Twenty Years of Single Center Experience in ESWL 1987–2007: An Evaluation of 3079 Patients

Use of ultra-low dose computed tomography versus abdominal plain film for assessment of stone-free rates after shock-wave lithotripsy: implications on emergency room visits, surgical procedures, and cost-effectiveness

The aims of this investigation were: (1) to compare residual stone-fragment (RSF) detection rates of ultra-low dose computed tomography (ULD-CT) and abdominal plain film (KUB) in urolithiasis patients undergoing shock-wave lithotripsy (SWL), and (2) to evaluate the downstream sequelae of utilizing these two disparate imaging pathways of differing diagnostic fidelity. A retrospective chart-review of patients undergoing SWL at two high-volume surgical centers was undertaken (2013-2016). RSF diagnostic rates of ULD-CT and KUB were assessed, and the impact of imaging modality used on subsequent emergency room (ER) visits, unplanned procedures, and cost-effectiveness was investigated. Adjusted analyses examined association between imaging modality used and outcomes, and Markov decision-tree analysis was performed to identify a cost advantageous scenario for ULD-CT over KUB. Of 417 patients studied, 57 (13.7%) underwent ULD-CT while the remaining 360 underwent KUB. The RSF rates were 36.8% and 22.8% in the ULD-CT and KUB groups, respectively (p = 0.019). A 5.6% and 18% of the patients deemed stone-free on ULD-CT and KUB, respectively, returned to the ER (p = 0.040). Similarly, 2.8% and 15.1% needed an unplanned surgery (p = 0.027). These findings were confirmed on multivariable analyses, Odds ratios CT-ULD versus KUB: 0.19 and 0.10, respectively, p < 0.05. With regards to cost-effectiveness, at low ULD-CT charges, the ULD-CT follow-up pathway was economically more favorable, but with increasing ULD-CT charges, the KUB follow-up pathway superseded. ULD-CT seems to provide a more 'true' estimate of stone-free status, and in consequence mitigates unwanted emergency and operating room visits by reducing untimely stent removals and false patient reassurances. Further, at low ULD-CT costs, it may also be economically more favorable.

Arguments for choosing extracorporeal shockwave lithotripsy for removal of urinary tract stones

At a time when there is an almost unlimited enthusiasm and preference among urologists for endoscopic stone removal, we have found it essential to meet some of the frequently presented arguments on why extracorporeal shockwave lithotripsy (SWL) should not be used. We have based our considerations in this brief article on our 30-35 years' experience with the non-invasive or least invasive technique that SWL represents. Stone disintegration, requirement of repeated treatment sessions, the concern of residual fragments, complications and economic aspects are some points that are discussed.

Focused ultrasound to expel calculi from the kidney: safety and efficacy of a clinical prototype device

PURPOSE

Focused ultrasound has the potential to expel small stones or residual stone fragments from the kidney, or move obstructing stones to a nonobstructing location. We evaluated the efficacy and safety of ultrasonic propulsion in a live porcine model.

MATERIALS AND METHODS

Calcium oxalate monohydrate kidney stones and laboratory model stones (2 to 8 mm) were ureteroscopically implanted in the renal pelvicalyceal system of 12 kidneys in a total of 8 domestic swine. Transcutaneous ultrasonic propulsion was performed using an HDI C5-2 imaging transducer (ATL/Philips, Bothell, Washington) and the Verasonics® diagnostic ultrasound platform. Successful stone relocation was defined as stone movement from the calyx to the renal pelvis, ureteropelvic junction or proximal ureter. Efficacy and procedure time was determined. Three blinded experts evaluated histological injury to the kidney in the control, sham treatment and treatment arms.

RESULTS

All 26 stones were observed to move during treatment and 17 (65%) were relocated successfully to the renal pelvis (3), ureteropelvic junction (2) or ureter (12). Average ± SD successful procedure time was 14 ± 8 minutes and a mean of 23 ± 16 ultrasound bursts, each about 1 second in duration, were required. There was no evidence of gross or histological injury to the renal parenchyma in kidneys exposed to 20 bursts (1 second in duration at 33-second intervals) at the same output (2,400 W/cm(2)) used to push stones.

CONCLUSIONS

Noninvasive transcutaneous ultrasonic propulsion is a safe, effective and time efficient means to relocate calyceal stones to the renal pelvis, ureteropelvic junction or ureter. This technology holds promise as a useful adjunct to surgical management for renal calculi.

