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Introduction: Malignant ureteral obstruction is associated with a poor prognosis, with a median survival of 3 to 7 months. These patients are ideal candidates for concurrent palliative care services, consistent with American Society of Clinical Oncology guidelines. We aimed to characterize palliative care, hospice, and end-of-life health care utilization in patients with malignant ureteral obstruction., Methods: Patients ≥ 18 years old at our institution and diagnosed with malignant ureteral obstruction between May 2014 and August 2020 were retrospectively identified and pertinent data extracted. Palliative care, hospice, and end-of-life health care utilization was described, and factors associated with each were assessed with logistic regression models. Overall survival was assessed with Cox proportional hazard regression models., Results: One hundred fifteen patients qualified for analysis; 39.1% (45/115) utilized palliative care and spent a median of 12.5 days (IQR 3-52 days) on nonhospice palliative care. On adjusted analysis Black ethnicity (aOR 3.44, 95% CI: 1.08-10.94) was associated with palliative care utilization. Of the patients, 53.9% (62/115) utilized hospice. The median time from hospice initiation to death was 12 days (IQR 5-23 days). On adjusted analysis, prior extirpative surgery (aOR 3.63, 95% CI 1.01-13.05) and palliative care utilization (aOR 4.38, 95% CI 1.70-11.31) were associated with hospice utilization. Median survival following diagnosis was 141 days (IQR 37.5-442.5). Of the patients, 43.0% (37/86) had high end-of-life health care utilization. On multivariable analysis, only hospice (aOR 0.03, 95% CI 0.01-0.14) was associated with less end-of-life health care utilization., Conclusions: Palliative care is underutilized in malignant ureteral obstruction. Hospice, but not palliative care utilization, was associated with decreased end-of-life health care utilization.

Purpose: As the prevalence of urolithiasis increases and ureteroscopy is used more frequently, the risks of uncommon complications such as ureteral stricture may become more notable. Our objective is to assess the rate and associated risk factors of ureteral stricture formation in patients undergoing ureteroscopy., Materials and Methods: Utilizing the IBM MarketScan research database, we evaluated data from 2008 to 2019 and compared ureteral stricture rates and their management following ureteroscopy to subjects who had shock wave lithotripsy. Shock wave lithotripsy was used as a comparison group to represent the rate of stricture from stone disease alone. A third group of those having both shock wave lithotripsy and ureteroscopy was included. Patients and secondary procedures were identified using Current Procedural Terminology, and International Classification of Diseases-9 and -10 codes., Results: A total of 329,776 patients received ureteroscopy, shock wave lithotripsy, or shock wave lithotripsy+ureteroscopy between 2008 and 2019. Stricture developed in 2.9% of patients after ureteroscopy, 1.5% after shock wave lithotripsy, and 2.6% after shock wave lithotripsy+ureteroscopy. In the multivariable model, rates of stricture were 1.7-fold higher after ureteroscopy vs shock wave lithotripsy (OR:1.71, 95% CI 1.62-1.81). Preoperative hydronephrosis, age, prior stones/intervention, and concurrent kidney and ureteral stones were associated with increased risk of stricture. Of those with strictures incurred after ureteroscopy, 35% required drainage, 21% had endoscopic intervention, 4.8% required reconstructive surgery, and 1.7% underwent nephrectomy., Conclusions: Ureteral stricture rate after ureteroscopy of nearly 3% was higher than expected and approximately twice the rate attributable to stone disease alone. Factors associated with the stone as well as instrumentation were found to be risk factors. The morbidity of stricture disease following ureteroscopy was significant.

