The Morbidity of Ureteral Strictures in Patients with Prior Ureteroscopic Stone Surgery: Multi-Institutional Outcomes

Dynamic renal scans as a modality for follow-up of flexible ureteroscopy

OBJECTIVE

To determine whether dynamic renal scans - DTPA or MAG3 - routinely performed after flexible ureteroscopies (f-URS) could detect the development of an obstruction and thus promote prompt early intervention for kidney preservation.

PATIENTS AND METHODS

In this retrospective study, with all the data recorded prospectively between April 2010 and October 2023, 250 renal units in 242 patients with upper urinary tract stones (UUTS) who underwent ureterorenoscopy by one surgeon in the same medical center were evaluated. Stone-free rate (SFR) was defined as no residual fragments at all using an intraoperative "triple test". The following characteristics were examined: gender, BMI, age, Hounsfield unit, stone diameter, laterality, renal/ureteral stones, stone-free rate, and auxiliary procedures per renal unit. The Clavien-Dindo classification was used to report complications. Renal units with residual stones were scheduled for a 2nd f-URS. Post- flexible ureteroscopy ureteral obstruction and renal function were detected using renal scan DTPA or MAG-3. The primary outcome was renal/ ureteral obstruction.

RESULTS

The mean patient age was 53 years. The mean stone size was 12.3 mm. Stones in renal pelvis, upper, middle and lower calyces were treated in 9.2% (23), 27.6% (69), and 30.8% (77) of cases, respectively; 44% (110) ureteral stones were also treated. The single- and second-session SFRs were 94.8% and 99.7%, respectively. A third auxiliary procedure was needed in one renal unit (0.4%). The mean number of procedures per renal unit was 1.06 (264/250). Ureteral double-J stents were inserted in 53.6% (134) of the cases. In 37 (14.8%) cases, a stent was placed before surgery. Post-operative complications were minor, with readmission and pain control needed in only two patients (0.8%). No avulsion or perforation of the ureters was observed. In six patients with t1/2 between 10-20 minutes, a second renal scan revealed spontaneous improvement and no obstruction in five patients. One patient with large stones and a history of prior ureteroscopy developed a ureteral stricture (0.4%) and needed treatment with laser endoureterotomy.

CONCLUSIONS

Post-flexible ureteroscopy obstruction due to ureteral stricture is very rare. A routine renal scan post-operatively may be used in potentially high-risk patients.

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.

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.

Evaluation of a novel circulation system for ureteroscopic laser lithotripsy in vitro

PURPOSE

To evaluate the cooling effect and other advantages of a novel circulation system for ureteroscopic holmium laser lithotripsy (URSL) in a standardized in vitro model.

MATERIALS AND METHODS

The novel circulation system was assembled by connecting a 4Fr ureteral catheter and a filter. Trails were divided into a new URSL group and a conventional URSL group. First, different power settings (18-30 W) of the holmium laser and irrigation flow rates (20-50 mL/min) were used to evaluate the thermal effect on the lithotripsy site of all groups. Then, renal pelvic temperature and pressure were assessed during URSL at a power of 1.5 J/20 Hz and irrigation flow rates of (20-50 mL/min). Finally, the whole process of lithotripsy was performed at 1.5 J/20 Hz (operator duty cycle ODC: 50%) with an irrigation flow rate of 30 mL/min. The time required for lithotripsy, visual field clarity, and stone migration were observed.

RESULTS

Temperature of the lithotripsy point was significantly lower in the new URSL group than in the conventional group (P < 0.05) with irrigation rates (20, 30 mL/min). The renal pelvic pressure of the new group was significantly lower than that of the conventional group in which intrarenal hypertension developed at an irrigation rate of 50 ml/min. The new group had better visual clarity and lesser stone upward migration when lithotripsy was performed at 1.5 J/20 Hz and 30 ml/min.

CONCLUSION

The novel circulation system is more effective in reducing the thermal effects of URSL, pelvic pressure, stone upward migration, and improving the visual clarity of the operative field.

Percutaneous antegrade management of large proximal ureteral stones using non-papillary puncture

Objective

To evaluate the feasibility and the safety of medial non-papillary percutaneous nephrolithotomy (npPCNL) for the management of large proximal ureteral stones.

