The mean Hounsfield unit range acquired from different slices produces superior predictive accuracy for pyonephrosis in obstructive uropathy.

PURPOSE: To determine the non-contrast computer tomography imaging features of pyonephrosis and evaluate the predictive value of Hounsfield units (HUs) in different hydronephrotic region slices. MATERIALS AND METHODS: We retrospectively reviewed data from patients with hydronephrosis who had renal-ureteral calculi. All patients were categorized into pyonephrosis and simple hydronephrosis groups. Baseline characteristics, the mean HU values in the maximal hydronephrotic region (uHU) slice, and the range of uHU in different slices (ΔuHU) were compared between the two groups. Univariate and multivariate analyses were performed to identify risk factors for pyonephrosis. RESULTS: Among the 181 patients enrolled in the current study, 71 patients (39.2%) were diagnosed with pyonephrosis. The mean dilated pelvis surface areas were comparable between patients with pyonephrosis and simple hydronephrosis (822.61 mm² vs. 877.23 mm², p=0.722). Collecting system debris (p=0.022), a higher uHU (p=0.038), and a higher ΔuHU (p<0.001) were identified as independent risk factors for pyonephrosis based on multivariate analysis. The ΔuHU sensitivity and specificity were 88.7% and 86.4%, respectively, at a cutoff value of 6.56 (p<0.001), whereas the sensitivity and specificity for detecting pyonephrosis at a uHU cutoff value of 7.96 was 50.7% and 70.9%, respectively (p=0.003). CONCLUSIONS: Non-contrast computer tomography was shown to accurately distinguish simple hydronephrosis from pyonephrosis in patients with obstructive uropathy. Evaluation of the ΔuHU in different slices may be more reliable than the uHU acquired from a single slice in predicting pyonephrosis.

Utility of ultrasound-based scoring system in post-pyeloplasty recovery.

BACKGROUND/OBJECTIVE: Differentiation of uretero-pelvic junction obstruction (UPJO) from non-obstructive dilatation (NOD) is a major challenge. The aim of this retrospective study is to determine whether pyeloplasty prediction score (PPS) could predict the need for surgery and resolution after surgery. METHODS: Among patients with antenatally diagnosed hydronephrosis, those who were stable during post-natal follow-up were considered NOD. The UPJO group were the ones who worsened and underwent pyeloplasty based on conventional indications. All patients with UPJO underwent laparoscopic dismembered pyeloplasty. PPS was determined based on three ultrasound parameters obtained retrospectively: Society of Fetal Urology (SFU) grade of hydronephrosis, transverse anteroposterior (APD), and the absolute percentage difference of ipsilateral and contralateral renal lengths. RESULTS: Among 137 patients included (R:L = 59:73; M:F 102:35), 96 were conservatively managed (NOD), while 41 patients (29%) needed pyeloplasty (UPJO). Mean PPS was 4.2 (1.2) in the NOD group and it was significantly higher at 10.8 (1.63) in the UPJO group (p = 0.001). All patients with PPS > 8 needed a pyeloplasty, while two patients with PPS of 7 needed pyeloplasty due to drop in renal function. PPS cutoff value of >8 had a sensitivity 95%, specificity 100% and a likelihood ratio of 20. Post-pyeloplasty PPS resolution was proportional to the duration of follow-up. CONCLUSIONS: A PPS cutoff value of 8 or above is associated with the presence of significant UPJO. PPS is also useful in the assessment of hydronephrosis recovery post-pyeloplasty. The limitation of PPS: it can only be applied in the presence of contralateral normal kidney.

Role of urinary N-acetyl-beta-D-glucosaminidase in predicting the prognosis of antenatal hydronephrosis.