Purpose: Ureteroenteric strictures represent the most common complication requiring reoperation after radical cystectomy. We investigated the prevalence, outcomes, predictors and management of ureteroenteric strictures., Materials and Methods: We retrospectively reviewed our quality assurance, robot assisted radical cystectomy database to identify patients in whom ureteroenteric strictures developed. Data were reviewed for demographics, perioperative outcomes and ureteroenteric stricture characteristics. The Kaplan-Meier method was used to calculate time to ureteroenteric stricture and multivariable stepwise regression was done to evaluate predictors of ureteroenteric strictures., Results: Ureteroenteric strictures developed in 12%, 16% and 19% of 51 patients (13%) at 1, 3 and 5 years after robot assisted radical cystectomy, respectively. All patients were initially treated endoscopically or percutaneously, including 57% treated only endoscopically or percutaneously and 43% who required surgery, which was open repair in 6 and robot assisted repair in 16. At a median followup of 23 months 33 patients (65%) were free of disease, including 13 after endoscopic or percutaneous treatment, 15 after robot assisted repair and 5 after open revision. Open and robot assisted revisions showed comparable perioperative outcomes. On multivariable analysis the predictors of ureteroenteric anastomotic strictures were body mass index (OR 1.07, 95% CI 1.01-1.13, p = 0.02), intracorporeal urinary diversion (OR 3.28, 95% CI 1.41-7.61, p = 0.006), length of the right resected ureter (OR 0.66, 95% CI 0.50-0.88, p = 0.004), estimated glomerular filtration rate 30 days after assisted radical cystectomy (OR 0.85, 95% CI 0.74-0.98, p = 0.03), urinary tract infection (OR 2.68, 95% CI 1.31-5.49, p = 0.007) and leakage (OR 3.85, 95% CI 1.05-14.1, p = 0.04). Male gender (OR 0.19, 95% CI 0.04-0.96, p = 0.04) and higher body mass index (OR 0.85, 95% CI 0.72-0.996, p = 0.05) were associated with lower odds of successful endoscopic management., Conclusions: Multiple modifiable factors were associated with ureteroenteric anastomotic strictures following robot assisted radical cystectomy. Surgical revision can provide a definitive management with comparable outcomes for open and robotic repairs., (Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Ureteral stent placement for decompressing renal units obstructed by calculi is safe and can be potentially lifesaving in the prompt resolution of the sequelae of renal obstruction, infection and an obstructing stone. At many institutions there can be prolonged delay in getting patients to the operating room for stent placement. We hypothesized that it is safe and efficacious to attempt ureteral stent placement using local anesthesia at the bedside without live fluoroscopic guidance., Materials and Methods: Patients presenting with symptomatic, obstructing ureteral calculi were given the option of bedside ureteral stent placement. Viscous lidocaine was placed into the urethra before flexible cystoscopic examination. A 260 cm Glidewire® was used as initial access with only 1 attempt at passage. All stent placements were confirmed with immediate post-procedure radiograph. Prospectively collected data were retrospectively analyzed for all patients who underwent attempted bedside ureteral stent placement., Results: A total of 42 patients underwent attempted bedside stent placement under local anesthesia without fluoroscopic guidance. Mean stone size was 8.3 mm and 71% of stones were in the proximal ureter. Ureteral stent placement was pursued in 14% of patients for infection and in 59% for intractable pain. Ureteral stent placement was successful in 30 patients (71%). Statistical analysis did not reveal any significant predictors of successful stent placement in this cohort of patients., Conclusions: In our cohort bedside ureteral stent placement was well tolerated, safe and efficacious, thus expediting upper tract decompression in the setting of obstructed renal units in more than 70% of patients., (Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: During ureteroscopy ureteral balloon dilation may be necessary to allow for passage of endoscopic instruments or access sheaths. We assessed the efficacy and complications associated with ureteral balloon dilation., Materials and Methods: We retrospectively reviewed the records at 2 institutions from 2000 to 2012 to identify patients who underwent ureteral balloon dilation during ureteroscopic treatment of upper tract stones. An 18Fr balloon dilator was used in all cases. Patients with documented ureteral stricture, radiation therapy or urothelial cancer were excluded from analysis. Primary outcomes were the stone-free rate, operative complications, balloon dilation failure and the postoperative ureteral stricture rate. Complications were divided into intraoperative and postoperative groups according to the Satava and Clavien-Dindo classifications, respectively., Results: A total of 151 patients fulfilled study criteria. Median followup was 12 months. The stone-free rate was 72% and median time to first postoperative imaging was 2.8 months. Balloon dilation failed in only 8 patients (5%). Eight intraoperative ureteral perforations (5%) were identified, which were managed by a ureteral stent in 7 patients and a percutaneous tube in 1. Endoscopic re-treatment was required in 4 patients with Satava 2b postoperative complications. The postoperative complication rate was 8% (11 cases). A single ureteral stricture was attributable to balloon dilation., Conclusions: In this contemporary review balloon dilation of the ureter before endoscopic treatment of stone disease was associated with a high success rate and few complications. Ureteral balloon dilation may decrease the need for a secondary procedure in patients undergoing ureteroscopy to manage proximal ureteral and intrarenal stones., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We studied the effect of stachydrine on the expression of caspase-12 and 9 in rats with unilateral ureteral obstruction., Materials and Methods: An animal model of renal interstitial fibrosis was established using unilateral ureteral obstruction with enalapril as the positive control. Rats were randomly divided into 6 groups, including sham treated, model, enalapril, and high, medium and low stachydrine. On day 14 postoperatively the rats were sacrificed. Serum was collected to determine serum creatinine and blood urea nitrogen. Tubular injury index was measured by hematoxylin and eosin staining. Renal interstitial collagen deposition was analyzed semiquantitatively by Masson staining. Expression of the apoptotic factors caspase-12 and 9 in renal tissues was determined by immunohistochemistry., Results: The renal tubular interstitial damage index, degree of renal interstitial fibrosis, serum creatinine, blood urea nitrogen, and expression of caspase-12 and 9 in the treatment groups were significantly decreased compared to the model group (p <0.05 and <0.01, respectively). Serum creatinine, blood urea nitrogen, renal tubular injury, collagen deposition, and expression of caspase-12 and 9 in the high stachydrine group were significantly decreased compared with the enalapril group (p <0.05)., Conclusions: Stachydrine interfered with the endoplasmic reticulum stress mediated apoptosis pathway by decreasing caspase-12 expression and inhibiting caspase-9 activation. Ultimately renal tubular epithelial cell apoptosis was suppressed and renal interstitial fibrosis development was postponed., (Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Little data are available on noninvasive magnetic resonance imaging based assessment of renal function during upper urinary tract obstruction. We determined whether functional multiparametric kidney magnetic resonance imaging could monitor the treatment response in cases of acute unilateral upper urinary tract obstruction., Material and Methods: Between January 2008 and January 2010, 18 patients with acute unilateral upper urinary tract obstruction due to calculi were prospectively enrolled to undergo kidney magnetic resonance imaging with conventional, blood oxygen level dependent and diffusion-weighted sequences upon emergency hospital admission and after release of obstruction. We assessed functional imaging parameters of obstructed and contralateral unobstructed kidneys derived from blood oxygen level dependent (apparent spin relaxation rate) and diffusion-weighted (total apparent diffusion coefficient, pure diffusion coefficient and perfusion fraction) sequences during acute upper urinary tract obstruction and after its release., Results: During acute obstruction the apparent spin relaxation rate and perfusion fraction were lower in the cortex (p=0.020 and 0.031) and medulla (p=0.012 and 0.190, respectively) of obstructed kidneys compared to contralateral unobstructed kidneys. After obstruction release the apparent spin relaxation rate and perfusion fraction increased in the cortex (p=0.016 and 0.004) and medulla (p=0.071 and 0.044, respectively) of formerly obstructed kidneys to values similar to those in contralateral kidneys. Total apparent diffusion coefficient and pure diffusion coefficient values did not significantly differ between obstructed and contralateral unobstructed kidneys during or after obstruction., Conclusions: In our patients with acute unilateral upper urinary tract obstruction due to calculi functional kidney magnetic resonance imaging using blood oxygen level dependent and diffusion-weighted sequences enabled us to monitor pathophysiological changes in obstructed kidneys during obstruction and after its release., (Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We present 5 years of outcome data on metallic ureteral stents in a cohort of patients treated for chronic ureteral obstruction., Materials and Methods: We retrospectively identified and analyzed the records of all patients in whom a Resonance® Metallic Ureteral Stent was placed between early 2007 and late 2011 at our institution. We performed a descriptive analysis of key outcomes, including the failure and death rates, and stenting duration, defined as the time from initial stent placement to last stent failure or patient death. We also performed a secondary comparative analysis of patients with a benign vs malignant etiology of obstruction., Results: A total of 139 metallic stents were placed in 47 patients, including 27 (57%) with malignant and 20 (43%) with a benign etiology. Of the patients 15 (32%) had bilateral obstruction. Maximum followup was 59 months (mean 20, median 13, IQR 4-31). Stent failure occurred in 13 patients (28%), including 4 in the benign and 9 in the malignant group (p = 0.35). The median duration of stenting for benign and malignant obstruction was 22 (IQR 9-39) vs 7 months (IQR 3-25) (p = 0.106). Stenting duration was equivalent when controlling for the higher death rate in the malignant group., Conclusions: Resonance metallic stents are an adequate management strategy for benign and malignant ureteral obstruction. A subset of patients in each group continued to do well at more than a 3-year overall duration of stenting. Failure rates were similar for benign and malignant etiologies., (Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We evaluated outcomes of nonoperative management of primary nonrefluxing megaureter at long-term followup to identify clinical predictors of spontaneous resolution., Materials and Methods: A total of 75 patients (88 primary megaureters) were diagnosed between 1990 and 2005 and followed for more than 6 months. Of the patients 63 (74 primary megaureters) were included in the main study population. Indications for surgery were obstructive hydroureteronephrosis, functional impairment and persistent symptoms., Results: Of the 74 primary megaureters 20 (27%) required surgery up to 7 years after diagnosis. Surgery was not indicated in 82% of primary megaureters with grade I or II hydronephrosis vs 62.9% of those with grade III or higher hydronephrosis (difference not significant), nor in 76.5% of types I and II primary megaureters vs 33.3% of type III primary megaureters (p = 0.040), 78.7% of renal units with differential function 40% or greater vs 0% with differential function less than 40% (p = 0.027), 80% of primary megaureters with a nonobstructive washout pattern vs 44.4% with an intermediate/obstructive pattern (p = 0.032), 67.9% of patients with perinatal presentation vs 25% with postneonatal presentation (p = 0.008) or 63.2% of patients presenting with symptoms vs 76.4% of those who were asymptomatic (difference not significant). On multivariate analysis age at presentation and washout pattern were significant predictors of spontaneous resolution., Conclusions: Most cases of primary megaureter resolve spontaneously or improve without loss of function or development of symptoms. Careful observation allows surgery to be delayed beyond the neonatal period in most patients. Long-term followup is recommended because symptoms can develop years later. Washout pattern and age at presentation are statistically significant predictors of spontaneous resolution., (Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We determined the outcome of minimally symptomatic adult ureteropelvic junction obstruction in a group of patients treated conservatively with an active surveillance regimen., Materials and Methods: A total of 27 patients with asymptomatic or minimally symptomatic ureteropelvic junction obstruction were treated conservatively. All patients were evaluated with diuretic renograms. Ureteropelvic junction obstruction was defined by an obstructive pattern of the clearance curve and/or T1/2 greater than 20 minutes. Followup consisted of an office visit and renogram every 6 to 12 months. Cases of greater than 10% loss of relative renal function of the affected kidney, development of pyelonephritis and/or more than 1 episode of acute pain were considered active surveillance failures, and treatment was recommended., Results: Of the 27 patients 6 were lost to followup, leaving 21 (median age 47 years) with sufficient followup for analysis. In the 4 patients (19%) who initially presented with mild pain that led to the diagnosis of ureteropelvic junction obstruction, the pain completely resolved. Ipsilateral relative renal function decreased significantly in 2 patients (9.5%, mean reduction 14%). Pain worsened in 3 patients (14.3%) and de novo pain occurred in 1 (4.7%). Surgical intervention for ureteropelvic junction obstruction was required in 6 patients (29%) at an average of 34 months. In total 15 patients (71%) remained on surveillance with a mean followup of 48 months., Conclusions: Active surveillance seems to be a reasonable initial option for asymptomatic or mildly symptomatic adult patients with ureteropelvic junction obstruction because only approximately 30% have progression to surgical intervention within 4 years of diagnosis. This strategy offers the advantage of individualizing therapy according to symptoms and renographic findings., (Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We analyzed the prognostic factors associated with overall survival and predictive factors of stent failure in patients treated with an indwelling retrograde ureteral stent for malignant ureteral obstruction., Materials and Methods: Among 186 Japanese patients treated with an indwelling retrograde ureteral stent for ureteral obstruction from January 2005 to March 2010, 61 with malignant ureteral obstruction and 95 ureteral units were analyzed retrospectively., Results: Median survival was estimated at 228 days. Unfavorable prognostic factors of overall survival were no treatment after indwelling retrograde ureteral stent placement (p = 0.023) and a serum creatinine before indwelling retrograde ureteral stent placement of 1.2 mg/dl or greater (p = 0.016). Overall survival differed significantly among cancer groups (p <0.001) as did stent failure-free survival (p = 0.011). Overall survival differed significantly among 3 risk groups divided according to the score calculated with regard to prognostic factors (p <0.001)., Conclusions: Gynecologic cancer was a significant favorable predictor of stent failure-free survival. Patients treated with an indwelling retrograde ureteral stent for malignant ureteral obstruction were divided into 3 groups, which showed significant differences in overall survival. This risk classification may help urologists predict survival time., (Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We validated the Italian version of the Ureteral Stent Symptoms Questionnaire in male and female patients with an indwelling ureteral stent., Materials and Methods: A double-back translation of the original Ureteral Stent Symptoms Questionnaire was performed by 3 urologists and 4 professional translators. A total of 78 patients (cases) with and 35 healthy subjects without (controls) an indwelling ureteral stent were asked to complete the Italian version of the Ureteral Stent Symptoms Questionnaire and a visual analog scale for pain as well as the International Prostate Symptom Score (men) and Urogenital Distress Inventory-6 plus Incontinence Impact Questionnaire-7 (women). Cases were evaluated at weeks 1 and 4 after stent placement, and at week 4 after removal, while controls were evaluated once. The psychometric properties of the questionnaire were analyzed., Results: A total of 66 cases and 30 controls were suitable for analysis. The questionnaire showed good internal consistency in all domains except global quality of life compared with that of the International Prostate Symptom Score (Cronbach's alpha >0.75). Test-retest reliability was good except for the sexual matters domain (Pearson's coefficient >0.7). Relatively high correlation coefficients (greater than 0.65) were found for the visual analog scale for pain, the International Prostate Symptom Score, the Urogenital Distress Inventory-6 and the Incontinence Impact Questionnaire-7 with the corresponding Ureteral Stent Symptoms Questionnaire domains, suggesting good convergent validity. Sensitivity to change and discriminant validity were also good (p <0.001)., Conclusions: The Italian version of the Ureteral Stent Symptoms Questionnaire is a reliable and robust instrument that can be self-administered to male and female Italian patients with an indwelling ureteral stent in the clinical and research settings.

