Predictors of forniceal rupture in patients with obstructing ureteral calculi: Analysis of multicenter data.

Background: Renal forniceal rupture (FR) is a unique complication of obstructive uropathy. This study aimed to identify the predictors of FR among patients presenting with renal colic due to obstructing ureteral calculi. Materials and Methods: After obtaining ethics approval, electronic records of patients from three National Guard hospitals in Saudi Arabia were reviewed between 2016 and 2020 to identify patients who presented with renal colic and were diagnosed with FR due to obstructive ureteric stones (FR group). An equivalent number of consecutive patients presenting with renal colic due to obstructing ureteric stones without FR was selected as a control group (non-FR group). Patients were grouped according to age group (<30, 30-40, 41-50, and >50 years), body mass index (BMI) class, gender, comorbidities, grade of hydronephrosis, location of the stone in the ureter, size of the stone (<3 mm, 3-7 mm, and >7 mm), and stone former status. Baseline patients' and stone characteristics were compared, and a regression analysis was performed to identify predictors of FR. Results: A total of 50 patients with FR were identified, and a control group of 50 patients without FR were selected. The baseline patients' and stone demographic characteristics in terms of age (P = 0.42), gender (P = 0.275), BMI (P = 0.672), comorbidity, grade of hydronephrosis (P = 0.201), and stone location (P = 0.639) were comparable between the FR group and the non-FR group. However, the stone size was statistically significant between both groups (P = 0.014). On multivariable analysis, it was found that the stone size was associated with a significantly higher increase in the incidence of FR (odds ratio [OR]: 6.5 [1.235-34.434]; P = 0.027). Furthermore, the age group between 30 and 40 years was potentially at a lower risk for FR (OR: 0.262 [0.069-0.999]; P = 0.049). Conclusion: This multicenter study showed that the stone size 3-7 mm had a six-fold increase in the chance of FR, and the age group between 30 and 40 years is potentially at a lower risk for FR.

Safety and Efficacy of Ureteroscopic Laser Lithotripsy in the Management of Ureteric Calculi in Pregnancy-Experience of a Tertiary Care Center.

Introduction: Ureteric colic in pregnancy is one of the common non-obstetric reasons for emergency department visits. Ureteric calculi present a significant threat to maternal and fetal health and definitive management often becomes necessary. Our aim is to assess the safety and efficacy of ureteroscopic laser lithotripsy in the management of ureteric stones in pregnancy. Material and methods: This is a prospective observational study of 3 years carried at a tertiary referral center. It includes all pregnant patients who underwent ureteroscopic laser lithotripsy for ureteric stones. Results: A total of 29 pregnant patients underwent ureteroscopic laser lithotripsy at our center in 3 years. The mean age of patients was 33.5 ± 6.2 years, and the mean gestation age at the time of ureteroscopy was 23.34 ± 5.9 weeks. The average stone size was 8.3 ± 3.6 mm and was predominantly found in upper ureter (62%). The mean operative time was 31 ± 8.9 min, and the average laser energy spent was 4.3 ± 1.1 kJ/case. There was no major Intraoperative complication, and the average hospital stay was 2.5 ± 1.5 days. Complete stone clearance was achieved in 93.1% of cases. Conclusion: Ureteroscopic laser lithotripsy is safe and effective treatment of ureteric stones in terms of obstetric outcome and stone clearance in pregnancy.

Understanding ureteroscopy complications according to modified Clavien classification system.

OBJECTIVE: To determine the complications of ureteric stone treatment with semi-rigid uretero-renoscopy in accordance with the modified Clavien classification system. METHODS: The descriptive, prospective study was conducted at the Department of Urology, Sindh Institute of Urology and Transplantation, Karachi, from June 30, 2020, to December 29, 2021, and comprised patients of either gender aged 18-70 years having ureteric stones. All patients were subjected to ureterorenoscopy using a semi-rigid ureteroscope under general anaesthesia. The patients were followed up for 2 months. All complications were noted and graded in line with the Modified Clavien Complication System. Ultrasound and X-ray were used to determine the stone-free rate. Data was analysed using SPSS 23. RESULTS: Of the 414 patients, 304(73.4%) were males and 110(26.5%) were females. The overall mean age was 40.22±13.10 years. There were 106(25.6%) proximal, 134(32.3%) middle, and 174(42%) distal ureteric stones. Stent placement was done in 56(13.5%) cases. There were 260(62.8%) patients with no complication, 90(21.7%) with grade I complications, 34(8.2%) with grade II complications, 10(2.4%) with grade IIIa, 8(1.9%) with grade IIIb, and 12 (2.9%) with grade IVa complications. CONCLUSIONS: Uretero-renoscopy was found to be a safe procedure, as it had minimal associated complications with optimal stone clearance and great dexterity. The Modified Clavien classification system was found to be an easy way to classify surgical complications of uretero-renoscopy.

