Predictive role of ureteral wall thickness and patient characteristics in endoscopic treatment outcomes for ureteral stricture disease following stone surgery.

PURPOSE: To evaluate the role of certain radiological parameters and patient characteristics in predicting the success of endoscopic treatment in ureteral stricture disease. METHODS: Fifty one adult patients with ureteral stricture disease (< 1 cm) after developing due to upper ureteral stones with ureteroscopic laser disintegration were included and in addition to stone and patient parameters, radiological parameters including ureteral wall thickness (UWT) at the impacted stone site were also measured on computed tomography (CT) images. Patients were divided into two groups: Group 1: Patients with endoscopic treatment success and Group 2: Patients with endoscopic treatment failure. The possible relationship between the UWT values and other radiological parameter was comparatively evaluated. RESULTS: Mean UWT value assessed at the treated stone site was significantly higher in cases unresponsive to endoscopic treatment with values of 2.77 ± 1.03 mm and 4.25 ± 1.32 mm in Group 1 and 2 respectively. A cut off value 3.55 mm for UWT was found to be highly predictive for endoscopic treatment failure. CONCLUSIONS: Our current results indicated that assessment of UWT value at the obstructing stone could be helpful enough to predict the likelihood of failure following endoscopic management of strictures with high sensitivity and specificity. Evaluation of this particular parameter could let the endourologists to look for more rational treatment alternatives with necessary measures taken on time.

Comparison of diagnostic accuracy of ultra low-dose computed tomography and X-ray of the kidneys, ureters and bladder for urolithiasis in the follow-up setting.

INTRODUCTION: Urolithiasis is frequently followed up with a low-dose computed tomography of the kidneys ureters and bladder (LD-CTKUB) with doses typically less than 3 millisieverts. Although X-ray is a lower dose (0.5-1.1 mSv) alternative for follow up, it has lower diagnostic accuracy and is limited to radiopaque calculi. This study aims to compare the diagnostic accuracy of sub-millisievert ultra-low dose CT (ULD-CTKUB) against X-ray KUB for the follow up of urolithiasis when both are compared against the standard of care of a low-dose CT KUB (LD-CTKUB). METHODS: This prospective study included patients with a known diagnosis of urolithiasis on prior CTKUB presenting for follow up. Each patient underwent a repeat reference LD-CTKUB, ULD-CTKUB and X-ray KUB. All imaging studies were interpreted by three readers. The radiation dose and quantitative noise was calculated for each CT. Both CT and X-ray were assessed for the presence, number and size of all calculi ≥2 mm. RESULTS: A total of 58 patients were included in this study. LD-CTKUB identified 197 calculi. ULD-CTKUB in our study had a mean effective dose of 0.5 mSv compared to X-ray KUB where doses range in the literature from 0.5 to 1.1 mSv. Per-patient pooled analysis for intrarenal calculi when comparing ULD-CTKUB versus X-ray KUB against a reference LD-CTKUB found a sensitivity of 90% versus 67% (P < 0.01) and specificity of 93% versus 98% (P = 0.18) respectively. For ureteric calculi, the sensitivity was 67% versus 33% (P < 0.01) and specificity 94% versus 94% (P = 1.00) respectively. Per-stone pooled analysis detection rate was 79% for ULD-CTKUB versus 48% for X-ray (P < 0.01) when each was compared to the reference LD-CTKUB. Interobserver agreement was high for intrarenal calculi and moderate for ureteric calculi. CONCLUSION: Sub-millisievert ULD-CTKUB had lower doses and higher sensitivity than X-ray in patients requiring follow up of known urolithiasis.

Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones.

To establish a safer and more efficient treatment strategy with mini-endoscopic combined intrarenal surgery (ECIRS), the present study aimed to develop models to predict the outcomes of mini-ECIRS in patients with renal and/or ureteral stones. We retrospectively analysed consecutive patients with renal and/or ureteral stones who underwent mini-ECIRS at three Japanese tertiary institutions. Final treatment outcome was evaluated by CT imaging at 1 month postoperatively and stone free (SF) was defined as completely no residual stone or residual stone fragments ≤ 2 mm. Three prognostic models (multiple logistic regression, classification tree analysis, and machine learning-based random forest) were developed to predict surgical outcomes using preoperative clinical factors. Clinical data from 1432 ECIRS were pooled from a database registered at three institutions, and 996 single sessions of mini-ECIRS were analysed in this study. The overall SF rate was 62.3%. The multiple logistic regression model consisted of stone burden (P < 0.001), number of involved calyces (P < 0.001), nephrostomy prior to mini-ECIRS (P = 0.091), and ECOG-PS (P = 0.110), wherein the area under the curve (AUC) was 70.7%. The classification tree analysis consisted of the number of involved calyces with an AUC of 61.7%. The random forest model showed that the top predictive variable was the number of calyces involved, with an AUC of 91.9%. Internal validation revealed that the AUCs for the multiple logistic regression model, classification tree analysis and random forest models were 70.4, 69.6 and 85.9%, respectively. The number of involved calyces, and a smaller stone burden implied a SF outcome. The machine learning-based model showed remarkably high accuracy and may be a promising tool for physicians and patients to obtain proper consent, avoid inefficient surgery, and decide preoperatively on the most efficient treatment strategies, including staged mini-ECIRS.

