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

Predictive value of NCCT quantitative analysis for proximal and middle impacted ureteral stones

The purpose of the study was to explore the predictive value of preoperative quantitative NCCT analysis for proximal and middle ureteral stone impaction. Data of 128 patients who diagnosed with proximal and middle ureteral stones were analyzed. Stone size, upper diameter of the ureter(D1), lower diameter of the ureter (D2), CT attenuation of the ureter above the stone (HA, 'HU above'), CT attenuation of the ureter below the stone (HB, 'HU below'), CT attenuation values of the stone's proximal segments (C1), CT attenuation values of the stone's distal segments (C2), and ureteral wall thickness(UWT)were recorded. Logistic regression was used to perform univariate and multivariate analyses of the data to determine the independent predictors of proximal and middle ureteral stone impaction. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performance. Among the 128 patients, 52 (40.6%) had impacted stones, while 76 (59.4%) did not. Multivariate logistic regression analysis showed that stone size > 9.45 mm (OR = 1.372, 95% CI = 1.071-1.756, P = 0.012), UWT > 3.22 mm (OR = 4.217, 95% CI = 2.165 ~ 8.213, P < 0.001)、DDR > 2.10 (OR = 4.901, 95% CI = 1.797 ~ 13.365, P = 0.002)and HBA > 1.58 (OR = 5.237,95% CI = 1.502 ~ 18.259, P = 0.009)were independent risk factors for predicting ureteral stone impaction. In conclusion, stone size, UWT, DDR, and HBA show crucial predictive value for impaction of stones.

Treatment of Urolithiasis with Thulium Fiber Laser in Fragmentation Mode Using Optimized Pulse Sequences

Objectives: The super-pulsed thulium fiber laser (SP TFL) is a new alternative to high-power holmium laser for intracorporeal lithotripsy. The SP TFL has shown advantages in dusting regimes, but benefits in fragmentation regimes are less understood. The second-generation SP TFL introduces an advanced fragmentation pulse (AFP) sequence to maximize SP TFL's efficiency in fragmentation. This study evaluates safety and efficacy of the SP TFL fragmentation mode in ureteroscopy (URS) and mini percutaneous nephrolithotomy (mini-PCNL). Materials and Methods: The study was conducted in two phases. Safety of a new AFP was compared ex vivo to standard SP TFL fragmentation settings by measuring the dimensions of wounds created in porcine kidney after laser exposure for 0.5, 1.0, and 2.0 s. The resulting wounds were evaluated histologically using nitro blue tetrazolium chloride (NBTC) stain. In the clinical phase, the second-generation SP TFL was used to fragment and extract ureteral and renal stones in 40 patients using ureteroscopic and percutaneous approaches. The stone size, volume, density, laser-on-time, and total energy were recorded for each patient. In addition, the chemical composition, ablation rate, and ablation efficiency were assessed for each stone treatment. Results: The ex vivo mucosa damage profiles caused by AFP were similar to those caused by regular pulses. In clinical phase, the median volume and density for ureteral stones were 0.4 cm3 and 1029 Hounsfield units (HU), for renal stones 1.3 cm3 and 1113 HU, respectively. Different stone types were crushed into fragments suitable for extraction. The mean AFP energy was 3 J and the average power for ureteral stones was 10.5 W, whereas for renal stones it was 28.5 J and 31 W, respectively. The overall complication rate was low in both groups. Conclusion: ST PFL with AFP capability facilitates effective fragmentation of ureteral and renal stones of any composition during URS and mini-PCNL with minimal complication rates.

