Simple and practical nomograms for predicting the stone-free rate after shock wave lithotripsy in patients with a solitary upper ureteral stone

Role of Noncontrast Computed Tomography Parameters in Predicting the Outcome of Extracorporeal Shock Wave Lithotripsy for Upper Urinary Stones Cases: A Meta-analysis

RATIONALE

Extracorporeal shock wave lithotripsy (ESWL) is widely considered the primary approach for managing urinary tract stones. This study aimed to assess the predictive factors associated with non-contrast computed tomography (NCCT)-based parameters of upper urinary stones in relation to the outcomes of ESWL.

MATERIALS AND METHODS

A systematic search was conducted in PubMed, ScienceDirect, Web of Science, and Cochrane Library to identify all relevant studies published up to June 3, 2023. Several NCCT-based parameters to predict ESWL outcomes, comprised of mean stone density (MSD), skin-to-stone distance (SSD), and stone size, were extracted and analyzed using Review Manager software.

RESULTS

Out of 979 publications screened, a total of 39 publications, involving 7869 patients, were enrolled in the analysis. The pooled estimate demonstrated significant differences between MSD, and stone size between successful and failure of stone fragmentation groups, in which lower values of these parameters are associated with successful ESWL outcomes.

CONCLUSION

The results from the current study suggested that lower NCCT parameters, notably MSD, SSD, and stone size, are significantly associated with successful ESWL outcome. However, additional large-scale prospective studies are required to utilize these parameters effectively, and the optimal cutoff value should be determined.

Which frequency is better for pediatric shock wave lithotripsy? Low intermediate or high: A systematic review and meta-analysis

Background

To explore the optimal frequency for pediatric extracorporeal shock wave lithotripsy (ESWL) in the treatment of upper urinary stones.

Methods

A systematic literature search was undertaken using PubMed, Embase, Web of Science and Cochrane Central Register of Controlled Trials databases to identify eligible studies published before January 2023. Primary outcomes were perioperative efficacy parameters, including ESWL time, anesthesia time for ESWL sessions, success rates after each session, additional interventions needed, and treatment sessions per patient. Secondary outcomes were postoperative complications and efficiency quotient.

Results

Four controlled studies involving 263 pediatric patients were enrolled in our meta-analysis. In the comparison between the low-frequency and intermediate-frequency groups, we observed no significant difference as regards anesthesia time for ESWL session (WMD = −4.98, 95% CI −21.55∼11.58, p = 0.56), success rates after ESWL sessions (first session: OR = 0.02 95%CI −0.12∼0.17, p = 0.74; second session: OR = 1.04 95%CI 0.56∼1.90, p = 0.91; third session: OR = 1.62 95%CI 0.73∼3.60, p = 0.24), treatment sessions needed (WMD = 0.08 95%CI −0.21∼0.36, p = 0.60), additional interventions after ESWL (OR=0.99 95%CI 0.40∼2.47, p = 0.99) and rates of Clavien grade 2 complications (OR = 0.92 95%CI 0.18∼4.69, p = 0.92). However, the intermediate-frequency group may exhibit potential benefits in Clavien grade 1 complications. In the comparison between intermediate-frequency and high-frequency, the eligible studies exhibited higher success rates in the intermediate-frequency group after the first session, the second session and the third session. More sessions may be required in the high-frequency group. With respect to other perioperative, postoperative parameters and major complications, the results were similar.

Conclusions

Intermediate-frequency and low-frequency had similar success rates and seemed to be the optimal frequency for pediatric ESWL. Nevertheless, future large-volume, well-designed RCTs are awaited to confirm and update the findings of this analysis.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022333646.

Development and validation of a predictive model for stone-free failure after extracorporeal shockwave lithotripsy in patients with ureteral stone in a large prospective cohort

PURPOSE

To develop and validate a nomogram for predicting stone-free failure after shock wave lithotripsy (SWL) guided by ultrasound in patients with ureteral stones.

METHODS

The development cohort consisted of 1698 patients who underwent SWL guided by ultrasound at our center from June 2020 through August 2021. Multivariate unconditional logistic regression analysis was used for building a predictive nomogram with regression coefficients. An independent validation cohort consisted of 712 consecutive patients from September 2020 through April 2021. The performance of the predictive model was assessed in regard to discrimination, calibration, and clinical usefulness.