Methods

We evaluated prospectively collected data of 37 patients with large proximal ureteral stones more than 1.5 cm in diameter treated by prone npPCNL. Depending on stone size, in-toto stone removal or lithotripsy using the Lithoclast® Trilogy (EMS Medical, Nyon, Switzerland) was performed. Perioperative parameters including operative time (from start of puncture to the skin suturing), stone extraction time (from the first insertion of the nephroscope to the extraction of all stone fragments), and the stone-free rate were evaluated.

Results

Twenty-one males and 16 females underwent npPCNL for the management of large upper ureteral calculi. The median age and stone size of treated patients were 58 (interquartile range [IQR]: 51-69) years and 19.3 (IQR: 18.0-22.0) mm, respectively. The median operative time and stone extraction time were 25 (IQR: 21-29) min and 8 (IQR: 7-10) min, respectively. One case (2.7%) of postoperative bleeding and two cases (5.4%) of prolonged fever were managed conservatively. The stone-free rate at a 1-month follow-up was 94.6%.

Conclusion

The npPCNL provides a straight route to the ureteropelvic junction and proximal ureter. Approaching from a dilated portion of the ureter under low irrigation pressure with larger diameter instruments results in effective and safe stone extraction within a few minutes.

Thermoexpandable Memokath stent: Usage and efficacy in ureteral and urethral strictures in Saudi Arabia

Objectives

Double J (DJ) stent is widely used in cases of ureteric strictures as a temporary solution; however, it has certain limitations, such as the need for frequent exchange. Alternatively, a long-lasting thermoexpandable stent (Memokath™ 051) has been used to relieve ureteral obstructions in comorbid patients with multiple reported advantages, such as longer durability which avoids the need of frequent exchanges. In addition, it can be used in certain cases of urethral strictures. Our study is the first in the region to report the experience and outcome of Memokath stent with ureteral and urethral strictures.

Materials and Methods

After local IRB approval, we retrospectively reviewed records of 21 patients who underwent insertion of Memokath 051 stent in the ureter and Memokath 045 in the urethra between 2013 and 2021. Indications of insertion, indwelling duration, and causes of removal were collected and analyzed by SPSS.

Results

Twenty-one patients received 21 Memokath stents for 11 ureteral strictures and 10 urethral strictures. Fifty-five percent of ureteral strictures were malignant, and 27.3% of the benign ureteric strictures were transplant ureters. Ureteric memokath stents remained functioning for a mean of 16.1 months. Mean indwelling time for transplant ureteric memokath stents was 24.3 months. Total 4 ureteric stents had migrated, 4 stents blocked, and 2 stents were removed as planned and 1 stent removed due to febrile urinary tract infection (UTI). Ten urethral stents remained in place for mean of 14 months. Three stents were removed as planned with resolution of stricture, two were removed due to blockage, three stents had UTI, one was removed due to pain, and one stent remained functioning until the patient expired.

Conclusion

Our outcome is comparable to other published studies, suggesting that ureteric Memokath stent is a better option with adequate indwelling time, especially in transplant ureters, in comparison with DJ stents. In addition, Memokath stents can be used in selected recurrent urethral strictures where surgical reconstruction is not feasible.

Factors associated with ureteral strictures following ureteroscopy for impacted ureteral stones? A multicenter study by EAU-YAU endourology and urolithiasis working party

OBJECTIVE

To determine the relation between ureteral stone impaction and ureteral stricture formation and associated factors.

MATERIAL AND METHODS

We retrospectively analyzed the medical records of all patients who underwent endoscopic ureteral stone surgery for impacted ureteral stone at three academic institutions in Turkey, United Kingdom and Spain between June 2019 and January 2022. Examined parameters included patient demographics, stone side, size and localization, time between initiation of symptoms and surgery, type of ureteroscopy (rigid/flexible), presence of nephrostomy or double-J stent prior to URS, intraoperative complications (avulsion/perforation, stone-free status, number of procedures required for stone-free status, postoperative imaging results.