Propensity score matched comparison of transperitoneal laparoscopic ureterolithotomy and percutaneous nephrolithotomy for management of large impacted proximal ureteral stones with long-term follow-up

Impacted proximal ureteral stones (IPUS) present challenging clinical scenarios due to their persistent nature and associated complications. While ureterorenoscopy (URS) lithotripsy is recommended as the primary treatment, controversies exist regarding the optimal management of such stones. In this retrospective analysis, we compared the operative outcomes and long-term results of transperitoneal laparoscopic ureterolithotomy (LU) and percutaneous nephrolithotomy (PCNL) for IPUS larger than 15 mm. Propensity score matching (PSM) was employed to mitigate potential selection biases. Following PSM, 83 patients in each cohort exhibited comparable baseline characteristics. LU demonstrated a superior surgical success rate (100% vs. 96.4%, p = 0.244) and significantly lower perioperative hemoglobin decline (0.6 ± 0.4 g/dL vs. 1.5 ± 0.7 g/dL, p = 0.036) compared to PCNL. Additionally, LU exhibited a higher stone-free rate after 2 months (100% vs. 91.6%, p = 0.043), but a longer duration of catheterization (7.4 ± 1.2 days vs. 3.5 ± 2.2 days vs., p = 0.011). Conversely, PCNL was associated with a higher incidence of total complications (21.7% vs. 9.6%, p = 0.033) and stone recurrence during a mean period of 40-month follow-up (20.5% vs. 8.4%, p = 0.027). Transperitoneal LU and PCNL represent effective interventions for managing IPUS exceeding 15 mm. Notably, LU emerges as a preferable option over PCNL, offering superior stone clearance rates, reduced perioperative complications, and lower recurrence rates.

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.

Prospective observational study on the prognosis of ureteral lesions caused by impacted stones via dual-energy spectral computed tomography

Objective

Ureteral lesions caused by impacted ureteral stones are likely to result in postoperative ureteral stricture. On this basis, the study aimed to investigate if dual-energy spectral computed tomography can predict ureteral hardening caused by impacted stones and to explore the relationship between different types of ureteral lesions and the risk of ureteral stricture.

Methods

This prospective study collected data of 93 patients with impacted stones from hospital automation system during January 2018 to October 2019. They underwent an abdominal scan on a dual-energy spectral computed tomography. During surgery, the operator used ureteroscopy to identify ureteral lesions, which were classified into four categories: edema, polyps, pallor, and hardening. Seven months later, 90 patients were reviewed for the degree of hydronephrosis.

Results

Endoscopic observations revealed 38 (41%) cases of ureteral edema, 20 (22%) cases of polyps, 13 (14%) cases of pallor, and 22 (24%) cases of hardening. There were significant differences in hydronephrosis, the period of impaction, the calcium concentration of the ureter, and the slope of the spectral Hounsfield unit curve between the four groups. After that, we evaluated the factors associated with ureteral hardening and found that the calcium concentration of the ureter and hydronephrosis remained independent predictors of ureteral hardening. Receiver operating characteristic curve analysis showed that 5.3 mg/cm³ calcium concentration of the ureter is an optimal cut-off value to predict ureteral hardening. The result of follow-up showed that 80 patients had complete remission of hydronephrosis, with a complete remission rate of 61.9% (13/21) in the hardening group and 97.1% (67/69) in the non-hardening group (p<0.001).

Conclusion

Calcium concentration of the ureter is an independent predictor of ureteral hardening. Patients with ureteral hardening have more severe hydronephrosis after ureteroscopic lithotripsy. When the calcium concentration of the ureter is less than 5.3 mg/cm³, ureteral lesions should be actively treated.

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.

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.

Ureteral inflammatory edema grading clinical application

Purpose

To evaluate the relationship between endoscopic ureteral inflammatory edema (UIE) and ureteral lumen, formulate a preliminary grading method for the severity of UIE, and analyze the impact of different grades of UIE on endoscopic ureteral calculi surgery and prognosis.

Materials and methods

We retrospectively analyzed 185 patients who underwent ureteroscopic lithotripsy (URSL) for upper urinary tract stones between January 2021 and November 2021. The UIE grade and lumen conditions were assessed by endoscopic observation. The effect of UIE grade on URSL and on patient prognosis were analyzed by multiple linear regression and binary logistic regression.

