Ureteral wall thickness at the impacted ureteral stone site: a critical predictor for success rates after SWL

Management of urinary stones: state of the art and future perspectives by experts in stone disease

AIM

To present state of the art on the management of urinary stones from a panel of globally recognized urolithiasis experts who met during the Experts in Stone Disease Congress in Valencia in January 2024. Options of treatment: The surgical treatment modalities of renal and ureteral stones are well defined by the guidelines of international societies, although for some index cases more alternative options are possible. For 1.5 cm renal stones, both m-PCNL and RIRS have proven to be valid treatment alternatives with comparable stone-free rates. The m-PCNL has proven to be more cost effective and requires a shorter operative time, while the RIRS has demonstrated lower morbidity in terms of blood loss and shorter recovery times. SWL has proven to be less effective at least for lower calyceal stones but has the highest safety profile. For a 6mm obstructing stone of the pelviureteric junction (PUJ) stone, SWL should be the first choice for a stone less than 1 cm, due to less invasiveness and lower risk of complications although it has a lower stone free-rate. RIRS has advantages in certain conditions such as anticoagulant treatment, obesity, or body deformity. Technical issues of the surgical procedures for stone removal: In patients receiving antithrombotic therapy, SWL, PCN and open surgery are at elevated risk of hemorrhage or perinephric hematoma. URS, is associated with less morbidity in these cases. An individualized combined evaluation of risks of bleeding and thromboembolism should determine the perioperative thromboprophylactic strategy. Pre-interventional urine culture and antibiotic therapy are mandatory although UTI treatment is becoming more challenging due to increasing resistance to routinely applied antibiotics. The use of an intrarenal urine culture and stone culture is recommended to adapt antibiotic therapy in case of postoperative infectious complications. Measurements of temperature and pressure during RIRS are vital for ensuring patient safety and optimizing surgical outcomes although techniques of measurements and methods for data analysis are still to be refined. Ureteral stents were improved by the development of new biomaterials, new coatings, and new stent designs. Topics of current research are the development of drug eluting and bioresorbable stents. Complications of endoscopic treatment: PCNL is considered the most invasive surgical option. Fever and sepsis were observed in 11 and 0.5% and need for transfusion and embolization for bleeding in 7 and 0.4%. Major complications, as colonic, splenic, liver, gall bladder and bowel injuries are quite rare but are associated with significant morbidity. Ureteroscopy causes less complications, although some of them can be severe. They depend on high pressure in the urinary tract (sepsis or renal bleeding) or application of excessive force to the urinary tract (ureteral avulsion or stricture). Diagnostic work up:  Genetic testing consents the diagnosis of monogenetic conditions causing stones. It should be carried out in children and in selected adults. In adults, monogenetic diseases can be diagnosed by systematic genetic testing in no more than 4%, when cystinuria, APRT deficiency, and xanthinuria are excluded. A reliable stone analysis by infrared spectroscopy or X-ray diffraction is mandatory and should be associated to examination of the stone under a stereomicroscope. The analysis of digital images of stones by deep convolutional neural networks in dry laboratory or during endoscopic examination could allow the classification of stones based on their color and texture. Scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) is another fundamental research tool for the study of kidney stones. The combination of metagenomic analysis using Next Generation Sequencing (NGS) techniques and the enhanced quantitative urine culture (EQUC) protocol can be used to evaluate the urobiome of renal stone formers. Twenty-four hour urine analysis has a place during patient evaluation together with repeated measurements of urinary pH with a digital pH meter. Urinary supersaturation is the most comprehensive physicochemical risk factor employed in urolithiasis research. Urinary macromolecules can act as both promoters or inhibitors of stone formation depending on the chemical composition of urine in which they are operating. At the moment, there are no clinical applications of macromolecules in stone management or prophylaxis. Patients should be evaluated for the association with systemic pathologies.

PROPHYLAXIS

Personalized medicine and public health interventions are complementary to prevent stone recurrence. Personalized medicine addresses a small part of stone patients with a high risk of recurrence and systemic complications requiring specific dietary and pharmacological treatment to prevent stone recurrence and complications of associated systemic diseases. The more numerous subjects who form one or a few stones during their entire lifespan should be treated by modifications of diet and lifestyle. Primary prevention by public health interventions is advisable to reduce prevalence of stones in the general population. Renal stone formers at "high-risk" for recurrence need early diagnosis to start specific treatment. Stone analysis allows the identification of most "high-risk" patients forming non-calcium stones: infection stones (struvite), uric acid and urates, cystine and other rare stones (dihydroxyadenine, xanthine). Patients at "high-risk" forming calcium stones require a more difficult diagnosis by clinical and laboratory evaluation. Particularly, patients with cystinuria and primary hyperoxaluria should be actively searched.

FUTURE RESEARCH

Application of Artificial Intelligence are promising for automated identification of ureteral stones on CT imaging, prediction of stone composition and 24-hour urinary risk factors by demographics and clinical parameters, assessment of stone composition by evaluation of endoscopic images and prediction of outcomes of stone treatments. The synergy between urologists, nephrologists, and scientists in basic kidney stone research will enhance the depth and breadth of investigations, leading to a more comprehensive understanding of kidney stone formation.

Area of hydronephrosis is a useful predictive factor of impacted ureteral stones

Ureteroscopic lithotripsy for impacted stones is challenging, but it is important to predict impacted stones preoperatively. Hydronephrosis, which is evaluated by a grading system, is often apparent in impacted stones. However, the currently used grading system is a qualitative evaluation. We, therefore, focused on a quantitative evaluation: the area of hydronephrosis. The aim of this study was to investigate whether the area of hydronephrosis could predict impacted stones more accurately than Society for Fetal Urology grade. We retrospectively identified 160 patients who underwent ureteroscopic lithotripsy for ureteral stones at our hospital between January 2014 and April 2022. Impacted stones were defined as stones fixed to the ureteral wall that could not be moved by means of ureteroscopic manipulation or water pressure. Of the 160 patients, 54 (33.8%) had impacted stones. Comparing patient characteristics, there were significant differences in stone size, ureteral wall thickness, Society for Fetal Urology grade, renal pelvic width and area of hydronephrosis (all P < 0.01). Receiver operating characteristic analysis showed that area of hydronephrosis was the more significant predictive value (area under the curve 0.781) compared with Society for Fetal Urology grade (area under the curve 0.676, P < 0.01). Multivariate analysis revealed that significant independent predictive factors of impacted stones were thicker ureteral wall thickness and larger area of hydronephrosis (both P < 0.01). The area of hydronephrosis and ureteral wall thickness were significant predictors of impacted stones in patients undergoing ureteroscopic lithotripsy for ureteral stones. These factors may be useful for selecting the treatment and preoperative settings.

Ureteral wall thickness as a predictor for non-invasive treatment success for steinstrasse. Can we save time?

PURPOSE

We aimed to define factors affecting the non-invasive overall treatment success (medical expulsive therapy (MET) ± shock wave lithotripsy (SWL)) for uncomplicated ureteral steinstrasse (SS) clearance.

METHODS

We retrospectively evaluated consecutive patients who underwent SWL for renal stones between 2017 and 2021. Patients with uncomplicated SS were included. All patient's demographic and radiological data, e.g., age, gender, pre-SWL stenting, SS site, type, leading stone size in widest diameter (< 10 mm and ≥ 10 mm), ureteral wall thickness (UWT) in mm against the leading stone were collected. If SS was diagnosed, medical treatment was given for 4 weeks. In case of MET failure, either SWL for the leading stones + MET or direct URS was done. Non-invasive treatment success (SFR) was considered if complete clearance of SS occurred with no complications or the need for invasive intervention.

