An evaluation of ureteral diameter ratio and vesicoureteral reflux index in the treatment of primary vesicoureteral reflux

Objective:Vesicoureteral reflux(VUR)index is a simple,validated tool that reliably predicts significant improvement and spontaneous resolution of primary reflux in children.The aim of this study was to evaluate and compare the ureter diameter ratio(UDR)and VUR index(VURx)of patients treated with endoscopic injection(EI)and ureteroneocystostomy(UNC)methods in the pediatric age group due to primary VUR.Methods:Patients under the age of 18 years old who underwent EI and UNC with the diagnosis of primary VUR between January 2011 and September 2021 were determined as the participants.The UDR was assessed using voiding cystourethrography,and the VURx score was determined prior to treatment based on hospital records included in the study.Results:A total of 255 patients,60(23.5%)boys and 195(76.5%)girls,with a mean age of 76.5(range 13.0e204.0)months,were included in the study.EI was applied to 130(51.0%)patients and UNC was applied to 125(49.0%)patients due to primary VUR.The optimum cut-off for the distal UDR was obtained as 0.17 with sensitivity and specificity of 73.0%and 63.0%,respectively.The positive and negative predictive values were 66.0%and 70.0%,respectively.Conclusion:When the UDR and VURx score are evaluated together for the surgical treatment of primary VUR in the pediatric age group,it is thought that it may be useful in predicting the clinical course of the disease and evaluating surgical treatment options.

Migration of varicocele coil leading to ureteral obstruction and hydronephrosis:A case report

BACKGROUND Varicocele embolization,a minimally invasive treatment for symptomatic varicoceles,carries a rare risk of complications like ureteral obstruction and hydronephrosis.This case report documents such a case to raise awareness of these potential complications and showcase minimally invasive surgical management as a successful solution.CASE SUMMARY A 35-year-old male presented with flank pain and hematuria following varicocele embolization.Imaging confirmed left ureteral obstruction and hydronephrosis.Laparoscopic ureterolysis successfully removed the embolization coil and repaired the ureter,resolving the patient's symptoms.Follow-up at six months and two years showed sustained improvement.CONCLUSION Minimally invasive surgery offers an effective treatment option for rare complications like ureteral obstruction arising from varicocele embolization.

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.

Minimally invasive reconstruction of extensive mid-lower ureteral strictures using a bilateral Boari flap

Objective:To describe and evaluate the technique using bilateral Boari flap ureteroneocystostomy(BBFUNC)for bilateral mid-lower ureteral strictures.Methods:We retrospectively reviewed five patients who underwent minimally invasive BBFUNC in our institution(Union Hospital,Wuhan,China)between July 2019 and December 2021.The bilateral ureters were mobilized and transected above the stenotic segments.The bladder was isolated and incised longitudinally from the middle of the anterior wall.Then,an inverted U-shaped bladder flap was created on both sides,fixed onto the psoas tendon,and anastomosed to the ipsilateral distal normal ureter.Following double-J stenting,the Boari flaps were tubularized,and the bladder was closed with continuous sutures.The patients’perioperative data and follow-up outcomes were collected,and a descriptive statistical analysis was performed.Results:No case converted to open surgery,and no intraoperative complication occurred.The median surgical time was 230(range 203-294)min.The median length of the bladder flaps was 6.2(range 4.3-10.0)cm on the left and 5.5(range 4.7-10.5)cm on the right side.All patients had not developed recurrent ureteral stenosis during the median follow-up time of 17(range 16-45)months and had a normal maximum flow rate after surgery.The median post-void residual was 7(range 0-19)mL.The maximal bladder capacity was decreased in one(20%)patient.Conclusion:The present study demonstrates that minimally invasive BBFUNC is feasible and safe in treating is limited.

