Ureteral strictures revisited…trying to see the light at the end of the tunnel: a comprehensive review

Recent developments in ureteral stent: Substrate material, coating polymer and technology, therapeutic function

The ureteral stent is an effective treatment for clinical ureteral stricture following urological surgery, and the functional coating of the stent could effectively inhibit bacterial colonization and other complications. The present review provides an analysis and description of the materials used in ureteral stents and their coatings. Emphasis is placed on the technological advancements of functional coatings, taking into consideration the characteristics of these materials and the properties of their active substances. Furthermore, recent advances in enhancing the therapeutic efficacy of functional coatings are also reviewed. It is anticipated that this article will serve as a valuable reference providing insights for future research development on new drug-loaded ureteral stents.

Contemporary status of diagnostic endoluminal ultrasound and optical coherence tomography in the ureter

Objective

To evaluate via a review of published literature, the efficacy of endoluminal ultrasound (ELUS) and optical coherence tomography (OCT) in the following ureteric diseases: urolithiasis, upper tract urothelial carcinoma, stricture disease and pelvic-ureteric junction obstruction (PUJO).

Patients and methods

Ureteric high-frequency ELUS provides 360° imaging, to a depth of 20 mm, and has been demonstrated to assess ureteric stricture length, degree of fibrosis and aetiology. OCT produces high-quality images with a penetration depth of 2 mm. ELUS has proven to be useful at the time of endopyelotomy for PUJO as it can identify crossing vessels, some not detectable on CT angiography, allowing the urologist to avoid these when making their incision. Ureteric ELUS may be utilised for submucosal ureteric stones as they are highly visible. Endoluminal ultrasound may be deployed in the case of known sub-mucosal urolithiasis when the ureter appears stone-free. It may help identify sub-mucosal stones or stones within diverticulum.

Results

Endoluminal ultrasound has been analysed for its use in determining muscle-invasive urothelial carcinoma of the ureter. The PPV for ≥pT2 was only 16.7% in one study of six patients with MIBC and 76.2% in 21 patients with

Conclusions

Ureteric ELUS has been reported to be a useful tool in endopyelotomy, urolithiasis and stricture disease. The staging of ureteric urothelial carcinoma remains unsatisfactory with current imaging techniques and biopsy methods, and, based on the current literature, ELUS does not appear to have a strong enough PPV to determine muscle invasion. Ureteric OCT may be a useful tool in the future staging of upper tract urothelial carcinoma, particularly in differentiating the stage of small tumours. Further studies are needed in this area.

Collapse

Key Words

• endoluminal ultrasound
• optical coherence tomography
• ureter

Collapse

MESH Headings Collapse

Grants Collapse

Affiliation(s)

Samuel Sii Department of SurgeryUniversity of Melbourne, Austin HealthMelbourneVictoriaAustralia
Jeremy Bolton Monash UniversityMelbourneVictoriaAustralia
Jake Tempo Department of SurgeryUniversity of Melbourne, Austin HealthMelbourneVictoriaAustralia
Damien Bolton Department of SurgeryUniversity of Melbourne, Austin HealthMelbourneVictoriaAustralia

Collapse

Robot-Assisted Ureteroplasty with Labial Mucosal Onlay Grafting for Long Left-Sided Proximal Ureteral Stenosis in Children and Adolescents: Technical Tips and Functional Outcomes

Purpose: To evaluate functional outcomes of robot-assisted ureteroplasty with labial mucosa grafting for long proximal ureteral stenosis (LPUS) in children and adolescents. Methods: Included in this study were 15 patients who underwent robot-assisted ureteroplasty with labial mucosal grafting in our center between July 2017 and September 2021. The left affected stenotic ureter was repaired using labial mucosal grafting. If the ureter was simply strictured but not obliterated, the ureter was spatulated longitudinally along the ventral side and the labial mucosa graft was interposed and anastomosed in a continuous manner. Faced with the obliterated segment, it was excised and the spatulated portion re-anastomosed with a pelvic flap as the dorsal wall. The labial mucosa graft was placed as the ventral wall. The preoperative clinical data and follow-up outcomes were collected and evaluated. Results: Labial mucosa graft onlay ureteroplasty was well performed in all the 15 patients with no occurrence of intraoperative complications or surgical conversion. Five patients underwent an onlay ureteroplasty, and 10 patients underwent a dorsally augmented pelvic flap anastomotic ureteroplasty. The mean (range) stricture length was 7.1 (3-10) cm. The mean operative time was 371.2 (216-480) minutes, and the median blood loss was 40 mL. At the median follow-up of 35 months (range 12-58 months), the overall success rate was 93.3%. Conclusions: Labial mucosa grafting appears to be safe and feasible for repairing long ureteral strictures in pediatric and adolescent patients. Our experience may provide beneficial references and conveniences to solve complex problems in LPUS. This study was approved by the institutional review board, and written informed consent was obtained from each participant (ethics number: 2017-30).

Ileal ureter replacement and ileocystoplasty for the treatment of bilateral ureteral strictures and bladder contracture: technique and outcomes

BACKGROUND

The aim of this study was to explore the feasibility of ileal ureter replacement and ileocystoplasty for the treatment of bilateral long-segment ureteral strictures combined with bladder contracture.

METHODS

A retrospective review of clinical data from seven patients who underwent bilateral Ileal Ureter Replacement and ileocystoplasty from April 2019 to February 2023 was conducted. The surgeries were performed using open, laparoscopic, and robot-assisted laparoscopic approaches. Baseline characteristics, perioperative, and mid-term results of the patients were collected. Follow-up period of 3-28 months. A detailed description of the technique was reported.

RESULTS

The mean age of the patients was 52.86±6.06 years. The average duration of surgery was 365±28.54 minutes, and the estimated intraoperative blood loss was 357.14±184.06 mL. The mean length of harvested ileum was 37.86±8.40 cm. The preoperative serum creatinine level was 88.02±18.05 μmol/L, postoperative day 1 creatinine level was 90.7±12.93μmol/L, postoperative 3-month creatinine level was 93.77±33.34 μmol/L, and the mean creatinine level at the last follow-up was 94.89±27.89μmol/L. The postoperative bladder capacity was 249.43±32.50 mL on average. The average length of hospital stay was 26.57±15.46 days. No complications of Clavien-Dindo grade 3 or higher were observed. During the follow-up period, no patients experienced deterioration of renal function after surgery.

CONCLUSIONS

Bilateral ileal ureter replacement and ileocystoplasty are effective surgical technique for the treatment of bilateral long-segment ureteral strictures combined with bladder contracture caused by radiation therapy.

Robot-Assisted Repair of Ureteroenteric Strictures After Cystectomy with Urinary Diversion: Technique Description and Outcomes from the European Robotic Urology Section Scientific Working Group

Background: Robot-assisted repair of benign ureteroenteric anastomotic strictures (UAS) provides an alternative to the open approach. We aimed to report short-, medium-, and long-term outcomes for robotic repair of benign UAS, and to provide a detailed video demonstration of critical operative techniques in performing this procedure robotically. Materials and Methods: Between January 2013 and September 2022, 31 patients from seven institutions who previously underwent radical cystectomy and subsequently developed UAS underwent robotic repair of UAS. Perioperative variables were prospectively collected, and postoperative outcomes were assessed. The surgery starts with a lysis of adhesions after previous surgery. Ureters are dissected, and the level of the stricture is identified. The ureter is then divided, and the stricture is resected. Finally, the ureter is spatulated and reimplanted with Nesbit technique after stenting with Double-J stents. In cases where both ureters show strictures, Wallace technique for reimplantation can be applied. Results: After robotic or open cystectomy, 31 patients had a total of 43 UAS at a median (interquartile range) follow-up of 21 (9-43) months. Median stricture length was 2.0 (1.0-3.25) cm, operative duration was 141 (121-232) minutes, estimated blood loss was 100 (50-150) mL, and length of hospital stay was 5 (3-9) days. One (3.2%) case was converted to open and one (3.2%) intraoperative complication occurred. Seven (22.6%) patients experienced postoperative complications, including four (12.9%) Clavien-Dindo grade 3 complications. No Clavien-Dindo grade 4 or 5 complications occurred. Stricture recurrence occurred in 2 (6.5%) patients. Conclusions: These results demonstrate that robotic repair of UAS is feasible and effective approach with outcomes in line with prior open series. Patient Consent Statement: Authors have received and archived patient consent for video recording and publication in advance of video recording of procedure.

Evaluation of risk factors, treatment options, and prognostic-related factors in patients with benign ureteral strictures: An 8-year single-center experience

OBJECTIVES

To investigate the etiology, therapeutic effect, and prognosis-related factors of benign ureteral strictures.