PURPOSE: Urinary biomarkers are known to be able to diagnose renal damage caused by obstruction at an early stage. We evaluated the usefulness of urine N-acetyl-beta-D-glucosaminidase (NAG) to determine the prognosis of antenatal hydronephrosis. MATERIALS AND METHODS: From January 2019 to December 2021, a retrospective study was performed on patients with grade 3 or 4 hydronephrosis. We analyzed the ultrasonographic findings and the urinary NAG/Cr ratio between the laparoscopic pyeloplasty (LP) group and active surveillance (AS) group. RESULTS: A total of 21 children underwent LP for ureteropelvic junction (UPJ) obstruction and 14 children underwent AS. The mean age at the time of examination was 3.7 months (1.7-7.5 months) in the LP and 5.2 months (0.5-21.5 months) in the AS (p=0.564). The mean anteroposterior pelvic diameter was 30.0 mm (15.0-49.0 mm) in the LP and 16.7 mm (9.0-31.3 mm) in the AS (p=0.003). The mean renal parenchymal thickness was 2.6 mm (1.2-3.7 mm) in the LP and 3.8 mm (2.9-5.5 mm) in the AS (p=0.017). The urinary NAG/Cr ratio was 26.1 IU/g (9.8-47.4 IU/g) in the LP and 11.1 IU/g (2.6-18.1 IU/g) in the AS (p=0.003). After LP, the urinary NAG/Cr ratio was significantly reduced to 10.4 IU/g (3.4-14.2 IU/g) (p=0.023). CONCLUSIONS: The urinary NAG/Cr ratio, one of the biomarkers of acute renal injury, is closely related to the degree of hydronephrosis. Therefore, it may be useful to determine whether to perform surgery on the UPJ obstruction and to predict the prognosis.

Hydronephrotic lower moiety of duplex systems: Observations using diuresis renography.

PURPOSE: The purpose of this study is to characterize the prevalence and behavior of hydronephrosis of non-refluxing lower moiety of duplex kidneys using MAG-3 diuresis renography. We compare our data to previous case series and ureteropelvic junction obstruction of single systems. MATERIALS AND METHODS: An IRB-approved database of over 5000 diuresis renograms performed in 2025 patients was queried to identify cases of hydronephrosis of lower moiety of duplex kidneys suspicious for ureteropelvic obstruction, excluding those with hydroureter or reflux. Kidney function and post-furosemide drainage parameters on initial and follow-up diuresis renograms were recorded. Medical records and patient outcomes were reviewed. RESULTS: In total, 19 renal units were identified in 18 patients (11 male, 7 female), age range 0.5 months to 17.8 years, including one patient with bilateral lower moiety hydronephrosis. Initial diuresis renograms in 12 asymptomatic patients (13 renal units) with antenatal hydronephrosis demonstrated varying drainage patterns from normal to obstructed. Follow-up studies showed worsening drainage in 3 patients, who all underwent surgery. Drainage improved in 4 patients and remained unchanged in 5 patients (6 renal units). Of the 6 patients presenting with Dietl's crisis, 5 showed obstructive drainage on initial diuresis renogram, 2/5 with decreased function. All 5 obstructed patients underwent surgery. CONCLUSION: Hydronephrosis of the lower moiety of a duplex system is rare and behaves similarly to single systems. The majority are diagnosed antenatally, display a dynamic nature, and may present with acute obstruction. Diuresis renography is a valuable tool in its evaluation and management.

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.

PET image-guided kidney injury theranostics enabled by a bipyramidal DNA framework.

Understanding the pharmacokinetic profiles of nanomaterials in living organisms is essential for their application in disease treatment. Bipyramidal DNA frameworks (BDFs) are a type of DNA nanomaterial that have shown prospects in the fields of molecular imaging and therapy. To serve as a reference for disease-related studies involving the BDF, we constructed a 68Ga-BDF and employed positron emission tomography (PET) imaging to establish its pharmacokinetic model in healthy mice. Our investigation revealed that the BDF was primarily eliminated from the body via the urinary system. Ureteral obstruction could significantly alter the metabolism of the urinary system. By utilizing the established pharmacokinetic model, we sensitively observed distinct imaging indicators in unilateral ureteral obstruction and acute kidney injury (a complication of ureteral obstruction) mouse models. Furthermore, we observed that the BDF showed therapeutic effects in an AKI model. We believe that the established pharmacokinetic model and unique renal excretion characteristics of the BDF will provide researchers with more information for studying kidney diseases.