Effectiveness of Combined Dual-lens Treatment of Ureteral Stenosis after Ureteral Stone Surgery

Objective:To investigate the clinical effect of dual-lens combined treatment of ureteral stenosis after ureteral stone surgery.Methods:The study period was from January 2023 to December 2023,and the sample was selected from 76 patients with ureteral stenosis after ureteral stone surgery admitted to our hospital,which was randomly grouped into the experimental group(n=38)and the control group(n=38)by using the numerical table lottery method.The control group was treated with urethroplasty,and the experimental group was treated with a dual-lens combination,comparing the intraoperative blood loss,postoperative recovery time,hospitalization time,and complication rate between the two groups.Results:The intraoperative blood loss,postoperative recovery time and hospitalization time of the experimental group were lower than those of the control group(P<0.05);the complication rate of the experimental group was lower than that of the control group(P<0.05).Conclusion:Dual-lens combined treatment can reduce intraoperative blood loss,shorten postoperative recovery time and hospital stay and reduce the incidence of complications,which has the value of popularization and application.

The optimal stent pusher position to achieve successful ureteral stent insertion under fluoroscopic guidance

Objective: To examine factors to predict the optimal stent pusher position when inserting ureteral stents under fluoroscopy.Methods: We retrospectively reviewed 327 patients who underwent ureteral stent insertion. We considered the pubic bone as a useful anatomical landmark to insert ureteral stents under fluoroscopic guidance. Thus, we categorized patients into three groups (proximal, middle, and distal groups) according to the position of the radiopaque tip of the push catheter when inserting the ureteral stent. Success was defined as a completely curled ureteral stent tail. We compared stent insertion success rates among the three groups. A multivariate analysis was performed to identify the factors affecting stent insertion success.Results: In men, 36 (63.2%) cases were deemed successful in the proximal group compared with 40 (80.0%) cases in the middle group and 12 (20.7%) cases in the distal group (p<0.001). In women, 26 (45.6%) cases were deemed successful in the proximal group compared with 54 (98.2%) cases in the middle group and 38 (76.0%) cases in the distal group (p<0.001). With the multivariate analysis, the stent pusher position was the most significant factor influencing successful stent insertion (men: odds ratio 6.00, 95% confidence interval 2.66-13.51, p<0.001;women: odds ratio 37.80, 95% confidence interval 4.94-289.22, p<0.001).Conclusion: The position of the stent pusher affects stent insertion success. The middle of the pubic symphysis is the optimal position for the radiopaque tip of the pusher when inserting ureteral stents under fluoroscopic guidance.

Understanding intrarenal backflow: Intrarenal pressure during ureteroscopy and beyond

The number of ureterorenoscopic procedures for upper urinary tract stone management has increased dramatically during recent years worldwide[1].Developments in flexible ureteroscope and laser technology have made it possible to successfully address larger and more complex stone scenarios retrogradely.On the other hand,this means that more and more patients are exposed to the potential adverse effects of ureteroscopy[2].In general,ureteroscopy is considered a safe procedure.However,serious complications and even deaths do occur,and these events are most likely underreported[3,4].

Role of buccal mucosa graft ureteroplasty in the surgical management of pyeloplasty failure

Objective:Secondary pyeloplasty for recurrent ureteropelvic junction obstructions may be a safe and feasible surgical option for patients.This study aimed to demonstrate outcomes of utilizing a non-transecting buccal mucosa graft ureteroplasty for management of recurrent ureteropelvic junction obstruction after prior failed pyeloplasty.Methods:We performed a retrospective review of our Collaborative of Reconstructive Robotic Ureteral Surgery database for all consecutive patients who underwent buccal mucosa graft ureteroplasty between April 2012 and June 2022 for management of recurrent ureteropelvic junction obstructions after prior failed pyeloplasty.The primary outcome included surgical success which was defined as the absence of flank pain and no obstruction on imaging.Results:Overall,ten patients were included in our analysis.The median stricture length was 2.5(interquartile range[IQR]1.8-4.0)cm.The median operative time was 230.5(IQR 199.5-287.0)min and median estimated blood loss was 50.0(IQR 28.8-102.5)mL.At a median follow-up of 10.3(IQR 6.2-14.8)months,80%of patients were surgically successful and there were no major(ClavieneDindo Grade>2)complications.Conclusion:Buccal mucosa graft ureteroplasty is a valuable non-transecting surgical option for patients with recurrent ureteropelvic junction obstructions who failed prior pyeloplasty and has comparable outcomes to the literature regarding standard transecting techniques.