RESULTS

A total of 145 patients were included with mean age of 45.9 ± 12.4 years. SFR in case of MET only occurred in 27.9%. Complications happened in 26 patients (17.9%). Non-invasive treatment SFR was achieved in 78 patients (53.8%) totally where SS type I, leading stone size ≤ 10 mm type and decreased UWT around the leading stone increased treatment success.

CONCLUSION

Ureteral wall thickness is an important factor predicting SS management success. Besides the decreased UWT, non-invasive management should be offered for type I SS with leading stone ≤ 10 mm.

Ureteral stricture formation after endoscopic removal of obstructing stones: could it be predicted with well-assessed radiological parameters?

The possible role of well-assessed radiological parameters in the prediction of ureteral stricture formation in cases with impacted obstructive ureteral calculi has been evaluated. 46 adult patients with or without ureteral stricture formation after ureteroscopic stone management were included. In addition to stone size and some certain radiological parameters including ureteral wall thickness (UWT) of the involved ureter at the impacted stone site was also measured and noted on computed tomography (CT) images. Parameters were evaluated in two subgroups of cases, namely: Group 1: patients in whom a ureteral stricture formed after endoscopic stone removal and Group 2: patients normal ureteral anatomy without any stricture formation. The possible relationship between the UWT values and degree of hydronephrosis (HN) with subsequent stricture formation was comparatively evaluated. All of the stones were proximal ureteral calculi in both groups. Both the degree of HN and proximal ureteral diameter (PUD) parenchymal was higher in cases with stricture formation. In addition, mean parenchymal thickness was lower and mean values of UWT measurements at the stone site were 3.70 ± 0.97 mm and 2.17 ± 0.26 mm in Groups 1 and 2, respectively. A cutoff value 2.49 mm for UWT was found to be highly predictive for stricture formation. UWT value calculated at the obstructing stone site was found to be predictive enough for the likelihood of ureteral stricture formation with high sensitivity and specificity . This evaluation along with some other radiological parameters may enable the urologists to follow such cases on this aspect with necessary measures taken.

Outcomes of primary ureteroscopic lithotripsy: The role of maximum ureteral wall thickness at the site of stone impaction

OBJECTIVES

To verify if the maximum thickness of the ureteral wall at the stone site (m-UWT) can affect the outcomes of primary retrograde ureteroscopic lithotripsy (P-URSL) within a single-center dataset.

MATERIAL AND METHODS

We retrospectively reviewed data on 354 consecutive URSL performed from January 2020 to May 2022 at "Fondazione Poliambulanza" in Brescia (Italy). We included patients older than 18 years who underwent URSL for a single ureteral stone with a maximum diameter ranging from 5 to 10 mm. Patients with anatomical abnormalities, a positive preoperative urinary culture, or without a NCCT performed during the acute event were excluded. Patients were treated in an emergency setting (P-URSL within 48 h from the diagnosis of acute ureteral colic) or in a delayed one (D-URSL after a period of maximum 90 days of ureteral double-j stenting). For the resulting 139 patients we recorded demographic, clinical and stone-related features and perioperative data. We processed these data by univariate and multivariate analysis, and with a logistic regression analysis.

RESULTS

Of the 139 included procedures, 63 were P-URSL and 76 D-URSL. At the univariate analysis we found that stone diameter (OR 0.845, p = 0.017), stone volume (OR 0.023, p = 0.001), stone density (OR 0.998, p = 0.000) and m-UWT (OR 0.499, p = 0.013) are predictors of P-URSL. Stone density (OR 0.998, p = 0.002) is an independent predictor of P-URSL at the multivariate analysis. At a logistic regression analysis, a distal ureteric position (OR 0.189, p = 0.014), stone diameter (OR 1.289, p = 0.006), and m-UWT (OR 2.297, p = 0.02) were found to be statistically significant predictors of incomplete stone clearance in patients undergoing P-URSL. m-UWT is the only predictor of short-term postoperative adverse events in patients undergoing P-URSL (OR 3.386, p < 0.001). From a descriptive analysis, it emerged that an increased m-UWT (>2 mm) significantly correlates to an endoscopic finding of ureteritis' signs and to an increase in operative time, hospital stay and post-procedural stenting time. A m-UWT greater than 2 mm also correlates with a lower stone free rate (SFR) and with a significant increase in both short and long-term postoperative complications.

CONCLUSIONS

Our study confirmed a connection between m-UWT and poor endoscopic findings, as well as a direct correlation with the main morphometric parameters of the stone and finally with the outcomes of P-URSL itself. Further studies are necessary to validate our results, so that m-UWT might be routinely considered a useful tool in the decision-making process for P-URSL.

Medial deviation of the ureter is a new sign that could predict stone impaction: a pilot study

OBJECTIVE

To assess the value medial deviation of the ureter at site of ureteric stone as a sign of ureteric stone impaction.

PATIENTS AND METHODS

All cases with medial deviation of the ureter at site of ureteric stones in our department over 4 years were enrolled in this pilot study. All cases were diagnosed with KUB and non-contrast CT (NCCT). Radiological and ureteroscopic findings were recorded.

RESULTS

A total of 32 patients with a single impacted stone in the proximal and middle third of the ureter were included in the study. Medial deviation of the ureter at the site of the stone was detected in the upper third of the ureter in 24 (75%) cases and in the middle third in 8 (25%) cases. There were mucosal polyps and mucosal erythema (inflammatory changes) seen by ureteroscopy in all cases (100%). Ureteroscopy was successfully completed with stone fragmentation in 23 (71.8%) patients: 8 of them needed ureteric catheter and 15 required JJ stent insertion. Failure of ureteroscopy with insertion of JJ stent was done in 5 (15.6%) patients. Removal of the stent and ureteroscopy was done after 4 weeks.

CONCLUSION

We conclude from this study that medial deviation of the ureter is a new reliable radiological sign of ureteric stone impaction.

Korean Society of Endourology and Robotics (KSER) recommendation on the diagnosis, treatment, and prevention of urolithiasis

This article provides evidence-based recommendations and expert opinions to aid urologists in making optimal decisions regarding managing urolithiasis in various clinical scenarios. The most frequently asked questions by urologists in their clinical practice have been collected and answered in the form of FAQs; based on the latest evidence and expert opinions. The natural history of urolithiasis is divided into active treatment and silent phases, with the active treatment stage divided into typical and special situations and peri-treatment management. The authors address 28 key questions, offering practical guidance for the proper diagnosis, treatment, and prevention of urolithiasis in clinical practice. This article is expected to be served as a valuable resource for urologists.