Purpose: Treatment of ureteral obstruction due to advanced abdominal or pelvic malignancy is a clinical challenge. We discuss improvements and modern day outcomes in the palliative treatment of patients with ureteral obstruction by antegrade or retrograde ureteral decompression. Also, potential areas of clinical investigation involving ureteral stent improvement and pharmacological management of relief of symptoms resulting from ureteral obstruction are discussed., Materials and Methods: A literature search was performed using the Entrez-PubMed(R) database. All relevant literature on ureteral obstruction, advanced malignancy and nephrostomy, ureteral stent and associated topics concerning palliative care and quality of life were reviewed and analyzed., Results: Presenting symptoms are varied and depend on the acuity of the underlying problem. Mechanisms underlying the pain and symptoms of extrinsic ureteral compression have not fully been explored but they may include prostaglandin and renin-angiotensin pathways with medical interventions potentially directed at such therapeutic targets. Progressive obstructive uropathy may likely lead to clinical manifestations, such as uremia, electrolyte imbalances and persistent urinary tract infections, if obstruction is not bypassed. New approaches to antegrade and retrograde stenting, and the evaluation of new stent materials may help minimize the complications and side effects of such procedures. Unfortunately the finding of ureteral obstruction due to malignancy carries a poor prognosis with a resulting median survival of 3 to 7 months. This prognosis highlights the importance of maintaining quality of life in these patients., Conclusions: Patients presenting with symptoms of ureteral obstruction due to advanced malignancy should be informed of the therapeutic options in the context of the poor prognosis. In the meantime research is needed to find methods of urinary diversion and pharmacological intervention for symptomatic relief without compromising quality of life in patients at the end of life.