OBSTRUCTIVE UROPATHY FROM BILATERAL URETERIC CALCULI IN AN INFANT WITH DIARRHOEA DISEASE.

Introduction: Urolithiasis is the presence of mineral deposits in the urinary tract. It is rare in under-5 children and in Sub-Saharan Africa. Although metabolic abnormality is implicated in 50% of cases, infection, decreased urine volume and flow (dehydration state) have been implicated. We report a case of bilateral ureteric calculi in an infant with diarrhoea disease and dehydration. Case Report: A.S, is an 8-month-old male with prolonged loose, large-volume stool, large-volume vomiting, high-grade fever, body weakness, and peri-orbital swelling that progressed to generalized body swelling and absent urine for 2 days. He was conscious, afebrile (36.90C), pale with anasarca. Had distended abdomen with ascites. Dyspnea, coarse crepitation, and hypoxemia. Tachycardia (PR -180/min) Hypertensive (BP - 125/79mmHg). PCV - 20%, WBC - 24,000/l, platelet - 110,000/l. Creatinine (1030 umol/l), Urea - 30mmol/l, Multi drug resistant E.Coli. Bilateral Grade II nephritis, hydro-uretero-nephrosis, right pelvi-ureteric and left vesico-ureteric junction calculi. Managed for Diarrhoea disease complicated with Bilateral Obstructive uropathy secondary to Bilateral Ureteric Calculi. Had bilateral open ureteric exploration, ureterolithotomy, Stenting, intraoperative transfusion, antibiotics, analgesics, and IVF. 24-hr post-surgery: urine output (3.26ml/kg/hr): right stent (210ml), left stent (423ml) while urethral catheter (150ml), 742umol/l, Urea: 26mmol/l 48-hr post-surgery: Urine output 5.1ml/kg/hr (1224ml/24hr); Cr: 424umol/l, Urea: 16mmo/l 5 days post-surgery: Urine output 3.1ml/kg/hr (725ml/24hr); Cr: 47umol/l, Urea: 4.6 mmo/l, Patient was discharged home and currently on follow-up in paediatric nephrology and urology clinics. Conclusion: A high index of suspicion of obstructive uropathy in children with diarrhoea disease, and dehydration, who have developed acute kidney injury is recommended.

Bilateral Synchronous 3-Port Trans-peritoneal Laparoscopic Ureterolithotomy: a Case Report.

Trans-peritoneal laparoscopic ureterolithotomy is a well-established minimally invasive procedure for management of large impacted ureteric stones since the last 3 decades. We present a case of a 51-year old gentleman, who presented with bilateral large upper ureteric calculi with obstructive uropathy and azotemia, managed successfully with bilateral synchronous 3-port trans-peritoneal laparoscopic ureterolithotomy, and to our knowledge is the first such case to be reported in literature. Supplementary Information: The online version contains supplementary material available at 10.1007/s42399-022-01190-5.

Renal and ureteric stones: a clinical review.

This clinical review on renal and ureteric stones discusses how stones form, the incidence, risks, and complications associated with calculi. It reflects on the management and treatment options available, and highlights the important contribution by nurses and those working in advanced clinical practice roles in using their knowledge and rational clinical decision making to ensure timely recognition, prompt investigation, management and ongoing health promotion.

Likelihood of Distal Ureteric Calculi to Pass Spontaneously: Systematic Review and Cumulative Analysis of the Placebo Arm of Randomized-Controlled Trials.