Results

A total of 185 patients were included in the study. UIE grade showed a significant correlation with age, hydronephrosis grading (HG), ureteroscope placement time (UPT), surgery time (ST), hemoglobin disparity value (HDV), and postoperative ureteral stenosis (PUS) (P < 0.05). Logistics regression analysis showed a gradual increase in intraoperative UPT and ST with increase in UIE grade. The severity of UIE showed a negative correlation with improvement of postoperative hydronephrosis (IPH) and the appearance of PUS. HDV was significantly increased in patients with UIE grade 3.

Conclusions

UIE grading can be used as an adjunctive clinical guide for endoscopic treatment of upper urinary tract stones. The postoperative management measures proposed in this study can help inform treatment strategy for ureteral stones.

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.

Predicting narrow ureters before ureteroscopic lithotripsy with a neural network: a retrospective bicenter study

In some patients, the passage of semi-rigid ureteroscopes up the ureter is impossible due to narrow ureteral lumen. We established a neural network to predict the inability of the ureter to accommodate the semi-rigid ureteroscope and the need for active or passive dilatation using non-contrast computed tomography (CT) images. Data were collected retrospectively from two centers of 1989 eligible patients who underwent ureteroscopic lithotripsy with ureteral stones. Patients were categorized into two groups: control and narrow ureter. The network was designed and trained for predicting a narrow ureter during initial ureteroscopic lithotripsy, which integrated multi-scale features of the ureter. The predictive efficacy of neural networks DenseNet3D, ResNet3D, ResNet3D MC, and TimeSformer was compared. Furthermore, a previous ureteroscopy or a history of double-J stent placement, ureteral wall thickness and Hounsfield unit (HU) density of the ureter under the stone were compared. Model performance was assessed based on the accuracy, area under the receiver operating characteristic curve (AUC ROC), etc. The DenseNet3D-based network achieved an AUC ROC score of 0.884 and an accuracy of 85.29%, followed by the ResNet3D-based network, the ResNet3D MC-based network, and the TimeSformer-based network. The DenseNet3D-based network significantly outperformed other candidate predictors. Furthermore, the networks were validated in an external test set. Decision curve analysis showed the clinical utility of the neural network. The neural network provides an individualized preoperative prediction of narrow ureter based on non-contrast CT images, which could be employed as part of a surgical decision-making support system.

Primary impact of simultaneous use of double devices through one-working channel when performing flexible ureteroscope with ureteral access sheath for single ureteral stone: In bench and retrospective clinical study

OBJECTIVES

This study aimed to compare the simultaneous use of two devices versus a single device through a single working channel in flexible ureteroscopy using a ureteral access sheath for single ureteral stones.

METHODS

In a bench study, the time to (i) set laser fiber, (ii) exchange laser fiber and nitinol basket through working channel, and (iii) pull out the device from working channel were measured 10 times in each step. In a clinical study, 156 patients who underwent flexible ureteroscopy with a ureteral access sheath for a ureteral stone in middle and upper ureter between April 2019 and November 2021 were assessed. One device was used at a time for 79 patients (S-Group) and two were simultaneously used for 77 (D-Group). Surgical outcomes and complications were compared.

RESULTS

In the bench study, the mean time to change from laser fiber to basket and from basket to laser fiber through the working channel were 26.1 ± 3.7 s and 23.6 ± 2.0 s (p = 0.084), respectively, which were significantly longer than the laser setup time (p < 0.001). In the clinical study, although the stone-free rate was not significantly different between the groups (S-Group 89.8%, D-Group 93.5%; p = 0.412), the median operation time was significantly shorter (p < 0.001) and the rate of postoperative stenting was significantly lower (p = 0.002) in the D-Group. There were no significant between-group differences in intra- and post-operative complications.

CONCLUSION

The simultaneous use of two devices through a single working channel is safe and could help save the time needed to exchange the laser fiber and nitinol basket.

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.

Predicting ureteral status below the ureteral calculi in patients undergoing ureteroscopic lithotomy

BACKGROUND

During ureteroscopy, severe ureter straightness or contortion may occur before the stone is passed.

PURPOSE

To identify clinical factors associated with distal ureteral status below the ureteral calculi in patients before surgery.