Purpose: We quantified the burden of ureteropelvic junction obstruction in the United States by identifying trends in the use of health care resources and estimating the economic impact of the disease., Materials and Methods: The analytical methods used to generate these results were described previously., Results: Inpatient hospitalization rates were highest in children younger than 3 years. Most patients were male and hospitalizations occurred almost exclusively at urban centers. Patients with a primary diagnosis of ureteropelvic junction obstruction between 1994 and 2000 had an overall decrease in the age adjusted rate of inpatient hospitalization from 1.1/100,000 to 0.8/100,000. Physician office visits by Medicare beneficiaries with ureteropelvic junction obstruction as the primary diagnosis showed stable overall age adjusted rates during the reported years. Between 1999 and 2003 mean inpatient length of stay and cost per child hospitalized with the primary diagnosis of ureteropelvic junction obstruction was 2.9 days and $7,728, respectively. Average length of stay decreased more for children than for adults but total inpatient spending remained stable at about $12 million., Conclusions: The majority of ureteropelvic junction obstructions are diagnosed in the perinatal period. Surgical intervention for pediatric patients has decreased with time, while there has been an increasing trend toward the conservative management of this condition.

Purpose: We developed an algorithm for the management of ureteral obstruction due to malignant extrinsic compression., Materials and Methods: We retrospectively reviewed all ureteral stents placed for noncalculous reasons at our institution from January 1, 1990 to January 1, 2004. Further clinical information was gathered from 157 patients with malignant extrinsic ureteral compression. Failure was defined as recurrent ureteral obstruction or an inability to place stents cystoscopically., Results: A total of 157 patients underwent retrograde ureteral stent attempt for malignant extrinsic ureteral obstruction. Mean patient age was 54.7 years (range 23 to 83) and average followup was 13.6 months. Of our patients 61% were women, and the most common cancer diagnoses were ovarian cancer (in 26), lymphoma (17) and cervical cancer (16). A total of 24 patients required immediate percutaneous nephrostomy (PCN) referral. There were 32 patients who experienced a late failure and required PCN (average 180 days after initial stent), and 83 patients in our series (52.9%) who experienced 110 major complications. Type of cancer did not predict need for PCN. However, when invasion into the bladder was noted on cystoscopy, 55.9% (19 of 34, p = 0.008) progressed to PCN referral. A total of 77 patients underwent stent replacement on average 2.8 times and with an interval of 95 days., Conclusions: In our series patients with malignant extrinsic ureteral compression presenting for ureteral stent(s) experienced a failure rate of 35.7% (56 of 157). Invasion at cystoscopy had a significant predictive value for progression to PCN. We present an algorithm on the management of extrinsic malignant ureteral obstruction.

Purpose: We sought to evaluate the use of passive dilation by stenting of ureteral orifices that were inaccessible at initial cystoscopic evaluation in children before a ureteroscopic procedure., Materials and Methods: We evaluated all patients younger than 18 years undergoing a ureteroscopic procedure in whom the ureteral orifice could not be accessed endoscopically by a ureteroscope., Results: A total of 26 children (14 boys and 12 girls) 7.3 to 14.1 years old (median age 10.3 years) underwent 28 passive dilations of initially inaccessible ureters. Stents remained indwelling for 2 to 8 weeks (median 3). All patients underwent successful ureteroscopy with a semirigid and/or flexible ureteroscope after preoperative stent placement. No patient required active dilation of the ureteral orifice at ureteroscopy. There were no complications from stent placement before the ureteroscopic procedures. No patient had a urinary tract infection or bladder spasms requiring anticholinergic therapy from stent insertion and/or early stent removal., Conclusions: Our study shows that passive dilation of the ureteral orifice in preparation for ureteroscopy is a straightforward, successful and beneficial technique in children, with no associated complications.

Purpose: More than 30 years ago the decreased renal blood flow and glomerular filtration rate characteristic of unilateral ureteral obstruction (UUO) was described. In the ensuing time, much has been learned about the involvement of nitric oxide (NO) and transforming growth factor-beta (TGF-beta) in the pathophysiology of UUO., Materials and Methods: We measured renal blood flow and glomerular filtration rate in dogs and rats, and assessed the effect of altering the availability of NO on these parameters. In rats and mice we used an antibody to TGF-beta, NO synthase gene deletion and inducible nitric oxide synthase gene therapy to assess the role of TGF-beta and NO in renal fibrosis., Results: Results of our studies suggest 2 strategies that have the potential to be incorporated into clinical trials. The first would be replenishment of the NO system with arginine (or a NO donor) to decrease renovascular resistance and increase renal nitric oxide. Either in addition to the first strategy or separately, interstitial fibrosis could be targeted. Strategies for inhibiting fibrosis include antibody to TGF-beta, use of antisense oligonucleotides to TGF-beta, use of drugs that inhibit other pro-fibrotic mediators or gene therapy to inhibit fibrosis., Conclusions: While these studies have primarily centered on acute UUO, the findings in this model of renal injury may potentially be transferable to other entities that are characterized by decreased renal function and increased renal fibrosis such as different forms of interstitial nephropathy or diabetic glomerulopathy.

Purpose: We assessed the success of retrograde placement of indwelling ureteral stents in the management of ureteral obstruction due to extrinsic compression., Materials and Methods: Between July 1987 and December 2002 adequate followup was available for 101 patients who underwent primary retrograde ureteral stenting for extrinsic ureteral obstruction. Mean age at presentation was 61.4 years (range 33 to 90). Chart review was performed on all patients for primary diagnosis, symptomatology, degree of hydronephrosis, creatinine levels (baseline, treatment and posttreatment), location of compression, size and number of stents used, progression to percutaneous nephrostomy tube (PNT), stent failure, days to stent failure, post-stent therapy and status at last followup., Results: Mean length of followup was 11 months (range 1 to 127). In 101 patients 138 ureteral units (UU) were stented. Total stent failure occurred in 41 (40.6%) patients and 58 (42.0%) UU. A total of 40 (29.0%) UU required PNTs at a mean of 40.3 days (range 0 to 330) with 18 PNTs placed in less than 1 week. Cases of stent failure that did not undergo PNT placement included 18 (13.0%) UU at a mean of 52.4 days (range 3 to 128). A total of 90 (89.1%) patients had metastatic cancer at stenting with 32.2% dead at 5.8 months (range 1 to 32). Univariate and multivariate analyses identified cancer diagnosis, baseline creatinine greater than 1.3 mg/dl and post-stent systemic treatment as predictors of stent failure. Proximal location of compression and treatment creatinine greater than 3.11 mg/dl were marginal predictors of failure on univariate analysis, while proximal location of obstruction was also marginally significant on multivariate analysis. No predictors were identified for early stent failure (less than 1 week)., Conclusions: At almost 1 year followup stent failure due to extrinsic compression occurred in nearly half of treated patients. Analysis of data revealed a diagnosis of cancer, baseline mild renal insufficiency and metastatic disease requiring chemotherapy or radiation as predictors of stent failure. Managing extrinsic compression by retrograde stenting continues to be a practical but guarded decision and should be tailored to each patient.

