Search

Background: Fibroepithelial polyp of the ureter is a very rare benign tumor of the urinary tract that can present complications as urinary tract infection, hematuria, or urinary retention. Its incidence has increased in recent years. Its recognition and proper management are important to avoid invasive surgeries. Case Presentation: We present the case of a 24-year-old Latin pregnant woman with gross hematuria, right flank pain, and a bladder tumor as seen on a pelvic ultrasonography. Cystoscopy and MRI showed a right ureteral tumor that protruded through the ureteral meatus. Endoscopic resection using a holmium:YAG laser was performed during the second trimester of pregnancy. A ureteral tumor of 6.5 cm was completely resected. Histopathology showed morphological findings compatible with a fibroepithelial ureteral polyp. The postoperative evolution was satisfactory with no complications or recurrences to date. Conclusion: Fibroepithelial polyp of the ureter is a benign tumor that can be present in any of the ureter's segments. It usually affects people between 20 and 40 years. Endoscopic resection with holmium laser has become the preferred surgical treatment during the last time. It is associated with the advantages of a minimal invasive technique and a short period of convalescence.

Introduction Emergency drainage of the urinary tract is the first necessary approach in patients with urosepsis secondary to obstructive ureteral calculi. The appropriate waiting time before definitive treatment has not been determined. We hypothesized that early ureteroscopic treatment after the patient has been stabilized is as safe as deferred treatment. Material and methods A pilot study was developed between November 2013 and September 2017. Patients with urosepsis associated with ureteral calculi were included. All the patients were initially decompressed with a ureteral stent. Patients were randomized to early ureteroscopic treatment (EUT), who received definitive treatment during the initial hospitalization, or deferred ureteroscopic treatment (DUT), that received definitive treatment in a second hospitalization. The stone location and size, sex distribution, age, APACHE II score, length of hospital stay, days with ureteral catheter and complications were registered. Statistical analysis was performed using Stata 12.0. Results A total of 13 patients were included in the EUT group and 13 in the DUT group. No differences in sex distribution, stone location, APACHE II score, age, stone size and time between admission and urinary drainage were found. Total length of hospital stay and complications were also similar between both groups. A statistically significant difference was found in terms of duration of antibiotic treatment (p = 0.04) and total days with double J catheter (p = 0.0009). Conclusions EUT for ureteral stone is as safe as DUT in patients admitted with urosepsis secondary to ureterolithiasis. EUT is associated with a shorter period of ureteral stent and it is not associated with an increase in complications.

We report a case of a 53-year-old woman affected by a left kidney stone and persistent positive urinary culture treated by retrograde intrarenal surgery. During postoperative day 1, she developed a sudden back pain associated with a decrease in hemoglobin. CT scan showed a subcapsular hematoma giving the impression of partial compression of kidney and upper urinary tract. For that reason, in the first instance, a Double-J ureteral stent was installed. Unfortunately, an open surgical drainage was necessary because a secondary infection of the hematoma was evident during the following days.

Retrograde intrarenal surgery (RIRS), also known as flexible ureterorenoscopy (fURS) is an effective and safe method for the management of intrarenal stones. Its use has increased in recent years with several reports showing stone-free rates as high as shock wave lithotripsy (SWL) for intrarenal stones. This improvement in efficacy of retrograde intrarenal surgery (RIRS) is related to technological advances and improvements in endoscopic techniques that have made retrograde stone removal easier. The main advantage of RIRS compared to open operative or percutaneous intervention is a decrease in operative morbidity for the patient, as well as a faster recovery. RIRS should be considered in patients with kidney stones if they have a contraindication for SWL or percutaneous nephrolithotomy (PCNL), such as the presence of a bleeding diathesis, some cases of morbid obesity, musculoskeletal deformities, or infundibular stenosis.

Background: Early inappropriate antibiotic therapy for the management of urosepsis is associated with higher mortality. Therefore, to establish an adequate empirical therapy is crucial. Aim: To determine an optimal antibiotic treatment, adjusted according local bacterial resistance in patients diagnosed with urosepsis secondary to ureteral lithiasis. Material and Methods: Urine cultures and blood cultures from a prospective cohort of patients with ureteral lithiasis admitted for urosepsis in our center between November 2013 and May 2016, were reviewed. Patients who presented two or more criteria of systemic inflammatory response syndrome (SIRS) and positive blood or urine cultures were admitted. Antimicrobial sensitivity patters derived from cultures were analyzed to describe bacterial susceptibility to commonly used antibiotics. Results: Data from 31 patients were analyzed. Seventeen blood cultures (55%) and 29 urine cultures (94%) were positive. The most commonly isolated pathogens were Escherichia coli in 65% of the cultures, followed by Klebsiella pneumoniae, Proteus mirabilis and Enterococcus faecalis. After performing an analysis of sensitivity and resistance for all bacteria in both blood and urine cultures, amikacin showed the highest sensitivity (100%), followed by 2nd and 3rd generation cephalosporins. Conclusions: Amikacin demonstrated higher antibiotic sensitivity in comparison to other antibiotics for empirical management of patients with urosepsis secondary to ureteral lithiasis.

