Success Rate Of Shock Wave Lithotripsy Research Articles

Impact of hydronephrosis on shockwave lithotripsy outcomes for upper ureteral stones.

To investigate the effect of the degree of hydronephrosis on extracorporeal shockwave lithotripsy (SWL) success in patients who underwent SWL due to upper ureteral stones. Medical records of 878 patients who underwent SWL were retrospectively reviewed. Patients with isolated unilateral 6-10mm radiopaque upper ureteral stones above the upper border of the sacroiliac joint were included in the study. The primary endpoint of the study was the relationship between the degree of hydronephrosis with upper ureteral stones and the stone clearance time, number of SWL sessions, and success, while the secondary endpoint was the effect of the presence of severe hydronephrosis (SFU grade 3) on SWL success. The mean age of the patients was 41.3 ± 10.9years. The mean stone size was 8.2 (6-10) mm. Ureteropelvic junction stones were present in 24 (20%) patients. The mean stone clearance time was 14.6 ± 9.7days. One-month SWL success was determined as 85%. SWL success rates decreased as the degree of hydronephrosis increased (p = 0.047). Being 45years of age and older increased the risk of SWL failure by 16.25 times (OR = 16.25, p = 0.017). Increasing the stone clearance time by 1day increased the risk of SWL failure by 1.17 times (OR = 1.17, p = 0.006), and increasing the number of SWL sessions by 1 session increased the risk of SWL failure by 7.69 times (OR = 7.69, p = 0.016). The presence of severe hydronephrosis (grade 3) did not affect SWL success (OR = 5.56, p = 0.071). According to our study results, as the degree of hydronephrosis increases in 6-10mm upper ureteral stones, the number of SWL sessions increases, stone expulsion times prolong, and 1-month success rates decrease.

Vücut Dışı Şok Dalgası İle Taş Kırma Başarısında Ultrason Kılavuzluğu ile X Işını Kılavuzluğunun Karşılaştırılması

Objective: This retrospective study aims to compare the success rates of shock wave lithotripsy (SWL) using ultrasound (US) targeting versus X-ray targeting. Material and Methods: A retrospective chart review was conducted on patients who underwent SWL for urinary tract stones between January 1, 2018, and December 31, 2020. The patients were divided into two groups based on the imaging modality used for stone targeting during SWL: the US group and the X-ray group. The success rates of SWL, defined as complete stone clearance or clinically insignificant residual fragments (<4mm), were compared between the two groups. Results: A total of 200 patients were included in the study, with 100 patients in each group. The demographics and stone characteristics of the patients were similar between the two groups. The success rate of SWL in the US group was 84%, compared to 72% in the X-ray group (p=0.041). The odds ratio for success in the US group compared to X-ray group was 2.04 (95% confidence interval: 1.02-4.07) Conclusion: This retrospective study suggests that SWL with US targeting may have a higher success rate compared to X-ray targeting. US provides a safe and effective alternative for stone targeting during SWL, avoiding the use of ionizing radiation. Further research is warranted to confirm these findings and explore the potential benefits of US guided SWL in clinical practice.

Development and validation of a predictive model for treatment outcome after emergency extracorporeal shockwave lithotripsy in patients with symptomatic ureteral stones during the COVID-19 pandemic: in a large prospective cohort.

The predictors of treatment outcome after emergency extracorporeal shockwave lithotripsy (SWL) are not well characterized. Therefore, based on a large prospective cohort, we aimed to develop and validate a nomogram for predicting treatment outcome after emergency SWL in patients with symptomatic ureteral stones. The development cohort included 358 patients with symptomatic ureteral stones who underwent emergency SWL between June 2020 and August 2021 in our hospital. One hundred and twenty-nine patients with symptomatic ureteral stones participated in the validation cohort from September 2021 to April 2022. The data were prospectively recorded. The backward stepwise selection was applied using the likelihood ratio test with Akaike's information criterion as the stopping rule. The efficacy of this predictive model was assessed concerning its clinical usefulness, calibration, and discrimination. Finally, 15.6% (56/358) of patients in the development cohort and 14.0% (18/129) of those in the validation cohort suffered from stone-free failure after emergency SWL. We identified four predictors for stone-free failure: stone size, stone density, skin to stone distance (SSD), and degree of hydronephrosis. This model showed good discrimination with an area under the receiver operating characteristic (AUROC) curves of 0.935 (0.899-0.971) and good calibration (P = 0.059). The decision curve analysis showed that the model was clinically valuable. In this large prospective cohort, we found that stone size, stone density, SSD, and degree of hydronephrosis were predictors of treatment outcome after emergency SWL. This nomogram will be helpful in preoperative risk stratification to provide individualized treatment recommendations for each patient. Furthermore, early identification and appropriate management of patients may increase the success rate of emergency SWL during the COVID-19 pandemic.