RESULTS

Predictors of stone-free failure included distal stone location (odds ratio = 1.540, P < 0.001), larger stone size (odds ratio = 1.722, P < 0.001), higher stone density (odds ratio = 1.722, P < 0.001), larger skin to stone distance (SSD) (odds ratio = 1.058, P < 0.001), and higher grade of hydronephrosis (odds ratio = 1.755, P = 0.010). For the validation cohort, the model showed good discrimination with an area under the receiver operating characteristic curve of 0.925 (95% confidence interval, 0.898, 0.953) and good calibration (unreliability test, P = 0.412). Decision curve analysis demonstrated that the model was also clinically useful.

CONCLUSIONS

This study demonstrated that stone location, stone size, stone density, SSD, and hydronephrosis grade were significant predictors of stone-free failure after SWL guided by ultrasound in patients with ureteral stones. This may guide clinical practice.

Non-contrast computed tomography-based factors in predicting ESWL success: A systematic review and meta-analysis

PURPOSE

We assessed the efficacy of some predictive factors that can be measured with non-contrast computed tomography and may affect ESWL success with a systematic review and meta-analysis.

MATERIALS AND METHODS

All data sources were broadly investigated up to April 2022. Data were extracted from the relevant studies and analyzed with RevMan software. In a random effects model, standard mean difference (SMD) and risk ratio (RR) values were given with 95% confidence intervals.

RESULTS

In total, pooled analysis included 7148 patients in 43 studies. The combined effect estimate showed significant differences between the ESWL success and ESWL failure groups in terms of Hounsfield unit (HU), Hounsfield density (HD), skin to stone distance (SSD), ureteral wall thickness (UWT), stone volume, stone area, abdominal fat parameters, diameter of proximal ureter, and hydronephrosis. However, perinephric stranding and renal cortical thickness were not found to be statistically significant between the study groups.

CONCLUSIONS

HU, HD, SSD, UWT, stone volume, stone area, abdominal fat parameters, diameter of proximal ureter and hydronephrosis are effective factors for prediction of ESWL success. It is important to decide on treatment before the procedure for stones with appropriate diameter for ESWL.

A Comparative Study of Stone Re-Treatment after Lithotripsy

The high recurrence rate has always been a problem associated with urolithiasis. This study aimed to explore the effectiveness of single interventions, combined therapies, and surgical and nonsurgical interventions. Herein, three lithotripsy procedures—extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), and ureteroscopic lithotripsy (URSL)—were assessed and a retrospective cohort was selected in order to further analyze the association with several risk factors. Firstly, a population-based cohort from the Taiwan National Health Insurance Research Database (NHIRD) from 1997 to 2010 was selected. In this study, 350 lithotripsy patients who underwent re-treatment were followed up for at least six years to compare re-treatment rates, with 1400 patients without any lithotripsy treatment being used as the comparison cohort. A Cox proportional hazards regression model was applied. Our results indicate that the risk of repeat urolithiasis treatment was 1.71-fold higher in patients that received lithotripsy when compared to patients that were not treated with lithotripsy (hazard ratio (HR) 1.71; 95% confidence interval (CI) = 1.427−2.048; p < 0.001). Furthermore, a high percentage of repeated treatment was observed in the ESWL group (HR 1.60; 95% CI = 1.292−1.978; p < 0.001). Similarly, the PCNL group was also independently associated with a high chance of repeated treatment (HR 2.32; 95% CI = 1.616−3.329; p < 0.001). Furthermore, age, season, level of care, and Charlson comorbidities index (CCI) should always be taken into consideration as effect factors that are highly correlated with repeated treatment rates.

Atlas of scoring systems, grading tools and nomograms in Endourology: A comprehensive overview from The TOWER Endourological Society research group

INTRODUCTION

With an increase in the prevalence of kidney stone disease (KSD), there has been a universal drive to develop reliable and user-friendly tools such as grading systems and predictive nomograms. An atlas of scoring systems, grading tools and nomograms in Endourology is provided in this paper.

METHODS

A comprehensive search of world literature was performed to identify nomograms, grading systems and classification tools in endourology related to KSD. Each of these were reviewed by the authors and have been evaluated in a narrative format with details on those which are externally validated and their respective citation count on google scholar.