MATERIAL AND METHODS

From October 2016 to March 2017, 101 patients with ureteral calculi who underwent ureteroscopic lithotripsy were reviewed. Patients who lacked clinical data and underwent preoperative indwelling ureteral stent placement were excluded. Univariate and multivariate analyses were performed to determine the clinical factors associated with intraoperative findings.

RESULTS

A total of 101 patients were enrolled in the study (mean age  =  54 years; mean stone size  =  7.9 ± 4.5 mm). Overall, 25 of the 101 patients (24.7%) were diagnosed with poor distal ureteral status defined as intraoperative ureterostenosis or contortion resulting in a ureteroscope being unable to pass during the initial attempt. Univariate analysis showed significant differences in renal parenchyma thickness, ureteral wall thickening on imaging, and stone location (all, P < 0.05) with and without poor distal ureteral status. On multivariable analysis, renal parenchyma thickness (adjusted odds ratio [aOR] 0.288; 95% confidence interval [CI] 0.099-0.838; P = 0.022) and ureteral wall thickening on imaging (aOR 6.114; 95% CI 2.015-18.548; P = 0.001) independently predicted poor distal ureteral status. However, only renal parenchyma thickness was associated with severe ureter straightness or tortuosity that resulted in conversion.

CONCLUSION

In conclusion, renal parenchyma thickness and ureteral wall thickening on imaging were associated with poor distal ureteral status. Therefore, patients with these predictive factors should undergo more intensive preparation before surgery.

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.

Preoperative hydronephrosis is a predictive factor of ureteral stenosis after flexible ureteroscopy: a propensity scores matching analysis

Objectives

Ureteral stenosis is a serious complication of flexible ureteroscopy. How to predict the possibility of stricture before surgery is an important topic. This research retrospectively studied the influence of preoperative hydronephrosis on ureteral stenosis after flexible ureteroscopy, to explore whether the preoperative hydronephrosis could predict postoperative ureteral stenosis.

Methods

We conducted a retrospective study on patients who received flexible ureteroscopy in our hospital for upper ureteral calculi from January 2015 to June 2018. Patients were followed-up for 36 months after surgery, and intraoperative and postoperative complications were recorded. We divided patients into the mild hydronephrosis group and moderate to severe hydronephrosis group. Preoperative clinical baseline data of the patients were adjusted by propensity matching score analysis. Differences of intraoperative ureteral injury, operative time, postoperative ureteral stricture, and SFR one month after surgery was statistically analyzed. Kaplan–Meier’s method and Log-rank test were used to compare the differences in the cumulative incidence of ureteral stenosis between the two groups. Cox regression was used to compare the hazard ratio of ureteral stenosis between the two groups.

Results

A total of 447 patients with 469 sides surgery were included, including 349 sides in the mild hydronephrosis group and 120 sides in the moderate to severe hydronephrosis group. Twenty-nine patients with 30 sides developed ureteral stenosis. Before and after propensity, the incidence of ureteral stricture matching analysis was 6.4% and 8%, respectively. There were statistical differences in ureteral stricture and injury, but the statistical differences in SFR and operation time were inconsistent. Kaplan–Meier showed a significant difference in the cumulative incidence of ureteral stenosis between the two groups.

Conclusions

Patients with moderate to severe hydronephrosis before surgery were more likely to have an intraoperative ureteral injury and postoperative ureteral stricture after FRUS. Preoperative hydronephrosis is an important predictor of ureteral stricture.

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.

Is there any predictive value of the ratio of the upper to the lower diameter of the ureter for ureteral stone impaction?

Background:

We aimed to determine if the ratio of the upper to the lower diameter of the ureter could have any predictive value for ureteral stone impaction.

Materials and methods:

Patients who had a solitary unilateral ureteric stone, determined by noncontrast computerized tomography, were assessed if they had undergone ureteroscopic lithotripsy. A total of 111 patients, 84 males (76%), and 27 females (24%), were recruited to the study. Demographic data of the patients and preoperative radiological parameters based on noncontrast computerized tomography were recorded. The impaction status was also assessed during the operation.