Can we predict the ancillary treatments after extracorporeal shockwave lithotripsy for renal and upper ureteral stones?

To quantify the predictors for the ancillary treatments after extracorporeal shock wave lithotripsy (SWL) for renal and upper ureteral stones. From January 2014 to January 2017, patients undergoing SWL using an electromagnetic lithotripter machine (Compact Delta; Dornier MedTech GmbH, Wessling, Germany) for renal and upper ureteral stones ≤ 20 mm were retrospectively reviewed. All patients underwent CT urography prior to SWL. The cohort was subdivided into three groups according to stone attenuation values in Hounsfield Units (HU). Group I; HU < 500 (n = 20), group II; HU 500-1000 (n = 51) and group III; HU ≥ 1000 (n = 180). The parameters included for multivariate analysis were stone size, location, multiplicity, stone attenuation value, number of shocks and stone clearance rate by 3 months. The ancillary treatments were ureteroscopy (URS), ureteral stenting and hospital readmission for pain or fever. A total of 251 patients were included in the study. The overall SWL success rate was 92.4%. Mean stone size was 10.9 ± 2.1, 11.6 ± 3 and 11.4 ± 3.6 mm and mean stone attenuation values were 364 ± 125, 811 ± 154 and 1285 ± 171 HU for groups I, II and III respectively. The stone clearance rates by 3 months were 96%, 92% and 88.4% for groups I, II and III respectively. On subgroup analysis, group III required ancillary treatments in 70% of patients whereas group I, II, did not require any ancillary treatments. On multivariate analysis, stone multiplicity, stone location (lower calyceal stones) and HU were independent significant predictors for the need for ancillary treatments after SWL (p values < 0.05). Patients with stone attenuation value (HU) > 1000, multiple stones and/or lower calyceal stones have higher risk to necessitate ancillary treatments after SWL. These patients would likely benefit from upfront endoscopic lithotripsy for treating symptomatic renal or upper ureteral stones.

The effect of stone and patient characteristics in predicting extra-corporal shock wave lithotripsy success rate: A cross sectional study

IntroductionWe determine the effect of patient characteristics (age, sex, and body mass index BMI) and stone characteristics (density, location, and size) by non-contrast computed tomography of the kidneys, ureters, and bladder (CT-KUB) in predicting the success of extracorporeal shock wave lithotripsy (ESWL) in the treatment of kidney and ureteric stones. We present this study to further enrich the knowledge of physicians towards the effect of different patient characteristics upon predicting extra-corporal shock wave lithotripsy success rates. MethodsWe evaluated 155 patients who received ESWL for renal and ureteric stone measuring 3–20 mm (mm), over a 3-month period. The stone size in millimeters, density in Hounsfield units (HU) and its location was determined on pre-treatment CT-KUB. ESWL was successful if post-treatment residual renal stone fragments were ≤3 mm and for ureteric stones should be totally cleared. ResultsThe overall success of ESWL treatment was observed in 65.8% of the 155 patients. There was no significant difference seen when the effect of patients age, sex and BMI were studied with ESWL outcome with P values were 0.155, 0.101 and 0.415 respectively. Also, stone location either in the kidney or ureter has no statistically significant effect on ESWL response rate. while stone density and size determined on CT KUB have statistically significant effect on the success rate of ESWL with a P-value of 0.002 and 0.000 respectively. ConclusionsThis study shows that determination of stone density and stone size on CT KUB pre ESWL can help to predict the outcome of ESWL. We propose that stone density <500 HU and stone size < 5 mm are highly likely to result in successful ESWL.

Impact of Case Volume on Shock Wave Lithotripsy Outcomes: Data from the National Shock Wave Lithotripsy Database of New Zealand.