METHODS

We analyzed the date of 142 patients with benign ureteral strictures from 2013 to 2021. Ninety-five patients received endourological treatment and 47 patients underwent reconstruction. Preoperative, intraoperative, and postoperative information were compared and analyzed. Symptomatic improvement and radiographic blockage alleviation defined therapeutic success.

RESULTS

Stone-related factors caused 85.2% of cases. The overall success rate of endourological treatment was 51.6% versus 95.7% of reconstruction (p < 0.01). However, endourological treatment was better in terms of postoperative hospital stay time, operation time, and intraoperative blood loss (p < 0.001). In endourological group, patients with stricture length ≤2 cm, mild-to-moderate hydronephrosis, proximal or distal stricture had a higher success rate. Multivariate regression analysis showed that the surgical method was the only independent risk factor affecting success and recurrence. Reconstruction success rate was higher than endourological treatment (p = 0.001, OR 0.057, 95% CI (0.011-0.291)), and recurrence rate was also lower (p = 0.001, HR 0.074, 95% CI (0.016-0.338)). No obvious recurrence was seen in reconstruction, and the median recurrence time in endourological treatment was 51 months.

CONCLUSIONS

Stone-related factors are an important cause of benign ureteral strictures. Reconstruction is the gold standard treatment due to its high success rate and low recurrence rate. Endourological therapy is also preferred as the initial treatment in proximal or distal ureter with length ≤2 cm and mild-to-moderate hydronephrosis. Further close follow-up is required after treatment.

Unveiling the Challenges in Tandem Ureteral Stent Management for Malignant Ureteral Obstruction: Failure Rate, Risk Factors, and Durability of Their Replacement

BACKGROUND

Malignant ureteral obstruction (MUO) is a sequela of advanced malignant disease that requires renal drainage, with tandem ureteral stents (TUSs) being a viable option. This study aimed to evaluate the TUS failure rate, associated risk factors, and the feasibility of replacing failed TUSs with a new pair of stents.

METHODS

A retrospective analysis of MUO patients treated with TUS insertion from 2014 to 2022 was conducted. TUS failure was defined as urosepsis, recurrent urinary tract infections, acute kidney failure, or new hydronephrosis on imaging. Cox proportional hazard regression analysis identified the independent predictors of TUS failure.

RESULTS

A total of 240 procedures were performed on 186 patients, with TUS drainage failing in 67 patients (36%). The median time to failure was 7 months. Multivariate analysis revealed female gender (OR = 3.46, p = 0.002), pelvic mass (OR = 1.75, p = 0.001), and distal ureteral obstruction (OR = 2.27, p = 0.04) as significant risk factors for TUS failure. Of the failure group, 42 patients (22.6%) underwent TUS replacement for a new pair. Yet, 24 (57.2%) experienced a second failure, with a median time of 4.5 months. The risk factors for TUS second failure included a stricture longer than 30 mm (OR = 11.8, p = 0.04), replacement with TUSs of the same diameter (OR = 43, p = 0.003), and initial TUS failure within 6 months (OR = 19.2, p = 0.006).

CONCLUSIONS

TUS insertion for the treatment of MUO is feasible and has good outcomes with a relatively low failure rate. Primary pelvic mass and distal ureteral obstruction pose higher risks for TUS failure. Replacing failed TUSs with a new pair has a success rate of 42.8%. Consideration should be given to placing larger diameter stents when replacing failed TUS.

Management for Benign Ureteral Stricture: Comparison of robot-assisted laparoscopy, conventional laparoscopy, and balloon dilation

PURPOSE

Robot-assisted laparoscopy (RALP), conventional laparoscopy (LP), and balloon dilation (BD) have all been identified as common treatments for benign ureteral stricture (BUS). The purpose of the research would be to compare the safety and efficacy differences in the three groups.

PATIENTS AND METHODS

Patients who received RALP, LP, or BD for BUS were studied retrospectively from January 2016 through December 2020. Professional and experienced surgeons performed all operations. We collect and analyze baseline characteristics, stricture details, peri-operative, and follow-up information.

RESULTS

The results showed no statistically significant differences between the three groups for baseline characteristics and stricture details. No statistical differences were also found between RALP and LP in specific surgical techniques. The average operative time was longer in the LP group than RALP and BD groups (178 min vs 150 min vs 67 min, respectively, P<0.001). BD had a lower estimated blood loss than RALP and LP (14 ml vs 40 ml vs 32 ml, p<0.001) and similar between the RALP and LP groups (p=0.238). The BD group had the shortest postoperative hospital stay compared with the RALP and LP groups (3 d vs 5 d vs 7 d, P<0.001), and no statistically significant differences existed between the RALP and LP groups (P=0.098). RALP had considerably greater hospitalization expenses than both LP (P<0.001) and BD (P<0.001). Complications and short-term success rates (6 months) were similar. The BD group had poorer long-term success (12 and 24 months) than the RALP and LP groups, whereas there was no statistically significant difference between the RALP and LP groups.

CONCLUSIONS

For the management of BUS, RALP, LP, and BD are all safe and effective, with equivalent complication rates and short-term success. In long-term success rates, BD is low than RPLP and LP.

Long-term, single-center study comparing open and laparoscopic procedures for congenital midureteral obstruction in children

PURPOSE

To compare the safety and outcomes of open and laparoscopic procedures in the management of congenital midureteral obstruction in children (CMO).

METHODS

Between February 2008 and February 2022, a total of 18 patients underwent open ureteroureterostomy (OU group), and 26 underwent laparoscopic ureteroureterostomy (LU group). The operative time, postoperative hospital stay, hospital costs, postoperative complications, and success rates of the two groups were compared.

RESULTS

The median age of the patients was 59 months, with 29 patients presenting with asymptomatic hydronephrosis, 12 with intermittent abdominal pain, and 3 with flank mass. The median follow-up time was 42 months, and all patients were successfully treated surgically. The operative time and postoperative hospital stay in the LU group were shorter than those in the OU group (106.3 ± 21.4 vs. 85.8 ± 16.5 min, 11.6 ± 1.9 vs. 8.3 ± 1.7 days, respectively; p < 0.05). The OU group had two postoperative complications, both of which were classified as Clavien-Dindo grade II based on the Clavien-Dindo classification. One case of postoperative complication occurred in the LU group, which was classified as Clavien-Dindo Grade II. There was no significant statistical difference in complications between the two groups (P > 0.05).

CONCLUSIONS

Our data showed that laparoscopic ureteroureterostomy is a safe and effective treatment for congenital midureteral obstruction in children, and provides several advantages, including fewer postoperative complications, shorter postoperative hospital stay, and a shorter operative time. Laparoscopic procedures should be the first choice for treating children with congenital midureteral obstructions.

Long-term maintenance treatment of recurrent ureteropelvic junction obstruction with covered metallic ureteral stent

Whether or not the covered metallic ureteral stent can be used as maintenance treatment for recurrent ureteropelvic junction obstruction (UPJO) after pyeloplasty is unknown. Therefore, this study aims to analyze its feasibility. We retrospectively analyzed the records of 20 patients with recurrent UPJO who were treated with the covered metallic ureteral stents from March 2019 to June 2021 at our institution. Then, we assessed their renal function, stent patency and stent-related quality of life by the blood creatinine, renal ultrasound (or computed tomography), and the Chinese version of the ureteral symptom score questionnaire (USSQ). The last follow-up mean blood creatinine dropped from 0.98 ± 0.22 to 0.91 ± 0.21 mg/dL (P = .04), and the median renal pelvic width was reduced from 3.25 (3.10) to 2.00 (1.67) cm (P = .03) compared with the preoperative conditions. Meanwhile, the last follow-up mean USSQ total score of the covered metallic ureteral stent among the 16 patients with preoperative indwelling double-J ureteral stent was 78.56 ± 14.75, significantly lower than the preoperative USSQ total score, which was 102.25 ± 5.57 (P < .001). During the median duration of follow-up of 27.00 (18.00) months, 85% (17/20) of patients maintained unobstructed drainage from the renal pelvis to the ureter. Stent-related complications occurred in 7 patients, 3 of which failed because of complications, including stent migration (1 patient), stent encrustation (1 patient), and stent-related infection (1 patient). The covered metallic ureteral stent is feasible for the long-term maintenance treatment of recurrent UPJO after pyeloplasty.

Uretero-neocystostomy: a retrospective comparison of open, laparoscopic and robotic techniques

BACKGROUND

Uretero-neocystostomy (UNC) is the gold-standard for distal-ureter repair. Whether the surgery should be conducted minimally invasive (laparoscopic (LAP), robotic RAL)) or open remains unanswered by the literature.