Different factors can determine the outcomes of percutaneous nephrolithotomy (PNL). We analyzed the effect of tract length (TL) on outcomes after PNL. We performed a retrospective review of patients undergoing PNL between 2006 and 2011. Patients with preoperative computed tomography (CT), one percutaneous access tract and follow-up imaging within 3 months were included. TL was defined as distance between the skin to the calyx of puncture as measured on preoperative CT. Measurements were independently performed by two urologists and the average was used for analysis. Stone-free rate (SFR) was defined as zero fragments on follow-up imaging. Factors independently associated with the likelihood of being stone-free after PNL were determined using multivariable analysis adjusted for TL, location of access, the presence of incomplete or complete staghorn calculi and type of follow-up imaging. Complications (Clavien score) were independently assessed. A total of 222 patients were included. Median stone burden and body mass index (BMI) was 239.4 mm2 and 30.5 [interquartile range (IQR): 25.7–36.2]. The median TL was 85.0 mm (IQR: 70.3–100.0) and highly correlated with BMI (ρ = 0.66, p

Objective To determine organ-specific doses (ODs) and effective dose (ED) for digital tomosynthesis (DT) and compare it with our institutional renal stone protocol noncontrast computed tomography (NCCT). Methods A validated anthropomorphic male phantom was placed supine on a digital GE Definium 8000 radiological scanner. Thermoluminescent dosimeters were placed in 256 locations and used to measure OD. A routine DT study was performed consisting of 2 scout images and 1 tomographic sweep in a 14.2-degree arc over the phantom. Software is used to recreate a series of coronal images from the sweep. ODs were determined as the sum of the doses for the study. Equivalent doses were calculated by multiplying OD with the appropriate tissue weighting factor. ED is the summation of the equivalent doses. OD and ED were determined in a similar fashion (using dosimeters) for a renal stone protocol NCCT and doses were compared. Results ODs for DT are significantly lower compared with NCCT. The ED for NCCT is 3.04 ± 0.34 mSv. The calculated ED for DT is 0.87 ± 0.15 mSv (2 scouts at 0.17 mSv and 0.14 mSv and 1 sweep at 0.56 mSv), P Conclusion DT exposes patients to substantially less radiation than NCCT. This is particularly true for radiation-sensitive organs. Further studies are needed to compare the sensitivity and specificity of DT as compared with NCCT. However, its low overall radiation dose makes it an ideal study for the follow-up of recurrent stone formers in the office setting.

Computerized tomography use increased exponentially in the last 3 decades, and it is commonly used to evaluate many urological conditions. Ionizing radiation exposure from medical imaging is linked to the risk of malignancy. We measured the organ and calculated effective doses of different studies to determine whether the dose-length product method is an accurate estimation of radiation exposure.An anthropomorphic male phantom validated for human organ dosimetry measurements was used to determine radiation doses. High sensitivity metal oxide semiconductor field effect transistor dosimeters were placed at 20 organ locations to measure specific organ doses. For each study the phantom was scanned 3 times using our institutional protocols. Organ doses were measured and effective doses were calculated on dosimetry. Effective doses measured by a metal oxide semiconductor field effect transistor dosimeter were compared to calculated effective doses derived from the dose-length product.The mean±SD effective dose on dosimetry for stone protocol, chest and abdominopelvic computerized tomography, computerized tomography urogram and renal cell carcinoma protocol computerized tomography was 3.04±0.34, 4.34±0.27, 5.19±0.64, 9.73±0.71 and 11.42±0.24 mSv, respectively. The calculated effective dose for these studies Was 3.33, 2.92, 5.84, 9.64 and 10.06 mSv, respectively (p=0.8478).The effective dose varies considerable for different urological computerized tomography studies. Renal stone protocol computerized tomography shows the lowest dose, and computerized tomography urogram and the renal cell carcinoma protocol accumulate the highest effective doses. The calculated effective dose derived from the dose-length product is a reasonable estimate of patient radiation exposure.