INTRODUCTION: Distal ureteric calculi remain a widely debated topic without clear consensus on expectant management. This systematic review aims to assess the placebo arms of RCTs to extrapolate data on the natural history of distal ureteral stones and ascertain the success rate of expectant management. METHODS: A literature search was performed, and 3 reviewers used a predefined inclusion criterion to independently select articles for inclusion. A cumulative analysis was undertaken, and risk of bias assessed using the Cochrane tool. RESULTS: Stone expulsion was recorded in 1,823/2,447 (74.5%) patients overall. The expulsion rate of study participants receiving placebo varied widely from 35.2 to 88.9%. The overall expulsion rate of stones ≤5 mm was 486/561 (87%) as opposed to 814/1,093 (75%) in stones >5 mm in size. Time to stone expulsion varied from 8.54 to 24.5 days. A re rate of 2% was reported. CONCLUSIONS: Spontaneous passage of distal ureteric calculi is dependent on stone size and location within the ureter. Provided a patient does not portray symptoms of uncontrollable pain, infection, obstruction, or declining renal function, it is reasonable to trial a period of expectant management. Follow-up should be arranged to ensure symptom resolution, and alternative treatment can be offered if required.

Postoperative myocardial injury in a patient with left ureteric stone and asymptomatic COVID-19 disease.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was first identified on 8thDecember 2019 in Wuhan, Hubei, China, and has since spread globally to become an emergency of international concern. Patients infected with SARS-CoV-2 may be asymptomatic or present with symptoms ranging from mild clinical manifestations: such as fever, cough, and sore throat to moderate and severe form of the disease such as pneumonia and acute respiratory distress syndrome (ARDS). In some patients, SARS-CoV-2 can affect the heart and cause myocardial injury which is evidenced either by electrocardiographic (ECG) changes or by a rise in serum troponin level. Patients with myocardial involvement are generally at risk of developing severe illness and tend to have a poor outcome. We hereby present a case of a hypertensive male patient with undiagnosed, asymptomatic COVID-19, who underwent an emergency urologic procedure for ureteric calculi. He eventually sustained a postoperative myocardial injury resulting in his demise. This case highlights the importance of detailed preoperative assessment and anticipation of complications during this global pandemic.

The correlation between demographic factors and upper urinary tract stone composition in the Thai population.

OBJECTIVE: To identify the correlation between demographic factors and upper urinary tract stone composition in the Thai population. METHOD: A retrospective observational study of first-time upper urinary tract stone former patients aged over 18 years who underwent stone surgery was performed in a tertiary referral university hospital from January 2013 to May 2018. Collected data included demographic information and stone composition information, which were analysed by the Fourier Transform-Infrared Spectroscopy (FTIR) method. The correlation between the demographic factors and major upper urinary tract stone composition was analysed using Fisher's exact test. RESULTS: A total of 480 patients were included in this study. The stones were 319 (66.5%) renal calculi and 161 (33.5%) ureteric calculi. There were 248 (51.7%) single composition stones and 232 (48.3%) mixed composition stones. The major stone compositions were 288 (60.0%) calcium oxalate (CaOx), 125 (26.0%) calcium phosphate (CaP), 40 (8.3%) uric acid (UA), 19 (4.0%) magnesium ammonium phosphate (MAP), five (1.0%) cystine, and three (0.6%) ammonium hydrogen urate (AHU). Gender was correlated with the major stone composition. In females, a correlation was found between the major stone composition and age, diabetes mellitus (DM), and glomerular filtration rate (GFR). The study showed no significant correlation between the major stone composition and dyslipidemia (DLP), hypertension (HT), gout, and body mass index (BMI) in both genders. CONCLUSION: Gender, age, DM, and GFR were the factors affecting the stone composition.

Role of Dual-Energy Computed Tomography in Characterization of Ureteric Calculi and Urinary Obstruction.