Purpose: Fetal urinary obstructive uropathy and consecutive oligohydramnios result in a poor outcome. Usually renal insufficiency and life threatening lung hypoplasia have developed at term. We report a case of in utero fetal cystoscopy and successful placement of a transurethral vesico-amniotic Double-J (Medical Engineering Corp., New York, New York) stent. Indications, results and the potential benefits of different techniques are discussed., Material and Methods: A 36-year-old woman (primipara) was evaluated at week 26 due to a male fetus with bilateral hydronephrosis, massive distended bladder and an open posterior urethra. Using local anesthesia the fetal bladder was punctured, a 2.6 mm endoscope was inserted and a wire was advanced antegrade through the penis. A 2.8Fr Double-J stent was then placed between the bladder and amniotic cavity., Results: The bladder drained into the amnion, hydronephrosis disappeared and the lung developed normally. At week 37 a healthy infant was delivered who voided spontaneously., Conclusions: After careful selection of candidates for fetal intervention in obstructive uropathy direct vision fetoscopy and transurethral stent placement can be performed in patients with oligohydramnios, favorable urinary electrolytes and normal appearing kidneys.

Purpose: A criticism of the Cohen cross-trigonal reimplantation is the potential difficulty of retrograde access to the ureter. With the advent of modern endourological equipment, we devised a novel technique that obviates the aforementioned difficulty and permits even retrograde ureteroscopy., Materials and Methods: Cystoscopy is performed and a curved tip vascular access catheter is directed towards the ureteral orifice. An angle tipped glide wire with a torque device attached is passed through the catheter and directed into the orifice. The combination of the curved catheter and angled glide wire permits passage of the wire in an axis perpendicular to that of the cystoscope. Once the glide wire has been passed into the proximal ureter it is exchanged for a super stiff guide wire. The latter literally straightens the ureter permitting direct retrograde passage of a catheter, stent or rigid ureteroscope., Results: This technique was successful in 6 children. Of the patients 4 underwent retrograde ureteroscopy with stone extraction, 1 underwent retrograde studies followed by stent insertion and 1 underwent retrograde catheterization alone for radiographic studies., Conclusions: It is distinctly uncommon to have to access a ureter in a retrograde fashion after cross-trigonal reimplantation. However, when required the technique described reliably permits retrograde access and should dispel fears of long-term consequences of the Cohen ureteral reimplantation.

Purpose: A prospective randomized controlled trial was conducted to evaluate whether postoperative ureteral stenting is necessary after ureteroscopic laser lithotripsy., Materials and Methods: A total of 58 patients with unilateral ureteral stones were randomized into either stented or unstented groups. Ureteroscopic laser lithotripsy was performed using a semirigid ureteroscope (6.5/7Fr) and holmium laser without ureteral orifice dilation. There were no selection criteria regarding stone size, location, preoperative ureteral obstruction and hydronephrosis. Endoscopic evidence of stone impaction or mucosal edema/damage did not exclude a patient from the study. Ureteral perforation on completion retrograde pyelogram was the only intraoperative criterion for study exclusion. Postoperative pain scores and symptoms were recorded. Excretory urography was performed to document stone-free status and stricture formation. Radionuclide scan was performed selectively to exclude functional obstruction when ureteral narrowing was found on excretory urogram., Results: Mean stone size +/- SD was 9.7 +/- 4.0 mm. (range 4 to 27). Proximal ureteral stones accounted for 43% of all stones. Stented and unstented groups were comparable with respect to demographic data, stone parameters, preoperative obstruction and hydronephrosis. There was no significant difference in operating time, laser energy used, stone impaction and mucosal edema/damage between the 2 groups. Postoperative pain and symptoms were more severe and frequent (p <0.05) in the stented group. However, there was no difference in the incidence of postoperative sepsis and unplanned medical visits. The stone-free and stricture formation rates showed no statistical difference between the 2 groups., Conclusions: Ureteral stenting is not necessary after uncomplicated ureteroscopic laser lithotripsy for ureteral stones. Ureteral stent increases the incidence of pain and urinary symptoms but does not prevent postoperative urinary sepsis and unplanned medical visits. Severity of preoperative obstruction and intraoperative ureteral trauma were not shown to be determining factors for stenting.

Purpose: We report our experience with auto-expandable metallic stents for treating ureteropelvic junction obstruction., Materials and Methods: We treated 4 patients with a mean age of 45 years who had ureteropelvic junction obstruction with placement of a self-expandable intraureteral metallic stent (Wallstent, Schneider, Zurich, Switzerland). All patients presented with recurrent ureteropelvic junction obstruction after open pyeloplasty. Excretory urography and 3-dimensional reconstruction computerized tomography were performed 1 and 6 months after stent insertion. Virtual endoscopy images were obtained at followup due to the need to define ureteral patency., Results: Mean followup was 16 months (range 9 to 24). Wallstent placement was successful and immediate patency was achieved in all cases. During followup 3 patients required no further intervention and the stented ureteropelvic junction remained patent. In the remaining patient stricture recurred 2 months after initial stent insertion due to the ingrowth of scar tissue through the prosthesis. Additional intervention was deemed necessary after placing a longer 6 cm., completely coaxial overlapping metal stent. Virtual endoscopy and excretory urography findings concurred. Virtual endoscopy allows visualization of the stented ureteropelvic junction lumen cephalad and caudal to the prosthesis. It also enables easy navigation within the stent at different angles of view., Conclusions: The concept of applying metallic stents for ureteropelvic junction obstruction and adjacent adynamic ureteral segments combined with virtual endoscopy is strengthened by the results of this study.

Purpose: We developed a minimally invasive (noncystoscopic) method for retrieving ureteral stents., Materials and Methods: A total of 30 consecutive patients underwent placement of a ureteral stent with a stainless steel bead attached to its distal end. The stent was later removed by a urethral catheter with a rare earth magnet attached to its proximal end., Results: In 29 of the 30 patients the stent with the attached bead was removed without difficulty or patient discomfort. The single failure occurred in a patient with a large median prostate lobe., Conclusions: Minimally invasive, nonendoscopic ureteral stent retrieval was achieved in 97% of patients. The attractive force of the magnet for the bead was sufficient to attract and extract the stent. No adverse effects of the procedure or the stainless steel bead were noted. This magnet retrieval system is a feasible, simpler and less invasive alternative to cystoscopic retrieval of ureteral stents.