METHODS

Retrospective analysis of surgical outcome of patients treated with UNC for distal ureteral stenosis (January 2012 - October 2021). Patient demographics, estimated blood loss (EBL), surgical technique, operative time, complications and length of hospital stay (LOS) were recorded. During the follow-up period, patient underwent renal ultrasound and kidney function tests. Success was defined as relieve of symptoms or no findings of obstruction needing urine drainage.

RESULTS

60 patients were included (9 RAL, 25 LAP, 26 open). The different cohorts were similar of age, gender, American Society of Anesthesiologists (ASA) score, body-mass index and history of prior treatment of the ureter. No intraoperative complications were detected in all groups. There was no conversion to open surgery in the RAL group, whereas one was found in the LAP arm. Six patients had a recurrent stricture, but with no significant difference between the cohorts. EBL was not different between the groups. LOS was significantly lower in the RAL + LAP group compared to open (7 vs. 13 days, p = 0.005) despite significantly longer operating times (186 vs. 125.5 min, p = 0.005).

CONCLUSION

Minimal invasive UNC, especially RAL, is a feasible and safe surgical method and provides similar results in terms of success rates in comparison to open approach. A shorter LOS could be detected. Further prospective studies need to be done.

Analysis of the Efficacy and Risk Factors for Failure of Balloon Dilation for Benign Ureteral Stricture

This study aimed to investigate the efficacy of balloon dilation in ureteral stricture and to analyze the risk factors for the failure of balloon dilation, which will hopefully provide some reference for clinicians to develop treatment plans. We retrospectively analyzed 196 patients who underwent balloon dilation between January 2012 and August 2022, 127 of whom had complete baseline and follow-up data. General clinical data, perioperative data, balloon parameters at the time of surgery, and follow-up results were collected from the patients. Univariate and multivariate logistic regression analyses were performed for the risk factors for surgical failure in patients undergoing balloon dilatation. The success rates of balloon dilatation (n = 30) and balloon dilatation combined with endoureterotomy (n = 37) for lower ureteral stricture at 3 months, 6 months, and 1 year were 81.08%, 78.38%, and 78.38% and 90%, 90%, and 86.67%, respectively. The success rates of balloon dilation at 3 months, 6 months, and 1 year in patients with recurrent upper ureteral stricture after pyeloplasty (n = 15) and primary treatment (n = 30) were 73.33%, 60%, and 53.33% and 80%, 80%, and 73.33%, respectively. The success rates of surgery at 3 months, 6 months, and 1 year for patients with recurrence of lower ureteral stricture after ureteral reimplantation or endoureterotomy (n = 4) and primary treatment with balloon dilatation (n = 34) were 75%, 75%, and 75% and 85.29%, 79.41%, and 79.41%, respectively. Multivariate analysis of the failure of balloon dilation showed that balloon circumference and multiple ureteral strictures were risk factors for balloon dilation failure (OR = 0.143, 95% CI: 0.023-0.895, p = 0.038; OR = 1.221, 95% CI: 1.002-1.491, p = 0.05). Balloon dilation combined with endoureterotomy in lower ureteral stricture had a higher success rate than balloon dilation alone. The success rate of balloon dilation in the primary treatment of the upper and lower ureter was higher than that of balloon dilation in the secondary treatment after failed repair surgery. Balloon circumference and multiple ureteral strictures are risk factors for balloon dilation failure.

A method for reducing thermal injury during the ureteroscopic holmium laser lithotripsy

Objective

Many studies have demonstrated the heat effect from the holmium laser lithotripsy can cause persistent thermal injury to the ureter. The purpose of this study was to elucidate the use of a modified ureteral catheter with appropriate firing and irrigation to reduce the thermal injury to the "ureter" during the ureteroscopic holmium laser lithotripsy in vitro.

Methods

An in vitro lithotripsy was performed using a modified catheter (5 Fr) as the entrance for the irrigation and the holmium laser fiber while using the remaining space in the ureteroscopic channel as an outlet. Different laser power settings (10 W, 20 W, and 30 W) with various firing times (3 s, 5 s, and 10 s) and rates of irrigation (15 mL/min, 20 mL/min, and 30 mL/min) were applied in the experiment. Temperature changes in the "ureter" were recorded with a thermometer during and after the lithotripsy.

Results

During the lithotripsy, the local highest mean temperature was 60.3 °C and the lowest mean temperature was 26.7 °C. When the power was set to 10 w, the temperature was maintained below 43 °C regardless of laser firing time or irrigation flow. Regardless of the power or firing time selected, the temperature was below 43 °C at the rate of 30 mL/min. There was a significant difference in temperature decrease when continuous 3 s drainage after continuous firing (3 s, 5 s, or 10 s) compared to with not drainage (p<0.05) except for two conditions of 0.5 J×20 Hz, 30 mL/min, firing 5 s, and 1.0 J×10 Hz, 30 mL/min, firing 5 s.

Conclusion

Our modified catheter with timely drainage reducing hot irrigation may significantly reduce the local thermal injury effect, especially along with the special interrupted-time firing setting during the simulated holmium laser procedure.

Whole ureter replacement with Yang-Monti principle: successful treatment of challenging conditions

BACKGROUND

No clear consensus has been reached on the reconstruction of long-segment or total ureter discontinuation. Here we present our experience using the Yang-Monti technique in total ureter reconstruction.

METHODS

This study was a single-center retrospective study of patients who underwent Yang-Monti ileal whole ureter reconstruction (from the ureteropelvic junction[UPJ] to the ureterovesical junction). Data were collected on patients' baseline characteristics, stricture etiology, the time interval between insult and surgical repair, pre/postoperative serum creatinine, estimated glomerular filtration rate (eGFR), split renal function, complications during admission and follow-ups, and the indwelling durations of JJ tubes and nephrostomy tubes, if presented.

RESULTS

Seven patients underwent Yang-Monti ileal ureter reconstruction in 2010-2020 at our hospital. One of the patients underwent single-session bilateral ureter repair. Radiation therapy-related fibrosis and degloving injury were the most common etiologies for ureter injury. The median interval between ureter insult and operation was 8 months. The median follow-up was 36.7 months. The average operation time was 11.4 h, and the average blood loss was 273 ml. Postoperatively, no significant differences were found in serum creatinine, eGFR, or split renal function. As for postoperative complications, two patients experienced ileus and were treated conservatively. One patient had UPJ stenosis, which resolved after re-anastomosis surgery 11 months later. Metabolic acidosis or electrolyte imbalance was not reported.

CONCLUSION

We found that ileal replacement of total ureteral loss using the Yang-Monti principle is effective and durable. This is the largest cohort study conducted with more than 2 years of follow-up.

Is endourological intervention a suitable treatment option in the management of iatrogenic thermal ureteral injury? A contemporary case series

BACKGROUND

Iatrogenic ureteral injury (IUI) is relatively rare, however, can cause sepsis, kidney failure, and death. Most cases of IUI are not recognized until the patient presents with symptoms following pelvic surgery or radiotherapy. Recently, minimally invasive approaches have been used more frequently in the treatment of IUI. This study evaluates urological intervention success rates and long-term clinical outcomes according to the type of IUI following hysterectomy.

METHODS

Twenty-seven patients who underwent surgery due to IUI in our clinic following hysterectomy were evaluated between January 2011 and April 2018. Patients were classified according to the time of diagnosis of IUI. The IUI cases diagnosed within the first 24 h following hysterectomy were designated as "immediate" IUI, while that diagnosed late period was considered 'delayed' IUI. The type of IUI was categorized as "cold transection" if it was due to surgical dissection or ligation without any thermal energy, and "thermal injury" if it was related to any energy-based surgical device. Patient information, laboratory and perioperative data, imaging studies, and complications were assessed retrospectively.

RESULTS

All cases of delayed diagnosis IUI were secondary to laparoscopic hysterectomy (P = 0.041). Patients with thermal injury to the ureter were mostly diagnosed late (delayed) (P = 0.029). While 31% of the patients who underwent endourological intervention were diagnosed immediately, 69% of them were diagnosed as delayed. These rates were roughly reversed for open reconstructive surgery: 73% and 27% (P = 0.041), respectively. We detected eight ureteral complications in our patient cohort following the urological intervention. In all these failed cases, the cause of IUI was a thermal injury (P = 0.046) and the patients had received endourological treatment (P = 0.005). No complications were detected in patients who undergo open urological reconstructive surgery. While one of the patients who developed urological complications had an immediate diagnosis, seven were in the delayed group (P = 0.016).