Multi-aspect analysis of ureteral access sheath usage in retrograde intrarenal surgery: A RIRSearch group study

Objective:To evaluate the effect of ureteral access sheath(UAS)use and calibration change on stone-free rate and complications of retrograde intrarenal surgery(RIRS).Methods:Data from 568 patients undergoing RIRS for kidney or upper ureteral stones were retrospectively included.Firstly,patients were compared after 1:1 propensity score matching,according to UAS usage during RIRS(UAS used[+]87 and UAS non-used[−]87 patients).Then all UAS+patients(n=481)were subdivided according to UAS calibration:9.5-11.5 Fr,10-12 Fr,11-13 Fr,and 13-15 Fr.Primary outcomes of the study were the success and complications of RIRS.Results:Stone-free rate of UAS+patients(86.2%)was significantly higher than UAS−patients(70.1%)after propensity score matching(p=0.01).Stone-free rate increased with higher caliber UAS(9.5-11.5 Fr:66.7%;10-12 Fr:87.0%;11-13 Fr:90.6%;13-15 Fr:100%;p<0.001).Postoperative complications of UAS+patients(11.5%)were significantly lower than UAS−patients(27.6%)(p=0.01).Complications(8.7%)with 9.5-11.5 Fr UAS was lower than thicker UAS(17.2%)but was not statistically significant(p=0.09).UAS usage was an independent factor predicting stone-free status or peri-and post-operative complications(odds ratio[OR]3.654,95%confidence interval[CI]1.314-10.162;OR 4.443,95%CI 1.350-14.552;OR 4.107,95%CI 1.366-12.344,respectively).Conclusion:Use of UAS in RIRS may increase stone-free rates,which also increase with higher caliber UAS.UAS usage may reduce complications;however,complications seemingly increase with higher UAS calibration.

Percutaneous nephrostomy versus ureteral stent in hydronephrosis secondary to obstructive urolithiasis:A systematic review and meta-analysis

Objective: To assess if there is a preferable intervention between retrograde ureteral stent (RUS) and percutaneous nephrostomy (PCN) tube, in cases of upper urinary tract stone obstruction with complications requiring urgent drainage, by evaluating outcomes regarding urinary symptoms, quality of life (QoL), spontaneous stone passage, and length of hospital stays, since there is no literature stating the superiority of one modality over the other.Methods: We searched MEDLINE and other sources for relevant articles in June 2019 without any date restrictions or filters applied. The selection was done first by the title and abstract screening and then by full-text assessment for eligibility. Only randomized controlled trials or cohort studies in patients with hydronephrosis secondary to obstructive urolithiasis that presented comparative data between PCN and RUS placement concerning at least one of the defined outcome measures were included. Lastly, MEDLINE database and PubMed platform were screened again using the same terms, from June 2019 until November 2022.Results: Of 556 initial articles, seven were included in this review. Most works were considered of moderate-to-high quality. Three studies regarding QoL showed a tendency against stenting, even though only one demonstrated statistically significant negative impact on overall health state. Two works reported significantly more post-intervention urinary symptoms in stenting patients. One article found that PCN is a significant predictor of spontaneous stone passage, when adjusted for stone size and location. Findings on length of hospital stays were not consistent among articles.Conclusion: PCN appears to be the intervention better tolerated, with less impact on the patient’s perceived QoL and less post-operative urinary symptoms, in comparison with RUS. Nevertheless, further studies with larger samples and a randomized controlled design are suggested.

A review of complications after ureteral reconstruction

Objective:This study aimed to provide a comprehensive overview of the complications unique to ureteral reconstruction in adults,emphasizing their presentation,diagnosis,and management in the treatment of ureteral structure disease.Methods:This review involves an in-depth analysis of existing literature and case studies pertaining to ureteral reconstruction,with a focus on examining the range of complications that can arise post-surgery.Special attention is given to the presentation of each complication,the diagnostic process involved,and the subsequent management strategies.Results:Ureteral reconstruction can treat ureteral stricture disease with low morbidity;however,complications,although uncommon,can have severe consequences.The most notable complications include urinary extravasation,stricture recurrence,urinary tract infections,compartment syndrome,symptomatic vesicoureteral reflux,and Boari flap necrosis.Each complication presents unique diagnostic challenges and requires specific management approaches.Conclusion:Ureteral reconstruction is a highly effective treatment for ureteral stricture disease.Having a strong understanding of the potential complications that patients may experience following ureteral reconstruction is not only critical to adequately counsel patients but also facilitate prompt diagnosis and management of complications when they arise.