Purpose: Improved fiber optics and advanced intracorporeal lithotripsy devices have significantly decreased the incidence of complications during ureteroscopic procedures. Despite recent reports suggesting that radiographic imaging may not be necessary in all individuals after routine ureteroscopy silent obstruction may develop in some, ultimately resulting in renal damage. We determined the incidence of postoperative silent obstruction at our institution and assessed the need for routine functional radiographic studies after ureteroscopy., Materials and Methods: We retrospectively reviewed the charts of 320 patients who underwent a total of 459 ureteroscopic procedures for renal or ureteral calculi in a 3-year period. Complete followup with imaging was available for 241 patients (75%). Average patient age was 47.2 years. The variables of interest reviewed included preoperative pain, preoperative obstruction, targeted calculous site, stone-free rate, postoperative pain and postoperative obstruction. Mean followup was 5.4 months (range 2 to 43)., Results: A total of 241 patients with complete followup were identified in this analysis. Preoperative pain was present in 202 patients (84%) and 168 (70%) had preoperative obstruction. Overall targeted calculous clearance was successful in 73% of the patients and an additional 15.8% had residual fragments less than 4 mm. The renal, proximal or mid and distal ureteral stone-free rate was 32.1%, 81.9% and 90.5%, while in an additional 46.4%, 6.3% and 6.7% of cases, respectively, residual fragments were less than 4 mm. Of the 241 patients 30 (12.3%) had obstruction postoperatively due to residual stone in 25 (83.3%), stricture in 3 (10%), edema of the ureteral orifice in 1 (3.3%) and a retained encrusted stent in 1 (3.3%). Postoperatively obstruction correlated with postoperative pain in 23 of the 30 patients (76.7%). Pain was present postoperatively in 30 of the 211 patients (14%) without evidence of ureteral obstruction postoperatively. However, silent obstruction developed in 7 patients (23.3%) or 2.9% of the total cohort. All 7 patients underwent secondary ureteroscopy to alleviate obstruction. A single patient ultimately received chronic hemodialysis for renal failure, 1 was lost to followup and in 5 there was documented successful resolution of the cause of obstruction., Conclusions: Our analysis suggests that silent obstruction remains a potentially significant complication after stone management. Relying on postoperative pain to determine the necessity of postoperative imaging places patients at risk for progressive renal failure due to unrecognized obstruction. Therefore, we recommend that imaging of the collecting system should be performed by excretory urography, spiral computerized tomography or ultrasound within 3 months after routine ureteroscopic stone treatment to avoid the potential complications of unrecognized ureteral obstruction.

Purpose: We describe a technique that facilitates retrograde ureteral cannulation and stenting in patients with an ileal conduit., Materials and Methods: A standard flexible gastroscope is inserted into the ileal conduit. Guide wires are passed into the ureters under direct vision. Stents are inserted over the guide wires with the aid of the image intensifier., Results: The technique was used repeatedly in 1 patient with a complex history who had ureteral strictures. The procedure is technically easy and it was successful on each occasion., Conclusions: A fiber optic gastroscope may have advantages over conventional urological instrumentation for inserting ureteral stents in patients with an ileal conduit. This novel, simple technique is less invasive than percutaneous stenting and easier than fluoroscopic cannulation of the ureters. It is readily repeated.

Purpose: We evaluated retrograde double pigtail stent placement in patients with ureteroileal anastomosis., Materials and Methods: Procedures were performed under digital C-arm fluoroscopic guidance and the patient under sedation analgesia. Radiography of the conduit was done to delineate urinary diversion anatomy and identify ureteral reflux. A purpose designed, angled tip catheter was used to direct a straight glide wire across the ureteroileal anastomosis. The glide wire was exchanged for a stiff guide wire for stent placement. We retrospectively evaluated the clinical records of 7 men and 5 women with a mean age of 54.3 years in a 7-year period. In 11 patients a new stent was placed because of ureteroileal stricture in 5, anastomotic leakage in 3, ureterolithiasis in 2 and recurrent malignancy in 1., Results: New stent placement was successful in 10 of the 11 patients (90.9%, 13 of 16 ureters or 81.3%). Stent placement was successful in the 8 ureters in which reflux was noted on radiography of the conduit and in 5 of the 9 (55.6%) in which no reflux was noted. Stent replacement was accomplished in all 22 ureters (6 patients) in which it was attempted. Mean radiological screening time for new stent placement was 13.3 minutes (range 4.7 to 19.7), while for exchange it was 6.4 minutes (range 0.8 to 15.1). There were no immediate complications., Conclusions: This technique represents a useful approach to the ureter and should be considered an alternative to percutaneous nephrostomy and surgical revision. The approach is also useful for other ureteral procedures, including stone or migrated stent retrieval.

Purpose: We conducted a prospective, randomized controlled study to investigate the advantages and disadvantages of ureteral stenting after ureteroscopic lithotripsy., Materials and Methods: A total of 60 patients who underwent ureteroscopic lithotripsy were equally randomized into a stented or a nonstented group. The inclusion criteria were stone 6 to 10 mm., absence of polyp or stricture in the ureter and no mucosal injury during ureteroscopy. The operation was performed with a 6Fr rigid ureteroscope without ureteral dilation and stones were fragmented with a 1.9Fr electrohydraulic lithotriptor without extraction. A 7Fr double pigtail stent was placed in the stented group for 3 days after ureteroscopy. Urinalysis, plain x-ray and renosonography were performed before and after lithotripsy in each patient. Subjective symptoms and pain score were recorded on admission to the hospital and 3 days postoperatively., Results: The stone-free rate was 100% in each group and preoperative hydronephrosis equally resolved in both groups. Mean pain score plus or minus standard deviation improved significantly in the nonstented (6.33 +/- 1.81 preoperatively to 2.30 +/- 1.93 postoperatively, paired Student's t test p <0.0001) and stented (7.10 +/- 1.03 to 2.30 +/- 2.22, p < 0.0001) group. There was no statistical difference in pain reduction between the 2 groups (p = 0.18). The amount of extra parenteral analgesic used was similar in both groups. One patient in the nonstented group visited the emergency room for postoperative renal colic, 25 (83.3%) patients in the stented group complained of at least 1 irritative bladder symptom and only 4 (13.3%) in the nonstented group experienced bladder discomfort., Conclusions: After uncomplicated ureteroscopic electrohydraulic lithotripsy patients without ureteral stenting tend to have similar renal function recovery and satisfactory pain reduction with less irritative symptoms compared to those treated with a ureteral stent. We suggest that it is not necessary to place a ureteral stent routinely after uncomplicated ureteroscopic electrohydraulic lithotripsy for stones smaller than 1 cm.