Purpose: To assess the impact of individual operator case volume on shock wave lithotripsy (SWL) treatment outcomes in more than 9000 stone cases over a 20-year period in New Zealand. Materials and Methods: Stone cases treated with SWL on the Mobile Medical Technology (MMT) vehicle between June 19, 1995, and December 1, 2014, were identified. Data collection was undertaken prospectively for patient, stone, and treatment characteristics, and retrospectively for treatment outcomes. Multivariate analysis using binary logistic regression was undertaken to assess whether radiographer stone case volume (stones/year) was an independent predictor of SWL success (stone free or clinically insignificant residual fragments ≤4 mm at follow-up). Results: Sixteen radiographers delivered treatment to the included cohort (9039 stone cases), with a median case volume (stones/year) of 73 (range: 37-197) and median total of 425 stones treated (range: 71-1721). The two radiographers with highest case volumes achieved the highest success rates. Radiographer case volume (stones/year) was independently associated with SWL success (odds ratio [OR]: 1.004, 95% confidence interval [CI]: 1.003-1.005, p < 0.0001) and reduced need for post-SWL hospital admission (OR: 0.997, 95% CI: 0.994-1.000, p = 0.028), but there was no associated decrease in post-SWL urosepsis (OR: 0.999, 95% CI: 0.974-1.025, p = 0.941), perinephric hematoma (OR: 1.003, 95% CI: 0.985-1.020, p = 0.778), or need for auxiliary procedures (OR: 1.000, 95% CI: 0.998-1.002, p = 0.871). Conclusions: SWL success rates can be improved by increasing the frequency of cases performed by individual operators. In this multicenter cohort of more than 9000 stone cases treated over a 20-year period, the best outcomes were seen for those radiographers performing >150 cases per year.

Comparison of the results of shock wave lithotripsy with ultrasonic and fluoroscopic focus in pediatric age group; Fluoroscopic focusing how much is needed?

Aim: Shock wave lithotripsy (SWL) is a well-known technique used in the treatment of kidney stones since the early eighties. For successful SWL, accurate visualization of the shock waves is performed by ultrasound (US) or fluoroscope (FS) to fully focus the shock waves on the stone. In this study, we aimed to investigate the effect of US and FS methods used for focusing on stone in SWL treatment of renal stones in pediatric patients on side effect and treatment success.Material and Methods: Between January 2008 and January 2018, 495 children under 16 years of age who were treated with SWL using ultrasonic and fluoroscopic focusing were included in the study. Patients with fluoroscopic focus were classified as Group 1 and patients with ultrasonic focus were classified as Group 2. Demographic data, SWL parameters and success rates of the two groups were compared..Results: There was no significant difference between the demographic data, stone localization and stone sizes of the groups. SWL success rate was 90.5% in group 1 and 92.3% in group 2. There was no significant difference between the two groups in terms of success (p = 0.474). Complication rates were 0.2% (1 patient) and 0.4% (2 patients) in groups 1 and 2, respectively, and there was no statistically significant difference (p = 0.495). With increasing clinical experience, ultrasonic focusing rates have increased and fluoroscopic focusing rates have decreased over the years. Conclusion: In the pediatric age group, we recommend the use of ultrasonic focusing with the additional advantage of avoiding radiation, avoiding the fluoroscopic focusing method using ionized radiation for SWL. We believe that randomized prospective studies will be more informative and support our study.

Noncontrast Computed Tomography Parameters for Predicting Shock Wave Lithotripsy Outcome in Upper Urinary Tract Stone Cases.

Kidney stones are a major public health concern with continuously increasing worldwide prevalence. Shock wave lithotripsy (SWL) is the first line treatment choice for upper urinary tract calculi with ureteroscopy and has advantages of safety and noninvasiveness, but the treatment success rate of SWL is lower than that of other therapies. It is therefore important to identify predictive factors for SWL outcome and select a suitable treatment choice for patients with upper urinary tract calculi. In recent years, computed tomography (CT) has become the gold standard for diagnosis of upper urinary tract calculi. Several factors based on CT images, including skin-to-stone distance, mean stone density, stone heterogeneity index, and variation coefficient of stone density, have been reported to be useful for predicting SWL outcome. In addition, a new method of analysis, CT texture analysis, is reportedly useful for predicting SWL outcomes. This review aims to summarize CT parameters for predicting the outcome of shock wave lithotripsy in stone cases in the upper urinary tract.

