Extracorporeal shockwave lithotripsy of 2000 urinary calculi with the modulith SL-20: success and failure according to size and location of stones

Are the current nomograms sufficient to predict shockwave lithotripsy outcomes?

INTRODUCTION AND OBJECTIVES

To investigate factors affecting SWL outcomes, validate three current nomograms (Kim JK, Triple D and S3HoCKwave) and compare the predictive ability of the nomograms for SWL outcomes in upper urinary tract stones.

PATIENTS AND METHODS

Medical records of patients with renal and proximal ureteral stones treated with SWL between March 2013 and October 2020 were retrospectively reviewed. Factors affecting SWL success were analyzed with multivariate logistic regression analysis and the three predictive scoring systems compared with the area under the curve (AUC).

RESULTS

A total of 580 patients were included in our study. The overall stone free rate was 61% and 144/580 patients (24.8%) were stone free after one session. In multivariate logistic regression analysis, stone location at upper calyx (OR:2.988; 95%Cl: 1.350-6.612; p = 0.007), middle calyx (OR:3.036; 95%Cl: 1.472-6.258; p = 0.003), and lower calyx (OR:2.131; 95%Cl: 1.182-3.839; p = 0.012), as well as number of stones (OR:1.663; 95%Cl: 1.140-2.425; p = 0.008), maximum diameter of stone (OR:1.156; 95%Cl: 1.098-1.217; p < 0.001) and maximum Hounsfield Unit (OR:1.001; 95%Cl: 1.001-1.002; p < 0.001) were independent risk factors of SWL failure. The AUCs of the Kim JK, Triple D and S2HoCKwave scores for predicting SWL success were 0.678, 0.548, and 0.626 respectively.

CONCLUSIONS

Stone location, number, maximal diameter, and maximum HU were independent predictive factors for SWL outcome in the treatment of upper urinary tract stones. Current nomograms, "Kim JK nomogram", "Triple D score" and "S3HoCKwave score" can predict treatment success after SWL, but all of them have poor discrimination according to AUC analysis.

Role of Multi-Detector Computed Tomography Indices in Predicting Extracorporeal Shockwave Lithotripsy Outcome in Patients With Nephrolithiasis

Background

Nephrolithiasis is one of the most common renal pathologies and is routinely encountered in daily practice. Non-contrast computed tomography (NCCT) is the gold standard diagnostic imaging modality for urolithiasis. The role of HU (Hounsfield units) in calculus as a predictor of extracorporeal shock wave lithotripsy (ESWL) has been studied in the past. This study aims to evaluate the role of HU value and various other NCCT indices in predicting the outcome of ESWL.

Material and methods

This was a prospective observational study that included 45 patients suffering from nephrolithiasis who underwent NCCT-KUB (kidney, ureter, and bladder) followed by ESWL. The NCCT indices were evaluated and correlated with the outcome of ESWL. NCCT-KUB was performed using multidetector SIEMENS® SOMATOM EMOTION 16-slice CT scanner (SIEMENS, Munich, Germany).

Results

In our study, the HU value turned out to be a statistically significant predictor of ESWL success (p <0.05), and the renal pelvis also proved to be a good prognostic indicator for ESWL success. The cut-off value of <1179 HU favored a successful outcome of ESWL, while if >1179 HU, ESWL is likely to fail. Hence, the successful outcome of ESWL is inversely proportional to the HU value. Renal pelvic calculi (n=14) showed a 100% success rate, which was better than all other calculus locations (p<0.05). However, the rest of the indices did not show any statistical significance.

Conclusion

Multi-detector NCCT-KUB indices can help in the selection of patients with a good prognosis for ESWL, which will prevent the patient from undergoing undesired invasive procedures.

Clinical application of the therapeutic ultrasound in urologic disease: Part II of the therapeutic ultrasound in urology

This article aimed to review the clinical application and evidence of the therapeutic ultrasound in detail for urological diseases such as prostate cancer, kidney tumor, erectile dysfunction, and urolithiasis. We searched for articles about high-intensity focused ultrasound (HIFU), extracorporeal shock wave therapy, ultrasound lithotripsy, and extracorporeal shockwave lithotripsy (ESWL) in the MEDLINE and Embase. HIFU may be indicated as a primary treatment for low- or intermediate-risk prostate cancer, and salvage therapy for local recurrence as a promising way to address the limitations of current standard therapies. The application of HIFU in treating kidney tumors has scarcely been reported with unsatisfactory results. Evidence indicates that low-intensity shockwave therapy improves subjective and objective erectile function in patients with erectile dysfunction. Regarding the application of ultrasound in stone management, the novel combination of ultrasound lithotripsy and other energy sources in a single probe promises to be a game-changer in efficiently disintegrating large kidney stones in percutaneous nephrolithotomy. ESWL is losing its role in managing upper urinary tract calculi worldwide. The burst-wave lithotripsy and ultrasound propulsion could be the new hope to regain its position in the lithotripsy field. According to our investigations and reviews, cavitation bubbles of the therapeutic ultrasound are actively being used in the field of urology. Although clinical evidence has been accumulated in urological diseases such as prostate cancer, kidney tumor, erectile dysfunction, and lithotripsy, further development is needed to be a game-changer in treating these diseases.

The Outcomes of Extracorporeal Shock Wave Lithotripsy for High-Density Renal Stone on Non-Contrast Computed Tomography

Introduction Urinary lithiasis is usually managed by extracorporeal shock wave lithotripsy (ESWL). Patients are examined using non-contrast computed tomography (NCCT) in order to evaluate the feasibility of ESWL, according to where the stone is located and how big is its size. The objective of this study is to determine the outcomes of ESWL in patients having high-density renal stone, evaluated using NCCT. Materials and methods A descriptive case series study was conducted in the Department of Urology, Sindh Institute of Urology & Transplantation, Karachi for six months. Patients of either gender aged between 25-50 years, who presented with solitary renal and ureteric calculi of 0.5-2 cm in diameter and high-density renal stones [>750 hounsfield units (HU)] were enrolled. ESWL was performed and a satisfactory outcome was defined as complete stone clearance in less than or equal to three ESWL sessions. Statistical Package for Social Sciences (SPSS) (IBM Corp., Armonk, NY) was used to analyze frequencies and percentages of the number of ESWL sessions, complete renal stone clearances, and satisfactory outcomes at the end of 12 weeks. A p-value of <0.05 was considered significant. Results The mean age of the patient was reported to be 34.08 ± 9.53 years. 51.6% male preponderance was noticed. Renal and ureteric stones were found in 69.7% and 30.3% of patients, respectively. 21.3% of patients showed stone clearance after two ESWL sessions, 27% of patients after three ESWL sessions, and 51.6% of patients after four ESWL sessions. Stone clearance was found in 58.2% of patients and a satisfactory outcome was found in 42.6% of patients. Conclusions Our results signify a satisfactory outcome of extracorporeal shock wave lithotripsy for high-density renal stone on non-contrast computed tomography. Further studies on a larger scale are needed to validate these results.

The Predictive Role of Abdominal Fat Parameters and Stone Density on SWL Outcomes

BACKGROUND

Our aim was to detect the role of radiological abdominal fat parameters by tomography and stone density by plain X-ray on extracorporeal Shock Wave Lithotripsy (SWL) stone-free rate.

METHODS

The patients who had undergone SWL for a single opaque renal stone < 2 cm in diameter and proximal ureteric stone < 1 cm in diameter were collected retrospectively. The characteristics of patients and stones were recorded. The stone attitude, HU, abdominal fat parameters, paraperirenal fat area, perirenal infiltration and severity of hydronephrosis with pre-treatment Non- Contrast Computed Tomography (NCCT) and stone density with radiography were evaluated by a radiologist. Four weeks after the last SWL; all patients were evaluated by plain X-ray and categorized as Stone Free (SF) and Residual Fragment (RF) group.