RESULTS

A total of 41 patients whom 25 were male and 16 were female, from 3 institutions were included the study. The mean age of the patients was 48.2 ± 13.5 years. The median largest diameter of the stones was 9 mm (IQR: 8 mm). Total 14 (34.1%) patients developed ureteral strictures following ureteroscopy. There was no difference between patients who developed ureteral strictures and patients who did not developed strictures in terms of stone laterality, stone location, hydronephrosis and multiplicity, p = 0.58, p = 0.14, p = 0.79 and p = 0.31. Patients who developed ureteral strictures had a higher rate of preoperative urinary diversion such as nephrostomy or DJS, p = 0.000.

CONCLUSION

Interruption of urine passage through ureter via urinary diversion such as nephrostomy or DJS stent prior to ureteral stone surgery might lead ureteral stricture formation in the postoperative period.

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.

Cystine Stones: Developments in Minimally Invasive Surgery and Their Impact on Morbidity and Stone Clearance

Cystinuria is a rare genetic condition that is responsible for cystine stones. Besides stone recurrence, patients with cystine stones have reduced health-related quality of life, increased rates of chronic kidney disease and hypertension. Although lifestyle measures, medical therapy and close follow up are essential to reduce and monitor cystine stone recurrences, surgical intervention is frequently needed for most cystinuria patients. Shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy and active surveillance all have a role, and technological advances in endourology are vital in achieving a stone-free status and to prevent recurrences. The complexity of managing cystine stones necessitates a multidisciplinary team discussion, patient involvement and an individualised approach in a specialist centre for optimum management. Thulium fibre laser and virtual reality may have an increasing role in the future of cystine stone management.

Predictors of Ureteral Strictures after Retrograde Ureteroscopic Treatment of Impacted Ureteral Stones: A Systematic Literature Review

BACKGROUND

The stricture-formation rate following ureteroscopy ranges from 0.5 to 5% and might amount to 24% in patients with impacted ureteral stones. The pathogenesis of ureteral stricture formation is not yet fully understood. It is likely that the patient and stone characteristics, as well as intervention factors, play a role in this process. In this systematic review, we aimed to determine the potential factors responsible for ureteral stricture formation in patients having impacted ureteral stones.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria, we conducted systematic online research through PubMed and Web of Science without a time restriction, applying the keywords "ureteral stone", "ureteral calculus", "impacted stone", "ureteral stenosis", "ureteroscopic lithotripsy", "impacted calculus", and "ureteral strictures" singly or in combination.

RESULTS

After eliminating non-eligible studies, we identified five articles on ureteral stricture formation following treatment of impacted ureteral stones. Ureteral perforation and/or mucosal damage appeared as key predictors of ureteral stricture following retrograde ureteroscopy (URS) for impacted ureteral stones. Besides ureteral perforation stone size, embedded stone fragments into the ureter during lithotripsy, failed URS, degree of hydronephrosis, nephrostomy tube or double-J stent (DJS)/ureter catheter insertion were also suggested factors leading to ureteral strictures.

CONCLUSION

Ureteral perforation during surgery might be considered the main risk factor for ureteral stricture formation following retrograde ureteroscopic stone removal for impacted ureteral stones.

Non-Papillary Access for the Percutaneous Antegrade Treatment of Renal and Ureteral Stones

OBJECTIVE

To evaluate the feasibility and success of medial non-papillary percutaneous access for the antegrade treatment of different locations of ureteral stones, with and without concomitant renal stones.

METHODS

We performed an analysis of prospectively collected data of 72 patients, being subjected to percutaneous antegrade ureterolithotripsy. Stones located anywhere in the ureter with or without concomitant renal stones were included. A 12Fr, 22Fr, or 30Fr percutaneous tract dilation was performed based on the size of the stone pelvicalyceal system. Perioperative and demographic parameters were gathered and evaluated. The Lithoclast Trilogy (EMS Medical, Nyon, Switzerland) High-power holmium laser devices Cyber Ho 150 (Quanta System, Samarate, Italy) or MOSES Pulse 120H (Lumenis Ltd, Yokneam, Israel) were used for lithotripsy.