Finding the optimal candidate for shock wave lithotripsy: external validation and comparison of five prediction models

We aimed to externally validate five previously published predictive models (Ng score, Triple D score, S3HoCKwave score, Kim nomogram, Niwa nomogram) for shock wave lithotripsy (SWL) single-session outcomes in patients with a solitary stone in the upper ureter. The validation cohort included patients treated with SWL from September 2011 to December 2019 at our institution. Patient-related variables were retrospectively collected from the hospital records. Stone-related data including all measurements were retrieved from computed tomography prior to SWL. We estimated discrimination using area under the curve (AUC), calibration, and clinical net benefit based on decision curve analysis (DCA). A total of 384 patients with proximal ureter stones treated with SWL were included in the analysis. Median age was 55.5 years, and 282 (73%) of the sample were men. Median stone length was 8.0 mm. All models significantly predicted the SWL outcomes after one session. S3HoCKwave score, Niwa, and Kim nomograms had the highest accuracy in predicting outcomes, with AUC 0.716, 0.714 and 0.701, respectively. These three models outperformed both the Ng (AUC: 0.670) and Triple D (AUC: 0.667) scoring systems, approaching statistical significance (P = 0.05). Of all the models, the Niwa nomogram showed the strongest calibration and highest net benefit in DCA. To conclude, the models showed small differences in predictive power. The Niwa nomogram, however, demonstrated acceptable discrimination, the most accurate calibration, and the highest net benefit whilst having relatively simple design. Therefore, it could be useful for counselling patients with a solitary stone in the upper ureter.

A Prospective Evaluation of the Association of Ureteral Wall Thickness With Intraoperative Stone Impaction in Ureteroscopy

Background and objective In this study, we aimed to analyze the association of ureteral wall thickness (UWT) measured on non-contrast CT (NCCT) with stone impaction as found in ureteroscopy (URS). Materials and methods We analyzed 43 patients who underwent URS and pneumatic/laser lithotripsy for ureteric stones from May to November 2022. The UWT was measured by an experienced radiologist on NCCT. Clinical predictors of the impacted stone were calculated by univariate and multivariate regression analysis. The receiver operating characteristic (ROC) curve was calculated for the UWT cutoff to apply it for impaction with different parameters. We also evaluated the association of intra- and postoperative parameters of the two groups with UWT. Results Out of the 43 patients with stones, 26 (60.46%) patients had impacted stones. Univariate analysis was used to analyze the site (left-sided stone impacted more commonly), stone size, stone density [Hounsfield unit (HU)], hydronephrosis, UWT, and duration between initial presentation and surgery, and multivariate analysis was utilized to assess stone density, as well as UWT's association with impacted stones. The ROC curve showed a cutoff of 3.5 mm for UWT with an accuracy of 0.83. High UWT (≥3.5 mm) was associated with a significantly lower stone-free rate, more complications, and mean operative time as compared to low UWT (<3.5 mm) (p<0.05). Conclusion Based on our findings, high UWT is associated with high rates of impacted stones and a lower stone-free rate when compared to low UWT.

The association between ureteral wall thickness and need for additional procedures after primary ureteroscopy in patients with ureteral stones above the iliac crest

PURPOSE

To examine the parameters affecting the need for additional procedures in the primary ureteroscopy treatment in patients with ureteral stones above the iliac crest level.

METHODS

Seventy-one patients were included in the study who were ≥ 18 years old and had undergone ureteroscopy (URS) for ureteral stones above the iliac crest level between 2018-2020 and had a non-contrast-enhanced abdominal computed tomography before the procedures were included in the study. Patients and stone characteristics were prospectively collected. The results were evaluated six weeks after URS. The absence of any residual fragment was thought to indicate stone-free status. The patients with failure were referred for the additional procedures.

RESULTS

The median patient age was 51 years [interquartile range (IQR): 18-66]. The median transverse stone diameter was 9.5 mm (IQR: 7.1-11.4), and the median ureteral wall thickness (UWT) was 5.8 mm (IQR: 4.3-6.5). In the univariate analysis, UWT (p < 0.001), presence of multiple stones (p = 0.008), and stone length (p = 0.022) affected stone-free status. The multivariate analysis revealed UWT as the only independent factor affecting the need for additional procedures after URS (p = 0.028). In the receiver operating characteristic curve analysis, the best threshold value for UWT according to the outcomes was identified as 5.8 mm.

CONCLUSION

Ureteral wall thickness was the only independent parameter determining the need for additional procedures and affecting the treatment outcomes after the URS procedure.

Can shock wave lithotripsy lead to impaction of ureteral stones?

BACKGROUND

One of the underlying reasons for shock wave lithotripsy (SWL) resistance is the ureteral stone impaction. This study aimed to investigate the accuracy of the hypothesis, suggesting that SWL per se can be the reason for ureteral stone impaction.

METHODS

One hundred and seventy-six patients were enrolled in the study. Data of the patients (N.=50) treated with SWL and subsequent semirigid ureteroscopic laser lithotripsy (SULL) in our center between January 2014 and January 2020 were retrospectively reviewed compared with the data of the patients (N.=126) who underwent SULL without prior SWL treatment during the same period. Patients reported to have ureteral stone impaction during SULL were compared with those without stone impaction in terms of demographic parameters, stone characteristics and clinical data, including symptom duration and presence or absence of SWL history.

RESULTS

The success rate of SULL was determined as 80.1% (141/176). Univariable analysis revealed statistically significant differences between the patients with and without stone impaction concerning stone diameter, stone volume, pre-SULL SWL history, symptom duration and ureteral wall thickness (UWT). Multivariable logistic regression analysis revealed that symptom duration and UWT were independent predictive factors for ureteral stone impaction.

CONCLUSIONS

Symptom duration and UWT are independent predictors of ureteral stone impaction. Symptom duration and UWT should be considered during treatment planning and informed consent process before proceeding with SULL.

Value of preoperative ureteral wall thickness in prediction of impaction of ureteric stones stratified by size in laser ureteroscopic lithotripsy

OBJECTIVES

To evaluate the role of preoperative UWT in the prediction of impaction of ureteral stones stratified according to stone size in ureteroscopic laser lithotripsy.

PATIENT AND METHODS

This study included 154 patients submitted to URSL for ureteral stones. Radiological data comprised the presence of hydronephrosis, anteroposterior pelvic diameter (PAPD), proximal ureteric diameter (PUD), and maximum UWT at the stone site. Collected stone characteristics were stone size, side, number, site, and density.

RESULTS

The study included 154 patients subjected to URSL. They comprised 74 patients (48.1%) with impacted stones and 80 (51.9%) with non-impacted stones. Patients were stratified into those with stone size ≤ 10 mm and others with stone size > 10 mm. In the former group, we found that stone impaction was significantly associated with higher PAPD, PUD, and UWT. In patients with stone size > 10 mm, stone impaction was related to higher UWT, more stone number, and higher frequency of stones located in the lower ureter. ROC curve analysis revealed good power of UWT in discrimination of stone impaction in all patients [AUC (95% CI) 0.65 (0.55-0.74)] at a cut-off of 3.8 mm, in patients with stone size ≤ 10 mm [AUC (95% CI) 0.76 (0.61-0.91)] at a cut-off of 4.1 mm and in patients with stone size > 10 mm [AUC (95% CI) 0.72 (0.62-0.83)] at a cut-off of 3.0 mm.

CONCLUSIONS

Stratifying ureteric stones according to size would render UWT a more practical and clinically-oriented approach for the preoperative prediction of stone impaction.

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.