Endoscopic stone management in an ectopic ureter inserting into the prostatic urethra.

We report a case of successful endoscopic stone management in a patient with ectopic ureteric insertion. The patient had a complete duplex collecting system, with the upper moiety ureter inserting ectopically into his prostatic urethra, and an obstructing ureteric stone in the distal portion of the ectopic ureter. This made both characterisation of the patient's anatomy and initial emergency stone management challenging.The case offers several learning points for clinicians who may encounter similar situations. By describing the challenges of managing this patient's presentation, we highlight considerations in imaging interpretation and operative approach that may help the reader manage a similar presentation to their practice. Additionally, we remind the urologist to consider the implications of an ectopic duplex ureter on future procedures, such as transurethral resection of the prostate or radical prostatectomy.

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.

Real-world Practice Stone-free Rates After Ureteroscopy: Variation and Outcomes in a Surgical Collaborative.

BACKGROUND: Studies assessing the stone-free rate (SFR) after ureteroscopy are limited to expert centers with varied definitions of stone free. Real-world data including community practices related to surgeon characteristics and outcomes are lacking. OBJECTIVE: To evaluate the SFR for ureteroscopy and its predictors across diverse surgeons in Michigan. DESIGN, SETTING, AND PARTICIPANTS: We assessed the Michigan Urological Surgery Improvement Collaborative (MUSIC) clinical registry for patients with renal or ureteral stones treated with ureteroscopy between 2016 and 2021 who had postoperative imaging. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Stone free was defined as no fragments on imaging reports within 60 d entered by independent data abstractors. Factors associated with being stone free were examined using logistic regression, including annual surgeon volume. We then assessed variation in surgeon-level SFRs adjusted for risk factors. RESULTS AND LIMITATIONS: We identified 6487 ureteroscopies from 164 surgeons who treated 2091 (32.2%) renal and 4396 (67.8%) ureteral stones. The overall SFRs were 49.6% (renal) and 72.7% (ureteral). Increasing stone size, lower pole, proximal ureteral location, and multiplicity were associated with not being stone free. Female gender, positive urine culture, use of ureteral access sheath, and postoperative stenting were associated with residual fragments when treating ureteral stones. Adjusted surgeon-level SFRs varied for renal (26.1-72.4%; p < 0.001) and ureteral stones (52.2-90.2%; p < 0.001). Surgeon volume was not a predictor of being stone free for renal stones. Limitations include the lack of imaging in all patients and use of different imaging modalities. CONCLUSIONS: The real-world complete SFR after ureteroscopy is suboptimal with substantial surgeon-level variation. Interventions focused on surgical technique refinement are needed to improve outcomes for patients undergoing ureteroscopy and stone intervention. PATIENT SUMMARY: Results from a diverse group of community practicing and academic center urologists show that for a large number of patients, it is not possible to be completely stone free after ureteroscopy. There is substantial variation in surgeon outcomes. Quality improvement efforts are needed to address this.

Laparoscopic Ureterolithotomy and Single-Use Digital Flexible Ureteroscope For Unilateral Large Ureteral Stone and Small Renal Stone.

BACKGROUND The removal of concurrent ureteral and renal stones within a single procedure has always been a challenge for urological surgeons. The incorporation of single-use digital flexible ureteroscopes into laparoscopic ureterolithotomy procedures has demonstrated effective removal of concurrent stones with a good clearance rate and decreased risk of bleeding and trauma. We report the successful removal of a unilateral upper ureteral stone and a smaller renal stone with this procedure. CASE REPORT A 60-year-old man visited the outpatient clinic with an ultrasonography report that revealed a large proximal ureteral stone with moderate hydronephrosis, accompanied by bilateral renal stones and prostatic hyperplasia. He had been experiencing urinary urgency for a year and was determined to undergo lithotomy. Due to his longstanding history of coronary artery disease and myocardial ischemia, the urologists decided that concurrent stone removal within an operation would be the best treatment. A preoperative computed tomography urogram measured the left ureteral and renal stones to be 2.0×0.8 cm and 0.6 cm, respectively. Both stones were successfully removed by laparoscopic ureterolithotomy using a single-use digital flexible ureteroscope. The patient had an uneventful recovery and remained well 1 month post-operation. CONCLUSIONS The application of single-use digital flexible ureteroscopes for laparoscopic ureterolithotomy has demonstrated safety, efficiency, and cost-effectiveness. The authors believe that it is a safe alternative for the removal of concurrent ureteral and renal stones, especially in patients with multiple comorbidities.