RESULTS

The average age and cumulative stone size of the patients were 57.9 ± 27.1 years and 24.2 ± 5.4 mm, respectively. The mean manipulation time was 36.9 ± 14.8 minutes. The mean hospitalization time was 2.5 ± 0.5 days and the average hemoglobin loss was 1.02 ± 0.18 gr/dL. The stone-free rate after percutaneous antegrade ureterolithotripsy was 95.8 % (69 patients), while the overall complications rate was 5.6 %, with 3 cases of fever and one case of prolonged hematuria that were treated conservatively.

CONCLUSION

Non-papillary percutaneous antegrade ureterolithotripsy is a safe and reliable technique for the treatment of patients with ureteral stones, with or without the co-existence of renal stones. A high stone-free rate of 95.8% was reported at 1-month after the surgery carrying a weighted risk of developing postoperative complications.

[Long-term efficacy evaluation of coated metal stent implantation for ureteroscopic lithotripsy related refractory ureteral stricture]

OBJECTIVE

To comprehensively evaluate the long-term efficacy and safety of coated metal stent implantation for ureteroscopic lithotripsy related refractory ureteral stricture (URL-rUS).

METHODS

Electronic medical records of 30 patients (31 affected renal units) receiving coated metal stent implantation for URL-rUS from Sept. 2018 to Aug. 2021 at Peking University People' s Hospital were reviewed for analysis. Coated metal stents were implanted in retrograde approach via ureteroscope. Last outpatient follow-up was set as endpoint. Baseline information, stricture characteristics and decompression strategy before coated metal stent implantation were retrospectively collected. Serum creatinine (Scr) concentration and renal pelvis width (RPW) were used as renal function indicators. Peri-operative and long-term complications and according outcomes were recorded. For the patients who had double J tubes implanted for drainage before operation, Ureteral Stent Symptom Questionnaire (USSQ) was applied to evaluate the stent-related discomforts and quality of life (QoL) before and after surgery. Data analysis was conducted with SPSS (version 25.0; SPSS, Chicago, IL, USA).

RESULTS

Totally 30 patients with 31 affected renal units were included. All the patients previously underwent unsuccessful traditional endoscopic balloon dilation or endoureterotomy before receiving coated metal stent implantation. The mean age was (45.5±9.3) years old. The median follow-up time were 14 (6-36) months. All coated metal stents were successfully placed with a median duration of 60 (30-195) min. No severe peri-operative complications occurred. At endpoint, 28 (90.3%) sides of coated metal stents remained unobstructed with a longest indwelling time of 36 months. Causes of failures included stent migration (1 case, 3.2%), encrustation (1 case, 3.2%) and repeated stent related urinary tract infection (1 case, 3.2%). When compared with the baseline, significant reductions were observed in both Scr concentration and RPW at endpoint [(90.7±19.5) mmol/L vs. (83.1±18.5) μmol/L, P < 0.01, for Scr; (2.5±1.3) cm vs. (1.9±0.8) cm, P < 0.01, for RPW], indicating good preservation of renal function and remission of hydronephrosis. For 26 patients with double J stents before operation, significant reduction of USSQ average score (100.4±6.6 vs. 82.1±4.9, P < 0.01) evidenced better life quality preserving ability of coated metal stent versus double J stent.

CONCLUSION

Coated metal stent implantation is a safe and minimally invasive management of ureteral stricture providing a satisfying long-term patency rate, after which the patients' quality of life and renal function could be both improved. This method could serve as a promising alternative long-term maintenance treatment option for patients with URL-US, especially when traditional endoscopic interventions failed.

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.

Analysis of long-term effect of ureteral balloon dilatation combined with internal and external drainage tube in the treatment of benign ureteral stricture

PURPOSE

There are few reports about balloon dilatation combined with internal and external drainage tube in the treatment of ureteral stricture under interventional therapy. The aim of the study is to explore the safety, effectiveness and long-term efficacy of this treatment strategy.