RESULTS

51 patients with renal stones and 88 patients with proximal ureteral stones were included in the study. 24 (47%) and 63 (71%) patients were classified as SFfor renal and ureteral stones respectively. Only stone size was an independent predictor for stone-free rates after SWL for renal and proximal ureteral stones on multivariate analysis. The Receiver Operating Characteristic (ROC) curves for renal calculi revealed that creatinine level, stone size, stone attitude, Houns-Field Unit (HU) and Skin-to-Stone Distance (SSD) were the predictive factors for the SWL outcome (p< 0.05). The ROC curve for ureteral calculi demonstrated that HU, stone size and attitude were the predictive factors (p< 0.05).

CONCLUSION

All abdominal fat parameters and the stone density were not related to SWL failure. A large follow-up with more patients is essential to confirm the role of radiological parameters on the outcome of SWL.

Percutaneous nephrolithotomy versus shock wave lithotripsy for high-density moderate-sized renal stones: A prospective randomized study

Context:

The management of renal stones of high density (>1000 Hounsfield units) on non-contrast computed tomography (NCCT), and moderate sized (15-25 mm) is still debatable.

Aims:

The aim of this study was to compare the outcomes of percutaneous nephrolithotomy (PCNL) and shock wave lithotripsy (SWL) for the high-density and moderate-sized renal stones regarding the stone-free rate (SFR), morbidity, and patients' quality of life.

Settings and Design:

This is a prospective randomized study.

Patients and Methods:

Eighty consecutive patients with renal stones, excluding those with lower calyceal stones, were randomized to receive either PCNL or SWL (40 in each arm). Patients were followed up by abdominal ultrasound and plain X-ray (NCCT if indicated) till clearance of stone. Outcomes, complications, costs, and SF-8 Health Survey scoring were recorded for each group.

Statistical Analysis:

We used Stata software, version 9.2 (Intercooled STATA®; StataCorp LP College Station, Texas, USA). Comparison of the two groups was made with regard to patient and stone criteria and the procedure details. Continuous variables were compared using the Mann–Whitney U-test with values shown as the median and interquartile range. Categorical variables were compared using the Pearson's Chi-square/Fisher's exact test. Multivariate logistic regression analysis was used to identify variables independently associated with the stone clearance after two sessions of SWL. P < 0.05 was considered statistically significant.

Results:

The basic characteristics of both groups were comparable. After a single treatment session, the SFR was 80% and 27.5% for PCNL and SWL, respectively (P < 0.001). The overall 3-month SFR was 87.5% versus 90%, respectively (P = 0.723). The median number of the required maneuvers was 1 (range: 1–3) for PCNL versus 2 (range: 1–4) for SWL (P < 0.001). The complication rate was 10% and 7.5%, respectively (P = 0.692). The cost of SWL was significantly lower (P < 0.001). On multivariate analysis, a single stone was an independent predictor for stone clearance after two sessions of SWL (odds ratio: 7.26, 95% confidence interval: 1.13–46.62, P = 0.037).

Conclusions:

PCNL for the dense, and moderate-sized renal stone provides higher initial success and lower re-treatment rates compared with SWL with comparable outcome after 3 months of therapy. However, SWL is an alternative, especially for a single stone.

Factors Affecting the Outcome of Extracorporeal Shockwave Lithotripsy in Urinary Stone Treatment

Objectives

We sought to evaluate the factors affecting the outcome of extracorporeal shockwave lithotripsy (ESWL) in urinary stone treatment.

Methods

We conducted a retrospective review of 235 adult patients treated with ESWL, for radiopaque renal or ureteric stones between January 2015 and December 2016. Patient's age, sex, stone size, laterality, location, density, skin-to-stone distance (SSD), and presence of double J stent were studied as potential predictors. At the end of three months, the patients were divided into success and failure groups and the significance was determined.

Results

Of the 235 patients (188 males and 47 females) analyzed, ESWL was successful in 79.1%. Univariate analysis of both groups revealed no significant difference in patient's age and stone laterality. Statistically significant differences in gender, stone size, stone site, stone density, SSD, and patients with stents were observed. Statistically significant factors in multivariate logistic regression analysis were sex and stent. Females had three-times higher risk for ESWL failure than males (odds ratio (OR) = 3.213; 95% confidence interval (CI): 1.194-8.645; p = 0.021) and a higher failure rate when a stent was used (OR = 6.358; 95% CI: 2.228-18.143; p = 0.001).

Conclusions

This study revealed that ESWL can treat renal and ureteric stones successfully with an inverse association between outcome and predictors such as stone size and density, SSD, and stent presence. These factors can help us in improving patient selection and ensure better results at lower cost.

How to accelerate the upper urinary stone discharge after extracorporeal shockwave lithotripsy (ESWL) for < 15 mm upper urinary stones: a prospective multi-center randomized controlled trial about external physical vibration lithecbole (EPVL)

OBJECTIVE

To asset the efficacy and safety of EPVL plus ESWL compared with ESWL alone for the treatment of simple upper urinary stones (< 15 mm).

MATERIALS AND METHODS

All patients with upper urinary stones (< 15 mm) were prospectively randomized into two groups. In treatment group, patients were assigned to immediate EPVL after ESWL, while in control group, ESWL alone was offered. All patients were reexamined at 1, 2, and 4 weeks after ESWL. Stone size, stone location, stone-free rate (SFR), and complication rate were compared.

RESULTS

56 males and 20 females in treatment group were compared to 52 male and 25 females in control group (p = 0.404). Median ages were 42.9 ± 1.5 years in treatment group and 42.7 ± 1.3 years in control group (p = 0.943). Median stone size was 10.0 ± 0.4 mm (3-15 mm) in treatment group and 10.4 ± 0.4 mm (4-15 mm) in control group (p = 0.622). The stone clearance rate in treatment and control group at 1 week after ESWL was 51.3% (39/76) and 45.4% (35/77) (p > 0.05), at 2 weeks was 81.6% (62/76) and 64.9% (50/77) (p < 0.05), and at 4 weeks was 90.8% (69/76) and 75.3% (58/77) (p < 0.05), respectively.

CONCLUSIONS

EPVL is a noninvasive, effective, and safe adjunctive treatment which increases and accelerates upper urinary stones discharge after ESWL treatment.

Noncontrast computed tomography factors that predict the renal stone outcome after shock wave lithotripsy

OBJECTIVES

Extracorporeal shock wave lithotripsy (ESWL) is a popular treatment for nephrolithiasis. We took advantage of noncontrast abdominal computed tomography (NCCT) to search the possible prognostic factors including abdominal fat distribution influencing stone-free rate.

METHODS

From August 2008 to August 2010, 145 patients who had renal calculus and had undergone ESWL were retrospectively reviewed. All of them received NCCT assessment before ESWL and were followed up after 1 month for stone clearance. These patients were divided into two groups: one was the stone-free group and the other was the residual-stone group. Affecting parameters included stone size, location, stone surface area, Hounsfield unit density (HU density), skin-to-stone distance (SSD), and abdominal fat area as analyzed between these two groups.

RESULTS

Of 145 patients, 70 were stone-free and 75 had residual stone after ESWL treatment and 1-month follow-up. From univariate analysis, stone size, HU density, SSD, and stone surface area were significant predicting factors for ESWL success. On multivariate analysis, the important factors influencing ESWL outcomes were HU density and stone surface area (odds ratio 1.002 vs. 77.18, respectively; P<.05). Abdominal fat accumulation and distribution had no significant difference between these two groups.

CONCLUSION

This study revealed that stone size, HU density, SSD, and stone surface area were associated with stone-free rate after ESWL treatment. Therefore, these factors could be used to assess the feasibility of ESWL before deciding the treatment strategy. Abdominal fat distribution had no significant impact on ESWL outcome for renal stones.