Patients with recurrent nephrolithiasis are often evaluated and followed with computerized tomography. Obesity is a risk factor for nephrolithiasis. We evaluated the radiation dose of computerized tomography in obese and nonobese adults.We scanned a validated, anthropomorphic male phantom according to our institutional renal stone evaluation protocol. The obese model consisted of the phantom wrapped in 2 Custom Fat Layers (CIRS, Norfolk, Virginia), which have been verified to have the same radiographic tissue density as fat. High sensitivity metal oxide semiconductor field effect transistor dosimeters were placed at 20 organ locations in the phantoms to measure organ specific radiation doses. The nonobese and obese models have an approximate body mass index of 24 and 30 kg/m(2), respectively. Three runs of renal stone protocol computerized tomography were performed on each phantom under automatic tube current modulation. Organ specific absorbed doses were measured and effective doses were calculated.The bone marrow of each model received the highest dose and the skin received the second highest dose. The mean ± SD effective dose for the nonobese and obese models was 3.04 ± 0.34 and 10.22 ± 0.50 mSv, respectively (p0.0001).The effective dose of stone protocol computerized tomography in obese patients is more than threefold higher than the dose in nonobese patients using automatic tube current modulation. The implication of this finding extends beyond the urological stone population and adds to our understanding of radiation exposure from medical imaging.

Background and Purpose: Topical chemotherapy for urothelial cancer is dependent on adequate contact time of the chemotherapeutic agent with the urothelium. To date, there has not been a reliable method of maintaining this contact for renal or ureteral urothelial carcinoma. We evaluated the safety and feasibility of using a reverse thermosensitive polymer to improve dwell times of mitomycin C (MMC) in the upper tract. Materials and Methods: Using a porcine model, four animals were treated ureteroscopically with both upper urinary tracts receiving MMC mixed with iodinated contrast. One additional animal received MMC percutaneously. The treatment side had ureteral outflow blocked with a reverse thermosensitive polymer plug. MMC dwell time was monitored fluoroscopically and intrarenal pressures measured. Two animals were euthanized immediately, and three animals were euthanized 5 days afterward. Results: In control kidneys, drainage occurred at a mean of 5.3±0.58 minutes. Intrarenal pressures stayed ...

Flexible working angles and fine optical visualization are major requisite factors in performing laparoendoscopic single-site (LESS) urologic procedures. Multiple mechanical design approaches have been used to develop deflectable laparoscopes for LESS procedures. We compared the optical characteristics of three such devices using a bench top approach to simulate LESS in straight and deflected positions.A 10-mm fixed-rod rotating lens device (Storz EndoCameleon) and two 5-mm articulating devices (Olympus EndoEye and Stryker IdealEye) were compared using standard industry testing protocols for image resolution (United States Air Force-1951 test target), distortion (multifrequency grid distortion target), and color reproducibility (Gretag Macbeth color checker).The 10-mm fixed-rod rotating lens system demonstrated the highest image resolution (5.04 line pairs/mm), but also the highest distortion (22.8%). Among the 5-mm flexible articulating laparoscopes, resolution was superior with the Olympus EndoEye (4.00 line pairs/mm) compared with the Stryker IdealEye (3.17 line pairs/mm). Distortion (7.0%) and color reproduction (1.18) were superior with the IdealEye vs the EndoEye (18.8 %, 1.27). Laparoscope deflection resulted in attenuation of resolution by 11% with both articulating models, but not with the fixed rod system.Definition of these optical characteristics may inform further development and selection of laparoscopic systems optimized for LESS surgery. A narrow but flexible camera can be crucial in the limited working space available during these procedures. Further investigation is warranted to determine if these objective findings translate into improved surgeon performance.

Obesity has been shown to be a risk factor for kidney stone formation. Obesity leads to insulin resistance which subsequently leads to low urinary pH. Low urinary pH is typically treated with potassium citrate. We determined if the response to potassium citrate for the treatment of low urinary pH and hypocitraturia varied when patients were stratified by body mass index.We retrospectively reviewed the records of patients with urolithiasis and concomitant hypocitraturia and low urinary pH as unique abnormalities upon metabolic evaluation treated exclusively with potassium citrate. Based on body mass index the cohort was divided into the 4 groups of normal weight, overweight, obese and morbidly obese. Metabolic data were compared among the 4 groups at baseline and subsequent followup visits up to 2 years. We compared urinary pH and citrate in absolute values and the relative changes in these parameters from baseline. Similarly, we compared the rates of potassium citrate treatment failure.A total of 125 patients with hypocitraturia and low urinary pH were included in this study. Median patient age was 61 years, 80 patients were male and median body mass index was 30.4 kg/m(2). Patients with a higher body mass index tended to be younger (p=0.010), and had a lower urinary citrate but higher sodium, oxalate and uric acid levels. Urinary pH was similar across body mass index groups. pH values and their absolute changes from baseline were lower as body mass index increased (p ≤0.001). Similarly, we noted an association between increasing body mass index category and lower urinary citrate levels accompanied by a statistically significant trend indicating lower absolute changes in citrate with increasing body mass index (p ≤0.001). Potassium citrate dose was increased more frequently among the higher body mass index groups.Patients with a higher body mass index presented with a lower increase in citrate excretion and urinary pH levels after they were started on potassium citrate, and they needed more frequent adjustments to their therapy.