MATERIALS AND METHODS

It is a retrospective and observational study. From October 2013 to October 2016, 42 patients with benign lower ureteral stricture received interventional treatment. Balloon dilatation combined with internal and external drainage tube implantation were used. There were 25 male patients and 17 female patients. There were 7 cases (16.7%) with congenital ureteral stricture, 12 cases (28.6%) with inflammation, 15 cases (35.7%) with ureteral stricture after lithotomy or lithotripsy, and 8 cases (19.0%) with ureteral stricture after pelvic or abdominal surgery. After the drainage tube was removed, B ultrasound, enhanced CTU or IVP of urinary system were reexamined every six months. The follow-up time was 12-60 months.

RESULTS

The age was 52.9 ± 11.6 years. The length of ureteral stricture was 1.1 ± 0.5 cm. 42 patients completed interventional treatment, the technical success rate was 100%, no ureteral perforation, rupture or other complications were identified. Preoperative urea nitrogen 9.2 ± 2.3 mmol/L and creatinine 175.8 ± 82.8umol/L. Urea nitrogen and creatinine were 3.8-9.1 mmol/L and 45.2-189.6 umol/L when removing the drainage tube. There were significant differences in the levels of urea nitrogen and creatinine before and after tube removal (P < 0.05). The ureteral patency rate was 100% at 6 months, 93% at 12 months, 83% at 18 months, 79% at 24 months, 76% at 30 months and 73% at 36-60 months. The overall success rate was 73%. Multivariate Cox regression analysis showed that stenosis length was a risk factor for postoperative patency (P < 0.05).

CONCLUSION

Balloon dilatation combined with internal and external drainage tube implantation in the treatment of benign lower ureteral stricture is safe and effective.

When the sheath hits the fan: an argument against the routine use of ureteral access sheaths

n/a.

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.

Endoscopic Ureteral Dilation Balloon Catheter for a Difficult Ureter: A New Novel Approach

OBJECTIVES

This study aims to assess the safety and efficacy of INNOVEXTM ureteral dilation balloon catheter to promote the likelihood of passing the ureter to complete primary ureteroscopy (URS).

METHODS

This was a prospective case series of patients during URS between August 2018 and January 2020 at the Pudong New District People's Hospital. A 12-Fr INNOVEXTM ureteral dilation balloon catheter was used to dilate the ureter when a 5° Wolf 6.0/7.5-Fr ureteroscope encounters an unpredictable hindrance to retrograde access for ureteral stones. Patients with documented ureteral strictures, radiation therapy, or urothelial cancer were excluded from the analysis. The primary outcomes were to characterize the use, safety, and efficacy of ureteral dilation balloon catheter to promote stone treatment during URS.

RESULTS

Eight hundred and sixty-two patients underwent primary URS of ureteral stones over the study period. The use of a ureteral dilation balloon catheter to promote ureteral access was performed in 65 (7.54%) cases and effectively allowed completion of the procedure in 58 (89.23%) cases. No ureteral perforation and access loss occurred during the operation. Seven patients required ureteral stent placement for passive ureteral dilation, with definitive stone treatment later. Postoperative radiographic follow-up was available for 63 (96.92%) cases, and no ureteral stenosis was observed after balloon dilation.

CONCLUSION

The use of a new ureteral dilation balloon catheter before endoscopic treatment of ureteral stones was associated with a high success rate and few complications. The convenient use method under direct vision at the whole process may increase the willingness of doctors to use it. In addition, it may reduce the need for secondary procedures for patients undergoing URS to manage ureteral stones.

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.

Understanding Ureteral Access Sheath Use Within a Statewide Collaborative and Its Effect on Surgical and Clinical Outcomes