Objective The present study was carried out to assess the accuracy of dual-energy computed tomography (DECT) in the morphological and chemical characterization of ureteric calculi along with the prediction of the grade of urinary obstruction. Methods This was a prospective observational study that included 100 cases with ultrasonography (USG)-diagnosed ureteric calculi that underwent surgery or had spontaneous expulsion of ureteric calculi. At enrolment, DECT was performed for an in vivo evaluation of volume, chemical composition, and grade of obstruction by subjective assessment of the perinephric edema. After surgical intervention, in vitro evaluation of volume was done by fluid displacement followed by infrared spectroscopy (IRS) for chemical composition. DECT findings were compared with the biochemical analysis and degree of obstruction was validated against excretory CT urograms. Sensitivity, specificity, and the positive predictive and negative predictive values of DECT were assessed. Results No significant difference was observed between the mean volume of stones by fluid displacement (65.1±77.61 mm3) and DECT assessment (66.09±81.78 mm3). IRS revealed the composition of stones as hydroxyapatite, uric acid, cysteine, oxalic acid, and mixed type in 48, 23, 15, five, and nine cases. The sensitivity and specificity of DECT for hydroxyapatite, uric acid, cysteine, oxalic acid, and mixed types were 89.6% and 88.5%, 82.6% and 97.5%, 86.7% and 96.5%, 80% and 98.9%, and 88.9% and 98.9%, respectively. On CT urography, a total of 35 had a high-grade and 65 had a low-grade obstruction, whereas DECT revealed high- and low-grade obstructions in 42 and 58 cases. The sensitivity and specificity of DECT for a high-grade obstruction were 94.3% and 86.2%. Conclusions The findings of the study showed that DECT provides comprehensive information regarding the morphological, chemical, and anatomical characterization of ureteric stones.

Asymptomatic bilateral obstructing ureteric calculi resulting in Lactobacillaemia and endocarditis requiring emergency aortic valve replacement.

Ureteric calculi are a common cause of emergency presentation to hospitals in the United Kingdom and worldwide. A significant and life threatening complication of those stones that obstruct the ureter is pyonephrosis, bacteraemia and resulting sepsis. Whilst the majority of such cases present with the typical symptoms of loin pain and fever, here we describe the case of a 57 year old patient with asymptomatic bilateral obstructing ureteric calculi that led to bacteraemia from a rare bacterial pathogen, Lactobacillus jensenii, and subsequent severe bacterial endocarditis requiring emergency aortic valve replacement.

Case report of ureteroscopy assisted laparoscopic ureterolithotomy for multiple large ureteric calculi.

Managing patient having multiple large ureteric calculi at different locations in ureter with minimal invasive surgery is always a challenge for the surgeon. We hereby present the case report of ureteroscopy assisted laparoscopic ureterolithotomy for multiple large ureteric calculi in proximal and distal ureter in a young female. In this unique and novel method ureteroscopy and laparoscopy was done simultaneously over the patient using two camera units and two surgeons. This approach avoided open ureterolithotomy scar and also extensive dissection of ureter. This unique surgery can be considered as confluence of endourology and laparoscopy.

Spontaneous distal ureteric rupture: A rare case report and review of literature.

Spontaneous rupture of the ureter is a very interesting and unusual phenomenon which normally occurs due to ureteral obstruction. We present a case of spontaneous rupture of the distal ureter, secondary to a ureteric calculus. Our patient presented with a history of acute on chronic abdominal pain and was septic on arrival to hospital.

Comparing tamsulosin, silodosin versus silodosin plus tadalafil as medical expulsive therapy for lower ureteric stones: A randomised trial.

OBJECTIVE: To compare the efficacy of tamsulosin, silodosin, and silodosin plus tadalafil as medical expulsive therapy (MET) for distal ureteric calculi. METHODS: In all, 120 patients who met the inclusion criteria were randomised into one of three treatment arms: tamsulosin (Group A), silodosin (Group B), and silodosin plus tadalafil (Group C). The drugs were given for a maximum of 4 weeks. The primary endpoint was the stone expulsion rate and secondary endpoints were stone expulsion time, number of pain episodes, and side-effects associated with MET. The follow-up period was for 4 weeks, after which ureteroscopic lithotripsy was done to remove any stones that were not expelled. RESULTS: There was a statistically significantly higher stone expulsion rate in Group C (90%) as compared to groups A (57.5%) and B (77.5%) with a shorter mean time to stone expulsion. Also, there were statistically fewer pain episodes in Group C as compared to groups A and B. There were no serious side-effects. CONCLUSION: The present study concludes that the combination of silodosin and tadalafil increases the ureteric stone expulsion rate and decreases the expulsion time significantly. This combination provided significantly better control of pain without any serious side-effects.

A prospective randomised double-blind placebo-controlled trial to assess the effect of diuretics on shockwave lithotripsy of calculi.