Safety of ESWL in elderly: evaluation of independent predictors and comorbidity on stone-free rate and complications

AIM

Urinary stone disease affects people of all ages. With its satisfactory efficacy ranges in all age groups and lack of side-effects, extracorporeal shock wave lithotripsy (ESWL) has become the preferred treatment modality for uncomplicated renal and proximal calculi ≤ 20 mm. In the present study, we aimed to assess the safety and efficacy of the ESWL treatment in elderly patients.

METHODS

A retrospective study was carried out on patients aged over 65 years who underwent shock wave lithotripsy at our Department from 2009 to 2011, with a Siemens Lithostar electromagnetic shockwave lithotripter. A total of 231 patients (157 males, 74 females) out of 1694 (13.6%) were studied. The patients were divided into two groups (group 1 = 65-70; group 2 >70). The effect of age and other possible predicting factors (sex, stone localization and stone size) were investigated. Concomitant diseases and related complications were also evaluated.

RESULTS

An overall stone-free rate (SFR) of 82.2% was found. The influence of sex on SFR was non-significant. There was no significant difference when comparing SFR between the age groups. When patients were divided into those with renal and ureteral stones, the SFR were 94.4% and 67.6% (P < 0.01), respectively. The SFR of the stone size groups, ≤ 10 mm and > 10 mm were 80% and 84.4%, respectively. Comorbidity was present in 148 patients. Complications were noted in 56 of 231 patients. Of 56 patients, 43 had minor complications and 13 major complications.

CONCLUSION

ESWL seems to be an effective first-line treatment choice for urinary stones in elderly patients with careful patient selection and personalized preparation.

Strategic lithotripsy using the Doli S EMSE 220 F-XP for the management of staghorn renal calculi

AIM

The presentation of our results using the Dornier lithotripter (Doli) S electromagnetic shockwave emitter (EMSE) 220 F-XP for the strategic management of staghorn renal calculi.

METHODS

Sixteen patients with renal staghorn stones of more than 35 mm in maximum length on plain X-rays were treated by shock wave lithotripsy (SWL) monotherapy with the Doli S EMSE 220 F-XP. Double-J ureteral stent was inserted to all prior to the first SWL treatment. Shock wave counts varied from 2,500 to 3,600 with a shock release frequency of 70-80 pulses per minute. The number of sessions varied from 2 to 6. The interval between the SWL sessions was around 1 month. Fragmentation rate of 20-25% of the stone load per session was considered a valid criterion for progressing to further SWL sessions.

RESULTS

Nine patients became stone free at the end of SWL sessions and two patients had renal stone fragments smaller than 4 mm, which were eliminated 6 months later. Two patients developed streinstrasse that was managed with ureteroscopy. Auxiliary SWL was also performed on three patients with residual ureteral calculi. The mean follow up period was 12 months. The remaining five patients underwent open surgery for incomplete stone fragmentation. No major complications developed during the follow up period. The predominant composition of stones available for analysis was struvite.

CONCLUSION

Doli S EMSE 220 F-XP can be a safe and effective treatment option for renal staghorn stones on an outpatient basis.

Evaluation of outcome following lithotripsy

PURPOSE OF REVIEW

Shockwave lithotripsy (SWL) is considered as an initial option for a significant proportion of urinary tract stones. Despite efforts for standardized terminology and methodology, published studies on lithotripsy outcome are very different. This review will focus on a brief description of evidence-based medicine and recent literature results on SWL outcome.

RECENT FINDINGS

The introduction of hierarchy in scientific evidence is becoming more widespread. Various grading systems have attempted to rank recommendations according to type and amount of evidence. Different levels of evidence have been created for therapy, diagnosis and prognosis. Various authors have developed scoring systems and identified radiographic parameters to predict SWL outcome. The long-term safety of lithotripsy on renal function has been demonstrated. Randomized controlled trials and meta-analysis have shown that medical expulsive therapy and a slower shockwave rate will improve SWL outcome.

SUMMARY

Evidence-based medicine is rapidly becoming an indispensable part of everyday medical practice. Common terminology is necessary for proper evaluation of SWL. Different types of studies are required to investigate efficacy, compare SWL to other options, complications and so on. Randomized clinical trials are of the highest value; matched-pair analyses and well designed controlled studies can offer significant help.