Concomitant treatment of ureteral calculi and ipsilateral pelvic sciatic nerve schwannoma with transperitoneal laparoscopic approach: A case report

BACKGROUND Schwannomas are rare peripheral neural myelin sheath tumors that originate from Schwann cells.Of the different types of schwannomas,pelvic sciatic nerve schwannoma is extremely rare.Definite preoperative diagnosis of pelvic schwannomas is difficult,and surgical resection is the gold standard for its definite diagnosis and treatment.CASE SUMMARY We present a case of pelvic schwannoma arising from the sciatic nerve that was detected in a 40-year-old man who underwent computed tomography for intermittent right lower back pain caused exclusively by a right ureteral calculus.Subsequently,successful transperitoneal laparoscopic surgery was performed for the intact removal of the stone and en bloc resection of the schwannoma.The total operative time was 125 min,and the estimated blood loss was inconspicuous.The surgical procedure was uneventful.The patient was discharged on postoperative day 5 with the simultaneous removal of the urinary catheter.However,the patient presented with motor and sensory disorders of the right lower limb,caused by partial damage to the right sciatic nerve.No tumor recurrence was observed at the postoperative appointment.CONCLUSION Histopathological examination of the specimen confirmed the diagnosis of a schwannoma.Thus,laparoscopic surgery is safe and feasible for concomitant extirpation of pelvic schwannomas and other pelvic and abdominal diseases that require surgical treatment.

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/cm^(3)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/cm^(3),ureteral lesions should be actively treated.

Subadventitial resection of the ureterd-new method for surgical corrections of the ureteropelvic junction and ureterovesical junction obstructions

Objective:The aim of our study was to examine results of pyeloplasty using the new methoddsubadventitial resection of the ureter with preservation of the ureteral artery proposed by us and the possibility of using this method in one-stage surgery with ureteropelvic junction(UPJ)and ureterovesical junction(UVJ)obstructions or vesicoureteral reflux.Methods:A retrospective analysis of 108 patients with hydronephrosis(including two patients with hydroureteronephrosis)who received treatment from March 1998 to March 2020 was carried out,with an average follow-up period of 36 months.Dismembered pyeloplasty using a subadventitial technique with preservation of ureteral blood supply was performed in 108 patients(including bilateral in two cases).In one patient with UPJ and UVJ obstructions and in one patient with UPJ obstruction and vesicoureteral reflux subadventitial resection of the ureter were performed in both segments.Results:All patients managed to preserve the integrity of the ureteral artery during dismembered pyeloplasty,and two patients simultaneously underwent ureterocystostomy by subadventitial resection of the ureter.The method of pyeloureteroplasty with subadventitial resection of the ureter makes it possible to improve long-term results in patients with hydronephrosis,including those with lesions of the UPJ and UVJ segments.In all cases,it was feasible to achieve a decrease in the degree of hydronephrosis.Postoperative complications were observed in five cases(4.6%),in none of which there were complications associated with the surgical technique,and were eliminated without loss of renal function.Conclusion:Our 22 years of experience shows that the technique of subadventitial resection of the ureter allows us to preserve the ureteral blood circulation during dismembered pyeloplasty and thus creates conditions for prevention of restenosis of UPJ and for single-stage ureteroplasty on the upper and lower ureteral segments.

Retrocaval Ureter: A Case Series of Three Cases Managed with Uretrouretrostomy

Retrocaval ureter is a very rare congenital malformation. We report a 10 years’ experience in the diagnosis and treatment of retrocaval ureter, a case series of 3 cases in two different countries of the Middle East. This is a retrospective study that included 3 cases of retrocaval ureters in Egypt and Saudi Arabia. Standard open ureteroureteric anastomosis was performed through a flank incision for each case. Patients’ symptoms were re-evaluated after two to four months. Complete recovery from symptoms occurred, and hydroureter and hydronephrosis regressed in all cases. Early diagnosis and treatment are the keys to prevent hydronephrosis and deterioration of renal functions.