Intrinsic ureteric obstruction secondary to endometriosis: a rare clinical entity causing obstructive uropathy and renal failure.

Ureteral endometriosis is rare and can be a silent clinical entity, which can potentially lead to serious complications such as obstructive uropathy, sepsis and renal failure. A high clinical suspicion is required especially in childbearing age groups due to non-specific presentation such as renal colic, recurrent urinary tract infection (UTI), renal failure or asymptomatic hydronephrosis.A woman in her 40s presented with febrile UTI and flank pain. She reportedly suffered from recurrent UTIs in the past. Initial workup revealed an infected, obstructed left renal collecting system with gross hydronephrosis and hydroureter to the distal ureter on a significant gynaecological background of severe endometriosis requiring hysterectomy in the past.CT showed chronic obstructive changes and soft tissue nodules within the renal pelvis with no radio-opaque stones. She underwent emergent ureteric stent insertion. Functional imaging demonstrated only 1% contribution of the left kidney with a preserved estimated glomerular filtration rate of 65 mL/min/1.73 m2Endoscopic evaluation of ureters found extensive soft tissue lesions throughout the dilated left collecting system with biopsy-confirmed endometriosis. Subsequently, she underwent laparoscopic nephroureterectomy due to extensive ureteric involvement and chronically obstructed non-functioning kidney. Histopathology demonstrated completely obstructing ureteral endometriosis.Ureteric obstruction secondary to endometriosis can be due to extrinsic or intrinsic disease. In addition to initial assessment with CT urogram MRI may be helpful to evaluate soft tissue thickening. Endoscopic assessment with ureteroscopy and biopsy is required for tissue diagnosis. Surgery is often the treatment of choice, ranging from ureteroureterostomy, ureteroneocystostomy or nephroureterectomy in severe cases.Ureteral endometriosis is a rare clinical entity, clinicians should remain vigilant about common presentations of this rare entity, early diagnosis and prompt treatment is crucial to prevent progression to renal failure.

Complications Subsequent to Urinary Tract Stent Placement: An Overview Focusing on the Imaging of Cancer Patients.

Ureteral involvement by a tumor is common, and both partial and complete obstructions can result in symptoms that are distressing and debilitating, especially in cancer patients for whom the resection of the primary tumor is not considered an option. Maintaining ureteric patency in these patients is a challenge. In addition, in cases where a patient has undergone nephroureterectomy due to primary transitional cell cancer, it becomes necessary to decompress the urinary tract to preserve the contralateral kidney from irreversible damage. This is possibly due to ureteral stenting, both retrograde and anterograde, and percutaneous nephrostomy (PCN). Since imaging plays an important role in the routine monitoring of stents, their more and more increasing use requires radiologists to be familiar with these devices, their correct position, their potential complications, and their consequences. The aim of this review is to offer a comprehensive review of the imaging features of some urinary stents and to show the complications encountered in cancer patients as a direct consequence of an invasive diagnostic or therapeutic procedure. Specifically, we focus on ureteral stents and PCN.

Amide Proton Transfer-Weighted Magnetic Resonance Imaging for Application in Renal Fibrosis: A Radiological-Pathological-Based Analysis.

INTRODUCTION: Renal fibrosis (RF), being the most important pathological change in the progression of CKD, is currently assessed by the evaluation of a biopsy. This present study aimed to apply a novel functional MRI (fMRI) protocol named amide proton transfer (APT) weighting to evaluate RF noninvasively. METHODS: Male Sprague-Dawley (SD) rats were initially subjected to bilateral kidney ischemia/reperfusion injury (IRI), unilateral ureteral obstruction, and sham operation, respectively. All rats underwent APT mapping on the 7th and 14th days after operation. Besides, 26 patients underwent renal biopsy at the Nephrology Department of Shanghai Tongji Hospital between July 2022 and May 2023. Patients underwent APT and apparent diffusion coefficient (ADC) mappings within 1 week before biopsy. MRI results of both patients and rats were calculated by comparing with gold standard histology for fibrosis assessment. RESULTS: In animal models, the cortical APT (cAPT) and medullary APT (mAPT) values were positively correlated with the degree of RF. Compared to the sham group, IRI group showed significantly increased cAPT and mAPT values on the 7th and 14th days after surgery, but no group differences were found in ADC values. Similar results were found in human patients. Cortical/medullary APT values were significantly increased in patients with moderate-to-severe fibrosis than in patients with mild fibrosis. ROC curve analysis indicated that APT value displayed a better diagnostic value for RF. Furthermore, combination of cADC and cAPT improved fibrosis detection by imaging variables alone (p < 0.1). CONCLUSION: APT values had better diagnostic capability at early stage of RF compared to ADC values, and the addition of APT imaging to conventional ADC will significantly improve the diagnostic performance for predicting kidney fibrosis.