Shock Wave Lithotripsy is More Effective for Residual Fragments after Percutaneous Nephrolithotomy than for Primary Stones of the Same Size: A Matched Pair Cohort Study

Aims: To compare the outcome of shock wave lithotripsy (SWL) on post-percutaneous nephrolithotomy (PCNL) residual fragments (RFs) versus primary stones of the same size through a matched pair study. Methods: Patients with a single 5-15 mm fragment 3 months after PCNL were enrolled (study group n = 59). The control group (n = 67) consisted of all adult patients with a single 5-15 mm renal stone. Results: The success rate of SWL was significantly higher in the study group (81.4 vs. 59.7%; p = 0.008; OR: 2.95). With a cutoff point of Hounsfield units (HU) 750: the success rate was significantly lower in patients with a stone HU ≥ 750 (OR: 3.488). This HU cutoff value had no effect on the outcome of SWL in patients with post-PCNL RF (p = 0.14). On the other hand, the outcome of SWL was significantly more favorable in control group when HU < 750 (p = 0.02). Conclusion: The success rate of SWL was 2.95-fold higher for post-PCNL RFs than in a stone burden-matched control group. The likelihood of stone clearance after SWL was 3.488-fold greater when HU was less than 750. This effect of HU was more prominent in patients receiving SWL for their primary stones while SWL was evenly effective on post PCNL RFs with different HUs.

Advanced non-contrasted computed tomography post-processing by CT-Calculometry (CT-CM) outperforms established predictors for the outcome of shock wave lithotripsy.

To evaluate the predictive value of advanced non-contrasted computed tomography (NCCT) post-processing using novel CT-calculometry (CT-CM) parameters compared to established predictors of success of shock wave lithotripsy (SWL) for urinary calculi. NCCT post-processing was retrospectively performed in 312 patients suffering from upper tract urinary calculi who were treated by SWL. Established predictors such as skin to stone distance, body mass index, stone diameter or mean stone attenuation values were assessed. Precise stone size and shape metrics, 3-D greyscale measurements and homogeneity parameters such as skewness and kurtosis, were analysed using CT-CM. Predictive values for SWL outcome were analysed using logistic regression and receiver operating characteristics (ROC) statistics. Overall success rate (stone disintegration and no re-intervention needed) of SWL was 59% (184 patients). CT-CM metrics mainly outperformed established predictors. According to ROC analyses, stone volume and surface area performed better than established stone diameter, mean 3D attenuation value was a stronger predictor than established mean attenuation value, and parameters skewness and kurtosis performed better than recently emerged variation coefficient of stone density. Moreover, prediction of SWL outcome with 80% probability to be correct would be possible in a clearly higher number of patients (up to fivefold) using CT-CM-derived parameters. Advanced NCCT post-processing by CT-CM provides novel parameters that seem to outperform established predictors of SWL response. Implementation of these parameters into clinical routine might reduce SWL failure rates.

Extracorporeal Shock Wave Lithotripsy success rate for upper and lower ureteric stones in Azadi-teaching (Dohuk) hospital in Kurdistan Region-Iraq

Extracorporeal Shock Wave Lithotripsy success rate for upper and lower ureteric stones in Azadi-teaching (Dohuk) hospital in Kurdistan Region-Iraq

A prospective randomised double-blind placebo-controlled trial to assess the effect of diuretics on shockwave lithotripsy of calculi

ObjectiveTo assess the effect of diuretics with shockwave lithotripsy (SWL) on the treatment of renal and upper ureteric calculi. Patients and methodsAdult patients with a solitary non-obstructive radio-opaque renal or upper ureteric calculus with normal renal function were included. They were prospectively randomised to receive either SWL with placebo or SWL with diuretics (40mg parenteral furosemide) in a double-blind manner with a sample size of 48 patients in each arm. The primary outcomes were the SWL success and failure rates. The secondary outcomes were the number of shocks and sessions. ResultsComplete fragmentation was achieved in 89.6% of the patients in the furosemide arm as compared to 81.3% in the placebo arm. Clearance was achieved in 77.1% of the patients in the furosemide arm as compared to 70.8% in the placebo arm. The number of shocks and the number of sessions were higher in the placebo arm. These differences were not statistically significant. ConclusionThe use of diuretics along with SWL treatment of renal and upper ureteric calculi does not show a statistically significant improvement in fragmentation or clearance.

Has the pelvic renal stone position inside the upper loop of JJ stent any influence on the extracorporeal shock wave lithotripsy results?