CONCLUSION

Endourological intervention is performed more frequently in delayed diagnosed IUI following hysterectomy, however, the treatment success rate is low if thermal damage has developed in the ureter. Surgical reconstruction is should be preferred in these thermal injury cases to avoid further ureter-related complications.

Verapamil inhibited the development of ureteral stricture by blocking CaMK II-mediated STAT3 and Smad3/JunD pathways

BACKGROUND

Ureteral stricture (US) is a fibrotic process that leads to urinary tract obstruction and even kidney damage, with the characteristic of reduced extracellular matrix (ECM) degradation and increased collagen synthesis. Verapamil, as a calcium channel blocker, was reported to prevent scar formation. Our work aimed to investigate the biological effects and mechanism of verapamil in US.

METHODS

Fibroblasts were subjected to transforming growth factor-beta 1 (TGF-β1) to stimulate collagen synthesis, and the messenger ribonucleic acid (mRNA) and protein expressions in fibroblasts were assessed using quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The location of phosphorylation-signal transducer and activator of transcription 3 (p-STAT3) and Jund proto-oncogene subunit (JunD) in fibroblasts were determined by immunofluorescence (IF). The binding relationship between signal transducer and activator of transcription 3 (STAT3) and collagen type I alpha1 (COL1A1)/collagen type III alpha 1 chain (COL3A1) and the binding relationship between JunD and tissue inhibitor of metalloproteinases-1 (TIMP-1) were verified by dual luciferase reporter gene and chromatin Immunoprecipitation (ChIP) assays.

RESULTS

Herein, we found that verapamil could inhibit TGF-β1/Ca2 + ⁄calmodulin-dependent protein kinase II (CaMK II)-mediated STAT3 activation in fibroblasts, and STAT3 inhibition repressed collagen production. In addition, verapamil could inhibit TGF-β1/CaMK II-mediated Mothers against DPP homolog 3 (Smad3)/JunD pathway activation in fibroblasts, and JunD silencing inhibited TIMP1 (a matrix metalloproteinase inhibitor) expression. Our subsequent experiments revealed that STAT3 bound with COL1A1 promoter and COL3A1 promoter and activated their transcription, and JunD bound with TIMP1 promoter and activated its transcription. Moreover, as expected, STAT3 activation could eliminate the inhibitory effect of verapamil treatment on TGF-β1-induced collagen production in fibroblasts, and JunD overexpression reversed the inhibitory effect of verapamil treatment on TGF-β1-induced TIMP1 expression in fibroblasts.

CONCLUSION

Verapamil inhibited collagen production and TIMP-1 expression in US by blocking CaMK II-mediated STAT3 and Smad3/JunD pathways.

Establishment of mini-pig model of ureteral stricture by electrocoagulation under ureteroscopy

OBJECTIVE

To establish a mini-pig model of ureteral stricture by using electrocoagulation under ureteroscopy.

MATERIALS AND METHODS

Twelve female mini-pigs were included. Their ureters on one side and contralateral side were randomly divided into electrocoagulation and control groups, respectively. In the electrocoagulation group, the middle ureter was circumferentially electrocoagulated by using a self-made electrocoagulation device with the ureteroscope under direct vision, while the control group underwent ureteroscopy only without electrocoagulation. At 30 and 90 days after electrocoagulation, the glomerular filtration rate (GFR), formation of ureteral stricture, and histomorphological changes of ureteral tissues of each group were detected.

RESULTS

At 90 days after surgery, ureteroscopy and retrograde urography revealed ureteral stricture formation in the middle ureter in the electrocoagulation group. GFR was gradually decreased over time with prolonged washout half-time in the electrocoagulation group. A compensatory increase in GFR was observed in the control group. HE staining and Masson's Trichrome staining revealed fibroblast infiltration and fibrous tissue hyperplasia in the superficial muscular layers, and the muscular layers were arranged disorderly in the electrocoagulation group. Immunohistochemical staining showed accumulation and disorganization of ureteric epithelium in the narrow segment. In the control group, the epithelium was arranged neatly with normal structure.

CONCLUSION

A mini-pig model of ureteral stricture was successfully established using electrocoagulation under ureteroscopy. This method has the advantages of being simple to implement, having high accuracy and high success rate, which can provide an ideal animal model for studying ureteral stricture.

Preliminary Outcomes of Different Tactics of Ureteral Stent Placement in Patients with Ureteral Stricture Undergoing Balloon Dilatation: Experience from a Large-Scale Center

Purpose

Our aim is to demonstrate the optimal number of ureteral stent placements in patients with a ureteral stricture (US) after balloon dilatation (BD).

Methods

A retrospective analysis of 213 patients who underwent BD from 2011 to 2019 was conducted. All statistical analyses were completed by software SPSS 25.0.

Results

Of the patients enrolled, 119 were males and 94 were females. The average age was 44.71 years. One month after stent removal, the overall success rate of ureteral stent placement was 76.99%, and the success rates of single, double, and triple stent groups were 81.7%, 70.3%, and 79.3%, respectively. Six months after stent removal, the overall success rate was 61.9%, and the success rates of the three groups were 61.7%, 52.7%, and 74.1%, respectively. Twelve months after stent removal, the overall success rate was 55.9%, and the success rates of the three groups were 51.9%, 48.6%, and 70.7%, respectively. During indwelling of the stents, the proportions of severe bladder irritation symptoms in the three groups were 13.6%, 16.2%, and 20.7%, respectively. Multivariate analysis indicated the length of US and the time and number of ureteral stent placements were independent risk factors of the treatment effect at 6 months and 12 months after stent removal. Patients in the triple stent group had a better prognosis when compared to those in the single or double stent group.

Conclusion

The long-term effect of three stents was better than that of single and double stents, but the success rate of treatment reduced gradually over time.

Long-term outcomes of paclitaxel-coated balloons for non-malignant ureteral strictures

PURPOSE

To evaluate the clinical efficacy and safety of drug-coated balloon (DCB) ureteroplasty for the management of non-malignant ureteral strictures.

MATERIAL AND METHODS

A prospective "off-label" monocentric single-arm pilot study investigating the safety and efficacy of drug-coated balloon (DCB) (Lutonix^®; BD, USA) was performed. Twenty-five patients with benign ureteral strictures related to uretero-enteric anastomosis (n = 13); lithiasis (n = 5), post-surgical complications (iatrogenic n = 5), transplanted kidney (n = 1) and post-radiotherapy (n = 1) were included. Following lesion crossing, predilatation was performed using 4-7 mm high-pressure balloon catheter (5-6Fr) with a balloon pressure of 6-7 atm based on the manufacturer's recommendation. In the absence of rupture of the ureteral wall, the DCB was dilated for 4 min. across the lesion. The process was repeated if deemed necessary to a maximum of three stricture dilatations. We analysed both clinical and radiological primary patency (no signs of ipsilateral hydronephrosis or improvement of the existing residual dilatation at the follow-up examinations) and secondarily safety endpoints.

RESULTS

Mean lesion length was 40 ± 28.5 mm. Mean time follow up was 36 months ± 10.46 months. Strictures were located at upper ureteric (12%), lower ureteric (32%), ureterovesical anastomosis (4%) and uretero-enteric anastomosis (52%) levels. The overall radiological success at 1-year follow-up was 88% (22/25 patients). In 56% patients (14/25 patients with primary patency) the nephrostomy catheter was removed 21 days following a single DCB procedure. In 32% (8/25 patients) an additional dilatation sessions were required for maintaining the ureteral patency. The overall failure rate at 1-year follow-up was 12% (3/25 patients). Only one case of febrile urinary tract infection in a female patient (acute pyelonephritis) was encountered after the first dilatation.

CONCLUSIONS

Paclitaxel-coated balloon ureteroplasty proved to be safe and effective for the treatment of non-malignant ureteral strictures. Larger studies are warranted to validate these promising initial results.

The contribution of the immune system to genitourinary fibrosis

Fibrotic diseases of the genitourinary tract are devastating and incompletely understood pathologies. These diseases include urethral and ureteral strictures, retroperitoneal fibrosis, and Peyronie's disease. They can contribute to obstructive uropathy and sexual dysfunction. Poor understanding of the pathophysiology of these diseases severely limits our ability to prevent and treat them. Genitourinary fibrotic diseases likely represent related pathologies that share common underlying mechanisms involving wound healing in response to injury. These diseases share the common feature of extracellular matrix abnormalities-such as collagen deposition, transforming growth factor-β accumulation, and dysregulation of collagen maturation-leading to abnormal tissue stiffness. Given the association of many of these diseases with autoimmunity, a systemic pro-inflammatory state likely contributes to their associated fibrogenesis. Herein, we explore the immunologic contribution to fibrogenesis in several fibrotic diseases of the genitourinary system. Better understanding how the immune system contributes to fibrosis in these diseases may improve prevention and therapeutic strategies and elucidate the functions of immunologic contributors to fibrosis in general.