Predicting obstruction risk using common ultrasonography parameters in paediatric hydronephrosis with machine learning.

OBJECTIVE: To sensitively predict the risk of renal obstruction on diuretic renography using routine reported ultrasonography (US) findings, coupled with machine learning approaches, and determine safe criteria for deferral of diuretic renography. PATIENTS AND METHODS: Patients from two institutions with isolated hydronephrosis who underwent a diuretic renogram within 3 months following renal US were included. Age, sex, and routinely reported US findings (laterality, kidney length, anteroposterior diameter, Society for Fetal Urology [SFU] grade) were abstracted. The drainage half-times were collected from renography and stratified as low risk (<20 min, primary outcome), intermediate risk (20-60 min), and high risk of obstruction (>60 min). A random Forest model was trained to classify obstruction risk, here named the 'Artificial intelligence Evaluation of Renogram Obstruction' (AERO). Model performance was determined by measuring area under the receiver-operating-characteristic curve (AUROC) and decision curve analysis. RESULTS: A total of 304 patients met the inclusion criteria, with a median (interquartile range) age of diuretic renogram at 4 (2-7) months. Of all patients, 48 (16%) were low risk, 102 (33%) were intermediate risk, 156 (51%) were high risk of obstruction based on diuretic renogram. The AERO achieved a binary AUROC of 0.84, multi-class AUROC of 0.74 that was superior to the SFU grade, and external validation (n = 64) binary AUROC of 0.76. The most important features for prediction included age, anteroposterior diameter, and SFU grade. We deployed our application in an easy-to-use application (https://sickkidsurology.shinyapps.io/AERO/). At a threshold probability of 30%, the AERO would allow 66 more patients per 1000 to safely avoid a renogram without missing significant obstruction compared to a strategy in which a renogram is routinely performed for SFU Grade ≥3. CONCLUSIONS: Coupled with machine learning, routine US findings can improve the criteria to determine in which children with isolated hydronephrosis a diuretic renogram can be safely avoided. Further optimisation and validation are required prior to implementation into clinical practice.

Percutaneous Nephroureteral Stent Placement and Antegrade Forceps Biopsy of Ureteral Obstruction.

PURPOSE: To evaluate the feasibility of percutaneous transluminal ureteral biopsy (PTUB) combined with percutaneous nephroureteral stent placement for ureteral obstruction under fluoroscopy. MATERIALS AND METHODS: From September 2011 to July 2021, 37 patients (27 men and 10 women; median age, 65.0 years) who experienced ureteroscopic biopsy failure or refused or were unable to undergo ureteroscopic biopsy underwent PTUB for ureteral obstruction during nephroureteral stent placement under fluoroscopic guidance. Data on technical success, early adverse events, and radiation dose were collected. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) of PTUB were analyzed. RESULTS: The technical success of PTUB was 89.2%, with a mean irradiation dose of 76.9 mGy·cm2 ± 12.2. A total of 67.6% (25/37) of the cases were correctly diagnosed with malignancy, whereas 8 cases were confirmed to be true negatives. There were 4 false negatives and no false positives. PTUB had a sensitivity, specificity, PPV, NPV, and OA of 86.2% (25/29), 100% (8/8), 100% (25/25), 66.7% (8/12), and 89.2% (33/37), respectively. Eleven patients (29.7%) experienced Grade 1 adverse events (transient aggravated hematuria). CONCLUSIONS: PTUB appears to be a safe and effective alternative to ureteroscopic biopsy for ureteral obstruction.