RESULTS

A total of 54 endourological tools have been described in our atlas of endourological scoring systems, grading tools and nomograms. Of the tools, 23 (43%) are published in the last 3 years showing an increasing interest in this area. This includes 5 for percutaneous nephrolithotomy (PCNL), 6 for flexible ureteroscopy (fURS), 3 for semi-rigid URS (sURS), 9 for shockwave lithotripsy (SWL), 2 for stent encrustations, 3 for intra-operative appearance at the time of URS and 3 to classify intra-operative ureteric injury. There were 3 tools for renal colic assessment, one each for prediction of future stone event, stone classification and stone impaction and 2 for need of emergency intervention in ureteric stone. While 2 tools are related to stone recurrence, 6 are related to post-procedural complications. There are now 2 tools for simulation in endourology and 5 for patient reported outcome measures (PROMS).

CONCLUSIONS

A number of reliable and established tools exist currently in endourology. Each of these offers their own respective advantages and disadvantages. While nomograms and scoring systems can help in the decision making, these must be tailored to individual patients based on their specific clinical scenarios, expectations and informed consent.

Prediction of stone-free rates following extracorporeal shockwave lithotripsy in a contemporary cohort of patients with stone densities exceeding 1000 HU

Purpose: Nephrolithiasis is a common urologic problem, and its incidence is increasing. Shockwave Lithotripsy (SWL) has better results for patients with stones < 1000 HU. We attempted to identify SWL stone-free (SF) predictors for > 1000 HU stones.Methods: From January 2013 to September 2019, patient shared decision consecutive SWL for the treatment of a single > 1000 HU renal stone diagnosed by non-contrast computed tomography (NCCT). Endpoints: Fragmentation and SF or clinically insignificant residual fragments ≤ 4 mm at 4 weeks. Age, gender, stone side, location, size and density, number and average energy (Joules) of shocks were explored on uni- and multivariate regression analysis.Results: All sixty-one patients included were diagnosed with renal stone between 5 and 20 mm (maximum length) and underwent one SWL session only: 62.3% males, median age 48 (21-80) years, mean stone size 9.43 ± 2.9 mm (6.0-20.0), mean density 1210 ± 135 HU (1000-1558). There were 39 (63.9%) cases of SF, 16 (26.2%) of partial success and six (9.8%) of no success. Stone size was the only independent predictor of fragmentation, OR = 1.83, 95% CI = 1.32-2.55, p = 0.0003, and SF OR = 1.91, 95% CI = 1.31-2.78, p = 0.008. The best discriminatory stone size on ROC analysis was 1 cm.Conclusion: Stone size was the only significant success predictor in our cohort, with 76% SF rate for stones < 1 cm in 4 weeks follow-up, supporting that renal stones > 1000 HU may be suitable to SWL.

Factors affecting success in the treatment of proximal ureteral stones larger than 1 cm with extracorporeal shockwave lithotripsy in adult patients

The aim of the study was to analyze the factors predicting success for the treatment of proximal ureteral stones larger than 1 cm with extracorporeal shockwave lithotripsy (SWL) in adult patients. Between January 2014 and December 2018, 480 adult patients in total underwent SWL and data were retrospectively evaluated. Patients with multiple ureteral stones, solitary kidney, congenital abnormality, skeletal system abnormality, history of previous urinary system surgery and SWL, renal insufficiency, patients who could not tolerate SWL and pediatric patients were excluded from the study. The remaining 415 patients were divided into two groups as success (Group 1, n = 307) and failure (Group 2, n = 108). The overall success rate was 73.9%. The values of stone size, Hounsfield Unit (HU), skin to stone distance (SSD), ureteral wall thickness (UWT), proximal ureter diameter, renal pelvis diameter, hydronephrosis grade, and duration of renal colic were significantly higher in Group 2 compared to Group 1. In binary logistic regression analyses, HU, UWT, and proximal ureter diameter were found to be independent predictors. HU, UWT, and proximal ureter diameter had sensitivity and specificity of 92-92%, 88-23%, and 87-46%, with cutoff values of 740 HU, 2.5 mm and 8.5 mm, respectively. The area under the curve values were 0.96, 0.97, and 0.96 for HU, UWT, and proximal ureter diameter, respectively. The CT-based parameters, including HU, UWT, and proximal ureter diameter are independent predictive factors with excellent accuracy for the treatment of proximal ureteral stones larger than 1 cm with SWL in adult patients. Based on these factors, SWL can be considered for proximal ureteral stones larger than 1 cm.

Development and validation of a prediction model for failed shockwave lithotripsy of upper urinary tract calculi using computed tomography information: the S3HoCKwave score

Purpose

To develop and validate a new clinical prediction model that accurately predicts the failure of shockwave lithotripsy (SWL) using information obtained from non-contrast-enhanced computed tomography (NCCT).