OBJECTIVE: To assess the effect of diuretics with shockwave lithotripsy (SWL) on the treatment of renal and upper ureteric calculi. PATIENTS AND METHODS: Adult patients with a solitary non-obstructive radio-opaque renal or upper ureteric calculus with normal renal function were included. They were prospectively randomised to receive either SWL with placebo or SWL with diuretics (40 mg parenteral furosemide) in a double-blind manner with a sample size of 48 patients in each arm. The primary outcomes were the SWL success and failure rates. The secondary outcomes were the number of shocks and sessions. RESULTS: Complete fragmentation was achieved in 89.6% of the patients in the furosemide arm as compared to 81.3% in the placebo arm. Clearance was achieved in 77.1% of the patients in the furosemide arm as compared to 70.8% in the placebo arm. The number of shocks and the number of sessions were higher in the placebo arm. These differences were not statistically significant. CONCLUSION: The use of diuretics along with SWL treatment of renal and upper ureteric calculi does not show a statistically significant improvement in fragmentation or clearance.

Outcome of uncomplicated ureteric calculi managed with medical expulsive therapy in the outpatient clinic of a urology unit in Sri Lanka.

OBJECTIVE: Although medical expulsive therapy (MET) is shown to be effective for ureteric calculi, the optimum duration and the stone size suitable for MET are not well established yet. The objectives of the study were to determine the optimum duration and maximum stone size suitable for MET. RESULTS: All patients with radiologically confirmed uncomplicated ureteric calculi treated with MET using tamsulosin over a period of 6 months in the outpatient setting were followed up. There were 213 patients. 165 were men. Mean age was 42 years. At presentation 42 stones were in upper ureter (19.7%), 51 in mid ureter (23.9%), 120 in lower ureter (56.3%). The majority (82.7%) of stones were less than 10 mm. Seven stones (3.3%) were over 15 mm. Ninety-two (43.2%) patients had spontaneous passage of stones within 6-weeks of MET. Another 38.9% passed the stone within the next 6-weeks. Thirty-eight patients (17.8%) required surgery. Uncomplicated ureteric stones up to 10 mm can be given a trial of MET using tamsulosin which can be extended up to 12-weeks with a success rate over 92%. This may have substantial clinical and fiscal benefits by reducing the number of interventional procedures especially in resource-poor settings.

Minimally Invasive Surgical Ureterolithotomy Versus Ureteroscopic Lithotripsy for Large Ureteric Stones: A Systematic Review and Meta-analysis of the Literature.

CONTEXT: The management of large ureteric stones represents a technical and clinical challenge. OBJECTIVE: To investigate the safety and efficacy of minimally invasive surgical ureterolithotomy (MISU) in comparison with ureteroscopic lithotripsy (URS) for the treatment of large ureteric stones. EVIDENCE ACQUISITION: The Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines were followed for the conduction of the study, which was registered in the PROSPERO database. Search string was "(laparoscop* OR retroperito* OR robot*) AND ureterolitho*"; database scope included PubMed, SCOPUS, Cochrane, and EMBASE. Primary end points were the stone-free (SFR) and complications rates. Secondary end points included operative time and hospital stay. Subgroup analyses were performed for stones 1-2 and >2cm, as well as different lithotripters and ureteroscopes. Meta-analysis and forest-plot diagrams were performed with the RevMan 5.3.5 software. EVIDENCE SYNTHESIS: After screening 673 publications, seven randomized controlled trials were eligible to be included in the meta-analysis. A total of 778 patients were pooled after the elimination of the dropouts. No robotic cohorts were found. Only upper ureteral stones were treated in the included studies. The SFR at discharge and 3 mo was higher with MISU with odds ratios of 6.30 (95% confidence interval [CI]: 3.05, 13.01; I2=0%) and 5.34 (95% CI: 2.41, 8.81; I2=0%), respectively. The most common complications for MISU and URS were conversion to open surgery and stone migration to the renal pelvis, respectively. Favorable results in terms of operative time were observed in the case of URS with a mean difference of 29.5min (95% CI: 14.74, 44.26; I2=98%). Hospitalization time was favorable in the case of URS with a mean difference of 2.08 days (95% CI: 0.96, 3.20; I2=99%). CONCLUSIONS: This meta-analysis showed a significantly higher SFR at discharge and 3 mo for MISU in comparison with URS when upper ureteral stones were treated. Operative and hospitalization time favored URS over MISU. PATIENT SUMMARY: The current study investigated the literature on the minimally invasive management of large ureteric stones. The available evidence shows that both ureteroscopic lithotripsy and minimally invasive surgical ureterolithotomy could be considered for the treatment of these stones with similar results. The selection of the approach should be based on the advantages and disadvantages of each technique.