Results:

Of the 111 patients, ureteral stones in 63 (57%) patients were determined to be impacted, and ureteral stones in 48 (43%) were nonimpacted. Impacted stones were more common in older patients, female patients, and patients with an American Society of Anesthesiologists score of 2.

Conclusions:

Significant relationships were found between the impaction status and transverse stone length, longest stone length, upper diameter of the ureter, ratio (upper diameter of the ureter/lower diameter of the ureter), and anteroposterior diameter of the pelvis. These parameters were higher in patients with impacted stones.

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.

Comparison of mini-percutaneous nephrolithotomy and retroperitoneal laparoscopic ureterolithotomy for treatment of impacted proximal ureteral stones greater than 15 mm

BACKGROUND

The optimal treatment for large impacted proximal ureteral stones remains controversial. The aim of this study was to evaluate the efficacy, safety, and potential complications of mini-percutaneous nephrolithotomy (MPCNL) and retroperitoneal laparoscopic ureterolithotomy (RPLU) in the treatment of impacted proximal ureteral stones with size greater than 15 mm.

METHODS

A total of 268 patients with impacted proximal ureteral stones greater than 15 mm who received MPCNL or RPLU procedures were enrolled consecutively between January 2014 and January 2019. Data on surgical outcomes and complications were collected and analyzed.

RESULTS

Demographic and ureteral stone characteristics found between these two groups were not significantly different. The surgical success rate (139/142, 97.9% vs. 121/126, 96.0%, P = 0.595) and stone-free rate after 1 month (139/142, 97.9% vs. 119/126, 94.4%, P = 0.245) of RPLU group were marginally higher than that of the MPCNL group, but there was no significant difference. There was no significant difference in the drop of hemoglobin between the two groups (0.8 ± 0.6 vs. 0.4 ± 0. 2 g/dL, P = 0.621). The mean operative time (68.2 ± 12.5 vs. 87.2 ± 16.8 min, P = 0.041), post-operative analgesics usage (2/121, 1.7% vs. 13/139, 9.4%, P = 0.017), length of hospital stay after surgery (2.2 ± 0.6 vs. 4.8 ± 0.9 days, P < 0.001), double J stent time (3.2 ± 0.5 vs. 3.9 ± 0.8 days, P = 0.027), time of catheterization (1.1 ± 0.3 vs. 3.5 ± 0.5 days, P < 0.001), and time of drainage tube (2.3 ± 0.3 vs. 4.6 ± 0.6 days, P < 0.001) of MPCNL group were significantly shorter than that of the RPLU group. The complication rate was similar between the two groups (20/121, 16.5% vs. 31/139, 22.3%, P = 0.242).

CONCLUSIONS

MPCNL and RPLU have similar surgical success and stone clearance in treating impacted proximal ureteral stones greater than 15 mm, while patients undergoing MPCNL had a lower post-operative pain rate and a faster recovery.

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.

Spontaneous ureteral stone passage: a novel and comprehensive nomogram

BACKGROUND

Ureteral stones pose a high economic and medical burden among Emergency Department (ED) admissions. Management strategies vary from expectant therapy to surgical interventions. Since predictors of ureteral spontaneous stone passage (SSP) are still not well understood, we sought to create a novel nomogram to guide management decisions.

METHODS

Charts were retrospectively reviewed for patients who presented to our institution's ED with non-febrile renal colic and received a radiological diagnosis of ureteral stone ≤10 mm. Demographic, clinical, laboratory, and non-contrast CT data were collected. This novel nomogram incorporates the serum neutrophil-to-lymphocyte ratio (NLR) as a potential predictor of SSP. The model was derived from a multivariate logistic regression and was validated on a different cohort. A receiver operator characteristic (ROC) curve was constructed and the area under the curve (AUC) was computed.