Histotripsy methods in mechanical disintegration of tissue: towards clinical applications

In high intensity focused ultrasound (HIFU) therapy, an ultrasound beam is focused within the body to locally affect the targeted site without damaging intervening tissues. The most common HIFU regime is thermal ablation. Recently there has been increasing interest in generating purely mechanical lesions in tissue (histotripsy). This paper provides an overview of several studies on the development of histotripsy methods toward clinical applications. Two histotripsy approaches and examples of their applications are presented. In one approach, sequences of high-amplitude, short (microsecond-long), focused ultrasound pulses periodically produce dense, energetic bubble clouds that mechanically disintegrate tissue. In an alternative approach, longer (millisecond-long) pulses with shock fronts generate boiling bubbles and the interaction of shock fronts with the resulting vapour cavity causes tissue disintegration. Recent preclinical studies on histotripsy are reviewed for treating benign prostatic hyperplasia (BPH), liver and kidney tumours, kidney stone fragmentation, enhancing anti-tumour immune response, and tissue decellularisation for regenerative medicine applications. Potential clinical advantages of the histotripsy methods are discussed. Histotripsy methods can be used to mechanically ablate a wide variety of tissues, whilst selectivity sparing structures such as large vessels. Both ultrasound and MR imaging can be used for targeting and monitoring the treatment in real time. Although the two approaches utilise different mechanisms for tissue disintegration, both have many of the same advantages and offer a promising alternative method of non-invasive surgery.

Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones

BACKGROUND

Stones in the urinary tract are a common medical problem in the general population. At present, the great expansion in minimally invasive techniques has led to the decrease in open surgery. Extracorporeal shock wave lithotripsy (ESWL) has been introduced as an alternative approach which disintegrates stones in the kidney and upper urinary tract through the use of shock waves. Nevertheless, as there are limitations with the success rate in ESWL, other minimally invasive modalities for kidney stones such as percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) are also widely applied. This is an update of a review first published in 2009.

OBJECTIVES

This review aimed to assess the effectiveness and complications of ESWL for kidney stones compared with PCNL or RIRS.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 3 March 2014 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the use of ESWL compared to PCNL or RIRS for kidney stone management.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed all the studies for inclusion. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Five studies (338 patients) were included, four studies compared ESWL to PCNL and one compared ESWL with RIRS. Random sequence generation was reported in three studies and unclear in two. Allocation concealment was not reported in any of the included studies. Blinding of participants and investigators could not be undertaken due to the nature of the interventions; blinding of outcome assessors was not reported. Reporting bias was judged to be low risk in all studies. One study was funded by industry and in one study the number of participants in each group was unbalanced.The success of treatment at three months was significantly greater in the PCNL compared to the ESWL group (3 studies, 201 participants: RR 0.46, 95% CI 0.35 to 0.62). Re-treatment (1 study, 122 participants: RR 1.81, 95% CI 0.66 to 4.99) and using auxiliary procedures (2 studies, 184 participants: RR 9.06, 95% CI 1.20 to 68.64) was significantly increased with ESWL group compared to PCNL. The efficiency quotient (EQ; used to assess the effectiveness of procedures) higher for PCNL than ESWL; however EQ decreased when stone size increased. Duration of treatment (MD -36.00 min, 95% CI -54.10 to -17.90) and hospital stay (1 study, 49 participants: MD -3.30 days, 95% CI -5.45 to -1.15) were significantly shorter in the ESWL group. Overall more complications were reported with PCNL, however we were unable to meta-analyse the included studies due to the differing outcomes reported and the timing of the outcome measurements.One study compared ESWL versus RIRS for lower pole kidney stones. The success of treatment was not significantly different at the end of the third month (58 participants: RR 0.91, 95% CI 0.64 to 1.30). Mean procedural time and mean hospital stay was reported to be longer in the RIRS group.

AUTHORS' CONCLUSIONS

Results from five small studies, with low methodological quality, indicated ESWL is less effective for kidney stones than PCNL but not significantly different from RIRS. Hospital stay and duration of treatment was less with ESWL. Larger RCTs with high methodological quality are required to investigate the effectiveness and complications of ESWL for kidney stones compared to PCNL if there is any technological progress in the non-invasive elimination of the residual fragments. Moreover, further research is required for the outcomes of ESWL and RIRS in lower and non-lower pole studies including PCNL versus RIRS.

Efficacy of extracorporeal shockwave lithotripsy using Dornier SII in different levels of ureteral stones

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of the Dornier lithotripter S II system in the treatment of ureteral calculi.

PATIENTS AND METHODS

A total of 97 cases which consists of 54 males and 43 females with ureteral stones were treated by extracorporeal shock wave lithotripsy (ESWL). Mean age was 42.6 years. Inclusion criteria were solitary radiopaque ureteral stones of radiological stone size of ≤1 cm. The stones were not impacted, with normal kidney functions. Procedure time, number of shocks, energy used, number of sessions and complications were reported. The outcome of ESWL was also recorded.

RESULTS

Stones were in the abdominal (upper ureter) in 50% of patients, in pelvic (middle ureter) in 47% of patients. All patients had unilateral stones and the mean stone size in maximum length was) 10 mm). Good dye excretion passing the stone was noted in all patients. Mild hydronephrosis was found in 85% of cases. A total of 49 cases were treated by a single session, while in 35% of cases two sessions were enough and 16% received three sessions. The average number of shocks per session was 3125. The average number of shocks per patient was 5962.5 shocks and average energy was 204.3 Joules. The overall stone-free rate 3 months after lithotripsy was 94%. After a single session of lithotripsy, 49 patients (49%) became stone-free. Stone free rates after ESWL for upper, middle ureteral stones were 94%, 95.7% respectively. Additional procedures were needed in only 6 cases (6%) to render patients stone-free after lithotripsy. No serious complications occurred.

CONCLUSION

The Dornier lithotripter S II is very effective in the treatment of ureteral calculi with no major complications.

Efficacy of a mobile lithotripsy service: a one-year review of 222 patients

OBJECTIVE

Extracorporeal shockwave lithotripsy (ESWL) is the management of choice for ureteric and renal stones 20 mm or smaller, with a stone clearance rate of up to 89%. This study determined whether such a high success rate could apply to centres using mobile ESWL, by reviewing the performance at one centre that provides such a service.

MATERIAL AND METHODS

Between July 2011 and July 2012, 222 patients (median age 51 years, range 18-90 years) underwent one to five sessions of ESWL for ureteric and renal stones (mean size 15 mm, range 4-22 mm). Stone clearance was regarded as residual fragments 2 mm or smaller after completion of sessions.

RESULTS

In total, 110 out of 222 patients (49%) were clear of stones. Stones were radiopaque in 198 (89%) and radiolucent in 24 patients (11%), with clearance rates of 48% and 63%, respectively. Regarding size, 36 (16%) were 1-5 mm, 144 (65%) 5-10 mm, 28 (12%) 10-15 mm, eight (4%) 15-20 mm and six (3%) larger than 20 mm, with clearance rates of 61%, 55%, 18%, 13% and 50%, respectively. In total, 173 (78%) were renal stones and 49 (22%) ureteric, with respective clearance rates of 49% and 51%. For kidney stones, 15 (9%) were in the upper, 32 (18%) in the mid, 75 (43%) in the lower pole and 51 (30%) in the pelvis, with clearance rates of 52%, 59%, 49% and 41%; for ureteric stones, 32 (65%) were in the upper, 10 (20%) in the mid and seven (15%) in the lower ureter, with clearance rates of 47%, 70% and 43%, respectively.

CONCLUSION

The performance of mobile ESWL was significantly poorer than expected, and this may be related to a lack of clinical ownership. The authors believe that such a service should be permanently placed on site.

Double J stent reduces the efficacy of extracorporeal shock wave lithotripsy in the treatment of lumbar ureteral stones

Introduction

We evaluated the effect of the presence of a double J stent on the efficacy of extracorporeal shock wave lithotripsy (ESWL) in the treatment of lumbar ureteral stones.