Introduction: Ureteral access sheaths (UASs) are frequently used during ureteroscopy (URS), but their use is not without potential risk. We investigated patterns of UAS use and associated outcomes across practices in Michigan within a quality improvement collaborative. Methods: The Michigan Urological Surgery Improvement Collaborative (MUSIC) Reducing Operative Complications from Kidney Stones (ROCKS) initiative maintains a web-based, prospective clinical registry of patients undergoing URS for urinary stone disease (USD). We analyzed all patients undergoing primary URS for renal and ureteral stones from June 2016 to July 2018 in the ROCKS registry. We determined rates of UAS usage across practices and associated outcomes, including 30-day emergency department (ED) visits and hospitalization, as well as stone-free rates. Using multivariate logistical regression, we determined the predictors of UAS use as well as outcomes, including stone-free rates, ED visits, and hospitalizations, associated with UAS use. Results: Of the 5316 URS procedures identified, UASs were used in 1969 (37.7%) cases. Stones were significantly larger and more likely to be located in the kidney in cases with UAS use. UAS use during URS varied greatly across practices (1.9%-96%, p < 0.05). After adjusting for clinical and surgical risk factors, UAS use significantly increased the odds of postoperative ED visits (odds ratio [OR] = 1.50, 95% confidence interval [CI] 1.17-1.93, p < 0.05) and hospitalization (OR = 1.77, 95% CI 1.22-2.56, p < 0.05) as well as decreased the odds of being stone free (OR = 0.75, 95% CI 0.57-0.99, p < 0.05). Conclusions: In the current study, UAS use during URS for USD was not associated with an increased likelihood of being stone free; moreover, it increased the odds of a postoperative ED visit and or hospitalization. Our findings demonstrate that UAS use is not without risk and should be employed judiciously.

Etiology and Ureteral Reconstruction Strategy for Iatrogenic Ureteral Injuries: A Retrospective Single-Center Experience

OBJECTIVE

To analyze the etiology, characteristics, and ureteral reconstruction strategies of iatrogenic ureteric injuries in a high-volume center.

METHODS

Between September 2010 and August 2019, we retrospectively collected patients who underwent ureteral reconstruction due to iatrogenic ureteric injuries. Patient profiles, laboratory data, imaging studies, perioperative data, and complications were recorded.

RESULTS

Sixty-eight patients were enrolled in this study. The upper, middle, and lower thirds of the ureter were affected in 30, 2, and 36 cases, respectively. Of the 68 ureteric injuries, 69.1% occurred during urological procedures, followed by gynecological procedures, general surgery, radiotherapy, and orthopedic surgery. The majority of urological injuries (41, 87.2%) occurred due to stone removal. There was a significant difference in the age, sex, and location of ureteric injuries between the urological and nonurological groups. The median follow-up time was 17.9 months. The overall symptom remission rate was 91.2% and ranged from 87.5 to 100% for different reconstructive surgeries.

CONCLUSIONS

Urological procedures were the most common cause of iatrogenic ureteric injury; thus, extra care should be taken. Timely detection and appropriate treatment of the ureteric injuries are necessary. Treatment strategies should be depended on the location and length of injury.

Comparison of antegrade and retrograde ureterolithotripsy for proximal ureteral stones: a systematic review and meta-analysis

Background

Antegrade percutaneous ureterolithotripsy (URSL) could be a treatment option for large and/or impacted proximal ureteral stones, which are difficult to treat. To review the current approach and treatment outcomes and to compare the efficacy of retrograde and antegrade URSL for large proximal ureteral stones, we evaluated the unique perspectives of both surgical modalities.

Methods

This systematic literature review and meta-analysis was performed in July 2020. Articles on human studies and treatment of ureteral stones with URSL were extracted from the PubMed, MEDLINE, Embase, Cochrane Library, Scopus, and the Japan Medical Abstracts Society databases without any language restrictions. The risks of bias for randomized controlled trials (RCTs) and non-randomized controlled trials (non-RCTs) were assessed using the Cochrane risk of tool and the Risk of Bias in Non-randomized Studies- of Interventions tool, respectively.

Results

A total of 10 studies, including seven RCTs and three non-RCTs, were selected for the analysis; 433 and 420 cases underwent retrograde and antegrade URSL, respectively. The stone-free rate (SFR) was significantly higher in antegrade URSL than in retrograde URSL (SFR ratio: 1.17, 95% CI: 1.12-1.22; P<0.001), while the hospital stay was significantly longer in antegrade URSL than in retrograde URSL (standardized mean difference: 2.56, 95% CI: 0.67-4.46; P=0.008). There were no significant differences in the operation time and the overall complication rate between the two approaches.

Conclusions

Despite the heterogeneity of data and bias limitations, this latest evidence reflects real practice data, which may be useful for decision making.