RESULTS

A total of 1186 patients presented to our ED between January 2010 and October 2018. We randomly divided our population into a derivation and validation cohort in one to five ratio. A stone size ≥7 mm was the strongest predictor of SSP failure; OR=9.47; 95% CI: 6.03-14.88. Similarly, a NLR≥3.14 had 2.17; (1.58-2.98) the odds of retained stone. SSP failure was also correlated with proximal position, severe hydronephrosis, and leukocyte esterase ≥75, P=0.02, P=0.05, and P=0.006, respectively. The model had an AUC of 0.804 (0.776-0.832). The nomogram was also used to compute the risk of SSP failure (AUC 0.769 [0.709-0.829]).

CONCLUSIONS

Our novel nomogram can be used as a predictor for SSP and can be used clinically in decision making.

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.

Clinical and Radiological Predictors of Early Intervention in Acute Ureteral Colic

PURPOSE

Acute ureteric colic (AUC) is generally one of the most common reasons for emergency department attendance. Expectant management is recommended in non-complicated ureteral calculi. However, data regarding the optimal duration of observation or indications of early intervention (EI) are not well understood. This article describes the clinical and radiological factors that promote EI in AUC.

PATIENTS AND METHODS

This was an observational and retrospective cohort study. Patients with AUC diagnosed based on non-contrast computerized tomography (NCCT) between 2019 and 2020 were enrolled in the study. These patients were classified into two main categories: spontaneous passage of stone (SSP) and EI. In addition, a comparative analysis was performed to identify clinical and radiological variables that promote EI.

RESULTS

One-hundred and sixty-one patients were included. High WBCs are associated with a significant increase in EI. Forty-three percent (n=37) of patients with serum WBCs higher than 10 had an EI, while 23% had SSP (n=17;p<0.001). High CRP level is also significantly associated with EI (n=36; 86%; p<0.001). Upper and middle ureteral calculi are statistically associated with EI (n=54; 62%) in comparison to the SSP cohort (n=22; 30%;p<0.001). EI is also linked to the maximal length of ureteric calculi (MCL) of 9 mm (6-13mm), and HU density of stone of 700 (430-990) H.U (p<0.001). Ureteric stone volume of 0.2 (0.06-0.3) cm³ is significantly associated with EI (p<0.001). Ureteral wall thickness of 3 (2-3 mm), the presence of extrarenal pelvis (n=20; 23%), and AP diameter of renal pelvis 18 (13-28 mm) are all significantly associated with a higher rate of EI (p<0.001). Multiple binary logistic regression analysis showed that MCL is the strongest predictor of EI.

CONCLUSION

MCL is an independent and robust predictor of EI in AUC. Biochemical variables and radiological characteristics can also act as an adjunct to promote EI.

Role of conservative management of stones

Urinary tract stone disease is one of the most common pathologies of the modern era with a rising prevalence owing to incidentally detected renal stones from imaging for other reasons. Although there is consensus on active management of symptomatic and asymptomatic stones in high-risk patient groups, conservative management of stones is still controversial. We have reviewed the literature pertaining to conservative management of 3 groups of stones-asymptomatic calyceal stones, staghorn stones, and ureteric stones-and summarized the findings to provide guidance in the conservative management of stones. In the calyceal stone group, our review showed an average spontaneous stone passage rate of 18% (range, 8%-32%) and an average requirement for surgical intervention of 20% (range, 7%-40%), with 62% of patients remaining safely on surveillance over a mean time of 4 years. In the staghorn group, overall disease-specific mortality was noted to be 16% (range, 0%-30%) and chance of renal deterioration was 21% (range, 0%-34.5%), with a mean incidence of infection of 22%. In case of conservatively managed ureteric stones, the rate of spontaneous passage for stones smaller than 5 mm was 75%, compared with 62% for those larger than 5 mm. Based on the position in the ureter, spontaneous passage rates were 49%, 58%, and 68% for proximal, middle, and distal thirds, respectively. Conservative management may be recommended for asymptomatic patients and those who are deemed unfit for any procedures. However, careful patient selection and thorough counseling about the risks of conservative management could make it a suitable option for an appropriate subset of patients.

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.