The ratio of CT attenuation values of the ureter above/below ureteral stones is a useful preoperative factor for predicting impacted ureteral stones

Impacted stones typically make it difficult to perform ureteroscopic lithotripsy (URSL), so it is useful to preoperatively predict such impaction. We focused on CT attenuation values of the ureter above and below the stone ('HU above' and 'HU below') and calculated their ratio (HAB ratio; HU above/HU below ratio). The aim was to investigate whether HAB ratio could predict impacted stones preoperatively. Between 2011 and 2019, 171 patients from our hospital that had URSL for ureteral stones with pretreatment non-contrast computed tomography (NCCT) were retrospectively identified. Ureteral wall thickness (UWT), ureteral wall volume (UWV) and HAB ratio ('HU above' divided by 'HU below') were recorded. Impacted stones were defined as fixed stones that did not move by means of ureteroscopic manipulation or water pressure. Of the 171 procedures, 46 (27%) involved patients with impacted stones. Comparing patient characteristics and stone parameters according to impaction status, factors with significant difference included grade of hydronephrosis, UWT, and HAB ratio (all P < 0.01). Multivariate analysis indicated that significant independent predictors of impacted stones were thicker UWT and lower HAB ratio (all P < 0.01). HAB ratio was a significant preoperative predictor of stone impaction in patients undergoing URSL for ureteral stones. HAB ratio may be informative for selecting the treatment and preoperative preparations.

The role of inflammatory serum markers and ureteral wall thickness on spontaneous passage of ureteral stone < 10 mm: A prospective cohort study

Introduction

Ureteral stone is a worldwide disease and accounts for 20% of all urolithiasis. There is a widespread discussion on the preferred initial treatment method, whether medical or surgical, and each has its pros and cons. In this study, we aimed to assess the role of both ureteral wall thickness around the stone and inflammatory markers in guiding the decision-making process.

Methods

In this prospective study, 161 patients who presented with ureteric colic and were diagnosed with ureteral stone with NCCT were included. UWT around the stone was measured, and the NLR and PLR were calculated. The patients were given a single daily dose of tamsulosin 0.4 mg for 4 weeks with weekly follow-up to determine SSP or failure.

Results

Of the 161 patients with a mean age 40.12 ± 12.36 SD, 55.9% had a spontaneous stone passage. Receiver operating characteristics showed a cut off value of 2.45 mm UWT of non SSP patients with an 83% sensitivity and 86% specificity. Moreover, there was a significant correlation between higher NLR, PLR and increased UWT (Pearson correlation of 0.314 and 0.426 respectively). The combined higher NLR, PLR and increased UWT were associated with failure of SSP (p-value <0.001).

Conclusion

Many factors play a role in decision making for management of ureteral stones. Our study concludes that patients with high NLR, PLR, and UWT around the stone have lesser chance of SSP using MET. Their rise can be used as predictors to decide early intervention.

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Ureteral stone is a worldwide disease and accounts for 20% of all urolithiasis.

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Impacted ureteral stones occupy the majority of emergency department visits due to urolithiasis.

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The role of inflammatory serum markers and UWT around the stone on spontaneous passage are controversial.

Comprehensive endoscopic management of impacted ureteral stones: Literature review and expert opinions

Treatment of urolithiasis, a benign disease, requires high efficacy and safety. Endoscopic treatment of impacted ureteral stones remains a challenging procedure for urologists, despite recent remarkable advances in surgical technology in treatment of urolithiasis. The success rate of endoscopic treatment in patients with impacted stones is reported to be lower than that in patients with nonimpacted stones. Moreover, the presence of stone impaction is associated with high rates of intraoperative and postoperative complications. The best management for patients with impacted ureteral stones should therefore be devised based on the latest knowledge and techniques. The present review focuses on the preoperative prediction of stone impaction, the safest and most effective endoscopic surgical procedures, and the most appropriate management for postoperative ureteral strictures. We overview comprehensive endoscopic management for impacted ureteral stones based on literature review and expert opinions.

A novel model using computed tomography parameters to predict shock wave lithotripsy success in ureteral stones at different locations

OBJECTIVE

To combine non-contrast computerized tomography (NCCT)-based parameters with stone and patient characteristics that are already known to affect shock wave lithotripsy (SWL) success and assess this novel model's effectiveness in predicting SWL success for single ureteral stones in different locations.

MATERIALS AND METHODS

Data of patients treated by SWL for a single ureteral stone between January 2017 and January 2019 were retrospectively reviewed. Demographic parameters of patients and stone characteristics were combined with NCCT-based parameters. NCCT-based parameters included the presence or absence of hydronephrosis, perinephric stranding, periureteral edema, diameter of the proximal ureter, ureteral wall thickness (UWT) at ureteral stone site. The logistic regression method was used for the development of a useful predictive model. Subsequently, the receiver operating curve was used to determine cut-off levels, and a scoring system was developed for prediction of SWL success.

RESULTS

Stone-free rate was 77,1% (267/346) in the entire cohort. Univariate analysis revealed that age, stone volume, density, perinephric stranding, diameter of proximal ureter, and UWT, were associated with SWL success. In multivariate analysis, proximal ureteral stone location, stone volume, density, and UWT were independent predictors of SWL success. The formula used during logistic regression analysis was: 1/[1 + exp {-8.856 + 0.008 (stone volume) + 0.002 (stone density) + 0.673 (UWT) + 1026 (proximal ureteral stone)}]. The scores of 0, 1, 2, 3 and 4 were associated with 97,8%, 83,4%, 60,8%, 33,2% and 11,1% success rates, respectively, in the prediction model based on these parameters.

CONCLUSION

We conclude that our model can facilitate decision-making for SWL treatment of ureteral stones in different locations.

Ureteral wall thickness at the stone site: A critical predictor of success and complications in children undergoing semi-rigid ureteroscopy

INTRODUCTION

We retrospectively assessed the role of ureteral wall thickness (UWT) at the ureteral stone site in predicting the stone-free status and the complication rates in children undergoing semi-rigid ureterorenoscopy (URS).

PATIENTS AND METHODS

The children who underwent URS and had undergone non-contrast abdominal computerized tomography before the URS were included in the study. The following protocol was used to determine the outcome. Immediately before removing the stent, all children were evaluated by ultrasound (US) and plain film (KUB) for residual stones in the upper urinary tract and after removing the double J stent, the presence of stone fragments in the ureter was checked with URS. The children were considered stone-free if no residual fragments were identified in radiologic imaging and the evaluation of the ureter by URS. The case was accepted as a failure if any fragments were seen on immediate US, KUB, and/or during URS just after the stent removal. The patients who could not complete the standard primary URS procedure due to stone-related reasons (patients for whom we could not pass the safety guidewire behind the stone and/or the procedure was terminated due to pyuria during the procedure) were also accepted as a failure. The possible factors related to the patient, stone, ureter, and the operation that could affect the outcome and the complications following the URS were evaluated.

RESULTS

The children's median age was six years (1-17 years). Among the 89 children included in the study, 69 (78%) were stone-free, and 20 (22%) presented residual stone after the first URS session. The ROC analysis revealed that a UWT value of 4.5 mm (sensitivity 60%, specificity 92%) was the optimal cut-off value predictive of the URS outcome. The regression analysis revealed UWT >4.5 mm (p = 0.006) and multiple stone presentation (p = 0.005) as independent risk factors for residual stone. Complications were detected in 15 (17%) children. Thick ureteral wall (p = 0.012) and longer operative time (p = 0.016) were defined as the independent risk factors for complications.

DISCUSSION

Increased UWT is associated with the adverse outcomes of URS due to tissue hypertrophy, edema, and mucosal bleeding may cause difficulty in removing the stone. The thick ureteral wall might increase the risk of complications due to the necessity of manipulating the instruments or the involuntary forceful use of instruments while removing the stone.

CONCLUSION

UWT was the only independent variable affecting both increased failure and complication rates in children undergoing URS.

Development and validation of a preoperative nomogram for predicting patients with impacted ureteral stone: a retrospective analysis

Background

To develop and validate a practical nomogram for predicting the probability of patients with impacted ureteral stone.