Purpose: Retrograde ureteral stenting is often considered the first line option for relieving ureteral obstruction when temporary drainage is indicated. Several retrospective studies have implied that in cases of extrinsic obstruction retrograde ureteral stenting may fail and, therefore, percutaneous nephrostomy drainage is required. We examined the efficacy of retrograde ureteral stenting for resolving ureteral obstruction and identified clinical and radiological parameters predicting failure., Materials and Methods: Enrolled in our prospective study were 92 consecutive patients with ureteral obstruction, which was bilateral in 8. Retrograde ureteral stenting was attempted in all cases by the urologist on call. When stent insertion failed, drainage was achieved by percutaneous nephrostomy. Patients were followed at 3-week intervals for 3 months. Each followup visit included a medical interview, blood evaluation, urine culture and ultrasound. Stent malfunction was defined as continuous flank pain manifesting as recurrent episodes of acute renal colic, 1 or more episodes of pyelonephritis, persistent hydronephrosis or elevated creatinine. Preoperative data and outcomes were compared in cases of intrinsic and extrinsic obstruction. Univariate and multivariate analysis was done to identify predictors of the failure of ureteral stent insertion and long-term function., Results: The etiology of obstruction was intrinsic in 61% of patients and extrinsic in 39%. Extrinsic obstruction, which was associated with a greater degree of hydronephrosis, was located more distal. Retrograde ureteral stenting was successful in 94% and 73% of patients with intrinsic and extrinsic obstruction, respectively. At the 3-month followup stent function was maintained in all patients with intrinsic obstruction but in only 56.4% with extrinsic obstruction. On multivariate logistic regression the type of obstruction, level of obstruction and degree of hydronephrosis were the only predictors of stent function at 3 months. Stent diameter and preoperative creatinine had no predictive value., Conclusions: Retrograde ureteral stenting is a good solution for most acutely obstructed ureters. In patients with extrinsic ureteral obstruction a more distal level of obstruction and higher degree of hydronephrosis are associated with a greater likelihood of stent failure. These patients may be better served by percutaneous drainage.

Purpose: We present our 4-year experience with the thermo-expandable shape memory alloy Memokath 051 stent (Engineers and Doctors of Copenhagen, Copenhagen, Denmark) for managing long-term ureteral obstruction., Materials and Methods: We used a nickel-titanium shape memory alloy ureteral stent to treat 28 patients 29 to 86 years old (mean age 59.2). Ureteral obstruction was caused by malignancy in 18 cases and by recurrent benign disease in 10. A total of 37 stents were inserted from November 1996 to November 2000 using general anesthesia. Mean followup was 19.3 months (range 3 to 35)., Results: Upper tract decompression was achieved in all cases. Currently 15 stents are functional in 13 patients, while 8 patients died with a total of 13 functioning stents in place. In 7 patients 9 stents were removed for various reasons. There has been no radiological evidence of encrustation to date. No patient has been rehospitalized with stent related sepsis pain or hematuria, resulting in improved quality of life., Conclusions: This stent seems to provide a significant benefit over conventional Double-J (Medical Engineering Corp., New York, New York) and other metallic stents. Its remarkable thermal memory permits removal, a feature that until recently was not available in any other metallic ureteral stent. Durable and complication-free decompression of the upper tract can be achieved with the Memokath 051.

Purpose: We compared the long-term outcome of hydronephrosis due to pyeloureteral obstruction based on excretory urography findings and renal function in patients who did and did not undergo pyeloplasty., Materials and Methods: We followed 83 adults for a mean of 17 years after the diagnosis of hydronephrosis. The choice of conservative or surgical management was based on the results of excretory urography, pelvic manometry, fluoroscopy of pelvic and ureteral peristalsis, isotope renography and renal clearance studies but symptom severity was considered greatly important. Three patients not included in the study underwent primary nephrectomy due to poor ipsilateral function, while 47 underwent pyeloplasty and 36 no surgery., Results: Nephrectomy was later performed in 2 patients each in the pyeloplasty and no surgery group, respectively, because of pyelonephritis and stone formation in 3 and persistent pain in 1. Hypertension developed in 2 cases in each group. Renal pelvic size was considerably decreased after pyeloplasty and dilatation increased in only a few kidneys in the nonsurgical group. Excluding the 4 patients treated with late nephrectomy serum creatinine pathologically increased in only 1 who was treated conservatively. Split function improved from 40.8% to 47.1% of total function after pyeloplasty but the total glomerular filtration rate did not improve significantly., Conclusions: In the absence of infection and stone formation hydronephrosis in adults seems to be a fairly benign condition and followup should be directed mainly toward detecting these complications. Recurrent flank pain still seems to be the best indication of the need for surgery.

Purpose: We studied whether a subcutaneous ureteral bypass may be an alternative to a permanent nephrostomy tube in patients with ureteral obstruction caused by pelvic malignancy., Materials and Methods: Using local anesthesia we inserted an especially designed nephrovesical stent into subcutaneous tissue. The stent consists of 2 J stents that are joined by a connector after insertion into the renal pelvis and bladder., Results: In 8 patients 10 subcutaneous stents were inserted instead of a permanent nephrostomy tube. Nephrostomy was required because of obstructed ureters caused by metastatic prostate or invasive bladder cancer. Attempted Double-J stent insertion into the obstructed ureter had previously failed. The bypass has functioned well in all cases during 6 weeks to 18 months of followup (mean 5.5 months)., Conclusions: The high complication rate of a permanent nephrostomy tube and frequent rehospitalization render the subcutaneous stent an important alternative to nephrostomy. The subcutaneous stent eliminates external devices for urine drainage and improves patient quality of life.

Purpose: The Acucise endoureterotomy balloon catheter has proved to be a safe and effective alternative to open surgery for the management of ureteropelvic junction obstruction and benign ureteral stricture disease. The established management of ureteroenteric strictures following urinary diversion is open surgical revision. There are few reports evaluating the efficacy of Acucise endoureterotomy in patients with ureteroenteric strictures., Materials and Methods: The Acucise cutting balloon catheter was used to treat 9 patients with 12 ureteroenteric strictures 2 cm. or less in length. Median time from diversion to stricture was 48 months (range 13 to 192). Success was defined as resolution of symptoms and radiographic confirmation of patency., Results: Recurrence of malignancy accounted for failure in 1 patient with bilateral strictures. Of the remaining 10 benign strictures 7 (70%) required open revision or serial stent changes. The remaining 3 strictures in 2 patients have remained patent at 30 and 18 months of followup for a success rate of 30%. There were no perioperative or operative complications. Mean followup was 9 months after Acucise treatment before intervention was necessary., Conclusions: Acucise endoureterotomy for ureteroenteric strictures following urinary diversion is a low morbidity procedure. Although the success rate is only 30%, Acucise endoureterotomy offers an alternative to immediate open surgical revision.