Methods

This multicentre retrospective cohort study consecutively enrolled patients diagnosed with upper urinary tract calculi by NCCT at five hospitals in Japan from January 1, 2006 to December 31, 2016. Among the candidate predictors, we selected the six most significant predictors a priori. The main outcome was SWL failure after three sessions. Model calibration was evaluated by the calibration slope and the Hosmer–Lemeshow test. Discrimination was evaluated by the receiver-operating characteristic curves and the area under the curve (AUC). A multivariable logistic regression analysis was performed; based on the estimated β coefficients, predictive scores were generated.

Results

Of 2695 patients, 2271 were included. Patients were divided into the development cohort (1666 patients) and validation cohort (605 patients) according to geographical factors. We developed a clinical prediction model with scores ranging from 0 to 49 points. We named the prediction model the S₃HoCKwave score based on the initials of the predictors (sex, skin-to-stone distance, size, Hounsfield units, colic, and kidney or ureter). As a result of internal validation, the optimism-corrected AUC was 0.72. In the validation cohort, the Hosmer–Lemeshow test did not show statistical significance (P = 0.33), and the AUC was 0.71 (95% confidence interval 0.65–0.76).

Conclusions

The S₃HoCKwave score is easy to understand, has a relatively high predictive value, and allows clinicians to make appropriate treatment selections.

Electronic supplementary material

The online version of this article (10.1007/s00345-020-03125-y) contains supplementary material, which is available to authorized users.

The usefulness of the maximum Hounsfield units (HU) in predicting the shockwave lithotripsy outcome for ureteral stones and the proposal of novel indicators using the maximum HU

Computed tomography (CT) attenuation value of ureteral stones is one of the predictors of shockwave lithotripsy (SWL) outcome. It is common to use the mean Hounsfield units (HU) to describe the CT attenuation value. However, an observer bias can occur when measuring the mean HU in the conventional method. On the other hand, our way to obtain only the maximum HU is simpler and less biased. We retrospectively evaluated 464 patients with ureteral stones who underwent SWL and compared predictive accuracy of various factors including maximum and mean HU. Results were determined after a single SWL. Predictors of SWL success were examined by the statistical analysis of successful and failed groups. 324 of the 464 patients who underwent SWL were stone-free after a single SWL. Significant differences were found in factors related to CT attenuation value and stone size. As a result of receiver operating characteristic analysis, it was found that maximum HU and mean HU, major diameter and volume have equivalent prediction accuracy, respectively. Multivariate analysis revealed that maximum HU and major diameter were included in independent predictors. We also examined the new original indicators using maximum HU and major diameter. Stone-resistant probability obtained from the logistic model and Maximum HU and Major diameter Index obtained by multiplying maximum HU by major diameter were useful for predicting SWL success, respectively. In conclusion, maximum HU and mean HU have equivalent predictive accuracy, and maximum HU is easier to measure and less biased than mean HU.

Can intervals in extracorporeal shock wave lithotripsy sessions affect success in the treatment of upper ureteral stones?

Introduction

Managing upper ureteral stones with shock wave lithotripsy (SWL) has been done for many years. However, no conclusive data have been found on the intervals required between repeated SWL sessions.

Aim

To identify the most optimal intervals between SWL sessions.

Material and methods

Between September 2015 and December 2016, 80 patients undergoing elective outpatient lithotripsy who required repeated SWL sessions for ureteral stones were evaluated. These patients were categorised into two groups according to different SWL session intervals. The intervals between SWL sessions (n = 40) for the first group lasted one day, whereas those for the second group (n = 40) lasted 1 week. The data recorded during SWL included visual analogue scale (VAS) scores, total number of shocks, total energy used and number of sessions. The stone clearance rates, number of urinary tract infections, complication rates and VAS scores were compared between the two groups.

Results

All patients’ clinical outcomes after SWL therapy are shown in Table I. The stone clearance rate for group 1 was 70%, whereas that for group 2 was 72.5% (p = 0.805). Additionally, the number of urinary tract infections, complications and VAS scores were similar for both groups. In group 1, 3 patients had steinstrasse, two suffered from severe renal colic, and one had a urinary tract infection. In group 2, 3 patients endured steinstrasse, and 2 patients experienced severe renal colic during the study.

Conclusions

Short-interval SWL sessions are safe and effective for treating upper ureteral stones, and such sessions do not increase complication rates.