Methods

Between June 2020 to March 2021, 214 single ureteral stones received ureteroscopy lithotripsy (URSL) were selected in development group. While 82 single ureteral stones received URSL between April 2021 to May 2021 were included in validation group. Independent factors for predicting impacted ureteral stone were screened by univariate and multivariate logistic regression analysis. The relationship between preoperative factors and stone impaction was modeled according to the regression coefficients. Discrimination and calibration were estimated by area under the receiver operating characteristic (AUROC) curve and calibration curve respectively. Clinical usefulness of the nomogram was evaluated by decision curve analysis.

Results

Age, ipsilateral stone treatment history, hydronephrosis and maximum ureteral wall thickness (UWT_max) at the portion of stone were identified as independent predictors for impacted stone. The AUROC curve of development and validation group were 0.915 and 0.882 respectively. Calibration curve of two groups showed strong concordance between the predicted and actual probabilities. Decision curve analysis showed that the predictive nomogram had a superior net benefit than UWT_max for all examined probabilities.

Conclusions

We developed and validated an individualized model to predict impacted ureteral stone prior to surgery. Through this prediction model, urologists can select an optimal treatment method and decrease intraoperative and postoperative complications for patients with impacted ureteral calculus.

Ureteral wall thickness is an independent parameter affecting the success of extracorporeal shock wave lithotripsy treatment in ureteral stones above the iliac crest

BACKGROUND

To investigate the relationship between ureteral wall thickness (UWT) and other variables of patients who underwent extracorporeal shock wave lithotripsy (SWL) in the primary treatment of the ureteral stone above the iliac crest level.

MATERIAL AND METHODS

A total of 147 patients aged 18 years and older, who underwent SWL in our clinic between December 2016 and December 2019 for the treatment of ureteral stones above the iliac crest level and had non-contrast enhanced abdominal computed tomography scans before the procedure were included in the clinical study. The results were evaluated at 3 months after SWL. The absence of residual fragments was considered as stone-free status, and the existence of any size residual fragment was considered as treatment failure.

RESULTS

In our study, the mean age of the patients was 42.4 ± 12.8 years, and the stone-free rate was 92.5%. The median transverse stone size was 7.5 mm (min 2.8-max 15), and the median UWT was 4.2 mm (1-8.7). In the multivariate analysis, UWT (P = .002) and multiple stone presence (P = .027) were found to be independent factors affecting stone-free status. In the receiver operating characteristic curve analysis, the optimal threshold value for UWT was determined as 5.25 mm.

CONCLUSIONS

We found that UWT was the most important independent variable associated with increased failure in SWL treatment. The presence of multiple stones was another independent factor that increased the failure rates. Using SWL technology through experience accumulated with the mechanical hardware of the machine, we can select patients who are more suitable for this treatment and improve treatment outcomes.

Development of a Novel Nomogram and a Simple Scoring System Using Ureteral Jet Flow to Predict Impacted Ureteral Stone

PURPOSE

To examine the efficacy of ureteral jet flow measured by Doppler ultrasonography (USG) together with radiological parameters obtained by non-contrast enhanced computed tomography (CT) in predicting whether a ureteral stone is impacted.

MATERIAL-METHOD

A total of 178 patients that met the criteria were included in the study. Stone size, location, grade of hydronephrosis, HU values of the stone and the proximal and distal parts of the stone, and ureteral wall thickness (UWT) were obtained from non-contrast enhanced abdominal CT images. Ureteral jet flows (Vmax) were measured and recorded by Doppler USG. Thirty-eight cases in which the guide wire or opaque contrast material could not pass beyond the stone were included in the impacted ureteral stone (IUS) group while the remaining 140 patients constituted the non-impacted ureteral stone (non-IUS) group.

RESULTS

Significant independent predictors of IUS were determined as stone size [odds ratio (OR): 2.23, p=0.020), ureteral HU value under the stone (OR: 1.11, p=0.014), UWT (OR: 5.66, p=0.009), anteroposterior diameter (OR: 1.23, p=0.033), and the Vmax value of the stone side (OR: 0.76, p=0.011). The proposed scoring system predicted IUS with 89% sensitivity and 91% specificity at a cut-off value 11.5.

CONCLUSION

Determining whether a ureteral stone is impacted is important in deciding on the optimal treatment modality. The nomogram and scoring system that we created based on the data which were obtained with non-invasive methods can predict IUS with high sensitivity and specificity.

Can ureteral wall thickness (UWT) be used as a potential parameter for decision-making in uncomplicated distal ureteral stones 5-10 mm in size? A prospective study

OBJECTIVE

To evaluate the correlation between ureteral wall thickness (UWT) and stone passage (SP) and its cut-off value in distal uncomplicated ureteral stones.

PATIENTS AND METHODS

In the prospective study from January 2019 to January 2020 at a tertiary care hospital, we reviewed 212 patients aged above 18 years with single, symptomatic, radiopaque, and distal ureteric stone sized 5-10 mm, who were treated with MET (Silodosin 8 mg once daily) until SP or a maximum of 4 weeks. There were 2 groups: responders and non-responders. Demographic data of the patients and all stone radiological parameters including stone size, laterality, density, UWT, the diameter of the ureter proximal to the stone (PUD), and the degree of hydronephrosis were recorded and compared between the 2 groups.

RESULTS

There were 126 (59.4%) in the responder group and 86 (40.6%) in the non-responder group. On univariate analysis, gender, stone density, stone size, PUD, UWT, and the degree of hydronephrosis were significant factors for stone passage. However, using multivariate analysis, only UWT and the degree of hydronephrosis were significant. ROC analysis showed that 3.75 mm is the cut-off value for UWT, with 86% and 87.3% sensitivity and specificity, respectively.

CONCLUSIONS

UWT and hydronephrosis can be used as potential predictors for SP and can help with decision-making in patients with uncomplicated 5-10 mm lower ureteric stones.

Predictive value of ureteral wall thickness (UWT) assessment on the success of internal ureteral stent insertion in cases with obstructing ureteral calculi

To evaluate the possible role of ureteral wall thickness (UWT) assessment in the prediction of the success for stent placement in cases with obstructing ureteric stones. 227 adult patients with a single unilateral obstructing ureteral stone requiring internal ureteral stent placement were included. In addition to stone size, the ureteric wall thickness at the impacted stone site and the degree of hydronephrosis were also assigned on CT images. Patients were divided into two subgroups: Group 1: patients in whom internal ureteral stent could not be passed beyond the stone and Group 2: patients in whom an internal ureteral stent was passed successfully. The possible relationship between the UWT values and the success of stent placement, degree of hydronephrosis were comparatively evaluated. The majority of the stones were located in the proximal ureter in Group 1 and the degree of hydronephrosis was also higher in these cases. Moreover, while the mean value of UWT calculated on CT images was 4.3 ± 0.9 mm in Group 1, this value was noted to be 2.5 ± 0.8 mm in cases of group 2. A cutoff UWT value of 3.35 mm was highly predictive for the stent insertion and cases with higher values required additional procedures or percutaneous nephrostomy tube placement. UWT value calculated at the obstructing stone site was found to be predictive enough for the likelihood of internal ureteral stent passage with high sensitivity and specificity. This evaluation may enable the urologist to make the best decision for urinary diversion in such cases.