Clinical application of flexible ureteroscopic sheath with controllable intraluminal pressure in treating ureteral stones

Objective:The purpose of the study was to assess the clinical efficacy and safety of a combined perfusion suction platform with pressure feedback control function and an ureteroscopic suction sheath that can measure the ureteropelvic pressure in implementing lithotripsies.Methods:Fifty-two patients who underwent lithotripsy under intelligent monitoring of ureteral intraluminal pressure from June 2016 to January 2018 were retrospectively recruited.The inclusion standard was stone diameter>1.5 cm but<2.5 cm.After the 12/14 Fr suction sheath was placed,manometer interface and suction interface of the sheath were connected to the platform via the pressure sensor and suction tube,respectively.The ureteroscope was connected to the platform perfusion pump,and the crushed stones were aspirated out under negative pressure.Results:According to the location of the stone,21(40.4%)cases were classified as upper ureteral stones,19(36.5%)were midureteral stones,and 12(23.1%)were lower ureteral stones.Forty-seven patients underwent successful primary sheath placement and lithotripsy with a mean operative time of 34.5(standard deviation 18.3)min.Retrograde stone migration did not occur.There were eight patients with hematuria postoperatively.Serious complication was 1.9% with one case of ureteral perforation.Stone clearance was 95.7% at Day 1e2 postoperatively,and 100% at Day 30 postoperatively.Conclusion:Ureteroscopic lithotripsy with intelligent pressure control using our device improved the efficiency of the lithotripsy and rate of stone clearance.The safety of the operation can be ensured.It is worth popularization and application in clinical practice.

Long term outcomes of Cohen’s cross trigonal reimplantation for primary vesicoureteral reflux in poorly functioning kidney

BACKGROUND Open ureteric reimplantation by cross trigonal technique described by Cohen is considered a common surgical option for correction of vesicoureteral reflux(VUR). There is a lack of evidence in literature though for what happens to such kidneys, in the long run, particularly those which are poorly functioning.AIM To assess the long-term outcomes of ureteric reimplantation in poorly functioning kidneys in children with unilateral primary VUR.METHODS Children with unilateral primary VUR and a relative renal function of less than 35% who underwent open or laparoscopic ureteric reimplantation between January 2005 and January 2017 were included in the study. Patients who had a follow up of less than five years were excluded. Preoperative evaluation consisted of a voiding cystourethrogram and Dimercaptosuccinic acid(DMSA) scan. In the follow-up period, patients underwent a diuretic scan at 6 weeks and 6 months.Follow up ultrasound was done for change in grade of hydronephrosis and retrovesical ureteric diameter. Subsequent follow up was done at 6 monthly intervals with evaluation for proteinuria and hypertension and any recurrent urinary tract infection(UTI). For assessment of cortical function, DMSA was repeated annually for 5 years after surgery. A paired-samples t-test was used to test the mean difference of DMSA between pre-post observations.RESULTS During this period, 36 children underwent ureteric reimplantation for unilateral primary VUR. After excluding those with insufficient follow-up, 31 were included in the analysis. Most of the patients were males(n = 26/31, 83.8%). Patient’s age(mean ± SD, range) was 5.21 ± 3.71, 1-18 years. The grades of VUR were grade Ⅱ(1patient), grade Ⅲ(8 patients), grade Ⅳ(10 patients), and grade Ⅴ(12 patients). The pre and postoperative DMSA was 24.064 ± 12.02 and 24.06 ± 10.93, which was almost the same(statistically equal, paired-samples t-test: P = 0.873). The median(range) follow-up duration was 82(60-120)mo. One patient had persistent reflux after surgery(preoperative: grade Ⅳ, postoperative: grade Ⅲ), and the very same patient developed recurrent UTI. The difference in the preoperative and postoperative DRF was less than 10% in 29 patients. In one patient, the DRF decreased by 17%(22% to 05%) while in another patient, the DRF increased by 12%(25% to 37%) after surgery. None of the patients had an increase in scarring after surgery. 15% of patients were hypertensive before surgery and all of them continued to be hypertensive after surgery while none developed hypertension after surgery. None of the patients had significant proteinuria(> 150 mg/d) during the follow-up period.CONCLUSION Children with unilateral primary VUR and poorly functioning kidney maintain the renal function over the long term in most cases. Hypertension and proteinuria do not progress over time in these patients.

