This contemporary review illuminates technical aspects and improvements of lithotripsy over recent years in context with the current guideline recommendations.

RESULTS

Technical advances in lithotripsy such as shock wave generation, focusing, coupling, stone localization and modifications in therapy regimens are reviewed and presented.

CONCLUSIONS

Urologists are recommended to carefully select the appropriate therapy modality for a patient with urolithiasis. A more comprehensive understanding of the physics of shock waves could lead to much better results, thus, endorsing SWL as first-line therapy for urolithiasis instead of contemporary endourology treatment options.

MiniJFil®: A New Safe and Effective Stent for Well-Tolerated Repeated Extracorporeal Shockwave Lithotripsy or Ureteroscopy for Medium-to-Large Kidney Stones?

Background

Percutaneous nephrolithotomy (PCNL) is recommended for treating staghorn stones or stones measuring > 20 mm. Extracorporeal shockwave lithotripsy (ESWL) or flexible ureteroscopy (URS) may be used as a complement. However, PCNL can cause trauma to the kidney parenchyma, and patients may find a noninvasive procedure, such as ESWL, to be more attractive.

Objectives

The aim of this study was to evaluate the clinical efficiency of MiniJFil® stenting associated with ESWL or second-line URS for the treatment of medium-to-large kidney stones. The MiniJFil® is a stent reduced to a suture of 0.3F attached to a renal pigtail. The entire ureter is occupied only by the suture of the stent.

Methods

We retrospectively analyzed the data of 28 patients. Twenty-four patients had kidney stones measuring > 15 mm (group 1) and four patients had staghorn stones (group 2). All of the patients were fitted with MiniJFil® 2 - 3 weeks before any treatment. ESWL was always our first-line therapy. Stone-free (SF) status was defined as no evidence of stones.

Results

In group 1, the mean largest and cumulative stone diameters, respectively, were 18.7 ± 5.7 mm and 45.0 ± 12.0 mm. In group 2, the mean volume was 6,288.4 ± 2,733.0 mm³. The overall SF was 96.4% (100% for group 1 and 75% for group 2). The mean number of sessions of ESWL and URS, respectively, was 1.4 ± 0.7 and 0.8 ± 0.9 in group 1 and 4.0 ± 2.0 and 1.5 ± 1.3 in group 2. The mean times to achieve these rates were 3.2 ± 1.7 months and 5.6 ± 2.3 months for groups 1 and 2, respectively. One patient in group 2 was treated with only three sessions of ESWL. Renal colic was observed in only five patients (17.9%).

Conclusions

MiniJFil® stenting is safe and may be an alternative for the treatment of kidney stones during minimally invasive procedures.

Shock wave lithotripsy: the new phoenix?

INTRODUCTION

Following its introduction in 1980, shock wave lithotripsy (SWL) rapidly emerged as the first-line treatment for the majority of patients with urolithiasis. Millions of SWL therapies have since been performed worldwide, and nowadays, SWL still remains to be the least invasive therapy modality for urinary stones. During the last three decades, SWL technology has advanced in terms of shock wave generation, focusing, patient coupling and stone localization. The implementation of multifunctional lithotripters has made SWL available to urology departments worldwide. Indications for SWL have evolved as well. Although endoscopic treatment techniques have improved significantly and seem to take the lead in stone therapy in the western countries due to high stone-free rates, SWL continues to be considered as the first-line therapy for the treatment of most intra-renal stones and many ureteral stones.

METHODS

This paper reviews the fundamentals of SWL physics to facilitate a better understanding about how a lithotripter works and should be best utilized.

RESULTS

Advances in lithotripsy technology such as shock wave generation and focusing, advances in stone localization (imaging), different energy source concepts and coupling modalities are presented. Furthermore adjuncts to improve the efficacy of SWL including different treatment strategies are reviewed.

CONCLUSION

If urologists make use of a more comprehensive understanding of the pathophysiology and physics of shock waves, much better results could be achieved in the future. This may lead to a renaissance and encourage SWL as first-line therapy for urolithiasis in times of rapid progress in endoscopic treatment modalities.

Extracorporeal shock wave lithotripsy: An opinion on its future

The development of miniaturized nephroscopes which allow one-stage stone clearance with minimal morbidity has brought the role of shock wave lithotripsy (SWL) in stone management into question. Design innovations in SWL machines over the last decade have attempted to address this problem. We reviewed the recent literature on SWL using a MEDLINE/PUBMED research. For commenting on the future of SWL, we took the subjective opinion of two senior urologists, one mid-level expert, and an upcoming junior fellow. There have been a number of recent changes in lithotripter design and techniques. This includes the use of multiple focus machines and improved coupling designs. Additional changes involve better localization real-time monitoring. The main goal of stone treatment today seems to be to get rid of the stone in one session rather than being treated multiple times non-invasively. Stone treatment in the future will be individualized by genetic screening of stone formers, using improved SWL devices for small stones only. However, there is still no consensus about the design of the ideal lithotripter. Innovative concepts such as emergency SWL for ureteric stones may be implemented in clinical routine.