Association between time to lithotripsy and stone-free rate in patients with ureteral stones undergoing shock wave lithotripsy

Early shock wave lithotripsy is associated with higher stone-free rate compared to delayed treatment of ureteral stones, but may constitute overtreatment because ureteral stones can pass spontaneously. We studied the association between time to treatment and stone-free rate in patients with ureteral stones to determine optimal shock wave lithotripsy timing. We retrospectively analyzed 537 patients undergoing shock wave lithotripsy for ureteral stones. Patients were divided into five groups according to time from onset of symptoms to lithotripsy—urgent (0–3 days), early (4–30 days), late (31–60 days), long-delayed lithotripsy (≥ 61 days), and asymptomatic. Stone-free rates were compared among groups. Mean age and stone size were 55.6 ± 13.1 years and 7.48 ± 3.29 mm, respectively. Mean number of shock wave lithotripsy sessions and stone-free rate were 1.37 and 91.6%, respectively, in the overall population. Stone-free rates were 95.2%, 96.8%, 91.3%, 86.3%, and 82.7% in urgent, early, late, long-delayed lithotripsy, and asymptomatic groups, respectively. Long-delayed lithotripsy and asymptomatic groups had significantly more lithotripsy sessions and lower stone-free rate, compared to urgent and early lithotripsy groups. In multivariate analysis, time to lithotripsy [long-delayed lithotripsy (odds ratio: 0.273, p = 0.004) and asymptomatic nature (odds ratio: 0.236, p = 0.002)] and age (odds ratio: 0.959, p = 0.003) independently affected stone-free rate. In conclusion, time to lithotripsy is a strong predictive factor for stone-free status following shock wave lithotripsy. Urgent shock wave lithotripsy did not improve stone-free rate if performed within 1 month. However, time to shock wave lithotripsy > 2 months reduced likelihood of stone-free status.

Efficacy and Safety of External Physical Vibration Lithecbole After Extracorporeal Shock Wave Lithotripsy or Retrograde Intrarenal Surgery for Urinary Stone: A Systematic Review and Meta-analysis

Introduction: The current study evaluated the efficacy and safety of external physical vibration lithecbole (EPVL) after extracorporeal shock wave lithotripsy (SWL) or retrograde intrarenal surgery (RIRS) for urolithiasis. Methods: Publicized literature was systematically searched from EMBASE, Cochrane Library, PubMed, ScienceDirect, ClinicalTrials.gov, and Web of Science up to February 2020. Fixed-effects or random-effects model was chosen in risk ratio (RR) calculation according to heterogeneity. Quality of evidence was estimated under the guidance of Cochrane handbook. Stone expulsion rate, stone-free rates (SFRs), and complication rates were set as end points. Results: Six randomized controlled trials, including 853 patients, were eligible for analysis. EPVL significantly increased SFR within 3 weeks (RR = 1.17, 95% CI: 1.06-1.29, P = 0.001) and above 3 weeks (RR = 1.19, 95% CI: 1.03-1.37, P = 0.02) after SWL. EPVL also improved SFR within 3 weeks (RR = 1.84, 95% CI: 1.35-2.49, P < 0.0001) and above 3 weeks (RR = 1.53, 95% CI: 1.33-1.77, P < 0.00001) after RIRS. Besides, EPVL can significantly increase SFRs for stones in renal pelvis, lower calix, and multiple locations (all P-value <0.05). Although the overall complication rate was not significantly higher in EPVL + RIRS group, it was found to be 1.38 times higher in EPVL+SWL group (RR = 1.38, 95% CI: 1.06-1.79, P = 0.02), especially the incidence of flank pain (RR = 3.11, 95% CI: 1.02-9.46, P = 0.05). Conclusions: EPVL is effective and safe with high SFRs (especially in renal pelvis, lower calix, and multiple locations) after SWL or RIRS and lower overall complication rate after RIRS in patients with urolithiasis. However, the overall complication rate (especially the incidence of flank pain) was higher after EPVL + SWL.

Can CT-Based Stone Impaction Markers Augment the Predictive Ability of Spontaneous Stone Passage?

Introduction: A number of clinical and radiological predictors of either stone impaction or ureteral stone passage (SP) have been proposed. We aimed at identifying the key predictors of successful SP by using readily available CT-based tools/measurements. Methods: Patients presenting to the emergency department from February 2017 to February 2018 with an acute unilateral ureteral stone confirmed on non-contrast CT and managed conservatively were followed for SP. Patients with renal impairment, sepsis or requiring emergent intervention were excluded. Patients were followed at 1 month to confirm SP (stone collection/repeat imaging) or failure of passage. The CT variables analyzed included: Stone factors [location, size, volume, HU density (HUD)], impaction factors [ureteral HUD above and below the stone, maximal ureteral wall thickness (UWT) at the stone site, contralateral UWT, and ureteral diameter above and below the stone]. Binary logistic regression analysis was performed to identify predictors of SP. Results: Forty-nine patients met study inclusion criteria, of whom 32 (65.3%) passed the stone without further intervention. Patients with successful passage were more likely to have smaller, lower volume and less dense stones located in the distal ureter (p < 0.01). Lower ureteral HUD below the stone, lower maximal UWT, and lower ureteral diameter above the stone were associated with successful passage (p < 0.01). On multivariable logistic regression analysis, only maximal UWT at the stone site was a significant independent predictor of SP outcome (p = 0.01). Youden's criterion identified 2.3 mm as the optimal UWT cut-off point, which will accurately predict SP with 82.4% sensitivity and 87.5% specificity. Conclusions: Maximal UWT at the stone site was the most significant predictor of successful passage in acute unilateral ureteral stones, with an optimal cut-off point of 2.3 mm. Further prospective studies are needed to accurately predict spontaneous SP.

Study of ureteral and renal morphometry on the outcome of ureterorenoscopic lithotripsy: The critical role of maximum ureteral wall thickness at the site of ureteral stone impaction

Purpose:

The purpose is to study the association of stone, ureteral, and renal morphometric parameters with the relevant outcome variables, i.e., complication rate, stone-free rate (SFR), and operating time of ureterorenoscopic lithotripsy. Although a safe procedure, it still occasionally has major complications. Computed tomography (CT) scan is often performed to diagnose ureteral calculi, providing opportunities for ureteral morphometry that may have a bearing on the outcome of the procedure.

Materials and Methods:

Ureteric, renal, and stone morphometric parameters were measured from CT of the abdomen and pelvis of the 110 patients with ureteral calculi who underwent ureteroscopic lithotripsy (URSL). Data were collected retrospectively in 25 patients and prospectively in 85 patients. Association of these parameters with the outcome variables of the procedure mentioned above was studied.

Results:

On univariate analysis, body mass index, stone size, and maximum ureteral wall thickness (MUWT) were found to have a significant association with URSL complications, SFR, and duration of surgery. On multivariable analysis, only MUWT was found to be an independent risk factor for URSL complications. In 90% of total patients with residual stones, MUWT was found to be >4.8 mm.

Conclusion:

Ureteral wall thickness of >4.8 mm is associated with prolonged duration of surgery and lower SFR. Patients with ureteral wall thickness of >4.8 mm at the site of ureteral stone who are planned for URSL must be counseled about the higher chances of residual stones and the need for additional procedure.

Role of pretreatment Doppler ultrasound in the prediction of factors affecting stone-clearance post-shockwave lithotripsy for ureteral stones: a prospective study

PURPOSE

To identify the role of Doppler US (DUS) in the prediction of factors affecting stone-clearance post-SWL for ureteral stones in addition to its role in prediction of pretreatment stone impaction.