Purpose: Direct gene transfer to the ureter is an attractive approach to prevent restenosis after endourologic management of ureteral strictures. We therefore assessed the rationale for adenovirus-mediated gene transfer in the ureter in vitro and in vivo using a porcine model., Materials and Methods: Primary cultures of porcine ureteral epithelial and stromal cells were infected with an adenoviral solution carrying a nucleus-targeted beta-Galactosidase (beta-Gal) reporter gene (6.5 10(8) pfu/ml.). In addition, in order to mimic the human clinical situation, we have devised a model of thermally-induced stricture in porcine ureter which produced tight fibrotic stenosis within 8 days. Using a purposely designed channelled balloon catheter prototype, these strictures were endoscopically dilated and then instilled with the same beta-Gal adenoviral construction., Results: Application of recombinant adenovirus harboring a nucleus-targeted beta-Gal reporter gene to cultured porcine urothelial and stromal cells resulted in high transduction efficiency of up to 99% and 84% respectively. Seven days after infection, X-Gal staining of the strictured ureters demonstrated transfection up to 2 mm. depth within the fibrosis, confirmed by polymerase chain reaction (PCR) analysis. Adjacent and distal spread of the virus was excluded by histochemistry (X-Gal staining) and PCR., Conclusion: This data represents the first report of adenovirus-mediated gene transfer to the ureter. It remained site specific by endourologic retrograde clinically applicable techniques.

Purpose: Unilateral ureteral obstruction (UUO) for 24 hours results in a severe compromise of distal tubular function. The acidification defect is believed to be localized in the collecting duct. To characterize distal tubular function recovery one month after junction release, clearance studies in whole animals and enzyme studies in microdissected segments were performed in an experimental model of unilateral ureteral obstruction., Materials and Methods: Following release of ureteral obstruction of 24 hours duration, a significant decrease of whole kidney glomerular filtration rate was observed in the postobstructed kidney (POK) with a marked increase in urinary pH, fractional excretion of bicarbonate (FEHCO3-) and decrease in urinary osmolality. By orthograde stop flow experiment, bicarbonate excretion rate (Fr:Ff HCO3-/Fr:Ff Inutest) increased in the first and second urine fractions of 120 microl. corresponding to the collecting segment in the POK, one day after release. Decrease in U-P pCO2 (p<0.01) suggested an impaired H+ secretion on distal nephron in POK. Recovery of inulin clearance and values of urinary pH, FEHCO3- and urinary osmolality near contralateral and control kidneys were observed thirty days following ureteral release. The decline in enzyme activity in the distal nephron due to structural damage from high intratubular pressure was evaluated. Bafilomycin sensitive H+ -ATPase activity measurement in the medullary collecting duct segments of the POK showed an important decrease (68%), with lightly reduced activity (20%) in the cortical collecting duct, 24 hours after obstruction release. Localized in the connecting tubule cells and secreted into the tubular fluid in the late distal nephron, renal kallikrein has been involved in bicarbonate transport at cortical collecting duct segments. The renal kallikrein-like activity was reduced in POK (p<0.01)., Results: Recovery of enzyme activity was shown thirty days after unilateral ureteral obstruction. Our results show severe functional damage of the collecting duct after 24 hours of unilateral ureteral obstruction. H+ -ATPase activity was markedly decreased on medullary collecting duct segments., Conclusions: A correlation between the functional impairment of distal H+ secretion and decreased distal nephron enzyme activity has been shown. Recovery of both the functional and the enzyme activity at the distal nephron was demonstrated thirty days after obstruction release.

Purpose: We retrospectively reviewed the records of patients with prenatal hydronephrosis to characterize those in whom it was more likely to resolve with conservative management., Materials and Methods: We studied 51 patients in a 4-year period who presented with nonspecific unilateral hydronephrosis diagnosed by prenatal and confirmed by postnatal sonography. Patients were followed with sequential nuclear renograms with furosemide washout to evaluate function and drainage. In all cases a nonoperative approach was attempted. Pyeloplasty was performed only for poor or decreasing kidney function and/or drainage., Results: Four of the 51 patients were lost to followup, 21 of the remaining 47 (45%) eventually underwent surgery, and 26 (55%) had complete normalization of renal function and washout pattern without surgery. There was no statistically significant correlation between hydronephrosis grade on initial postnatal sonography and the likelihood of nonsurgical resolution. However, the shape of the washout curve on nuclear renography was informative for predicting outcome, since 86% of the cases with a nonobstructive drainage pattern normalized without surgery, while 62% with indeterminate and only 18% with obstructive curves resolved with conservative management (p <0.01). Notably in 83% of the cases of normalization without surgery resolution occurred before age 18 months. Also, an initial obstructed washout pattern was more likely to be associated with a poor outcome. Of the 6 patients with less than 40% final differential function 5 had an obstructed washout pattern on the initial nuclear renogram., Conclusions: Patients diagnosed by prenatal ultrasound with apparent unilateral ureteropelvic junction obstruction generally do well with conservative treatment. However, those who present with an obstructed washout pattern are less likely to have resolution without surgery and more likely to have poor final differential function.

Purpose: We compare the efficacy of percutaneous nephrostomy with retrograde ureteral catheterization for renal drainage in cases of obstruction and infection associated with ureteral calculi., Materials and Methods: We randomized 42 consecutive patients presenting with obstructing ureteral calculi and clinical signs of infection (temperature greater than 38 C and/or white blood count greater than 17,000/mm.3) to drainage with percutaneous nephrostomy or retrograde ureteral catheterization. Preoperative patient and stone characteristics, procedural parameters, clinical outcomes and costs were assessed for each group., Results: Urine cultures obtained at drainage were positive in 62.9% of percutaneous nephrostomy and 19.1% of retrograde ureteral catheterization patients. There was no significant difference in the time to treatment between the 2 groups. Procedural and fluoroscopy times were significantly shorter in the retrograde ureteral catheterization (32.7 and 5.1 minutes, respectively) compared with the percutaneous nephrostomy (49.2 and 7.7 minutes, respectively) group. One treatment failure occurred in the percutaneous nephrostomy group, which was successfully salvaged with retrograde ureteral catheterization. Time to normal temperature was 2.3 days in the percutaneous nephrostomy and 2.6 in the retrograde ureteral catheterization group, and time to normal white blood count was 2 days in the percutaneous nephrostomy and 1.7 days in the retrograde ureteral catheterization group (p not significant). Length of stay was 4.5 days in the percutaneous nephrostomy group compared with 3.2 days in the retrograde ureteral catheterization group (p not significant). Cost analysis revealed that retrograde ureteral catheterization was twice as costly as percutaneous nephrostomy., Conclusions: Retrograde ureteral catheterization and percutaneous nephrostomy effectively relieve obstruction and infection due to ureteral calculi. Neither modality demonstrated superiority in promoting a more rapid recovery after drainage. Percutaneous nephrostomy is less costly than retrograde ureteral catheterization. The decision of which mode of drainage to use may be based on logistical factors, surgeon preference and stone characteristics.