The feasibility of shockwave lithotripsy for treating solitary, lower calyceal stones over 1 cm in size

INTRODUCTION

Recently, few studies were reported about the treatment of large, solitary, renal calculi between shockwave lithotripsy (SWL) and percutaneous nephrolithotomy (PNL). We assess the feasibility of SWL for managing solitary, lower calyceal stones over 1 cm by comparing the results of lower pole calculi treatment between patients that underwent SWL or PNL.

METHODS

We retrospectively reviewed clinical data for patients who had undergone PNL or SWL due to lower calyceal stones over 1 cm. Group 1 consisted of patients who underwent SWL to treat lower pole renal calculi from 2010 to 2011. Group 2 included patients who underwent PNL to manage lower pole renal calculi from 2008 to 2009. We compared patient age, gender, stone size, comorbidities, postoperative complications, additional interventions and anatomical parameters between the two groups.

RESULTS

A total of 55 patients were enrolled in this study. The mean ages (±SD) of groups 1 (n = 33) and 2 (n = 22) were 55.1 (±13.0) and 50.0 (±10.6) years (p = 0.133) and mean stone sizes were 1.6 (±0.7) and 1.9 (±0.8) cm (p = 0.135), respectively. There were no significant differences in gender distribution, comorbidities or stone laterality between the two groups. No significant differences in various parameters were observed between patients with stones 1 to 2 cm and ones with stones 2 cm or larger.

CONCLUSIONS

Our results demonstrated that SWL is a safe, feasible treatment for solitary, lower calyceal stones over 1 cm.

Extracorporeal shock wave lithotripsy: What is new?

OBJECTIVES

Thirty years after its introduction, extracorporeal shockwave lithotripsy (ESWL) is still first-line treatment for more than half of all urinary tract stones, but machines and treatment strategies have significantly developed over time. In this review, we summarise the latest knowledge about the clinically important aspects of ESWL.

METHODS

We searched PubMed to identify relevant reports and the latest European Association of Urology guidelines, and standard urological textbooks were consulted.

RESULTS

New technical developments include: Twin-head and tandem-pulse shock-wave generators; wide-focus, low-pressure systems; optimised coupling; and automated location and acoustic tracking systems. Indications have been refined, making possible the identification of patients in whom ESWL treatment is likely to fail. By lowering the shock-wave rate, improving coupling, applying abdominal compression, power 'ramping' and postoperative medical expulsion therapy, treatment protocols have been optimised.

CONCLUSIONS

Promising new technical developments are under development, with the potential to increase the stone-free rate after ESWL. For optimal results, the refined indications need to be respected and optimised treatment protocols should be applied.

Shock wave technology and application: an update

CONTEXT

The introduction of new lithotripters has increased problems associated with shock wave application. Recent studies concerning mechanisms of stone disintegration, shock wave focusing, coupling, and application have appeared that may address some of these problems.

OBJECTIVE

To present a consensus with respect to the physics and techniques used by urologists, physicists, and representatives of European lithotripter companies.

EVIDENCE ACQUISITION

We reviewed recent literature (PubMed, Embase, Medline) that focused on the physics of shock waves, theories of stone disintegration, and studies on optimising shock wave application. In addition, we used relevant information from a consensus meeting of the German Society of Shock Wave Lithotripsy.

EVIDENCE SYNTHESIS

Besides established mechanisms describing initial fragmentation (tear and shear forces, spallation, cavitation, quasi-static squeezing), the model of dynamic squeezing offers new insight in stone comminution. Manufacturers have modified sources to either enlarge the focal zone or offer different focal sizes. The efficacy of extracorporeal shock wave lithotripsy (ESWL) can be increased by lowering the pulse rate to 60-80 shock waves/min and by ramping the shock wave energy. With the water cushion, the quality of coupling has become a critical factor that depends on the amount, viscosity, and temperature of the gel. Fluoroscopy time can be reduced by automated localisation or the use of optical and acoustic tracking systems. There is a trend towards larger focal zones and lower shock wave pressures.

CONCLUSIONS

New theories for stone disintegration favour the use of shock wave sources with larger focal zones. Use of slower pulse rates, ramping strategies, and adequate coupling of the shock wave head can significantly increase the efficacy and safety of ESWL.