METHODS

We prospectively included patients with ureteric stone for SWL between October 2018 and September 2019. Patient's demographics were collected. Using DUS, resistive index (RI), Δ RI, and ureteric jets were evaluated in both kidneys. Also, stone site, volume, density, skin to stone distance, degree of hydronephrosis, ureteral wall thickness (UWT) were evaluated by NCCT. Univariate and multivariate logistic regression analyses were performed to identify factors that contribute to treatment success. Correlation between ipsilateral RI with other radiological findings predicting stone impaction was done.

RESULTS

A total of 93 patients were finally included (61 males and 32 females). The mean age was 31.4 ± 7.7 years. The success rate (absence of significant residuals post 1 month by NCCT) was 51.6%. In multivariate analysis, the presence of ureteric jet, ipsilateral lower RI, and ipsilateral lower UWT were independent factors for treatment success (P = 0.0001, 0.002, and 0.03, respectively). Also, ipsilateral absence of ureteric jet, increased hydronephrosis, and increased UWT were correlated with higher ipsilateral RI in prediction of stone impaction. Ipsilateral higher RI was found to achieve higher accuracy in stone impaction prediction (PPV of 94.8%).

CONCLUSION

Pretreatment DUS is a useful, non-invasive with a less irradiative tool for prediction of stone impaction and stone-free rate post-SWL for ureteric stones.

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.

Could ureteral wall thickness have an impact on the operative and post-operative parameters in ureteroscopic management of proximal ureteral stones?

AIM

To evaluate the possible impact of stone impaction in terms of ureteral wall thickness (UWT) on the success and procedure related parameters of ureteroscopic management in proximal ureteral calculi.

PATIENTS AND METHODS

82 patients with proximal ureteric stones were included and were divided into 2subgroups where UWT was> 5mm in 38 cases; and <5mm in 44 cases. Stone size, degree of hydronehrosis, diameter of proximal ureteral luz, UWT and patient's demographics were evaluated. Semi-rigid ureteroscopy with Ho-YAG laser was performed and the possible impact of UWT as an objective parameter for stone impaction on the success rates and procedure related parameters was evaluated.

RESULTS

Mean patient age and stone size values were 47.55±1.78 years and 8.17±0.29mm respectively. Regarding the impact of UWT value at the stone site for the parameters mentioned above stone free rates particularly at 1-week after the procedure was higher in group 2 and the rate of residual fragments as well as the need for double J stent placement was higher in group 1. Additionally, mean duration of the procedures was significantly longer in Group 1 during which pathologic alterations were significantly higher in ureteral wall at stone site were observed in these cases (P=.0243).

CONCLUSIONS

UWT may be used to predict the success of ureteroscopic management and other procedure related parameters for proximal ureteral stones in an effective manner. With this approach a more rational operative plan with higher success rates, limited complications and auxiliary procedures could be made.

Systematic review and cumulative analysis of the managements for proximal impacted ureteral stones

PURPOSE

To compare the efficacy and safety of different treatment options for the management of proximal impacted ureteral stones (PIUS).

METHODS

A systematic literature search using Pubmed, Medline, Embase and Cochrane Library was conducted to obtain studies concerning different managements for PIUS up to Jan 2018. Summary odds ratios (ORs), standard mean differences (SMDs) or weighted mean differences with their 95% confidence intervals (CIs) were calculated to compare the efficacy and safety of all included treatment methods, registered in PROSPERO under number CRD42018092745.

RESULTS

A total of 15 comparative studies with 1780 patients were included. Meta-analyses of final stone-free rate (SFR) favored percutaneous nephrolithotomy (PCNL) over ureteroscopic lithotripsy (URL) (OR 10.35; 95% CI 5.26-20.35; P < 0.00001), laparoscopic ureterolithotomy over URL (OR 0.11; 95% CI 0.05-0.25; P < 0.00001) and URL over extracorporeal shockwave lithotripsy (OR 0.47; 95% CI 0.28-0.77; P = 0.003). As to complications, PCNL had a significantly higher blood transfusion rate (OR 7.47; 95% CI 1.3-42.85; P = 0.02) and a lower ureteral injury rate (OR 0.15; 95% CI 0.04-0.52; P = 0.003) compared with URL. It also shared a significantly lower stone-retropulsion rate (OR 0.03; 95% CI 0.01-0.15; P < 0.0001) and higher treatment costs (SMD = 2.71; 95% CI 0.71-4.70; P = 0.008) than URL.

CONCLUSIONS

Our meta-analysis suggested that PCNL might be the best option for PIUS owing to its higher successful rate. Complications such as hemorrhage could be decreased by the application on mini-PCNL.

Ureteral wall thickness as a significant factor in predicting spontaneous passage of ureteral stones of ≤ 10 mm: a preliminary report

PURPOSE

To evaluate the clinical significance of ureteral wall thickness (UWT) for predicting spontaneous passage (SP) of uncomplicated ureteral stones of ≤ 10 mm.

METHODS

We retrospectively reviewed 418 patients with a diagnosis of uncomplicated ureteral stones who presented to Kori Hospital from 2011 to 2018. The maximum stone diameter and UWT at the stone site were measured from axial computed tomography images. Clinical predictors of 4-week SP were assessed using univariate and multivariate analyses. Receiver operating characteristic (ROC) curve analysis was applied to evaluate the accuracy of factors in predicting SP of ureteral stones.

RESULTS

Of the 418 patients, 202 (48.3%) spontaneously passed their stones within 4 weeks of their initial visit. Multivariate analysis showed that stone location, stone size, and UWT (odds ratio, 0.40; P < 0.001) were independent predictors of 4-week SP. ROC analysis showed that 2.71 mm was the optimal cut-off value for UWT, with a predictive accuracy of 0.83. Low UWT had a significantly higher 4-week SP rate than high UWT (76.4% vs. 14.7%, respectively; P < 0.001). In addition, high UWT was associated with a higher risk of stone-related complications within 4 weeks compared with low UWT (16.4% vs. 7.2%, respectively; P = 0.0044).

CONCLUSIONS

UWT can serve as a potential predictive factor for 4-week SP and may help physicians to select patients who require immediate interventions among those with ≤ 10-mm ureteral stones.

Radiological noninvasive assessment of ureteral stone impaction into the ureteric wall: A critical evaluation with objective radiological parameters

PURPOSE

To determine the predictive value of certain radiological parameters for an objective asssessment of the presence of ureteral stone impaction.

MATERIALS AND METHODS

Seventy-nine patients with a single proximal ureteral stones were retrieved from the departmental database. Both clinical and particularly radiological data of all cases were well evaluated on this aspect. In addition to the time period between the first colic attack and definitive management; diameter of proximal ureter and renal pelvis, longitudinal and transverse stone size, Hounsfied unit (HU) of the stone and lastly ureteral wall thickness at the impacted stone site were all carefully evaluated and noted.

RESULTS

Patients had a single proximal ureteral stone. While mean age of the cases was ranged 20 to 78 years; mean stone size was 15.62±4.26 mm. Evaluation of our data demonstrated that although there was a statistically significant correlation between ureteral wall thickness and patients age, transverse diameter of the stone, ureteral diameter just proximal to the stone, renal pelvic diameter and the duration of renal colic attacks; no correlation could be demonstrated between patients sex and the HU of the stone.

CONCLUSIONS

Prediction of the presence and degree of proximal ureteral stone impaction is a challenging issue and our data indicated a highly significant correlation between ureteral wall thickness and the some certain radiological as well as clinical parameters evaluated which will give an objective information about the presence of impaction which may in turn be helpful in the follow-up and also management plans of such calculi.