Magnetic Compression Anastomosis of Benign Short-Segment Ureteral Obstruction.

PURPOSE: To investigate the feasibility, safety, and effectiveness of magnetic compression anastomosis of benign short-segment ureteral obstruction. MATERIALS AND METHODS: Patients referred for failure of ureteral double-J stent placement because of impassable benign ureteral obstruction were included. Eleven patients (11 ureters) with a mean age of 57.5 years (range, 19-85 years; 8 women) underwent ureteral magnetic compression anastomosis. All patients had indwelling nephrostomy catheters. In all patients, anterograde and retrograde ureteral stent placements were unsuccessful using either interventional or cystoscopic access. Ureteral magnetic compression anastomosis was performed as a 2-step procedure. In the first step, magnets were placed. In the second step, the stricture was traversed via magnetic compression anastomosis. Successful establishment of anastomosis and ureteral double-J stent placement were considered technical success. The mean time for complete magnetic adherence and fluoroscopy time for each procedure were recorded. RESULTS: Five patients (45%) had an ileal conduit. The technical success rate was 91% (n = 10/11). The mean time for magnetic adherence was 5.7 days (SD ± 1.3). The mean single-rotation fluoroscopy times during the first and second steps of the procedure were 9.45 minutes (SD ± 2.09) and 15.70 minutes (SD ± 2.62), respectively. Magnets were removed with the support of either balloon catheters (n = 9) or biopsy forceps (n = 2). No procedure-related adverse events occurred. CONCLUSIONS: Magnetic compression anastomosis of benign ureteral obstruction is feasible and safe and can be performed in an interventional radiology (IR) suite without the need for endoscopy.

Risk factors for adverse outcomes after pediatric pyeloplasty: A retrospective cohort study.

PURPOSE: To identify the risk factors for adverse outcomes after pediatric pyeloplasty. METHODS: We conducted a retrospective review of all children under the age of 14 years who underwent primary pyeloplasty for unilateral ureteropelvic junction (UPJ) obstruction at a single teaching hospital in Tunisia between January 1, 2013, and December 31, 2022. RESULTS: A total of 103 patients were included. Median age of patients at surgery was 27 months (interquartile range [IQR], 13-44). On ultrasound, median renal pelvic anteroposterior diameter was 3.2 cm (IQR, 2.3-4), and the median renal cortex thickness (RCT) was 2.5 mm (IQR, 2-3.5). Median differential renal function (DRF) on preoperative radionuclide renal scan was 40% (IQR, 30-46). Postoperative adverse outcomes occurred in 28 patients (27.2%). These included 19 cases of urinary tract infections (UTIs), 11 cases of UPJ restenosis, four cases of UPJ leakage, two cases of urinoma, and two cases of diversion-related complications. Multivariate logistic regression analysis revealed two factors significantly and independently related to postoperative negative outcomes: RCT <3 mm and DRF > 50%. CONCLUSION: Our study demonstrated that preoperative RCT on ultrasound of less than 3 mm and preoperative DRF on radionuclide renal scan of more than 50% were independent risk factors for adverse outcomes following pediatric pyeloplasty. These factors could be of interest in identifying, early on, patients who will develop postoperative negative outcomes, giving them more attention and support, and explaining the prognosis to the patient and family.

Analysis of the Efficacy of Elastography in Comparison with Dynamic Renal Nuclear Scintigraphy in the Evaluation of Unilateral Pelvi-Ureteric Junction Obstruction.