Material and methods

Between January 2007 and February 2012, we performed a retrospective cohort study. Forty–four patients were treated by ESWL for lumbar ureteral stones and included into two groups for the analysis: group 1, non–stented (n = 27) and group 2, stented patients (n = 17). Treatment efficacy was evaluated by abdominal X–ray or CT–scan at 1 month. Stone–free patients and those with a residual stone ≤4 mm were considered to be cured.

Results

Mean stone size and density in groups 1 and 2 were 8.2mm/831HU, and 9.7 mm/986HU respectively. Both groups were comparable for age, BMI, stone size and density, number, and power of ESWL shots given. The success rates in groups 1 and 2 where 81.5% and 47.1%, respectively (p = 0.017). There was no difference between the groups for stones measuring 8 mm or less (p = 0.574). For stones >8 mm, the success rates were respectively 76% and 22.2% for groups 1 and 2 (p = 0.030). Logistic regression analysis revealed a higher failure rate when a double J stent was associated with a stone >8 mm (p = 0.033).

Conclusions

The presence of a double J stent affects the efficacy of ESWL in the treatment of lumbar ureteral stones. This effect is significant for stones >8 mm. Ureteroscopy should be considered as the first–line treatment in such patients.

Impact of body mass index on clinical outcomes associated with percutaneous nephrolithotomy

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is the preferred treatment for patients with large renal calculi or stones that have not responded to extracorporeal shock wave lithotripsy (ESWL). The objective of this study was to compare outcomes and complications of PCNL in patients of various body mass indices (BMI) to determine the safety of this procedure in patients with elevated BMI.

METHODS

A retrospective chart review of 114 patients who underwent PCNL between 2006 and 2009 was performed. Patients were separated into 4 groups with respect to their BMI: (1) ideal body weight (BMI <25 kg/m(2)), (2) overweight (BMW 25-29 kg/m(2)), (3) obese (BMI 30-39 kg/m(2)) and (4) morbidly obese (BMI ≥40 kg/m(2)). One-way ANOVA and univariate logistic regression analysis were used to assess the association between BMI (classified into 4 levels) and variables including age, sex, stone size, length of stay, incidence of complications and stone-free rates.

RESULTS

The distribution of the 114 patients in each BMI category was: ideal body weight 39 (34%), overweight 24 (21%), obese 41 (36%), morbidly obese 10 (9%). There was no difference in the composition of groups with respect to age, sex, pharmacologically treated comorbidities or stone size. Mean length of stay in days, intra- and postoperative complication rates were not statistically different. Stone-free rates showed no significant difference between groups: 90% ideal body weight; 87% overweight; 90% obese; 80% morbidly obese (p = 0.83).

INTERPRETATION

Outcomes of PCNL were statistically independent of BMI. PCNL is a safe and efficacious treatment of stone disease in patients of all sizes.

Morbidity and efficacy of ureteroscopic stone treatment in patients with neurogenic bladder

PURPOSE

There is a lack of information on the safety and efficacy of ureteroscopy in the neurogenic bladder population. We hypothesized that ureteroscopy in patients with neurogenic bladder would be associated with an increased risk of complications and a lower stone clearance rate than in patients without neurological impairment.

MATERIALS AND METHODS

We reviewed a local registry of patients with ICD-9 codes for urolithiasis between 2004 and 2012. The study cohort was assembled from all eligible patients with neurogenic bladder and a randomly selected control group that had undergone ureteroscopy. Statistical analysis of demographic variables and surgical outcomes was performed. Complications were classified according to the Clavien system. Clearance was defined by computerized tomography, renal/bladder ultrasound or direct ureterorenoscopy.

RESULTS

Ureteroscopy was performed a total of 173 times in 127 controls and a total of 45 times in 20 patients with neurogenic bladder. There was no difference between presenting episodes by gender (p = 1.0), race (p = 0.654) or body mass index (p = 0.519). Bacteriuria was associated with the stone episode in 16.4% of controls and 67% of neurogenic bladder cases (p <0.001). Median operative time was significantly longer in those with neurogenic bladder (80.5 minutes, IQR 50-110.5 vs 52, IQR 33-78, p = 0.0003). The proportion of complications was significantly different (p = 0.013). Stones cleared in 86.6% of controls compared to 63% of neurogenic bladder cases (p = 0.004).

CONCLUSIONS

Patients with neurogenic bladder have increased morbidity after ureteroscopy for upper tract calculi compared to neurologically unaffected controls. Infection has a role in this morbidity. The clearance rate is lower but the stone burden is more significant in those with neurogenic bladder.

Evaluation of shock wave lithotripsy injury in the pig using a narrow focal zone lithotriptor

What's known on the subject? and What does the study add? Of all the SW lithotriptors manufactured to date, more research studies have been conducted on and more is known about the injury (both description of injury and how to manipulate injury size) produced by the Dornier HM-3 than any other machine. From this information have come suggestions for treatment protocols to reduce shock wave (SW)-induced injury for use in stone clinics. By contrast, much less is known about the injury produced by narrow-focus and high-pressure lithotriptors like the Storz Modulith SLX. In fact, a careful study looking at the morphology of the injury produced by the SLX itself is lacking, as is any study exploring ways to reduce renal injury by manipulating SW delivery variables of this lithotriptor. The present study quantitates the lesion size and describes the morphology of the injury produced by the SLX. In addition, we report that reducing the SW delivery rate, a manoeuvre known to lower injury in the HM-3, does not reduce lesion size in the SLX.

OBJECTIVE

• To assess renal injury in a pig model after treatment with a clinical dose of shock waves using a narrow focal zone (≈3 mm) lithotriptor (Modulith SLX, Karl Storz Lithotripsy).

MATERIALS AND METHODS

• The left kidney of anaesthetized female pigs were treated with 2000 or 4000 shock waves (SWs) at 120 SWs/min, or 2000 SWs at 60 SWs/min using the Storz SLX. • Measures of renal function (glomerular filtration rate and renal plasma flow) were collected before and 1 h after shock wave lithotripsy (SWL) and the kidneys were harvested for histological analysis and morphometric quantitation of haemorrhage in the renal parenchyma with lesion size expressed as a percentage of functional renal volume (FRV). • A fibre-optic probe hydrophone was used to determine acoustic output and map the focal width of the lithotriptor. • Data for the SLX were compared with data from a previously published study in which pigs of the same age (7-8 weeks) were treated (2000 SWs at 120 or 60 SWs/min) using an unmodified Dornier HM3 lithotriptor.

RESULTS

• Treatment with the SLX produced a highly focused lesion running from cortex to medulla and often spanning the full thickness of the kidney. Unlike the diffuse interstitial haemorrhage observed with the HM3, the SLX lesion bore a blood-filled core of near-complete tissue disruption devoid of histologically recognizable kidney structure. • Despite the intensity of tissue destruction at the core of the lesion, measures of lesion size based on macroscopic determination of haemorrhage in the parenchyma were not significantly different from kidneys treated using the HM3 (2000 SWs, 120 SWs/min: SLX, 1.86 ± 0.52% FRV; HM3, 3.93 ± 1.29% FRV). • Doubling the SW dose of the SLX from 2000 to 4000 SWs did not significantly increase lesion size. In addition, slowing the firing rate of the SLX to 60 SWs/min did not reduce the size of the lesion (2.16 ± 0.96% FRV) compared with treatment at 120 SWs/min, as was the case with the HM3 (0.42 ± 0.23% FRV vs 3.93 ± 1.29% FRV). • Renal function fell significantly below baseline in all treated groups but was similar for both lithotriptors. • Focal width of the SLX (≈2.6 mm) was about one-third that of the HM3 (≈8 mm) while peak pressures were higher (SLX at power level 9: P+≈90 MPa, P-≈-12 MPa; HM3 at 24 kV: P+≈46 MPa, P-≈-8 MPa).

CONCLUSIONS

• The lesion produced by the SLX (narrow focal width, high acoustic pressure) was a more focused, more intense form of tissue damage than occurs with the HM3. • Slowing the SW rate to 60 SWs/min, a strategy shown to be effective in reducing injury with the HM3, was not protective with the SLX. • These findings suggest that the focal width and acoustic output of a lithotriptor affect the renal response to SWL.