Initial Experience of Self-Expanding Metal Ureteral Stent in Recurrent Ureteral Stricture After Ureteroplasty

Background: The aim of this prospective study was to assess the safety and effectiveness of self-expanding metal ureteral stent (MUS) for the treatment of recurrent ureteral stricture after ureteroplasty.

Methods: We prospectively included 24 patients who underwent MUS implantation between February 2019 and August 2020. The inclusion criteria for the procedure were recurrent ureteral strictures after ureteroplasty. A paired T test was used to compare continuous variables before and after surgery.

Results: A total of 24 patients were finally included in this study. The stricture site was most common on the proximal ureter 19 (79.2%), followed by distal ureter 4 (16.7%) and middle ureter 1 (4.2%). The median length of ureteral stricture is 2.5 (range 1–18) cm. The median operative time was 51.5 min, and the median hospital stay time after surgery was 3 days. Post-operative complication included pain 1 (4.2%), urinary tract infection 2 (8.3%) and hematuria 2 (8.3%). After a median follow-up of 12 months, 19/24 (83.3%) patients were clinically and radiologically successful. We endoscopically adjusted or exchanged the failed stents. The volume of hydronephrosis (124.7 ± 132.5 vs. 66.4 ± 73.2 cm³, P = 0.015), blood creatinine level (104.5 ± 45.4 vs. 80.1 ± 23.2 μmol/L, P = 0.044) and urea nitrogen level (6.9 ± 2.4 vs. 4.8 ± 1.5 mmol/L, P = 0.003) decreased significantly after a median follow-up of 12 months.

Conclusions: MUS is a safe and effective way to manage recurrent ureteral strictures after ureteroplasty. This technique provides a new choice for the treatment of recurrent stricture.

A ureteral stricture disease score and classification system: correlation with upper urinary tract reconstructive surgery complexity

Background

To develop an original and standardized ureteral stricture disease (USD) score and classification system for quantifying ureter stricture characteristics, assessing complexity of the minimally invasive upper urinary tract reconstructive (UUTR) surgical procedure, formulating preoperative plans, and offering objective comparisons of surgical techniques between different institutions and surgeons.

Methods

We retrospectively reviewed a test set of 64 patients and a validation set of 170 patients who underwent minimally invasive UUTR surgery from January 2018 to January 2021. Three factors were selected to be included in the USD score and classification system: (I) stricture etiology (E, 1–2 points); (II) stricture segment (S, 0–3 points); and (III) length of stricture (L, 1–5 points). The UUTR surgery involves low-complex surgeries (cystoscopy with ureteral dilation and stent placement, ureteropyeloplasty, end to end repair, ureteral reimplantation) and high-complex surgeries (onlay repair (buccal mucosae, lingual mucosae, appendix mucosae), Boari flap repair and ileal ureter replacement). Estimated blood loss and operative time were used as surrogate indicators of surgical complexity.

Results

The interrater reliability of the USD score and classification system was 0.908. A linear relationship between the USD score and estimated blood loss was observed (rs =0.676, P<0.001). The USD score was also correlated with operative time (rs =0.638, P<0.001). A significant difference in USD scores was found between the high and low complexity surgery groups (4 vs. 7, P<0.001). Variability of UUTR surgery is based on USD classification system, but with regularity to conform to.

Conclusions

The USD score and classification system is a concise, easily applicable, and validated scale to delineate the clinically significant features of ureter stricture that correlate with the complexity of the UUTR surgical procedure. The use of this score and classification system can facilitate preoperative plan and comparison of USD treatments in clinical practice and urological literature. Research with large sample is needed to further examine and modify the use of the system.

Terminal augmented ureteroplasty with bladder onlay flap technique for recurrent distal ureteral stricture after ureteroneocystostomy: an initial case series

Background

Bladder flap has been shown to be a feasible treatment for distal ureteral stenosis; this technique has been improved such that it can be used to address complex urinary tract obstructions. The purpose of the present study was to describe a surgical technique of ureteroplasty with a bladder onlay flap, which consists of a nontransecting and terminal augmented anastomosis, for repairing recurrent distal strictures of the ureter.

Methods

We retrospectively reviewed 6 patients who underwent this procedure between May 2018 and November 2019. These patients were diagnosed with distal ureteral stenosis and had previously undergone ureteroneocystostomy (one with a Boari flap) but suffered recurrence of flank pain. Patient characteristics, perioperative data and follow-up outcomes were gathered. The success of the operation was judged by symptomatic relief (subjective success) and improved radiographic imaging and renal function (objective success).

Results

Preoperative computed tomography urography (CTU) showed hydronephrosis in all patients: severe hydronephrosis was observed in 83.3% of patients (5/6), and moderate hydronephrosis was observed in 16.7% (1/6). The mean stricture length was 2 cm. The mean operating time, estimated blood loss and postoperative hospital stays of the six patients were 193.3 min (160–270 min), 41.5 mL (10–58 mL) and 8.2 days (6–11 days), respectively. No serious complications (Clavien-Dindo grade ≥3) occurred during or after the operations. The mean follow-up time was 24.5 months (range, 14 to 29). The objective success rate was 83.3% (5/6), and the subjective success rate was 100%.

Conclusions

Our technique of ureteroplasty with a bladder onlay flap by nontransecting and terminal augmented anastomosis is feasible and improves the recovery rate after the repair of recurrent distal ureteral stenosis. Patients who have had previous unsuccessful surgeries might benefit from this approach.

A nomogram to predict stricture-free survival in patients with ureteral stricture after balloon dilation

Background

Balloon dilation is a commonly used minimally invasive endourological treatment of ureteral stricture, but the postoperative recurrence rate is relatively high. And factors contributing to recurrence after treatment are poorly understood. Herein, we sought to develop a novel clinical nomogram to predict ureteral stricture-free survival in patients suffering from ureter stricture and performed balloon dilation.

Methods

The nomogram was established based on a retrospective analysis of 321 patients who received endoscopic balloon dilation alone for ureter strictures from January 2016 to January 2020 in Sun Yat-sen Memorial Hospital using the Cox regression model. Perioperative clinical data and disease outcomes were analyzed. The primary endpoint was the onset of ureteral re-stricture after ureter balloon dilation. Discrimination of the nomogram was assessed by the concordance index (C-index) and the calibration curve. The results were internally validated using bootstrap resampling.

Results

Overall, 321 patients with a median follow-up of 590 days were enrolled in the study, among which 97 patients (30.2%) developed recurrence of ureteral stricture during follow-up. Five variables remained significant predictors of ureteral re-stricture after multivariable analyses: stricture nature (P < 0.001), urinary nitrite (P = 0.041), CKD (P = 0.005), stent retention time (P < 0.001), and balloon size (P = 0.029). The calibration craves for the probability of 1-, 3-, and 5-years stricture-free survival (SFS) presented satisfied with the consistency of nomogram prediction and actual observation. The C-index of the model was 0.74 (95% CI 0.70–0.79).

Conclusions

Our study developed the first nomogram to effectively predict stricture-free survival in patients suffering from ureter stricture after balloon dilation. It is helpful to identify the optimal patients with ureter stricture for balloon dilation and improve treatment outcomes. However, further external validation of the nomogram is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00896-3.

Fluoroscopy-free minimally invasive ureteral stricture balloon dilatation: a retrospective safety and efficacy cohort study

Background

Traditional ureteral stricture balloon dilation was performed with fluoroscopic assistance. The use of a C-arm X-ray machine delivered hazardous radiation to both surgeons and patients. In attempt to eliminate the radiation hazard, we developed a F4.5/6.5 ureteroscope assisted intraoperative X-ray free balloon dilation surgical approach to treat ureteral stricture and to verify its safety and efficacy. Specifically, this method had not been previously reported in the literature.

Methods

We demonstrated an intraoperative X-ray free balloon dilation with detailed step-by-step procedures description and video illustration. Clinical data of patients undergoing minimally invasive endourological treatment for ureteral stricture between February 2015 and November 2019 were retrospectively analyzed. All steps of X-ray free balloon dilation were carried out under direct vision of a ureteroscope, and two indwelling F7 ureteral stents were used for 3 months postoperatively. Preoperative, intraoperative, and postoperative clinical data were evaluated, and follow-up results were reported. Successful outcome was defined as disappearance of preoperative symptoms, relief of hydronephrosis and stable of renal function. Univariate and multivariate prognostic analyses were performed.