Complete ureteral stenosis after ureteroscopic lithotripsy successfully managed using a simultaneous retrograde and antegrade flexible ureteroscopic approach

Both retrograde and antegrade approach contributed to the success of a delicate endoscopic procedure. Even when guidewire did not pass thorough to the stenosis lesion, lightning and contrast reagents contributed the way through to the stenosis lesion.

Ureteral Strictures Following Ureteroscopic Stone Treatment

Background and Purpose: Ureteral stricture is a rare, but serious complication following ureteroscopy (URS) for stones. The aim of this study was to investigate how many patients ended up with a ureteral stricture after URS at our hospital and how these were treated. We also wanted to identify potential risk factors for postendoscopic stricture formation. Materials and Methods: A retrospective evaluation of 1001 URSs for stone treatment at the day-case surgery unit between 2013 and 2018 was performed. Data on pretreatment status, the surgical procedure, and follow-up were recorded. Exact χ² and independent samples t-tests were used comparing data among those who developed strictures and those who did not. Multiple logistic regression was performed analyzing risk factors for stricture formation. Results: In total, 1001 URSs were performed in 725 patients, 289 women and 436 men. Of these, 995 cases were eligible for analysis. At follow-up with CT after 3 months, 28 (3.0%) strictures were identified. Of these, 20 received endourologic treatment with balloon dilatation of which 15 (75%) were effective. Definitive treatment in the 13 patients with failed or unattempted endourologic treatment included nephrectomy, reconstructive surgery, permanent nephrostomy, or observation with no further treatment. In multiple regression analysis, use of ureteral access sheath (UAS; odds ratio [OR] 4.6, p = 0.011), ureteral perforation (OR 11.8, p < 0.0001), and surgical time >60 minutes (OR 5.7, p < 0.005) were found to be risk factors for stricture formation. Conclusion: Ureteral stricture is a rare complication of URS. Balloon dilatation should be the first line of treatment. Use of UAS, perforation, and excessive operating time were found to be risk factors for postendoscopic ureteral stricture formation. Special attention to these risk factors should be given to reduce the incidence of ureteral strictures.

Thermal effect of holmium laser during ureteroscopic lithotripsy

Background

Holmium laser lithotripsy is the most common technique for the management of ureteral stone. Studies founded that holmium laser firing can produce heat which will cause thermal injury towards ureter. The aim of our current study is to explore factors affecting thermal effect of holmium laser during ureteroscopic lithotripsy.

Methods

An in vitro experimental model is design to simulate the ureteroscopic lithotripsy procedure. Different laser power settings (10w (0.5JX20Hz, 1.0 JX10Hz), 20w (1.0 JX20Hz, 2.0 JX10Hz), 30w (1.5JX20Hz, 3.0 JX10Hz)) with various firing time (3 s, 5 s, 10s) and irrigation flow rates(10 ml/min, 15 ml/min, 20 ml/min and 30 ml/min) were employed in the experiment. The temperature around the laser tip was recorded by thermometer.

Results

The temperature in the “ureter” rises significantly with the increasing laser power, prolonging firing time and reducing irrigation flow. The highest regional temperature is 78.0 °C at the experimental set-up, and the lowest temperature is 23.5 °C. Higher frequency setting produces more heat at the same power. Laser power < =10w, irrigation flow> = 30 ml/min and “high-energy with low-frequency” can permit a safe working temperature.

Conclusion

We clarify that the thermal effect of holmium laser is related with both laser working parameters and irrigation flow. The proper setting is the key factor to ensure the safety during ureteroscopic holmium laser lithotripsy.