Contemporary management of ureteral stones

CONTEXT

Ureteral calculi represent a common condition that urologists encounter in everyday practice. Several treatment options are available for calculi that do not pass spontaneously or are unlikely to do so.

OBJECTIVE

In this nonsystematic review, we summarize the existing data on contemporary management of ureteral stones focusing on medical expulsive therapy (MET) and different treatment modalities.

EVIDENCE ACQUISITION

A PubMed search was performed. We reviewed the recent literature on the management of ureteral calculi. Articles were considered between 1997 and 2011. Older studies were included selectively if historically relevant.

EVIDENCE SYNTHESIS

For stones that do not pass spontaneously or with MET, shock wave lithotripsy (SWL) and ureteroscopy (URS) are the most common and efficient treatment modalities. Both techniques have obvious advantages and disadvantages as well as different patterns of complications. For select cases or patients, other modalities may be useful.

CONCLUSIONS

Ureteral stones of up to 10mm and eligible for observation may be offered MET. For most ureteral calculi that require treatment, advances in SWL and URS allow urologists to take a minimally invasive approach. Other more invasive treatments are reserved for select "nonstandard" cases.

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.

Which is more important in predicting the outcome of extracorporeal shockwave lithotripsy of solitary renal stones: stone location or stone burden?

PURPOSE

To assess the effect of stone location and burden on the outcome of extracorporeal shockwave lithotripsy (SWL) as a primary treatment of solitary renal stone.

PATIENTS AND METHODS

The study included 438 patients with a solitary renal stone who underwent SWL as a primary treatment for their stones. All were evaluated by plain radiography of the kidneys, ureters, and bladder (KUB), ultrasonography, intravenous urography, or noncontrast enhanced CT before SWL and followed up for 3 months after treatment by KUB radiography and/or ultrasonography. Patients were classified into four groups according to stone location (renal pelvis, lower, middle, and upper calix) and three groups according to stone burden (≤ 1 cm(2), 1.1-2 cm(2), and >2 cm(2)). Treatment outcome was considered successful if no residual fragments (stone free) or clinically insignificant nonobstructing residuals less than 4 mm remained after 3 months of follow-up.

RESULTS

The mean age of the patients was 45.1 ± 12.5 years. The mean stone burden, number of sessions, and shockwaves for the whole study were 1.3 ± 0.49 cm(2), 2.1 ± 0.7 sessions, and 5616.6 ± 2017.4 shockwaves, respectively. The stone-free rate of the study was 65.1%. The stone-free rates of the stones in the renal pelvis, lower, middle, and upper calices were 72.4%, 56%, 55.6%, and 69%, respectively. The stone-free rate of the stones ≤ 1 cm(2), 1.1 to 2 cm(2), and >2 cm(2) was 50.2%, 39.6%, and 10.2%, respectively (P<0.05).

CONCLUSION

Stone burden rather than stone location is considered as a predicting factor for the outcome of SWL in a solitary renal stone, especially in the renal pelvis and lower calix.

[Single-session extracorporeal shock wave lithotripsy for urinary calculi: factors predicting success after three weeks of follow-up]

INTRODUCTION

The aim of this study was to identify predictive factors of success following a single-session of shock wave lithotripsy (SWL) at 3 weeks of follow-up in our center.

MATERIAL AND METHODS

The medical records of 116 patients with solitary urinary calculi who underwent single-session SWL in our department between October 2007 and August 2009 were reviewed. All preoperative unenhanced computed axial tomographies were reviewed by two radiologists blinded to clinical outcome. Success was defined as complete clearance or the persistence of fragments ≤ 2 mm on a plain film at 3 weeks of follow-up. The impact of clinical and radiological factors on success was assessed by univariate and multivariate analyses.

RESULTS

The single-session SWL success rate at 3 weeks was 49.1%. Stone size <8 mm, stone area < 30 mm(2), stone location (mid- and distal ureter), stone density <1000 HU and intraoperative fragmentation showed a significant association with SWL success in the univariate analysis (p<0.05). Stone area (OR 2.9), ureteral stone location (OR 3.4) and intraoperative fragmentation (OR 4.2) were the only predictors of success in the multivariate analysis.

CONCLUSIONS

Stone area and ureteral stone location provide important information when deciding about the indication of a SWL in a patient with stone disease. However, successful resolution of only half of the cases after a single session at 3 weeks in our series undermines the relevance of informing patients about the potential need for additional treatment.

A clinical nomogram to predict the successful shock wave lithotripsy of renal and ureteral calculi

PURPOSE

Although shock wave lithotripsy is dependent on patient and stone related factors, there are few reliable algorithms predictive of its success. In this study we develop a comprehensive nomogram to predict renal and ureteral stone shock wave lithotripsy outcomes.

MATERIALS AND METHODS

During a 5-year period data from patients treated at our lithotripsy unit were reviewed. Analysis was restricted to patients with a solitary renal or ureteral calculus 20 mm or less. Demographic, stone, patient, treatment and 3-month followup data were collected from a prospective database. All patients were treated using the Philips Lithotron® lithotripter.

RESULTS

A total of 422 patients (69.7% male) were analyzed. Mean stone size was 52.3±39.3 mm2 for ureteral stones and 78.9±77.3 mm2 for renal stones, with 95 (43.6%) of the renal stones located in the lower pole. The single treatment success rates for ureteral and renal stones were 60.3% and 70.2%, respectively. On univariate analysis predictors of shock wave lithotripsy success, regardless of stone location, were age (p=0.01), body mass index (p=0.01), stone size (p<0.01), mean stone density (p<0.01) and skin to stone distance (p<0.01). By multivariate logistic regression for renal calculi, age, stone area and skin to stone distance were significant predictors with an AUC of 0.75. For ureteral calculi predictive factors included body mass index and stone size (AUC 0.70).

CONCLUSIONS

Patient and stone parameters have been identified to create a nomogram that predicts shock wave lithotripsy outcomes using the Lithotron lithotripter, which can facilitate optimal treatment based decisions and provide patients with more accurate single treatment success rates for shock wave lithotripsy tailored to patient specific situations.

In vitro comminution of model renal calculi using histotripsy

Shock wave lithotripsy (SWL) suffers from the fact that it can produce residual stone fragments of significant size (>2 mm). Mechanistically, cavitation has been shown to play an important role in the reduction of such fragments to smaller debris. In this study, we assessed the feasibility of using cavitationally-based pulsed ultrasound therapy (histotripsy) to erode kidney stones. Previous work has shown that histotripsy is capable of mechanically fractionating soft tissue into fine, acellular debris. Here, we investigated the potential for translating this technology to renal calculi through the use of a commonly accepted stone model. Stone models were sonicated using a 1-MHz focused transducer, with 5-cycle pulses delivered at a rate of 1 kHz. Pulses having peak negative pressures ranging from 3 to 21 MPa were tested. Results indicate that histotripsy is capable of effectively eroding the stone model, achieving an average stone erosion rate of 26 mg/min at maximum treatment pressure; substantial stone erosion was only observed in the presence of a dense cavitational bubble cloud. Sequential sieving of residual stone fragments indicated that debris produced by histotripsy was smaller than 100 μm in size, and treatment monitoring showed that both the cavitational bubble cloud and model stone appear as hyperechoic regions on B-mode imaging. These preliminary results indicate that histotripsy shows promise in its use for stone comminution, and an optimized erosion process may provide a potential adjunct to conventional SWL procedures.

Evaluation of pancreatic damage after extracorporeal shock wave lithotripsy, percutaneous stone surgery, and ureteroscopy

OBJECTIVES

To complete a prospective evaluation of serum amylase and lipase levels before and after shock wave lithotripsy (SWL) for renal stones. We also compared these serum levels to those of patients undergoing percutaneous and ureteroscopic stone surgery. SWL injury to the pancreas should be noted by an increase in serum amylase and lipase.