Background JJ stents are often encountered in patients with pelvic renal stones referred for shock wave lithotripsy, most of them being placed either for obstructive renal pelvic stones or for ureteric stones mobilized retrograde during the JJ stent insertion. The aim of the study was to determine whether the relative stone position in the upper loop of the JJ stent during extracorporeal shock wave lithotripsy (SWL) influences the efficiency of the procedure. The study was designed as a prospective cohort study on 162 patients addressing the same urological department, with single renal pelvic stone (primary or mobilized to the renal pelvis during the insertion of JJ stent), smaller than 15 mm, with JJ stent, treated by SWL using a second generation spark gap lithotripter, 18 kV, 3000 waves/session. Patients were divided in three groups according to the relative position of the stone to the upper loop of the JJ stent as appears on plain X-ray: stone-inside-loop, loop-crossing-stone and stone-outside the loop. The SWL success rate was the primary outcome of the study. p Value, Chi square and Kruskal–Wallis tests were used for statistical analysis.ResultsFor stone-inside-loop cases, SWL efficiency was 22.7 versus 42 % for all the other cases (p = 0.002). Other factors for decreased SWL success rate were: higher stone radio-opacity, larger JJ of stent and obese patients. Study limitation is represented by the relative small study group and by the evaluation of stone density using plain X-ray instead of computer tomography.ConclusionsFor pelvic renal stones having the same density characteristics studied by plain X-ray, the SWL efficiency is lower in stone-inside-loop cases comparing with the other positions. The overall stone free rate for renal pelvic stones could be explained by the second generation lithotripter used for all procedures.

Computed Tomography-Based Novel Prediction Model for the Outcome of Shockwave Lithotripsy in Proximal Ureteral Stones.

Computed tomography (CT) is one of the most commonly used diagnostic modalities for urinary stone disease. In this study we developed a CT and clinical parameter-based prediction model for shockwave lithotripsy (SWL) outcome in proximal ureteral stones. Data from 223 patients with single proximal ureteral stones treated with SWL between January 2009 and January 2015 were reviewed retrospectively. Clinical parameters including age, sex, body weight, and body mass index (BMI) were analyzed in combination with stone-related CT parameters (stone diameter, height, volume, location, Hounsfield units [HU], stone-to-skin distance [SSD]), and secondary signs (hydronephrosis, perinephric edema, and rim sign). Based on the cutoff values determined by c-statistics, a scoring system for the prediction of SWL outcome was developed. The success rate was 65.9% (147/223), and in a univariate analysis body weight, BMI, SSD (vertical, horizontal), HU, stone diameter, height, volume, and all secondary signs were significantly associated with the success of SWL. However, on multivariate analysis only BMI (odds ratio [OR] = 1.322, confidence interval [CI] 1.156, 1.512, p = 0.00), stone diameter (OR = 1.397, CI 1.259, 1.551, p = 0.00), and perinephric edema (grade 0-1 vs 3-4, OR = 2.831, CI 1.032, 7.764, p = 0.043) were independent predictors of SWL success. The prediction model based on the logistic regression analysis was as follows: SWL success = 1/[1 + exp (-10.165 + 0.279 × [BMI] + 0.334 × [diameter] + 1.040 [perinephric edema])], having an area under the curve of 0.881. In the prediction model based on these parameters, scores of 0, 1, 2, and 3 correlated with SWL success rates of 98.5%, 65.7%, 31.4%, and 0%, respectively. BMI, stone diameter, and perinephric edema were independent predictors of SWL outcome and a prediction model based on these parameters will facilitate decision-making for SWL in proximal ureteral stones.

Is scoring system of computed tomography based metric parameters can accurately predicts shock wave lithotripsy stone-free rates and aid in the development of treatment strategies?