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.

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.

Software-Estimated Stone Volume Is Better Predictor of Spontaneous Passage for Acute Nephrolithiasis.

Purpose: To evaluate whether computer program-estimated urolith stone volume (SV) was a better predictor of spontaneous passage (SP) compared with program-estimated stone diameter (PD) or manually measured stone diameter (MD), and whether utilizing SV and MD together provided additional value in SP prediction compared with MD alone. Materials and Methods: Retrospective analysis of patients with acute renal colic and single renal/ureteral stone on CT from July 2017 to April 2020. Diameter obtained from radiology reports or manually measured when report not available. Semiautomated stone analysis software (qSAS) was used to estimate SV and PD. ROC analysis was performed to compare accuracy of SV vs MD vs PD in predicting SP by 2, 4, and 6 weeks. Subgroup analysis was performed by stone size (

Ureteral wall thickness and distal ureteral density in patients with residual fragments after Ho:YAG laser semi-rigid ureterolithotripsy.

Recent data suggest that greater ureteral density distal to ureteral stones or increased ureteral wall thickness (UWT) can predict impacted stones. The aim of our study was to evaluate if patients with residual fragments present with greater ureteral density and larger UWT when compared to stone-free patients. From January onward, a consecutive series of patients undergoing semi rigid Ho:YAG laser ureterolithotripsy (ULT) for ureteral stones were enrolled. A non-contrast enhanced computed tomography (CT) scan was performed before the procedure to evaluate distal ureteral density (DUD) and wall ureteral thickness (UWT) at the site of ureteral stones. Patients with residual fragments were compared to stone-free patients using a matched-pair analysis (1:1 scenario). Cases were matched sequentially using the following criteria: age, gender, body mass index (BMI), stone length, hydronephrosis, location of stones, and mean Hounsfield unit (HU) of the stone. Overall, 160 patients were enrolled, mean age was 57.9 ± 14 years, mean BMI was 25.8 ± 4 kg/m2, mean length of the stone was 10.6 ± 4.9 mm, and mean UWT was 1.4 ± 1.6 mm. A total of 150/160 (94%) patients presented hydronephrosis; mean HU stone was 868 ± 327; mean DUD was 54 ± 17.8 HU. Ureteral distal density (51.7 vs 56.6; p = 0.535) and ureteral distal thickness (1.39 vs 1.54; p = 0.078) were similar in both groups of patients. In our study, the evaluation of distal ureteral density does not predict stone-free rate. Further studies should evaluate the role for preoperative computer tomography in predicting surgery outcome.

CT-Based Predictor for the Success of 12/14-Fr Ureteral Access Sheath Placement.

Purpose: Ureteral access sheaths (UAS) are widely used in retrograde intrarenal surgery (RIRS), and this study aimed to develop a model for predicting the success of UAS placement based on computed tomography. Methods: We analyzed the clinical data of 847 patients who received ureteroscopy. Data on patient and stone characteristics and several computed tomography (CT)-based measurements were collected. A nomogram predicting the success of UAS placement was developed and validated using R software. Results: Two hundred and forty-seven patients were identified. Twenty-five patients (10.1%) failed to pass through the UAS. A model with three factors including the short diameter of ureteral calculi, the short diameter of hydronephrosis, and the diameter of the narrowest part of the renal parenchyma was to be strongly practical and had a high area under the curve on internal validation (80.3%). Using a threshold cutoff of 92%, the sensitivity and specificity for predicting UAS placement were 0.35 and 0.92, respectively. Conclusion: Our study provides a nomogram for predicting the success of UAS placement, and this model could help discriminate patients who are likely to suffer from failed UAS insertion; preoperative ureteral stenting is recommended according to the prediction.

Laparoscopic transperitoneal ureterolithotomy is an effective and safe method for >15 mm impacted ureteral stones in elderly patients: single center 10-year experience.