METHODS

A prospective evaluation of 38 patients (16 who underwent SWL, 15 who underwent percutaneous nephrostolithotomy, and 7 who underwent ureteroscopic stone manipulation) who underwent treatment of renal calculi at our institution was completed. The control group was the combined group of patients who had undergone percutaneous nephrostolithotomy or ureteroscopic stone manipulation. The serum amylase and lipase levels were measured before the procedure, immediately after the procedure (2 hours), and ≥30 days after the procedure.

RESULTS

No statistically significant difference was found in the change from before to immediately after the procedure between the SWL group and the controls in amylase (median decrease 6 U/L vs 11 U/L, P = .45) or lipase (median decrease 4 U/L vs 9 U/L, P = .31). Also, no statistically significant evidence was seen in the change from before to >30 days after the procedure between the SWL group and controls in the amylase level (median increase 0 U/L vs 2 U/L, P = 1.00) or lipase (median change 2 U/L increase vs 1 U/L decrease, P = .96).

CONCLUSIONS

SWL does not appear to noticeably increase the serum amylase and lipase level directly postoperatively or >30 days after the procedure compared with baseline or compared with the controls.

Evaluating the importance of mean stone density and skin-to-stone distance in predicting successful shock wave lithotripsy of renal and ureteric calculi

Shock wave lithotripsy (SWL) is considered the first line treatment for the majority of patients with renal and ureteric calculi, with success rates from contemporary series varying from 60 to 90%. Success is dependent on many patient and stone-related factors. We conducted a retrospective analysis of mean stone CT density (MSD) and skin-to-stone distance (SSD) to determine their influence on the success of SWL of renal and ureteric calculi. Data from all patients treated at the St. Michael's Hospital Lithotripsy Unit from May 2004 to June 2009 were reviewed. Analysis was restricted to those patients with a pre-treatment non-contrast CT scan conducted at our center demonstrating a solitary renal or ureteric calculus < or =20 mm in maximal diameter. Successful treatment of renal stones was defined as those patients who were stone free or had asymptomatic, clinically insignificant residual fragments < or =4 mm in diameter, as measured by KUB X-ray, 3 months after a single SWL treatment. Successful treatment of ureteric stones was defined as being stone free on KUB X-ray, 2-weeks post-SWL. Demographic, stone, patient, treatment and follow-up data were collected from a prospective database and review of CT and KUB imaging by two independent urologists and one radiologist. Data were analyzed with logistic regression, Chi square analysis and ANOVA where appropriate. 422 patients (69.7% male) with a mean age of 51.4 years (SD 12.9) and mean BMI 27.0 kg/m(2) (SD 4.9) were analyzed. Mean stone size was 78.9 mm(2) (SD 77.3) for ureteral stones and 66.1 mm(2) (SD 63.2) for renal stones, with 95 (43.6%) of the renal stones located in the lower pole. The single-treatment success rates for ureteral and renal stones were 62.3% and 68.8%, respectively. On univariate analysis, predictors of SWL success, regardless of stone location, were age (p = 0.01), BMI (p = 0.01), stone size (p < 0.01), MSD (p < 0.01) and SSD (p < 0.01). On multivariate analysis, MSD >900 HU (OR = 0.49, CI: 0.32-0.75) and SSD >110 mm (OR = 0.49, CI: 0.31-0.78) were both significant predictors of outcome. We have identified in a large series of renal and ureteric calculi that both MSD and SSD can reliably predict SWL outcomes. This data can be used in combination with other patient and stone-related factors to facilitate optimal treatment-based decisions and provide patients with more accurate single-treatment success rates for SWL.

Treatment of large proximal ureteral stones: extra corporeal shock wave lithotripsy versus semi-rigid ureteroscope with lithoclast

Purpose

Assessment of safety and efficacy of extracorporeal shockwave lithotripsy versus semi-rigid ureteroscope with lithoclast for treatment of large proximal ureteral stones.

Materials and methods

The study included 147 patients with large upper ureteral stones. SWL and ureteroscopy were performed in 71 and 76 patients respectively. Patients in the SWL group were treated with Siemens: - Modularis lithovario under intravenous sedation on an out patient basis. Patients in the ureteroscopy group were treated with (7.5 Fr) semi-rigid ureteroscope and lithoclast under spinal anesthesia on a day care basis.

Results

Stone - free rate for in situ SWL was 58% (41 of 71) patients. For semi-rigid ureteroscope accessibility of the stones was 94% (72 of 76) and the stone free rate was 92% (70 of 76) No major complications were encountered in both groups.

Mean stone size was 1.34 ± 0.03 cm in the SWL group and 1.51 ± 0.04 in the ureteroscopy group.

Conclusions

Our study demonstrates that ureteroscopy with lithoclast can be considered as acceptable treatment modality for large proximal ureteral calculi and can be considered as fist line for treatment of large proximal ureteral stones.

Complications and outcomes following extracorporeal shock wave lithotripsy: a prospective study of 3,241 patients

Extracorporeal shock wave lithotripsy (SWL) has become the least invasive treatment modality with high success rates for urinary calculi; however, its established efficacy has been associated with a number of side effects and complications. This study sought to further evaluate the incidence rate and management of the post-SWL complications and also the efficiency of procedure in a large scale of patients. During a 51-month period, 3,241 consecutive adult patients with the mean age of 38.1 years (range 15-75) and urinary calculi (>or=4 mm) underwent SWL at our referral center and were followed for 3 months prospectively. Overall, 3,614 stones [kidneys (83.5%), ureters (15.8%) and bladder (0.7%)] in 3,241 patients were treated requiring 7,245 SWL sessions. Stone-free state occurred in 71.5% calculi and success rate in 79.8% patients. The re-treatment was necessary in 37.2% patients. Auxiliary procedure and efficiency quotient were 5.6% and 0.50, respectively. SWL success rate decreased as the stone size increased (P < 0.0001). The stone-free rate was correlated with the location of the stone. During the study period, 4,075 complications occurred in our patients. Colicky pain (40%) was the most frequent symptom followed by gross hematuria (32%) and steinstrasse (24.2%). Symptomatic bacteriuria developed in 9.7% patients; Escherichia coli (30.4%) was the most causative organism. In conclusion, the complication rate following SWL was high in our study; however, the majority was mild and managed conservatively or with the minimal intervention. Moreover, the management of urinary calculi in adults using SWL was proved to be safe and efficient, particularly for ureteral stones <10 mm, renal pelvic stones <20 mm, and bladder stones <30 mm.

Shock wave lithotripsy: a randomized, double-blind trial to compare immediate versus delayed voltage escalation

OBJECTIVES

To present a randomized trial investigating immediate vs delayed voltage escalation during shock wave lithotripsy (SWL). SWL efficiency is affected by the energy setting of the lithotripter, the consumption level of the electrode, and the rate of shock wave administration. Preliminary data have suggested that delaying voltage escalation for SWL might both improve fragmentation and minimize renal injury.

METHODS

A total of 160 patients with previously untreated radiopaque renal calculi were randomized to undergo immediate vs delayed voltage escalation SWL. Success was defined as an asymptomatic patient who was stone free or had adequate fragmentation (sand or fragments < or = 4 mm) at 3 months after treatment.

RESULTS

Of the 160 patients, 83 were treated with immediate voltage escalation SWL and 77 patients with delayed escalation. The groups were similar in sex, body mass index, stone area, and stone location. The overall success rate at 3 months was 72.5% for immediate vs 54.5% for delayed SWL (P = .021). After adjusting for body mass index, sex, and stone location, the stone area decreased more rapidly in patients treated with immediate voltage escalation (P = .002). A trend was also seen for immediate voltage escalation to be more effective in the treatment of smaller calculi with a cross-sectional area of < 100 mm(2) (P = .089) compared with calculi with a cross-sectional area of > or = 100 mm(2) (P = .248). No differences were seen in the complications or ancillary procedures between the 2 treatments (P = .667 and P = .355, respectively). No perinephric hematomas were observed in either group.