Use of a modified ureteral access sheath in semi-rigid ureteroscopy to treat large upper ureteral stones is associated with high stone free rates

Objective:To examine differences in outcomes of semi-rigid ureteroscopy(URS)with or without a modified-ureteral-access-sheath(mUAS)to treat large upper ureteral stones.Methods:Patients with single,radio-opaque large upper ureteral stone(≥10 mm)treated using semi-rigid URS between August 2013 and October 2016 were retrospectively evaluated.The stone-free status was determined from Kidney-ureter-bladder(KUB)X-ray films taken on postoperative Day 1 and after 1 month.Results:Of 103 patients meeting inclusion criteria,43(41.75%)and 60(58.25%)were treated with semi-rigid URS with and without mUAS,respectively.The immediate stone-free rate(SFR)for the mUAS group was significantly higher than the non-mUAS group(40[93.0%]vs.46[76.7%];p=0.033).The SFR at 1 month was also high for patients treated using mUAS,but not statistically different from patients not treated with mUAS(41[95.3%]mUAS vs.51[85.0%]non-mUAS;p=0.115).Auxiliary procedure rates were significantly lower for mUAS patients compared to non-mUAS patients(2[4.7%]vs.14[23.3%];p=0.01).There were no significant differences in surgical duration and hospital stays,and the overall complication rates were statistically similar for mUAS patients compared to non-mUAS patients(1[2.3%]vs.3[5.0%];p=0.638).

Compression Mechanical Performance Simulation and Parameter Optimization of Degradable Ureteral Stent Based on ABAQUS

The compression performance of a degradable ureteral stent is analyzed and the parameters are optimized by a finite element modeling method.The degradable ureteral stent explored in this paper is developed from poly(glycolic acid)(PGA)and poly(lactic-co-glycolic acid)(PLGA)degradable materials.Based on the actual measurement of fabric structure parameters,the three-dimensional model of the stent is established with the help of the modeling software.The finite element analysis software is used to simulate the compression process of the degradable ureteral stent.The parameters of materials,interactions and boundary conditions are set according to the compression environment of the stent for modeling and simulation.On this basis,the friction coefficient of yarns,the yarn radius,and the braided angle of the stent are further compared.The comparison test is carried out by a single variable.The experimental results show that the change of yarn friction coefficient has little influence on the compressive stress,while the yarn radius and the braided angle of the stent have a great influence on the compressive stress.

Ureteral reconstruction with decellularized small intestinal submucosa matrix for ureteral stricture: A preliminary report of two cases

Objective:To determine the feasibility of decellularized small intestinal submu-cosa(5IS)matrix in repairing ureteral strictures.Methods:Two patients with ureteral stenoses underwent ureteral reconstruction with SIS ma-trix at the Zhejiang Provincial Corps Hospital of Chinese People's Armed Forces between June 2014 and June 2016.The ureteral stenoses were repaired with a semi-tubular SIS matrix and the postoperative recoveries were observed.Results:Both operations were successfully completed.The average operative time was 90 min and the average length of hospital stay was 15 days.No fevers,incision infections,intestinal obstruction,graft rejection,or other serious complications were noted.After 2 months,ure-teroscopic examinations showed that the surfaces of the original patches were covered by mu-Cosa and there were no apparent stenoses in the lumens.The ureteral stents were replaced every 2 months postoperatively and removed 12 months postoperatively.No infections or uri-nary leakage occurred after removal of the stents.Intravenous urography was performed 6 and 12 months postoperatively.The results showed that the ureters were not obstructed and there was no apparent stenosis at the anastomosis sites.The average follow-up time was>12 months.Long-term follow-up is still ongoing,and computed tomography examin ations of the urinary tract have been conducted in the outpatient department of our hospital 1,3,and 6 months after removal of the double-J stents,suggesting the absence of hydronephrosis.The serum creatinine levels remained stable during the follow-up.Conclusion:SIS matrix reconstruction is a feasible method to repair ureters stenosis.