Advantages of retrograde flexible ureteroscopy in determining the etiology of painless hematuria originating from the upper urinary tract

The present study investigated the use of retrograde flexible ureteroscopy (RFU) in the discrimination of the etiology of hematuria that originates from the upper urinary tract (UUT). The present study collected retrospective data for patients who presented with hematuria and cystoscopy-detected bleeding from the UUT between June 2006 and August 2018 in Ningbo First Hospital. All patients accepted RFU to determine the etiology of hematuria. Data regarding imaging examinations, surgery, pathology and complications were also collected and analyzed. In total, 65 patients (males, 38; females, 27) with a mean age of 63 years underwent RFU to determine the etiology of hematuria originating from the UUT. Using RFU, UUT tumors were found in 29 cases. Stones, polyps and atypical hyperplasia were found in two cases, and a definite diagnosis was not found in three cases. There were 17 cases without obvious abnormalities and nine cases were unable to undergo RFU due to ureteral stenosis. In patients who could not be diagnosed by imaging examination, 34.4% (11/32) were diagnosed with urothelial carcinoma by RFU, and these results were also confirmed by postoperative pathology. In the present study, no patient had severe complications after RFU. The present results suggested RFU may be used as a sensitive method to diagnose UUT tumors (78.4%; 29/37) and has strong specificity. RFU could be performed as a routine examination for patients with hematuria from the UUT.

Post ureteroscopic stone surgery ureteral strictures management: a retrospective study

PURPOSE

To share experience in managing ureteral strictures following ureteroscopic lithotripsy.

METHODS

Ninety five patients diagnosed as ureteral strictures after ureteroscopic lithotripsy between January 2013 and January 2018 were included. 53 received endourological treatment, 34 underwent reconstruction, 6 underwent nephrectomy for severe renal impairment, and 2 chose routine ureteral stent replacement. Therapeutic success was defined as absence of clinical symptoms and radiologic relief of obstruction.

RESULTS

The follow-up time ranged from 13 to 57 months, with a median time of 24. It lasted more than 13 months in all patients, exception for 2 nephrectomies. Two patient groups including 69 endourological procedures and 37 reconstructions were used to compare therapeutic effects and complications. The overall success rate was 60.9% (42/69) in endourological intervention vs. 97.3% (36/37) in reconstruction (p < 0.001), while 74.4% (29/39) patients with stricture less than 1 cm and 68.8% (33/48) patients with mild-to-moderate hydronephrosis achieved success in endourological group. All except 1 failure appeared within the first year postoperatively. Subgroup analyses for endourological procedures revealed significant differences in the success rate of different stricture lengths and hydronephrosis (p = 0.004 and p = 0.043). Multivariate Cox regression analysis indicated that reconstruction was significantly related to a more successful outcome, compared with endourological procedures (HR 0.052, 95% CI 0.007-0.394, p = 0.004).

CONCLUSION

Reconstruction performs better than endourological procedures in surgical outcome. Endourological procedure provides an acceptable success rate in patients with stricture shorter than 1 cm and slight hydronephrosis. Most stricture recurrence appeared within the first year postoperatively.

A Prospective Study Analyzing the Association Between High-grade Ureteral Access Sheath Injuries and the Formation of Ureteral Strictures

OBJECTIVE

To assess the intermediate- and long-term effect of high-grade ureteral injuries from ureteral access sheaths.

METHODS

Patients undergoing ureteroscopy for upper tract calculi were prospectively enrolled at 2 sites from 2010 to 2015. A 12/14 French sheath was used and the ureter was inspected with a flexible ureteroscope during withdrawal of the sheath and recorded. The videos were then evaluated by 2 blinded endourologists, and any injuries were graded per the Traxer ureteral injury scale. Only high-grade injuries were included. The primary endpoint was defined as ongoing hydronephrosis without an obstructing stone on follow-up imaging indicating a ureteral stricture. Logistic regression analysis was used to assess the relationship between hydronephrosis, ureteral injury, and other patient variables.

RESULTS

Fifty-six patients were identified with high-grade ureteral injuries. Sixteen patients (28.6%) were female. Median age was 56.4 years (range 14-85). Median follow-up was 35.8 months (range 0-88). Three patients (5.5%) had hydronephrosis on follow-up imaging, only 1 of whom developed a de novo ureteral stricture. On univariate analysis, hydronephrosis was associated with a shorter stent duration (P = .11) and older age (P = .17).

CONCLUSION

Endoscopically identified high-grade ureteral lesions following ureteral access sheath placement do not lead to clinically significant sequelae on intermediate term follow-up, with a stricture rate comparable to those without visible injuries of 1.8%.