Objective:The objective was to determine the predicting success of shock wave lithotripsy (SWL) using a combination of computed tomography based metric parameters to improve the treatment plan.Patients and Methods:Consecutive 180 patients with symptomatic upper urinary tract calculi 20 mm or less were enrolled in our study underwent extracorporeal SWL were divided into two main groups, according to the stone size, Group A (92 patients with stone ≤10 mm) and Group B (88 patients with stone >10 mm). Both groups were evaluated, according to the skin to stone distance (SSD) and Hounsfield units (≤500, 500–1000 and >1000 HU).Results:Both groups were comparable in baseline data and stone characteristics. About 92.3% of Group A rendered stone-free, whereas 77.2% were stone-free in Group B (P = 0.001). Furthermore, in both group SWL success rates was a significantly higher for stones with lower attenuation <830 HU than with stones >830 HU (P < 0.034). SSD were statistically differences in SWL outcome (P < 0.02). Simultaneous consideration of three parameters stone size, stone attenuation value, and SSD; we found that stone-free rate (SFR) was 100% for stone attenuation value <830 HU for stone <10 mm or >10 mm but total number SWL sessions and shock waves required for the larger stone group were higher than in the smaller group (P < 0.01). Furthermore, SFR was 83.3% and 37.5% for stone <10 mm, mean HU >830, SSD 90 mm and SSD >120 mm, respectively. On the other hand, SFR was 52.6% and 28.57% for stone >10 mm, mean HU >830, SSD <90 mm and SSD >120 mm, respectively.Conclusion:Stone size, stone density (HU), and SSD is simple to calculate and can be reported by radiologists to applying combined score help to augment predictive power of SWL, reduce cost, and improving of treatment strategies.

Strategies to optimize shock wave lithotripsy outcome: Patient selection and treatment parameters

Shock wave lithotripsy (SWL) was introduced in 1980, modernizing the treatment of upper urinary tract stones, and quickly became the most commonly utilized technique to treat kidney stones. Over the past 5-10 years, however, use of SWL has been declining because it is not as reliably effective as more modern technology. SWL success rates vary considerably and there is abundant literature predicting outcome based on patient- and stone-specific parameters. Herein we discuss the ways to optimize SWL outcomes by reviewing proper patient selection utilizing stone characteristics and patient features. Stone size, number, location, density, composition, and patient body habitus and renal anatomy are all discussed. We also review the technical parameters during SWL that can be controlled to improve results further, including type of anesthesia, coupling, shock wave rate, focal zones, pressures, and active monitoring. Following these basic principles and selection criteria will help maximize success rate.

1823 EFFECT OF AN ULTRASONIC TARGETING METHOD FOR KIDNEY AND PROXIMAL URETER STONES ON THE SUCCESS RATE OF SHOCK WAVE LITHOTRIPSY

You have accessJournal of UrologyStone Disease: SWL, Ureteroscopy or Percutaneous Stone Removal (III)1 Apr 20131823 EFFECT OF AN ULTRASONIC TARGETING METHOD FOR KIDNEY AND PROXIMAL URETER STONES ON THE SUCCESS RATE OF SHOCK WAVE LITHOTRIPSY Atsushi Okada, Kazumi Taguchi, Ryosuke Ando, Yukihiro Umemoto, Yasunori Itoh, Takahiro Yasui, Shoichi Sasaki, Kenjiro Kohri, and Shuzo Hamamoto Atsushi OkadaAtsushi Okada Nagoya, Japan More articles by this author , Kazumi TaguchiKazumi Taguchi Nagoya, Japan More articles by this author , Ryosuke AndoRyosuke Ando Nagoya, Japan More articles by this author , Yukihiro UmemotoYukihiro Umemoto Nagoya, Japan More articles by this author , Yasunori ItohYasunori Itoh Nagoya, Japan More articles by this author , Takahiro YasuiTakahiro Yasui Nagoya, Japan More articles by this author , Shoichi SasakiShoichi Sasaki Nagoya, Japan More articles by this author , Kenjiro KohriKenjiro Kohri Nagoya, Japan More articles by this author , and Shuzo HamamotoShuzo Hamamoto Nagoya, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2186AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Shock wave lithotripsy (SWL) is the first-line treatment for urinary tract stones, particularly those in the kidney and proximal ureter, because of its simplicity and ease of operation. However, the success rate of SWL may not be as high as endoscopic surgery. At the AUA Annual Meeting 2012, we reported an SWL technology training program that significantly improved the SWL success rate. In the present study, we examined the influence of ultrasonic targeting for kidney and proximal ureter stones, which is a main component of the technical training process, on SWL treatment results. METHODS A total of 448 patients required SWL treatment of kidney and proximal ureter stones in Nagoya City University Hospital from January 2004 to June 2011. A Lithotripter S (Dornier MedTech, Wessling, Germany) was used to perform these treatments. The patients were divided into 2 groups according to the targeting method: the x-ray alone group (Xp group; n = 370) and the ultrasonography-combined group (US group; n = 78). Respective success rates were retrospectively analyzed. RESULTS There was no significant difference indicated in the medical attendants-estimated success rates of the 2 groups immediately after completion of SWL completion indicated no significant difference (81.4% and 87.2% in the Xp and US groups, respectively). However, the true success rates as determined 3 months later were 69.5% and 84.6% in Xp and US groups, respectively; a significant difference was observed (p = 0.007). In addition, the shock wave strength reported in the US group was significantly lower than that of the Xp group during the treatment of renal stones (p = 0.002), while a significantly higher number of shock waves were required to crush ureteral stones was reported in the US group compared with the Xp group (p = 0.021). CONCLUSIONS The ability of US to precisely visualize stone fragmentation allows clinicians to deliver optimized shock wave intensity and shock number, allowing for lower intensity shocks for kidney stones and an adequate number of shocks for ureteral stones. This flexibility reduces patient stress and increases efficacy of lithotripsy. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e749 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Atsushi Okada Nagoya, Japan More articles by this author Kazumi Taguchi Nagoya, Japan More articles by this author Ryosuke Ando Nagoya, Japan More articles by this author Yukihiro Umemoto Nagoya, Japan More articles by this author Yasunori Itoh Nagoya, Japan More articles by this author Takahiro Yasui Nagoya, Japan More articles by this author Shoichi Sasaki Nagoya, Japan More articles by this author Kenjiro Kohri Nagoya, Japan More articles by this author Shuzo Hamamoto Nagoya, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Kidney Stone Size and Hounsfield Units Predict Successful Shockwave Lithotripsy in Children