Results

We identified 109 patients who received endourological treatment for ureteral stricture in our hospital's medical database. After excluding patients undergone simple catheter dilation, endoureterotomy and other treatment method, 76 patients received balloon dilation without intraoperative fluoroscopic guidance were included in our study. 4/76 patients report a grade II complication (urinary tract infections, UTIs) according to Clavien Dindo classification. In the 22.5 months median follow-up time, the one-year cumulative success rate and two-year cumulative success rate were 85.9% and 80.2% (61/76), respectively, and the majority (13/15, 86.7%) recurrence of ureteral stricture or hydronephrosis deterioration were found within two years after surgery. The longer stenotic lesion length (>5 mm) or multiple ureter stenosis and compromised blood supply of ureter were significantly associated with postoperative stenosis recurrence.

Conclusions

X-ray free endoscopic balloon dilation is a safe and effective procedure that could be performed on patients with ureteral stenosis.

Grafting of CAG peptides and (polyethylene glycol) on unsaturated polyurethane films to promote selective adhesion and migration of urethral epithelial cells

Selective adhesion and migration of urethral epithelial cells (HUCs) over fibroblasts (FIBs) are very important in the reconstruction of the urethral epithelial layer and prevention of ureteral scarring and stenosis. In this study, unsaturated polyurethane (PPFU-CO-SS) films were co-grafted with a cell-resisting poly(ethylene glycol) (PEG) layer and HUC-selective Cys-Ala-Gly (CAG) peptides, whose physicochemical changes were confirmed by X-ray photon spectroscopy, fluorescence spectroscopy and water contact angle measurements. The adhesion and activation of platelets on the PEG/CAG grafted surface were significantly reduced compared to those on the PPFU-CO-SS, resulting in a similar status as that on a PEG-grafted surface. The HUC-selective material could obviously promote the adhesion and migration of HUCs. The ratio of the urethral epithelial cells to fibroblasts on the PEG/CAG grafted surface was nearly 3-fold that on the unmodified PPFU-CO-SS in a co-culture competitive environment. The urethral epithelial cells cultured on the PEG/CAG grafted surface also had the highest migration rate, which was 2.24-fold compared to that on the PPFU-CO-SS control.

Management of intraoperative complications during laparoscopic right colectomy

BACKGROUND

Minimally invasive right colectomy is increasingly performed as standard treatment for diseases of right colon. Complete mesocolic excision has been introduced for cancer treatment to improve oncological results. Both standard and complete mesocolic excision techniques are associated with intraoperative complications. The purpose of this study was to analyse incidence and management of intraoperative complications in patients who underwent laparoscopic right colectomy with complete mesocolic excision in a single institution.

METHODS

This is a retrospective study conducted in a single Italian centre from April 2017 to October 2020. Data of non-metastatic cancer patients who underwent laparoscopic right colectomy were collected to analyse onset of intraoperative complications, their management and rate of conversion to open surgery.

RESULTS

A total of 92 patients were included in this study. The 1.09% of patients were converted to open surgery due to adhesions and bowel occlusion. The 5.43% of patients had intraoperative complications: bleeding from Henle's trunk, pre-pancreatic plane and ileocolic artery stump account for 3.26%, gonadal vessel injury for 1.09% and bowel lesion for 1.09%.

CONCLUSIONS

Despite the limits of this study, it shows that bleeding is one of the most frequent complications in laparoscopic right colectomy. Bleeding, occlusion and adhesions are most common reasons for conversion to open surgery.

The Innovative Use of Ureter Catheter in the Surgery of Obstructive Uropathy

Purpose

Relieving obstruction and protecting renal function are the main therapeutic purposes of obstructive uropathy which often involve surgical treatment, and the ureter catheter is one of the surgical instruments commonly used in surgery. We aimed to explore the innovative use of a ureter catheter in the surgery of obstructive uropathy.

Methods

We used a ureteral catheter to innovate the surgical procedure of the most common causes of obstructive uropathy: ureteral calculi and stricture, establishing an internal circulation system (ICS), proposing a three-step dilatation method, and reviewing their effects on patients. Furthermore, we introduced a simple real-time intrapelvic pressure measurement device to monitor intrarenal pressure during operation.

Results

Postoperative laboratory examination showed that blood CRP, leukocyte neutrophil level, changes in the hemoglobin, urine occult blood, and positive rate of urine culture in the ICS group are significantly lower than those in the control group, corresponding to a lower incidence of bleeding and infection-related complications clinically. A three-month follow-up revealed 1/3 rate of ureteral stricture in the ICS group comparing to the control. We applied the three-step dilatation in patients with severe stenosis in which the balloon could not pass; the overall effective rate was 90.9%. The pressure of the renal pelvis was displayed on the monitor in real time. The surgeon could estimate the degree of filling of the renal pelvis and adjust the intake volume through the data.

Conclusion

The innovative application of ureteral catheters in the operation of obstructive uropathy can realize the real-time monitor of intraoperative renal pelvis pressure, reduce the incidence of lithotripsy postoperative complications, and expand the indications of balloon dilatation in ureteral stricture, which has certain clinical significance.

The bladder-flap ureteral augmentation: An original solution in case of complex distal stricture

An original surgical solution for complex stenosis of the distal ureter is presented. A young, single-kidney male patient developed a stricture of the pelvic ureter after ureteroscopy and laser lithotripsy. Surgical repair was planned after the failure of conservative management. The ureter was sectioned prevesically and spatulated; a bladder flap with the same dimensions of the ureteral plate was taken from the anterior wall, and used to augment the ureter; finally an omental flap was wrapped around the reconstructed tract. Further radiological and ureteroscopic controls showed a largely patent reconstructed ureter, and follow up proved a regularly maintained kidney function.

Electrospinning: Application and Prospects for Urologic Tissue Engineering

Functional disorders and injuries of urinary bladder, urethra, and ureter may necessitate the application of urologic reconstructive surgeries to recover normal urine passage, prevent progressive damages of these organs and upstream structures, and improve the quality of life of patients. Reconstructive surgeries are generally very invasive procedures that utilize autologous tissues. In addition to imperfect functional outcomes, these procedures are associated with significant complications owing to long-term contact of urine with unspecific tissues, donor site morbidity, and lack of sufficient tissue for vast reconstructions. Thanks to the extensive advancements in tissue engineering strategies, reconstruction of the diseased urologic organs through tissue engineering have provided promising vistas during the last two decades. Several biomaterials and fabrication methods have been utilized for reconstruction of the urinary tract in animal models and human subjects; however, limited success has been reported, which inspires the application of new methods and biomaterials. Electrospinning is the primary method for the production of nanofibers from a broad array of natural and synthetic biomaterials. The biomimetic structure of electrospun scaffolds provides an ECM-like matrix that can modulate cells' function. In addition, electrospinning is a versatile technique for the incorporation of drugs, biomolecules, and living cells into the constructed scaffolds. This method can also be integrated with other fabrication procedures to achieve hybrid smart constructs with improved performance. Herein, we reviewed the application and outcomes of electrospun scaffolds in tissue engineering of bladder, urethra, and ureter. First, we presented the current status of tissue engineering in each organ, then reviewed electrospun scaffolds from the simplest to the most intricate designs, and summarized the outcomes of preclinical (animal) studies in this area.

A new technique for ureteral reconstruction using lingual mucosa grafts in a beagle model

PURPOSE

To investigate the feasibility of ureteral reconstruction using lingual mucosa graft (LMG) and evaluate the histological changes of the engrafted LMG in beagles.

METHODS

Twelve male beagle dogs were randomly divided into groups A, B and C (n = 4). A ventral ureteral defect was created by excising half of the ureteral wall. The length of the defect was 3 cm, 6 cm, and 10 cm in groups A, B, and C, respectively. The LMGs were harvested and employed to repair the ureteral defects in onlay fashion. Two dogs per group were sacrificed after 6 months, with additional two dogs per group sacrificed after 12 months. Intravenous urography (IVU) and macroscopic examination were performed to evaluate renal function and ureteral patency. Histological changes in the engrafted LMGs during the tissue incorporation process were assessed by histological analysis.

RESULTS

There were no postoperative complications. Only one dog in group C developed a mild stricture near the proximal anastomosis. In the remaining 11 animals, IVU showed normal renal function and a wide ureteral caliber without stricture or fistula. The diameter of the LMG-reconstructed ureter was greater than that of the proximal and distal ureter (each p value < 0.01). The LMGs survived in situ with newly formed capillaries. The epithelium of the lingual mucosa resembled the urothelium in postoperative 12 months.

CONCLUSION

This new technique for ureteral reconstruction using LMGs is feasible. This approach is a promising alternative clinical treatment for curing long ureteral strictures.