CONCLUSIONS

These results suggest that delayed voltage escalation might not provide superior stone fragmentation compared with conventional, immediate voltage escalation.

Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones

BACKGROUND

Stones in the urinary tract are a common medical problem in the general population. At present, the great expansion in minimally invasive techniques has led to the decrease in open surgery. Extracorporeal shock wave lithotripsy (ESWL) has been introduced as an alternative approach which disintegrates stones in the kidney and upper urinary tract through the use of shock waves. Nevertheless, as there are limitations with the success rate in ESWL, other minimally invasive modalities for kidney stones such as percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) are also widely applied.

OBJECTIVES

To evaluate the effectiveness and complications of ESWL compared with PCNL or RIRS for managing kidney stones.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE, EMBASE and reference lists of articles without language restriction.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the use of ESWL compared to PCNL or RIRS for kidney stone management.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed all the studies for inclusion. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Three studies (214 patients) were included, however results could not be pooled. Two RCTs compared ESWL to PCNL. The success rate at three months for lower pole kidney stones was statistically higher for PCNL (RR 0.39, 95% CI 0.27 to 0.56). Re-treatment (RR 1.81, 95% CI 0.66 to 4.99) and using auxiliary procedures (RR 9.06, 95% CI 1.20 to 68.64) after PCNL were less compared to ESWL. The efficiency quotient (EQ) in PCNL was higher than ESWL. Hospital stay (MD -3.30 days, 95% CI -5.45 to -1.15), duration of treatment (MD -36.00 minutes, 95% CI -54.10 to -17.90) and complications were less for ESWL. One RCT compared ESWL versus RIRS for lower pole kidney stones. The success rate was not significantly different at the end of the third month (RR 0.91, 95% CI 0.64 to 1.30).

AUTHORS' CONCLUSIONS

Results from three small studies, with low methodological quality, indicated ESWL is less effective for lower pole kidney stones than PCNL but not significantly different from RIRS. Hospital stay and duration of treatment was less with ESWL. More RCTs are required to investigate the effectiveness and complications of ESWL for kidney stones compared to PCNL or RIRS.

Composition and clinically determined hardness of urinary tract stones

OBJECTIVES

To derive hardness factors for crystal phases of urinary tract stones and describe the hardness pattern in a stone population.

MATERIAL AND METHODS

In a retrospective study, recordings from patients treated with extracorporeal shock-wave lithotripsy (ESWL) (stone surface area < or = 100 mm2) were used to derive hardness factors. The number of re-treatments, the number of shock waves and the energy index (the voltage in kilovolts multiplied by the number of shock waves) required for a satisfactory stone disintegration were assumed to reflect the hardness. The stone composition in 2100 patients provided the basis for an average hardness pattern. A hardness index was calculated from the fraction of each crystal phase and its hardness factor.

RESULTS

The hardness factors were as follows: calcium oxalate monohydrate, 1.3; calcium oxalate dehydrate, 1.0; hydroxyapatite, 1.1; brushite, 2.2; uric acid/urate, 1.0; cystine, 2.4; carbonate apatite, 1.3; magnesium ammonium phosphate, 1.0; and mixed infection stones, 1.0. The hardness index for 114 stones (surface area 100-200 mm2) corresponded reasonably well to the ESWL treatment efforts. Calcium oxalate monohydrate, calcium oxalate dihydrate and hydroxyapatite were the most frequently encountered crystal phases in all 2100 stones. Only 21% of the stones were composed of only one crystal phase. There were two, three and more than three crystal phases in 26%, 38% and 15% of the stones, respectively. The hardness index calculated for 2100 stones ranged between 0.70 and 2.33, with a mean (SD) of 1.18 (0.15).

CONCLUSIONS

The hardness factors and hardness index derived in this study might be useful for describing the stone situation in individual patients and groups of patients and for comparison of various treatment strategies.

Low-frequency extracorporeal shock wave lithotripsy improves renal pelvic stone disintegration in a pig model

OBJECTIVE

To compare disintegration rates for renal stones treated by 60 vs 120 shock waves (SW)/min at the same energy settings, using standardized validated artificial stones in a pig model.

MATERIALS AND METHODS

Gypsum artificial stones (13 x 6 mm) were inserted into the renal pelvis on either side of 12 anaesthetized pigs by open surgery. Extracorporeal SW lithotripsy (ESWL) was applied using a new electromagnetic lithotripter (Lithoskop, Siemens AG Healthcare, Munich, Germany) at 60 and 120 SW/min; 3000 SW were applied to each kidney with the same energy settings. Stone fragments were collected after nephrectomy, passed through calibrated test sieves, and weighed. Fragment size categories were stratified according to the sieve hole size as set by the manufacturer. Fragments of < or =4.75 mm were defined as capable of spontaneous passage. For each pig the number of stone fragments of the respective size categories was counted and weighed. The results were analysed statistically using the Mann-Whitney U-test.

RESULTS

For fragments of >4.75 mm, the median (range) fragment counts were 0 (0-1) for 60 and 1 (0-3) for 120 SW/min (P = 0.006). For small fragments of 2.0-2.8 mm, the median fragment counts were 15 (4-24) for 60 and 10 (2-25) for 120 SW/min (P = 0.033); for fragments of 1.0-2.0 mm the respective values were 42.5 (9-81) and 21.5 (6-56) (P = 0.004). Of the total stone fragment mass in the 60 and 120 SW/min groups, 4.34% and 31.31% were >4.75 mm. There was complete disintegration yielding fragments capable of spontaneous passage in 10 of 12 renal units at 60 and in three of 12 renal units at 120 SW/min. The mean treatment time was 55.4 min for therapy at 60 and 34.3 min for therapy at 120 SW/min (P = 0.001). One parenchymal haematoma of 15 x 10 mm developed in the 60 SW/min group and another of 20 x 10 mm developed in the 120 SW/min group.

CONCLUSION

ESWL fragmentation with equal energy application yields significantly smaller fragments at 60 than at 120 SW/min. The theoretical stone passage rate could therefore be approximately 80% for 60 vs 25% for 120 SW/min ESWL. Renal haematoma formation was comparable in both groups.

Effect of skin-to-stone distance on shockwave lithotripsy success

PURPOSE

We evaluated the effect of increased body habitus on stone-free rates after shockwave lithotripsy (SWL), determined by three reproducible skin-to-stone distances (SSDs) on CT.

PATIENTS AND METHODS

We retrospectively reviewed the records of 85 patients with preoperative CT scans available on Stentor Radiology Imaging who underwent SWL with the unmodified Dornier HM3 lithotripter from 2002 to 2007. SSDs were measured at the following angles: 0 degrees (vertical), 30 degrees, and 90 degrees (horizontal). Successful therapy was defined as stone free (residual fragments <2 mm) on follow-up imaging. Data were analyzed using descriptive statistics, Student t test, and the Fisher exact test.

RESULTS

Four hundred and eighty patients underwent SWL at our institution from 2002 to 2007; 85 patients (50.6% men, mean age 50.8 +/- 15.7 years, mean body mass index [BMI] 28.8 +/- 6.6 kg/m2) had preoperative CT scans available for review. On follow-up imaging (142.7 +/- 217.2 days), 49.4% of patients were stone free. Mean SSDs (vertical, 30 degrees, horizontal) in patients who were stone-free v those with residual stone were 104.3 +/- 26.2 mm v 102.6 +/- 29.9 mm (P = 0.79), 103.9 +/- 28.2 mm v 101.0 +/- 31.5 mm (P = 0.66), and 106.6 +/- 25.3 mm v 107.1 +/- 29.3 mm (P = 0.94), respectively.

CONCLUSIONS

Multiple variables have been shown to be associated with SWL success. In our sample of patients with preoperative CT scans, SSD was found to have no effect on SWL success.