To define the preoperative kidney and stones characteristics on noncontrast-enhanced computed tomography that affect the success of extracorporeal shockwave lithotripsy (SWL) for treatment of renal calculi in pediatric patients. From 2005 to 2011, 57 children (age<16 years) with documented preoperative noncontrast-enhanced computed tomography scans underwent SWL for treatment of renal stones and were included in the present study. Stone size, site, multiplicity, average skin-to-stone distance, stone attenuation value, and kidney morphology were determined from the preoperative noncontrast-enhanced computed tomography scans. Success was defined as radiographically stone-free status at the 3-month follow-up examination after a single lithotripsy session without the need for additional sessions or ancillary procedures. After a single session of SWL, 24 children (42.1%) were stone free on the 3-month follow-up imaging study without the need for additional SWL sessions. Treatment failed in 33 patients (57.9), with residual fragments in 30 children, of whom 29 required repeat SWL, and 3 with stones that were considered unchanged and were finally treated with percutaneous nephrolithotomy. Logistic regression analysis revealed that stone attenuation in Hounsfield units (HU) and stone length were the only significant predictors of success. When the HU were stratified into 2 groups of≤600 and >600 HU, the SWL success rate was 82.1% and 20%, respectively (P=.023). When length was stratified as≤12mm and >12mm, the stone-free rate was 58.6% and 25.1%, respectively (P= .016). Stone attenuation≤600 HU and stone length≤12mm were significant independent predictors of SWL success in children.

Optimal Shock Wave Rate for Shock Wave Lithotripsy in Urolithiasis Treatment: A Prospective Randomized Study

PurposeWe aimed to compare the effects of a fast shock wave rate (120 shocks per minute) and a slow shock wave rate (60 shocks per minute) on the shock wave lithotripsy (SWL) success rate, patient's pain tolerance, and complications.Materials and MethodsA total of 165 patients with radiopaque renal pelvis or upper ureter stones were included in the study. Patients were classified by use of a random numbers table. Group I (81 patients) received 60 shock waves per minute and group II (84 patients) received 120 shock waves per minute. For each session, the success rate, pain measurement, and complication rate were recorded.ResultsNo statistically significant differences were observed in the patients according to age, sex, body mass index, stone size, side, location, total energy level, or number of shocks. The success rate of the first session was greater in group I than in group II (p=0.002). The visual analogue pain scale was lower in group I than in group II (p=0.001). The total number of sessions to success and the complication rate were significantly lower in group I than in group II (p=0.001).ConclusionsThe success rate of SWL is dependent on the interval between the shock waves. If the time between the shock waves is short, the rate of lithotripsy success decreases, and the pain measurement score and complications increase. We conclude slow SWL is the optimal shock wave rate.

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

IntroductionThe 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 methodsThe 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 ≤2mm 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. ResultsThe single-session SWL success rate at 3 weeks was 49.1%. Stone size <8mm, stone area <30mm2, stone location (mid- and distal ureter), stone density <1000HU 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. ConclusionsStone 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.