Onlay Repair Technique for the Management of Ureteral Strictures: A Comprehensive Review

Ureteroplasty using onlay grafts or flaps emerged as an innovative procedure for the management of proximal and midureteral strictures. Autologous grafts or flaps used commonly in ureteroplasty include the oral mucosae, bladder mucosae, ileal mucosae, and appendiceal mucosae. Oral mucosa grafts, especially buccal mucosa grafts (BMGs), have gained wide acceptance as a graft choice for ureteroplasty. The reported length of BMG ureteroplasty ranged from 1.5 to 11 cm with success rates of 71.4%-100%. However, several studies have demonstrated that ureteroplasty using lingual mucosa grafts yields better recipient site outcomes and fewer donor site complications than that using BMGs. In addition, there is no essential difference in the efficacy and complication rates of BMG ureteroplasty using an anterior approach or a posterior approach. Intestinal graft or flap ureteroplasty was also reported. And the reported length of ileal or appendiceal flap ureteroplasty ranged from 1 to 8 cm with success rates of 75%-100%. Moreover, the bladder mucosa, renal pelvis wall, and penile/preputial skin have also been reported to be used for ureteroplasty and have achieved satisfactory outcomes, but each graft or flap has unique advantages and potential problems. Tissue engineering-based ureteroplasty through the implantation of patched scaffolds, such as the small intestine submucosa, with or without cell seeding, has induced successful ureteral regeneration structurally close to that of the native ureter and has resulted in good functional outcomes in animal models.

A Multi-Institutional Experience With Robotic Appendiceal Ureteroplasty

OBJECTIVE

To report a multi-institutional experience with robotic appendiceal ureteroplasty.

METHODS

This is a retrospective review of 13 patients undergoing right appendiceal flap ureteroplasty at 2 institutions between April 2016 and October 2019. The primary endpoint was surgical success defined by the absence of flank pain and radiographic evidence of ureteral patency.

RESULTS

Eight of 13 (62%) underwent appendiceal onlay while 5/13 (38%) underwent appendiceal interposition. Mean length of stricture was 6.5 cm (range 1.5-15 cm) affecting anywhere along the right ureter. Mean operative time was 337 minutes (range 206-583), mean estimated blood loss was 116 mL (range 50-600), and median length of stay was 2.5 days (range 1-9). Balloon dilation was required in 1/12 (8%). One patient died on postoperative day 0 due to a sudden cardiovascular event. Otherwise, there were no complications (Clavien-Dindo > 2) within 30 days from surgery. At a mean follow up of 14.6 months, 11/12 (92%) were successful.

CONCLUSION

Robotic appendiceal ureteroplasty for right ureteral strictures is a versatile technique with high success rates across institutions.

Ureteral Reimplantation via Robotic Nontransecting Side-to-Side Anastomosis for Distal Ureteral Stricture

Objective: To describe a novel technique of ureteral reimplantation through robotic nontransecting side-to-side anastomosis. Although the standard approach to ureteroneocystostomy has a high rate of success, it involves transection of the ureter that may impair vascularity and contribute to recurrent strictures. Our method seeks to maximally preserve distal ureteral blood flow that may reduce this risk. Materials and Methods: We retrospectively reviewed a multi-institutional ureteral reconstruction database to identify patients who underwent this operation between 2014 and 2018, analyzing perioperative and postoperative outcomes. Results: Our technique was utilized in 16 patients across three U.S. academic institutions. Median operative time and estimated blood loss were 178 minutes (interquartile range [IQR] 150-204) and 50 mL (IQR 38-100), respectively. The median length of stay was 1 day (IQR 1-2). No intraoperative complications or postoperative complications with Clavien score ≥3 were reported. Postoperatively, 15 of 16 (93.8%) patients reported clinical improvement in flank pain, and all patients who underwent follow-up imaging had radiographic improvement with decrease in hydronephrosis at a median follow-up of 12.5 months. Conclusions: Ureteral reimplantation through a robotic nontransecting side-to-side anastomosis is a feasible and effective operation for distal ureteral stricture that may have advantages over the standard of care transecting ureteroneocystostomy.

Intestinal interposition for complex ureteral reconstruction: A comprehensive review

Long ureteral defects have remained a challenge to urologists for a long time. Bowel interposition, including ileal ureter, appendiceal interposition and reconfigured colon substitution, has gained wide acceptance, even though it is a complicated procedure and associated with some potential complications. Mucus obstruction and metabolic disorders are common complications of intestinal substitution. To circumvent these troubles, modified techniques, such as tapering the bowel graft, intestinal onlay flap and the Yang-Monti procedure, are used. In particular, Yang-Monti ileal ureter replacement is a highly effective option for ureteral reconstruction, and the incidence of complications would be significantly reduced in select patients. After being combined with the Boari flap or psoas hitch technique, the length of intestinal segment used can also be significantly reduced. Most recent long-term results suggest that ileal ureter replacement with antireflux anastomosis seems to be remarkably free of complications, and we highly praise the distal nipple valve technique. Appendiceal interposition is available for patients with normal appendix, and usually this procedure is limited to reconstructing the right ureter. Appendiceal onlay ureteroplasty has emerged as a feasible and effective option to manage patients with complex proximal and mid-ureteral strictures of the right side. The colon is rarely used for ureteral reconstruction because of its large caliber and mucous surface area. However, a reconfigured colon segment is a good substitute to reconstruct long-segment ureteral defects, and long-term follow up confirmed minimal complications and improved renal function. This review provides a comprehensive perspective on complex ureteral reconstruction and replacement using intestinal segments, in particular, ileal ureter replacement.

Robot-assisted laparoscopic ureteroneocystostomy in adults: A single surgeon experience and literature review

Objective

To present our experience and technique with robot-assisted ureteroneocystostomy (RAUN) procedure in adults.

Methods

Between February 2015 and August 2018, a total of 30 (34 ureters) patients who underwent RAUN surgery under a single surgeon were retrospectively reviewed. Perioperative data such as age, sex, body mass index (BMI), American society of anesthesiologists score, estimated blood loss, surgical technique, operative time, complications, length of hospital stay, and stent removal time were recorded. During the follow-up, patients underwent renal function test, urinalysis, and renal ultrasound examination for evaluation. Success was defined as symptomatic and radiologic relieve. Lastly, a literature search was conducted to review all published articles regarding RAUN surgery in adults.

Results

The patients’ mean age, BMI, EBL, operative time, and follow-up period were 45.4 years, 23.1 kg/m², 65.6 mL, 182.9 min, and 21.3 months, respectively. The two most common indications for the surgery were benign ureteral strictures and ureteric injuries secondary to a previous radical hysterectomy. Of the 34 cases, 26 (76.5%) and 8 (23.5%) patients received primary RAUN and RAUN with psoas hitch technique, respectively. Refluxing RAUN method was performed in all cases. No intraoperative complications were found. Two patients had a radiologic and symptomatic recurrence; one was managed with a repeat surgery while the other received ureteral dilatation treatment.

Conclusion

Both our study and the published literature showed that RAUN is a safe, less invasive, and effective surgical technique that can easily replicate the open ureteroneocystostomy for managing lower ureteral diseases.

Prognostic imaging of iatrogenic and traumatic ureteral injury by near-infrared fluorescence

Background

Iatrogenic or traumatic ureteral injuries are life-threatening but difficult to diagnose early. Ureteral visualization is essential for both the prevention and diagnosis of iatrogenic or traumatic ureter injuries. In the present study, we evaluated the feasibility of near-infrared (NIR) with ZW800-1C as a diagnostic tool of iatrogenic or traumatic ureteral injury in addition to ureter visualization, compared to methylene blue.

Methods

With mice model, we compared the image quality of ZW800-1C with methylene blue for ureter visualization. We also made ureter perforation, obstruction, crushing injury, and transection model with mice and evaluated the feasibility of ZW800-1C for diagnostic tool for ureteral injuries.

Results

We could confirm the ureter in the ZW800-1C images in maximally 30 minutes after injection, and the ureter was visible until NIR imaging concluded at 180 minutes after injection. However, methylene blue failed to provide clear ureter imaging during the same period. ZW800-1C imaging successfully visualized ureters subjected to obstruction, transection, perforation, and crush injuries, although urinary leakage was not visible by eye.

Conclusions

Our results indicate ZW800-1C is better suited for ureter visualization than methylene blue and that ZW800-1C has considerable potential for the early diagnosis of various ureteral injuries.

Iatrogenic ureteral injuries and their prevention in colorectal surgery: results from a nationwide survey

AIM

Iatrogenic ureteral injury (IUI) occurs rarely during colorectal surgery but is associated with significant mortality, morbidity and medicolegal issues. Few cases are reported, and recommendations regarding prevention are lacking. The aim of this study is to describe the current state of practice regarding IUI and its prevention among general surgeons in Switzerland.