To establish the construct validity of a semirigid ureteroscopy in a high-fidelity simulation model, incorporating hand motion analysis as a paramount part of evaluation. Participants were divided into 3 groups: group 1 (9 junior residents, without experience in ureteroscopy), group II (9 senior residents, with variable experience in ureteroscopy) and group III (2 experts in endourologist); each group performed a single practice session in the high-fidelity bench model, which was previously prepared with small urinary stone phantom in the mid-ureter. Assessment was done using motion tracking device (ICSAD). Procedures were recorded in external vision and endoscopic vision and scored by two blinded evaluators using a Global Rating Scale and ureteral checklist (OSATS). Significant differences were observed in time taken, path length, numbers of movements, Global Rating Scale and checklist in favor of the experts group. Subanalysis demonstrated no relevant differences between groups II and III in general dexterity parameters except for the non-dominant hand, where experts showed a significant less number of movement (34 vs 221; p = 0.03) and path length (12.1 vs 45.1; p = 0.03). The interrater reliability of the GRS was excellent (0.81; p

Objective To evaluate whether body mass index (BMI) has an impact on the outcomes of tubeless percutaneous nephrolithotomy (PCNL). Patients and Methods We retrospectively reviewed patients who underwent tubeless PCNL at our institution from 2006 to 2011. Specifically, stone-free rates, complications, and hospital length of stay (LOS) were assessed. Patients were divided into four groups based on BMI

To compare the effective doses (EDs) associated with imaging modalities for follow-up of patients with urolithiasis, including stone protocol non-contrast computed tomography (NCCT), kidney, ureter, and bladder radiograph (KUB), intravenous urogram (IVU), and digital tomosynthesis (DT).A validated Monte-Carlo simulation-based software PCXMC 2.0 (STUK) designed for estimation of patient dose from medical X-ray exposures was used to determine the ED for KUB, IVU (KUB scout plus three tomographic images), and DT (two scouts and one tomographic sweep). Simulations were performed using a two-dimensional stationary field onto the corresponding body area of the built-in digital phantom, with actual kVp, mAs, and geometrical parameters of the protocols. The ED for NCCT was determined using an anthropomorphic male phantom that was placed prone on a 64-slice GE Healthcare volume computed tomography (VCT) scanner. High-sensitivity metal oxide semiconductor field effect transistors dosimeters were placed at 20 organ locations and used to measure organ radiation doses.The ED for a stone protocol NCCT was 3.04±0.34 mSv. The ED for a KUB was 0.63 and 1.1 mSv for the additional tomographic film. The total ED for IVU was 3.93 mSv. The ED for DT performed with two scouts and one sweep (14.2°) was 0.83 mSv.Among the different imaging modalities for follow-up of patients with urolithiasis, DT was associated with the least radiation exposure (0.83 mSv). This ED corresponds to a fifth of NCCT or IVU studies. Further studies are needed to demonstrate the sensitivity and specificity of DT for the follow-up of nephrolithiasis patients.

tional hazards regression model was used to calculate the risk of upper urinary tract stone between study and control groups. RESULTS: After at least 8-year follow-up, 1761 (10.8%) of the 16292 study subjects and 4775 (9.8%) of the 48876 control subjects developed upper urinary tract stones. Chronic periodontitis was associated with a significantly increased risk of upper urinary stone (hazard ratio 1.139, 95% confidence interval, 1.078 1.203, p 0.001). After adjusting for age, gender, hypertension and diabetes, the stratified Cox proportional hazards regression analysis still showed that patients with chronic periodontitis were more likely to develop upper urinary tract stones than the patients without chronic periodontitis. The adjusted hazard ratio is 1.138 (95% confidence interval, 1.077 1.202, p 0.001). CONCLUSIONS: The findings of this study demonstrate that chronic periodontitis is an independent risk factor for upper urinary tract stone. Patients with chronic periodontitis are advised to receive regular urological check up for detecting urinary stone.