Ureteral Wall Thickness as a Preoperative Indicator of Impacted Stones in Patients With Ureteral Stones Undergoing Ureteroscopic Lithotripsy

OBJECTIVE

To evaluate the clinical significance of ureteral wall thickness (UWT) to predict the presence of impacted stones in patients with ureteral stones undergoing ureteroscopic lithotripsy (URSL).

MATERIALS AND METHODS

We retrospectively analyzed 130 procedures in patients with ureteral stones who underwent URSL between January 2014 and September 2016. Maximum UWT at the stone site was measured from computed tomography images. Clinical predictors of impacted stones were assessed using univariate and multivariate logistic regression analyses. Receiver operating characteristic curve analysis was applied to determine the UWT cutoff value and to evaluate its accuracy in predicting impacted stones. Moreover, we evaluated the association between UWT and endoscopic findings, as well as surgical outcomes.

RESULTS

Of the 130 procedures, 50 (38.5%) involved patients with impacted stones. The univariate analysis showed significant differences in age, hydronephrosis, stone location, stone burden, and UWT in patients with and without impacted stones, and the multivariate analysis showed that age, stones in the middle ureter, and UWT (odds ratio 5.43, P < .001) were independent predictors of impacted stones. The receiver operating characteristic analysis showed that 3.49 mm was the optimal cutoff value for UWT, with a predictive accuracy of 0.87. High UWTs were associated with the presence of ureteral edema, polyps, white lesions, stone fixation, longer operation time, and lower endoscopic stone-free rate, compared with low UWTs (P < .05 each).

CONCLUSION

High UWT is associated not only with a higher risk of impacted stones but also with poor endoscopic findings and adverse surgical outcomes in patients with ureteral stones undergoing URSL.

Characteristics and outcomes of ureteroscopic treatment in 2650 patients with impacted ureteral stones

Purpose

To describe stone-free rates and complications of ureteroscopic treatment for impacted compared with non-impacted ureteral stones and evaluate predictive variables for impaction.

Methods

The Clinical Research Office of the Endourological Society prospectively collected 1 consecutive year of data from 114 centers worldwide. Patients eligible for inclusion were patients treated with ureteroscopy for ureteral stones. Patient characteristics, treatment details, and outcomes were compared with regard to stone impaction. Logistic regression analyses were conducted to explore predictive variables for ureteral stone impaction and to analyse the effect of impaction on outcomes.

Results

Of the 8543 treated patients, 2650 (31%) had impacted and 5893 (69%) non-impacted stones. The stone-free rate was 87.1% for impacted stones, which is lower compared with 92.7% for non-impacted stones (p < 0.001). Intra-operative complication rates were higher for impacted stones (7.9 versus 3.0%, p < 0.001). Significantly higher ureteral perforation- and avulsion rates were reported in the impacted stone group compared with the non-impacted stone group. No association between stone impaction and post-operative complications could be shown. Female gender, ASA-score >1, prior stone treatment, positive pre-operative urine culture, and larger stones showed to be predictive variables for stone impaction.

Conclusions

Ureteroscopic treatment for impacted stones is associated with lower stone-free rates and higher intra-operative complication rates compared with treatment for non-impacted stones. The predictive variables for the presence of stone impaction may contribute to the identification of stone impaction during the diagnostic process. Moreover, identification of stone impaction may aid the selection of the optimal treatment modality.

Electronic supplementary material

The online version of this article (doi:10.1007/s00345-017-2028-2) contains supplementary material, which is available to authorized users.

Impaction of ureteral stones into the ureteral wall: Is it possible to predict?

To determine the possible predictive value of certain acute phase reactants CRP and ESR as well as radiologic parameters on the degree of impaction in ureteral stones. A total of 80 adult patients with a single opaque proximal ureteral stone were evaluated. A non-contrast CT was performed in all cases and all possible radiologic predictive parameters calculated. Additionally, to outline the degree of impaction at the stone site, two serum acute phase reactants namely CRP and ESR levels were also assessed. Patients were divided into two groups as follows; Group 1 (n:42) patients with normal CRP levels and Group 2 (n:38) patients with elevated levels of CRP. The data obtained in the subgroups were first comparatively evaluated with radiological parameters and the possible correlation between CRP values and these parameters was well evaluated. While the serum CRP levels were normal in 42 cases, they were elevated in 38 cases. Evaluation of the data from CRP subgroups and radiologic parameters showed that elevated levels of serum CRP were closely related with mean values of ureteral wall thickness (UWT) as well as mean level of hydronephrosis with a statistically significant difference. Additionally, a correlation analysis between serum CRP levels and all other parameters mentioned above demonstrated a statistically significant correlation between UWT, degree of hydronephrosis and serum ESR values. Evaluation of serum CRP and ESR values could let us to predict the UWT, a parameter which is closely related with the degree of stone impaction.

Age-related delay in urinary stone clearance in elderly patients with solitary proximal ureteral calculi treated by extracorporeal shock wave lithotripsy

We investigated the effects of aging on the stone-free rate (SFR) after shock wave lithotripsy (SWL) for the treatment of proximal ureteral calculi. A total of 247 consecutive patients were retrospectively selected, classified into seven groups set at 10 year increments (from 20 to 90 years), and examined for SFR after SWL. According to our final analysis, 185 male and 62 female patients with an average age of 54.1 years had stones with a diameter of 11.5 mm and a density of 893.1 Hounsfield units. On average, SFR was 74.9 % at 3 months after 1.7 SWL sessions. SFR gradually reached ≥ 90 % for each age-group after 1.5-2 years. Median durations to achieve 50 % SFR were estimated to be 21 and 86 days for those in their 20 and 80 s, respectively. However, the difference between the two estimates was not significant (p = 0.064). The durations to achieve 50 % SFR for the other groups lay between these two estimates. Aging does not affect long-term SFR, but patients aged ≥ 80 years might experience delayed stone clearance within the first 12 months after SWL.

Impact of colic pain as a significant factor for predicting the stone free rate of one-session shock wave lithotripsy for treating ureter stones: a Bayesian logistic regression model analysis

Purpose

This study was conducted to evaluate colic pain as a prognostic pretreatment factor that can influence ureter stone clearance and to estimate the probability of stone-free status in shock wave lithotripsy (SWL) patients with a ureter stone.

Materials and Methods

We retrospectively reviewed the medical records of 1,418 patients who underwent their first SWL between 2005 and 2013. Among these patients, 551 had a ureter stone measuring 4–20 mm and were thus eligible for our analyses. The colic pain as the chief complaint was defined as either subjective flank pain during history taking and physical examination. Propensity-scores for established for colic pain was calculated for each patient using multivariate logistic regression based upon the following covariates: age, maximal stone length (MSL), and mean stone density (MSD). Each factor was evaluated as predictor for stone-free status by Bayesian and non-Bayesian logistic regression model.

Results

After propensity-score matching, 217 patients were extracted in each group from the total patient cohort. There were no statistical differences in variables used in propensity- score matching. One-session success and stone-free rate were also higher in the painful group (73.7% and 71.0%, respectively) than in the painless group (63.6% and 60.4%, respectively). In multivariate non-Bayesian and Bayesian logistic regression models, a painful stone, shorter MSL, and lower MSD were significant factors for one-session stone-free status in patients who underwent SWL.

Conclusions

Colic pain in patients with ureter calculi was one of the significant predicting factors including MSL and MSD for one-session stone-free status of SWL.