The "Guidewire-Coil"-Technique to prevent retrograde stone migration of ureteric calculi during intracorporeal lithothripsy.

BACKGROUND: Stone retropulsion represents a challenge for intracorporeal lithotripsy of ureteral calculi. The consequences are an increased duration and cost of surgery as well as decreased stone-free rates. The use of additional tools to prevent proximal stone migration entails further costs and risks for ureteral injuries. We present the simple technique of using a coil of the routinely used guidewire to prevent stone retropulsion. METHODS: We retrospectively evaluated all patients with mid-to-proximal ureteral stones in 2014, which were treated by ureteroscopic lithotripsy (Ho: YAG and/or pneumatic lithotripsy). The preoperative stone burden was routinely assessed using low dose CT scan (if available) and/or intravenous pyelogram. RESULTS: The study population consisted of 55 patients with 61 mid-to-proximal calculi. Twentyseven patients underwent semirigid ureterorenoscopy using the "Guidewire-Coil-Technique", the second group (n = 28) served as control group using the guidewire as usual. There has been a statistically significant reduction of accidental stone retropulsion (2/27 vs. 8/28, p < 0.05) as well as a decreased use of auxiliary procedures (p < 0.05) compared to the control group. No difference was observed in operative time. One ureteral injury in the control group required a prolonged ureteral stenting. CONCLUSION: The "Guidewire-Coil-Technique" is a simple and safe procedure that may help to prevent proximal calculus migration and therefore may increase stone-free rates without causing additional costs.

Ultrasonography versus computed tomography for initial investigation of suspected nephrolithiasis.

UNLABELLED: Clinical question Is ultrasonography a safe and practical alternative to computed tomography for the initial investigation of suspected nephrolithiasis? Article chosen Smith-Bindman R, Aubin C, Bailitz J, et al. Ultrasonography versus computed tomography for suspected nephrolithiasis. N Engl J Med 2014;371(12):1100-10. OBJECTIVE: To assess the safety and efficacy of ultrasonography as a first-line imaging investigation for patients with suspected nephrolithiasis.

After urgent drainage of an obstructed kidney by internal ureteric stenting; is ureteroscopic stone extraction always needed?

OBJECTIVES: To assess the probability of spontaneous stone passage and its predictors after drainage of obstructed kidney by JJ stent, as insertion of an internal ureteric stent is often used for renal drainage in cases of calcular ureteric obstruction. PATIENTS AND METHODS: Between January 2011 and June 2013, patients for whom emergent drainage by ureteric stents were identified. The patients' demographics, presentation, and stone characteristics were reviewed. The primary endpoint for this study was stone-free status at the time of stent removal, where all patients underwent non-contrast spiral computed tomography (NCCT) before stent removal. Ureteroscopic stone extraction was performed for CT detectable ureteric stones at the time of stent removal. Potential factors affecting the need for ureteroscopic stone extraction at the time of stent removal were assessed using univariate and multivariate statistical analyses. RESULTS: Emergent ureteric stents were undertaken in 196 patients (112 males, 84 females) with a mean (SD) age of 53.7 (16.2) years, for renal obstruction drainage. At the time of stent removal, 83 patients (42.3%) were stone free; with the remaining 113 patients (57.7%) undergoing ureteroscopic stone extraction. On multivariate analysis, stone width [odds ratio (OR) 15.849, 95% confidence interval (CI) 2.83; P = 0.002) and radio-opaque stones (OR 12.035, 95% CI 4.65; P < 0.001) were independent predictors of the need for ureteroscopic stone extraction at the time of stent removal. CONCLUSION: Spontaneous ureteric stone passage is possible after emergent drainage of an obstructed kidney by ureteric stenting. Stone opacity, larger stone width, and positive preoperative urine culture are associated with a greater probability of requiring ureteroscopic stone extraction after emergent drainage by ureteric stenting.