Prospective evaluation and classification of endoscopic findings for ureteral calculi

Difficulty in performing ureteroscopic lithotripsy (URSL) depends on endoscopic findings surrounding calculi. In this multicentre prospective cohort study of 185 patients with a single ureteral stone who underwent ureteroscopic lithotripsy registered in the SMART study between January 2014 and February 2017, we established a classification of endoscopic findings and analysed risk factors for ureteral changes. We evaluated endoscopic findings (oedema, polyps, ureteral mucosa-stone adherence, and distal ureteric tightness) based on the SMART classification. Operative time and ureteral injuries were significantly correlated with endoscopic finding grades. Multivariate analyses revealed that mucosa-stone adherence (MSA) was strongly affected by hydronephrosis grade (odds ratio, 12.4; p = 0.022) and the interval before surgery (odds ratio, 1.10; p = 0.012). The cutoff value for MSA was 98 days, with a predictive accuracy of 0.78. Risk factors for distal ureteric tightness were age (odds ratio, 0.96; p = 0.004) and early intervention (odds ratio, 0.90; p = 0.023). The cutoff value was 34 days, with a predictive accuracy of 0.72. In conclusion, appropriate intervention around 34 days (limited to 98 days) after symptom onset is necessary for treating ureteral calculi. Even if intervention passed 98 days post-symptom onset, staged URSL, alternative procedures, and detailed informed consent should be planned in advance, assuming strong MSA.

Peri-Calculus Ureteral Thickness on Computed Tomography Predicts Stone Impaction at Time of Surgery: A Prospective Study

Introduction and Objectives: Ureteroscopic management of impacted ureteral stones poses multiple challenges. We examined whether ureteral thickness measured on preoperative noncontrast computed tomography (CT) is predictive of stone impaction at the time of ureteroscopy (URS). Methods: Thirty-eight patients with preoperative CT scan and undergoing URS for ureteral stones were prospectively studied. Ureteral thickness directly above, around (peri-calculus ureteral thickness [P-CUT]), and below the calculus were determined on CT scan. The cross-sectional surface area around the stone (P-CUT) was also calculated. Stones were considered impacted at surgery if contrast had difficulty passing, a guidewire could not pass, and the stone was visually impacted >5 on a Likert scale. The surgeon determining intraoperative impaction and the individual measuring the ureteral thickness on CT were blinded. Results: Fourteen of the 38 patients were found to have an impacted ureteral stone at the time of surgery. Patients with an intraoperative finding of an impacted stone had significantly higher ureteral thickness above, around (P-CUT), below the calculus, and P-CUT surface area with all four p-values <0.001. P-CUT surface area was independently predictive of impaction at the time of surgery on multivariate analysis. A mean P-CUT of 6.1 and 1.6 mm and P-CUT surface area of 92.6 and 15.4 mm² were noted for the impacted and nonimpacted stones, respectively. Conclusion: Ureteral thicknesses above, around (P-CUT), and below the calculus are readily measurable on CT scan. P-CUT surface area can also be calculated for a stronger representation of ureteral thickness. These four parameters are predictive of ureteral stone impaction and useful for surgical planning and patient counseling.

A study on the clinical application of a patented perfusion and suctioning platform and ureteral access sheath in the treatment of large ureteral stones below L4 level

Purpose

The purpose of the study was to evaluate the efficacy and safety of a patented perfusion and suctioning platform and ureteral access sheath in the treatment of large ureteral stones (≥ 1.5 cm) below L4 level.

Methods

We recruited 122 patients with large ureteral stones below L4 level at our hospital from December 2014 to June 2017. The patients were randomly divided into the study and control groups. Multiple operative and perioperative parameters were compared between the two groups.

Results

The study group had shorter operation time, less cases of postoperative fever, lower serum levels of PCT, IL-6 and BET within 24 h after surgery, as well as less number of cases receiving secondary surgery than the control group. Moreover, the former had a significantly higher stone clearance rate than the latter (P < 0.05; t-test or χ² test).

Conclusions

The patented perfusion and suctioning platform and ureteral access sheath are safe and effective in treating large ureteral stones (≥ 1.5 cm) below L4 level.

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.