INTRODUCTION: In hydronephrosis due to pelviureteric junction obstruction (PUJO), an obstruction to urine flow may lead to increased pelvic pressure, which may cause interstitial fibrosis and renal impairment. Recently, there have been reports on renal pelvic assessment using ultrasound elastography (USE). This study was conducted to see if USE can evaluate PUJO and if it can be correlated to the findings of the dynamic renal nuclear scan. MATERIAL AND METHODS: In this observational study, only patients with unilateral PUJO underwent acoustic radiation force impulse (ARFI) elastography. A rectangular region of interest (ROI) measuring 5 × 10 mm was positioned on the cortex region of the upper, mid, and lower poles of the affected kidney. Three valid measurements were obtained, from which a mean value was calculated. A dynamic renal nuclear scan using Technetium-99m ethylene dicysteine (EC or TC99 m EC) was obtained and split renal function (SRF) was used for comparison. RESULTS: In the group of 20 patients, the mean age was 3.37 years. The mean SRF of the affected kidney was 26.65 %, and the corresponding USE value was 0.45 kpa. The Spearman's rho correlation coefficient for SRF and USE was 1 and 0.672, respectively (p = 0.001). Elastography was not feasible if SRF was less than 20 %. CONCLUSION: USE may be able to comment on the renal functional status of hydronephrosis. If USE is reported as non-feasible, it may suggest that renal function is grossly compromised. It may serve as an alternative diagnostic modality for renal functional evaluation. LEVEL OF EVIDENCE: Level II, Prospective Cohort Study.

[Evaluation of the Effects of Long-Term Indwelling Ureteral Stents on Preserving Renal Parenchyma and Function in Patients with Ureteral Stenosis].

Although ureteral stenting is a common conservative treatment for ureteral stricture, it is unclear whether a long-term indwelling ureteral stent protects the kidney against parenchymal atrophy and functional deterioration. In this study, we evaluated the changes in renal parenchymal thickness (RPT) and estimated the glomerular filtration rates (eGFR) in patients with indwelling ureteral stents for one year or more. As a control, we also evaluated changes in RPT associated with indwelling percutaneous nephrostomy (PNS) for one year or more. Polymer ureteral stents were used and replaced every three months. RPT was measured using computed tomography (CT). Totally, 69 renal units in 55 patients with baseline and follow up CT scans available were enrolled. The median follow-up period was 29 months. The etiologies of ureteral obstruction were malignant and benign disease in 27 and 28, respectively. RPT was reduced obviously in most cases. At 1 year, the median reduction rate of RPT was 17.3% in unilateral cases, which was significantly higher than that in the healthy contralateral kidney. There was a strong correlation between eGFR and total RPT including the contralateral kidney. The reduction rate of RPT in kidneys with ureteral stents including bilateral cases was also significantly higher than that in 39 renal units of 35 patients with PNS. The results of this study suggest that the long-term efficacy of indwelling ureteral stents in preserving renal function is limited. Regular imaging may be essential to evaluate the residual renal function.

Combination of robot-assisted laparoscopy and ureteroscopy for the management of complex ureteral strictures.

BACKGROUND: To summarize the efficacy of combined robot-assisted laparoscopy and ureteroscopy in treating complex ureteral strictures. METHODS: Eleven patients underwent combined robot-assisted laparoscopy and ureteroscopy for ureteral strictures between January 2020 and August 2022. Preoperative B-ultrasound, glomerular filtration rate measurement, and intravenous pyelography showed different degrees of hydronephrosis in the affected kidney and moderate to severe stenosis in the corresponding part of the ureter. During the operation, stricture segment resection and end-to-end anastomosis were performed using the da Vinci robot to find the stricture point under the guidance of a ureteroscopic light source in the lateral or supine lithotomy position. RESULTS: All the patients underwent robot-assisted laparoscopy and ureteroscopy combined with end-to-end ureterostenosis. There were no conversions to open surgery or intraoperative complications. Significant ureteral stricture segments were found in all patients intraoperatively; however, stricture length was not significantly different from the imaging findings. Patients were followed up for 3-27 months. Two months postoperatively, the double-J stent was removed, a ureteroscopy was performed, the ureteral mucosa at the end-to-end anastomosis grew well, and the lumen was patent in all patients. Furthermore, imaging examination showed that hydronephrosis was significantly improved in all patients, with grade I hydronephrosis in three cases and grade 0 hydronephrosis in eight cases. No recurrence of ureteral stricture was observed in patients followed up for > 1 year. CONCLUSION: Robot-assisted laparoscopy combined with ureteroscopy is an effective method for treating complex ureteral strictures and can achieve accurate localization of the structured segment.