Stone attenuation and skin-to-stone distance on computed tomography predicts for stone fragmentation by shock wave lithotripsy

OBJECTIVES

To determine whether stone attenuation and the skin-to-stone distance (SSD) can predict for stone fragmentation by SWL independently. Identifying the factors predictive of shock wave lithotripsy (SWL) outcome would help streamline the care of patients with stones.

METHODS

A retrospective review was performed of 111 patients undergoing initial SWL for a solitary, 5-20 mm, renal calculus. Stone size, location, attenuation value, and SSD were determined on pretreatment noncontrast computed tomography. The outcome was categorized as stone free, complete fragmentation <5 mm, and incomplete fragmentation >or=5 mm or unchanged at 2 weeks on kidney/ureter/bladder radiography.

RESULTS

After SWL, 44 (40%) were stone free, 27 (24%) had complete fragmentation, and 40 (36%) of 111 patients had incomplete fragmentation. The stone attenuation of the successfully treated patients (stone free and complete fragmentation groups) was 837 +/- 277 Hounsfield units (HU) vs 1092 +/- 254 HU for those with treatment failure (incomplete fragmentation; P < .01). The mean SSD also differed: 9.6 cm +/- 2.0 vs 11.1 cm +/- 2.5 for the successful treatment group vs the treatment failure group, respectively (P = .01). On multivariate analysis, the factors that independently predicted the outcome were stone attenuation, SSD, and stone composition. When patients were stratified into 4 risk groups (stone <900 HU and SSD <9.0 cm, stone <900 HU and SSD >or=9.0 cm, stone >or=900 HU and SSD <9.0 cm, and stone >or=900 HU and SSD >or=9.0 cm), the SWL success rate was 91%, 79%, 58%, and 41%, respectively (odds ratio 7.1, 95% confidence interval 1.6-32 for <900 HU and SSD <9.0 cm group vs other 3 risk groups; P = .01).

CONCLUSIONS

The results of our study have shown that a stone attenuation of <900 HU, SSD of <9 cm, and stone composition predict for SWL success, independent of stone size, location, and body mass index. These factors will be considered important in the prospective design of a SWL treatment nomogram at our center.

Shock Wave Lithotripsy or Ureteroscopy for the Management of Proximal Ureteral Calculi: An Old Discussion Revisited

PURPOSE

The goal of treating ureteral calculi is to achieve complete stone clearance with minimal patient morbidity. Shock wave lithotripsy and ureteroscopy have become standards of care for ureteral calculi. However, the optimal choice of treatment depends on various factors, including stone size, composition and location, clinical patient factors, equipment availability and surgeon capability. Indications for and outcomes data on shock wave lithotripsy and ureteroscopy for proximal ureteral calculi were reviewed to provide recommendations on the optimal treatment choice for managing symptomatic ureteral calculi.

MATERIALS AND METHODS

A systematic review was performed based on an English literature search using the MEDLINE database between 1997 and 2005. The key words used were proximal ureteral calculi, ureteroscopy and shock wave lithotripsy.

RESULTS

A total of 87 articles were identified, of which 33 were selected for inclusion. Shock wave lithotripsy and ureteroscopy provided an excellent stone-free rate (86% to 90%) for stones less than 10 mm, whereas for larger stones ureteroscopy achieved better outcomes vs shock wave lithotripsy (67% vs 73%). Ureteroscopy was preferred over shock wave lithotripsy in patients with pregnancy or bleeding diathesis.

CONCLUSIONS

Ureteroscopy provides optimal stone clearance in patients with proximal ureteral calculi more than 10 mm. It is also recommended in patients with contraindications for shock wave lithotripsy. In patients with smaller stones (less than 10 mm) shock wave lithotripsy may be considered a reasonable alternative with outcomes similar to those of ureteroscopy.

Treatment Selection and Outcomes: Ureteral Calculi

The most important recent advances in the management of ureteral calculi have been the development of medical expulsive therapy to facilitate passage of ureteral stones, such that many calculi that would previously have required procedural treatment now exit the ureter with only pharmacologic treatment; and the improvements in ureteroscopic technology that have enabled retrograde ureteroscopy to become a first-line option for most ureteral stones. Shock wave lithotripsy still plays an important role for many ureteral calculi, particularly smaller ones, and the addition of percutaneous/antegrade ureteroscopy and laparoscopic ureterolithotomy rounds out the treatment options for large or impacted stones. Selection of treatment based upon factors such as size, location, and others will optimize outcome for patients who have ureteral calculi.

Observations on intrarenal geometry of the lower-caliceal system in relation to clearance of stone fragments after extracorporeal shockwave lithotripsy

PURPOSE

To study the intrarenal geometry of the lower-caliceal system in patients with and without residual fragments after extracorporeal shockwave lithotripsy (SWL) and to formulate a summarizing mathematical expression of relevant variables.

PATIENTS AND METHOD

In a series of patients consecutively treated by SWL, we analyzed the geometric anatomy in 47 patients with (group R) and 47 without (group NR) residual fragments in long-term follow-up. A number of distances and angles previously described in the literature were measured, to which was added the distance between the stone-bearing calix and the vertex of the lower renal lip (CL) and the angle (delta) this line formed with a vertical line.

RESULTS

There were significant differences between the groups in terms of infundibular length (P = 0.009), CL (P = 0.0020), and lower-caliceal height, CH (P = 0.0004). The calix width and the various angles did not differ significantly between the groups. The quotient CH/CL was used to calculate cos delta, and a summarizing expression (Index LC) was given the form CH(2)/CL which equals CH x cos delta. This index was significantly different in groups R and NR (P = 0.0036). Approximately 4% of the patients in group NR, compared with 28 percent in group R, had Index LC values >25.

CONCLUSION

Index LC, as an expression of the geometry of the lower-caliceal system, might be useful for simple description of the lower-caliceal anatomy and supportive for decisions on the use of fragment clearance-facilitating procedures or the selection of a more invasive approach than SWL.

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

OBJECTIVE

To assess the efficacy and safety of a transportable extracorporeal shock wave lithotripsy (ESWL) machine, the Modulith SLX-F2(TM) (Storz Medical Italia, Rome, Italy), in the management of solitary urinary calculi.

PATIENTS AND METHODS

The study included 233 patients (mean age 51 years; 172 male, 61 female) with symptomatic solitary renal (group A, 170, mean diameter 15.5 mm) or ureteric stones (group B, 63, mean diameter 9.5 mm) treated in a tertiary care institution. Exclusion criteria for the analysis were: pelvi-ureteric junction obstruction, multiple stones, stone diameter >2 cm, stones in a lower calyx with unfavourable anatomy, active infection, or impacted ureteric stones. Selected patients had ureteric stenting before treatment, and all patients were treated with no anaesthesia. Hospitalization, complications and subsequent auxiliary procedures were evaluated. Patients were assessed after a single ESWL session and after 3 months by a plain abdominal film and renal ultrasonography. Stone-free status was defined as no evidence of calculi, and clinical success as the presence of stone fragments of <4 mm. An efficiency quotient (EQ) was calculated for the ESWL treatment. Pain was assessed using a visual analogue scale.

RESULTS

The mean number of shocks used was 3779 and the mean (range) treatment time was 35 (5-55) min. The overall clinical success rate after one ESWL session was 83.7% and 82.5% for renal and ureteric stones, respectively, and the overall 3-month stone-free rate was 77% and 74.6%, respectively; the overall EQ was 0.64. When risk factors for persistent calculi were analysed simultaneously in a logistic regression model, only stones of >1 cm were statistically significant (P < 0.05). Most patients reported that pain during ESWL was mild to moderate and easily tolerated. Only minor complications occurred, with an overall complication rate of 3.8%.

CONCLUSIONS

This transportable lithotripter is a safe and effective device for managing solitary stones throughout the urinary tract. Its main advantage is represented by the dual-focus system. Moreover, it shares with other contemporary machines several important features such as outpatient setting, no need for anaesthesia, easy patient positioning, and the capability of ancillary procedures.