OBJECTIVE: The aim of our study is to investigate the efficacy and safety of laparoscopic ureterolithotomy operation in elderly patients with large and impacted ureteral stones. PATIENTS AND METHODS: Between January 2011 and July 2021, 66 elderly patients with impacted, > 15 mm upper and middle ureteral stones underwent laparoscopic ureterolithotomy in our center. The data for all patients were evaluated retrospectively. RESULTS: The mean age of the patients was 65 ± 5.43 years. The mean stone size was 20.2 ± 2.5 mm. The mean operation time was 93.6 ± 13.2 minutes. Among patients, 16 (24.2%) had history of unsuccessful shock wave lithotripsy and 12 (18.1%) patients had history of ureterorenoscopy. Stone-free rate was 95.4% in all patients. Modified Clavien grade 1 complications were seen in 18 patients (27.2%), but no significant perioperative and postoperative complications were observed. Urinary extravasation lasting 5, 7 and 9 days was observed in 5 patients (7.5%) who were treated conservatively. The mean hospital stay was 3.4 ± 1.52 days. The patients were asymptomatic at the 6th week post-op follow-up, and no stones were seen on direct X-ray and abdominal ultrasonography. Intravenous urography and non-contrast tomography (NCCT) taken 3 months later did not show any obstruction or stenosis in the ureter. CONCLUSIONS: Laparoscopic ureterolithotomy can be considered as the first treatment option for elderly patients with impacted and large ureteral stones, thanks to its high success and acceptable complication rates.

Evaluation of the relation between size of stone and its attenuation measured by Hounsfield units and the total laser energy required to fragment it.

BACKGROUND: Anticipating the total laser energy (TLE) of Holmium YAG laser required for ureteroscopic (URS) lithotripsy is essential to guide urologists in selecting the optimal fiber size. This study aimed at evaluating the relationship between stone size and stone attenuation measured by HU as predictors for the TLE during the procedure. METHODS: We conducted an observational prospective cohort study of patients undergoing URS lithotripsy at the Urology department of Ain Shams University Hospitals from September 2018 to September 2019 with the use of a holmium YAG laser as the lithotripsy method. Patients' demographic and clinical characteristics, stone location, stone size, stone attenuation measured by HU from the non-contrast CT, TLE, and procedure time were recorded. Data were analyzed using Jamovi software (version 2.0 for macOS). RESULTS: Forty patients were included in the study (22 males and 18 females) with a mean age of 57.8 years. The mean stone size was 9.8 mm3, the mean HU was 858.8 units, and the mean TLE was 3.5 KJ. Both stone size and stone attenuation measured by HU were positively correlated with TLE (r = 0.81 and 0.84, respectively; p < 0.001 for both). Further, regression analysis showed that both variables could significantly predict the TLE (ß = 0.001 and 0.71, respectively). CONCLUSIONS: Both stone attenuation, as measured by HU, and stone size positively correlate with TLE required for URS lithotripsy. Therefore, both HU and stone size can predict the TLE, which will be helpful to guide the urologist in selecting the optimal fiber size for the procedure.

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.

Ureteral calculi lithotripsy for single ureteral calculi: can DNN-assisted model help preoperatively predict risk factors for sepsis?

OBJECTIVES: To explore the utility of radiomics and deep learning model in assessing the risk factors for sepsis after flexible ureteroscopy lithotripsy (FURL) or percutaneous nephrolithotomy (PCNL) in patients with ureteral calculi. METHODS: This retrospective analysis included 847 patients with treatment-naive proximal ureteral calculi who received FURL or PCNL. All participants were preoperatively conducted non-contrast computed tomography scans, and relevant clinical information was meanwhile collected. After propensity score matching, the radiomics model was established to predict the onset of sepsis. A deep learning model was also adapted to further improve the prediction accuracy. Performance of these trained models was verified in another independent external validation set including 40 cases of ureteral calculi patients. RESULTS: The overall incidence of sepsis after FURL or PCNL was 5.9%. The least absolute shrinkage and selection operator (LASSO) regression analysis revealed 26 predictive variables, with an overall AUC of 0.881 (95% CI, 0.813-0.931) and an AUC of 0.783 (95% CI, 0.766-0.801) in external validation cohort. Judicious adaption of a deep neural network (DNN) model to our dataset improved the AUC to 0.920 (95% CI, 0.906-0.933) in the internal validation. To eliminate the overfitting, external validation was carried out for DNN model (AUC = 0.874 (95% CI, 0.858-0.891)). CONCLUSIONS: The DNN was more effective than the LASSO model in revealing risk factors for sepsis after FURL or PCNL in single ureteral calculi patients, and females are more susceptible to sepsis than males. Deep learning models have the potential to act as gatekeepers to facilitate patient stratification. KEY POINTS: • Both the least absolute shrinkage and selection operator (LASSO) and deep neural network (DNN) models were shown to be effective in sepsis prediction. • The DNN model achieved superior prediction capability, with an AUC of 0.920 (95% CI, 0.906-0.933). • DNN-assisted model has potential to serve as a gatekeeper to facilitate patient stratification.