Ultrasound monitoring of kidney stone extracorporeal shockwave lithotripsy with an external transducer: does fatty tissue cause image distortions that affect stone comminution?

INTRODUCTION

Ultrasound imaging, using either an inline or an external transducer, is a standard method for extracorporeal shockwave lithotripsy (SWL) monitoring. This study investigates whether image distortions caused by the low sound speed of fatty tissue could lead to incorrect stone positioning such that disintegration is affected.

MATERIALS AND METHODS

To define the accuracy needed for SWL monitoring, the dependency of fragmentation efficiency on the distance between stone center and SWL focus was examined by in vitro model stone tests. In a clinical study, 15 patients with kidney stones were treated with a Dornier Sigma FarSight. This lithotripter was equipped with both an inline and an external transducer. They were operated alternately to check for inconsistencies, which would indicate ultrasound image distortions. In addition, the ultrasound paths from the transducer to the SWL focus were analyzed for error estimation.

RESULTS AND DISCUSSION

In the model stone tests, the number of shock waves required for complete fragmentation doubled if the stone was about 7.5 to 10 mm off focus in lateral direction. In the clinical trial, the stone positions obtained from an inline and an external transducer coincided within a 5 mm range of tolerance, but that approach suffered from some practical difficulties, resulting in measurement imprecision. The sound path analysis showed that the lengths through fatty tissue were too short to result in significant image distortion. The body mass index (20-31 kg/m(2)) was representative, except for very obese patients. Additional confirmation of correct stone positioning could be achieved quite easily by looking for pixel movement in the B-mode image or employing Doppler hit/miss monitoring.

CONCLUSION

Within the study group, no image distortion caused by fatty tissue that could be clinically relevant for SWL was observed.

Lithotripsy

Shock wave lithotripsy (SWL) is the process of fragmentation of renal or ureteric stones by the use of repetitive shock waves generated outside the body and focused onto the stone. Following its introduction in 1980, SWL revolutionized the treatment of kidney stones by offering patients a non-invasive procedure. It is now seen as a mature technology and its use is perceived to be routine. It is noteworthy that, at the time of its introduction, there was a great effort to discover the mechanism(s) by which it works, and the type of sound field that is optimal. Although nearly three decades of subsequent research have increased the knowledge base significantly, the mechanisms are still controversial. Furthermore there is a growing body of evidence that SWL results in injury to the kidney which may have long-term side effects, such as new onset hypertension, although again there is much controversy within the field. Currently, use of lithotripsy is waning, particularly with the advent of minimally invasive ureteroscopic approaches. The goal here is to review the state of the art in SWL and to present the barriers and challenges that need to be addressed for SWL to deliver on its initial promise of a safe, effective, non-invasive treatment for kidney stones.

Dornier Lithotripter S 220 F EMSE: the first report of over 1000 treatments

OBJECTIVE

To assess the short-term efficacy and safety of extracorporeal shock wave lithotripsy (ESWL) with the standard Dornier Lithotripter S 220 F EMSE in the treatment of a large population of 736 patients with renal and ureteral stones. This is the only report with more than 1000 treatments performed with this device.

METHODS

Between January 2003 and July 2006, a total of 479 renal and 257 ureteral stones were treated with 1168 ESWL sessions. ESWL was performed on an outpatient basis. Patients were evaluated after 1 and 3 months. Stone size and location, total number of shockwaves, stone-free rate, and complications were investigated.

RESULTS

The stone-free rate for renal calculi was 60.5% at 1 month and 82.5% at 3 months. The stone-free rate for ureteral stones was 58% at 1 month and 82.9% at 3 months. The overall stone-free rate was 59.6% at 1 month and 82.5% at 3 months. Anesthesia was not needed in any case. Analgesia with hospital admission was necessary in 15 patients (2.0%). The major complications observed were renal hematoma in only 1 patient (0.1%), obstruction with sepsis in 3 patients (0.4%), and steinstrasse development in 5 patients (0.7%).

CONCLUSIONS

The Dornier Lithotripter S 220 F EMSE is a safe and effective tool in the treatment of urolithiasis; the lack of invasiveness and absence of anesthesia confirm its worthy role as an alternative to ureterorenoscopy and percutaneous nephrolitotomy.