METHOD

All Swiss general surgeons who are members of either the Swiss Association of Laparoscopic and Thoracoscopic Surgery or the Swiss Surgical Society were invited to participate in an anonymous online survey. Demographics, surgical practice, rate of IUI and methods used to prevent IUI were investigated.

RESULTS

All participants were board-certified general surgeons, 63.4% were certified visceral surgeons and 17.9% were certified colorectal surgeons. The mean level of experience in colorectal surgery was 15.6 ± 9.2 years. Formal ureter identification was considered mandatory during sigmoid or rectal surgery by 83.7% of participants, and 31.7% considered identification of the right ureter during right colectomy to be mandatory. In total, 61.8% of the participants and 78.4% of surgeons with more than 20 years of experience had encountered at least one IUI. Prophylactic ureteral stenting was considered useful in complex procedures by 93.5% of participants, and 56.9% had used stents at least once in the past 12 months. Noninvasive techniques for identifying ureters would be considered in regular daily practice by 54.5% of the participants.

CONCLUSION

Most general surgeons experience IUI. Ureter identification is widely integrated in colorectal procedures. Prophylactic stenting is widely used for difficult cases. Noninvasive methods to improve ureter identification are now needed.

Endoscopic Balloon Dilatation in the Treatment of Benign Ureteral Strictures: A Meta-Analysis and Systematic Review

BACKGROUND AND PURPOSE

Although balloon dilatation is one of the main endoscopic procedures used to treat benign ureteral strictures, its precise efficacy remains controversial. We aimed to identify, combine, and analyze existing published data to ascertain the efficacy of endoscopic balloon dilatation for benign ureteral strictures.

METHODS

In December 2018, a literature search was performed using Medline, Embase, and Web of Science databases. We included reports in which the study population consisted of patients who underwent endoscopic balloon dilatation for the treatment of benign ureteral strictures. Technical, short-term, and long-term success rates (expressed as mean ± standard error) were adopted as the outcome measures.

RESULTS

Using our search strategy, a total of 19 studies (all series reports) were included for analysis. Using a random-effects model, the pooled technical success rate of endoscopic balloon dilatation for benign ureteral strictures was found to be 89% ± 4%. Furthermore, the short-term success rate (i.e., 3 months after surgery) was 60% ± 10%, and the long-term success rate (i.e., 6-12 months after surgery) was 54% ± 14%. In the subgroup analysis, the success rate of endoscopic balloon dilatation for ≤2-cm benign ureteral strictures was significantly higher than that for >2-cm ones (odds ratio [OR]: 0.13; 95% confidence interval [CI]: 0.05-0.35). In addition, the success rate in cases with strictures of onset timing ≤3 months was relatively higher than that in cases with strictures of onset timing >3 months (OR: 0.46; 95% CI: 0.15-1.43).

CONCLUSION

Our study indicates that endoscopic balloon dilatation has a high success rate in the treatment of benign ureteral strictures with length ≤2 cm and onset timing ≤3 months. However, there is still no consensus on balloon type, dilatation pressure, expansion number, postoperative ureteral stent type, and stent retention time for the balloon dilatation technique.

Treating benign ureteroenteric strictures: 27-year experience comparing endourological techniques with open surgical approach

PURPOSE

To compare open surgical anastomotic revision with endourological techniques for the treatment of ureteroenteric strictures in patients with urinary diversions.

METHODS

All records of patients treated for ureteroenteric strictures in our clinic between 1989 and 2016 were retrospectively reviewed. In 76 patients, 161 completed procedures were analyzed: 26 open revisions vs. 135 endourological treatments, including balloon dilation, Wallstent and/or laser vaporization.

RESULTS

Median follow-up was 34 months. At 60 months, patency rates were 69% (95% CI 52-92%) after open vs. 27% (95% CI 19-39%) after endo-treatment (p = 0.003); median patency duration was 15.5 vs. 5 months, respectively (p = 0.014). Eventually, 15% of patients required open surgery after primary endo-treatment and 21% received endoscopic re-treatment after primary open surgery. Cox regression analysis revealed no confounding factors among the risk factors added to the model. Complication rates were higher after open surgery (27% Clavien 2, 12% Clavien 3-4 vs. 5% Clavien 1-2, 3% Clavien 3, p = 0.528). Median postoperative hospital stay was 14 days (open) vs. 2 days (endo), p < 0.001. Mean estimated glomerular filtration rate improved with + 17 (open) vs. + 8.1 (endo), p = 0.024. Renal function was compromised in 8% of patients in the open surgery group vs. 6% in the endo-treatment group.

CONCLUSIONS

In these patients, in terms of patency and patency duration, open surgery was superior to endourology. Nevertheless, endourological treatments offer a safe and less-invasive alternative to delay or avoid open surgery, especially in patients who are unfit for open surgery.

Bone marrow mesenchymal stem cells reduce ureteral stricture formation in a rat model via the paracrine effect of extracellular vesicles

With no effective therapy to prevent or treat ureteral stricture (US), a multifactorial fibrotic disease after iatrogenic injury of the ureter, the need for new therapies is urgent. Mesenchymal stem cells (MSCs) have been widely studied for treating tissue defects and excessive fibrosis, and recent studies established that one of the main therapeutic vectors of MSCs is comprised in their secretome and represented by extracellular vesicles (EVs). Thus, we have determined to explore the specific role of MSCs‐derived EVs (MSC‐EVs) treatment in a pre‐clinical model of US. The results firstly showed that either a bolus dose of MSCs or a bolus dose of MSC‐EVs (administration via renal‐arterial) significantly ameliorated ureteral fibrosis and recuperated ureter morphological development in a US rat model. We confirmed our observations through MSCs or MSC‐EVs treatment alleviated hydronephrosis, less renal dysfunction and blunted transforming growth factor‐β1 induced fibration. Due to MSC‐EVs are the equivalent dose of MSCs, and similar curative effects of transplantation of MSCs and MSC‐EVs were observed, we speculated the curative effect of MSCs in treating US might on account of the release of EVs through paracrine mechanisms. Our study demonstrated an innovative strategy to counteract ureteral stricture formation in a rat model of US.

Endoscopic Management of Ureteral Strictures: an Update

PURPOSE OF REVIEW

This review focuses on the role of endoscopic treatment of ureteral stricture disease (USD) in the era of minimally invasive surgery.

RECENT FINDINGS

There is a relative paucity of recent literature regarding the endoscopic treatment of USD. Laser endopyelotomy and balloon dilation are associated with good outcomes in treatment-naïve patients with short (< 2 cm), non-ischemic, benign ureteral strictures with a functional renal unit. If stricture recurs, repetitive dilation and laser endopyleotomy is not recommended, as success rates are low in this scenario. Patients with low-complexity ureteroenteric strictures and transplant strictures may benefit from endoscopic treatment options, although formal reconstruction offers higher rates of success. Formal ureteral reconstruction remains the gold-standard treatment for ureteral stricture disease as it is associated with higher rates of complete resolution. However, in carefully selected patients, endoscopic treatment modalities provide a low-cost, low-morbidity alternative.

Endoscopic Approaches to Upper Tract Urothelial Carcinoma

A select group of patients with upper tract urothelial carcinoma (UTUC) may meet indications for endoscopic management. Strategies for disease management are provided, based on a comprehensive review of the data using PubMed and Medline databases and marrying this with our experience with endoscopic management of UTUC. Endoscopic management of UTUC via retrograde or antegrade approaches is a viable treatment option for appropriately selected patients with low-risk UTUC, including those with low-grade, low-volume, and solitary tumors. However, recurrence risk limits these procedures to compliant patients under a vigilant surveillance program. Efficacious adjuvant therapies are needed to reduce local recurrences.

Adult iatrogenic ureteral injury and stricture-incidence and treatment strategies

Iatrogenic ureteral injuries and strictures are relatively common complication of pelvic surgery and radiation treatment. Left untreated they are associated with severe short- and long-term complications such as urinoma, septic state, renal failure, and loss of a renal unit. Treatment depends on timing of diagnosis, as well as extent of injury, and ranges from simple endoscopic management to complex surgical reconstruction under usage of pedicled grafts. While recent advances in ureteral tissue engineering are promising the topic is still underreported. Historically a domain of open surgery, laparoscopic and robotic-assisted approaches have proven their feasibility in small case series, and are increasingly being utilized as means of reconstructive surgery. This review aims to give an outline of incidence and treatment of ureteral injuries and strictures in light of the latest advances.