INTRODUCTION AND OBJECTIVES: Digital tomosynthesis (DT) is a novel imaging technique for the evaluation of patients of with nephrolithiasis. It consists of a plain abdominal radiograph (KUB) and one tomographic sweep. Software is used to recreate a series of coronal images from the tomographic sweep. We determined organ specific dose and effective dose (ED) for DT and compared it to our institutional “low dose” non contrast computed tomography (NCCT). METHODS: A validated anthropomorphic male phantom was placed supine on a GE Definium 8000 CT scanner. High sensitivity metal oxide semiconductor field effect transistors (MOSFET) dosimeters were placed at 20 organ locations and used to measure organ doses (OD). A routine DT study was performed consisting of two KUB (scout) images and one tomographic sweep in a 60 degree arc over the phantom. OD were determined as the sum of the doses for the study. Equivalent doses were calculated by multiplying OD and the appropriate tissue weighting factor. ED was calculated by the summation of the equivalent doses. OD and ED were determined in a similar fashion for a renal stone protocol NCCT and the doses were compared. RESULTS: Specific organ doses for DT (2 scouts and 1 tomographic sweep) and NCCT are shown in the table. The ED for NCCT is 3.04 ( 0.34) mSv. The calculated ED for digital tomosynthesis is 0.54 ( 0.07) mSv (2 scouts at 0.10mSv and 0.08mSv 1 sweep at 0.36mSv), p 0.0002. CONCLUSIONS: Digital tomosynthesis exposes patients to substantially less radiation than NCCT. This is particularly true for radiation sensitive organs. Further studies are needed to compare the sensitivity and specificity of DT as compared to NCCT. However, its low overall radiation dose make it an ideal study for the follow up of the recurrent stone former in the office setting.

the rate of potentially missed findings in this batch compared to the full NCCT and to calculate the radiation exposure which could be saved by using the limited field batch compared to the full study. METHODS: 40 patients with single stones in ureters were included. Stone size and locations were described. Patients who had retrograde manipulations were excluded. The full CT and batches were separately interpreted. CTDI was then calculated and translated to msv for all batches and full studies and Rx exposure was then compared calculating the Rx dose which could have been saved if only batches are used for F-U NCCT studies. RESULTS: 15/40 patients had stones located at the proximal ureter and 25 in the distal part. The average msv (graph) was 12 for the complete CT and 3.1 for the batches (in average 73% less Rx exposure More radiation was obviously saved in distal stones, which present more frequently . No other pathology was missed by the limited field batch compared to the full F-U NCCT, given that a complete NCCT is performed at presentation. Presence of hydronephrosis can be easily detected by ultrasound. CONCLUSIONS: Many patients are referred to repeated FU NCCT. We present a method of limited field NCCT. This, eventually combined with dose reduction protocols, may suggest a significant saving in Rx exposure for patients with ureteral calculi.

The acoustic lens of the Modularis electromagnetic shock wave lithotripter (Siemens, Malvern, Pennsylvania) was modified to produce a pressure waveform and focal zone more closely resembling that of the original HM3 device (Dornier Medtech, Wessling, Germany). We assessed the newly designed acoustic lens in vivo in an animal model.Stone fragmentation and tissue injury produced by the original and modified lenses of the Modularis lithotripter were evaluated in a swine model under equivalent acoustic pulse energy (about 45 mJ) at 1 Hz pulse repetition frequency. Stone fragmentation was determined by the weight percent of stone fragments less than 2 mm. To assess tissue injury, shock wave treated kidneys were perfused, dehydrated, cast in paraffin wax and sectioned. Digital images were captured every 120 μm and processed to determine functional renal volume damage.After 500 shocks, the mean ± SD stone fragmentation efficiency produced by the original and modified lenses was 48% ± 12% and 52% ± 17%, respectively (p = 0.60). However, after 2,000 shocks, the modified lens showed significantly improved stone fragmentation compared to the original lens (mean 86% ± 10% vs 72% ± 12%, p = 0.02). Tissue injury caused by the original and modified lenses was minimal at a mean of 0.57% ± 0.44% and 0.25% ± 0.25%, respectively (p = 0.27).With lens modification the Modularis lithotripter demonstrates significantly improved stone fragmentation with minimal tissue injury at a clinically relevant acoustic pulse energy. This new lens design could potentially be retrofitted to existing lithotripters, improving the effectiveness of electromagnetic lithotripters.

The EMS Swiss LithoBreaker is a new, portable, electrokinetic lithotripter. We compared its tip velocity and displacement characteristics with a handheld, pneumatic lithotripter LMA StoneBreaker.™ We also evaluated fragmentation efficiency using in vitro models of percutaneous and ureteroscopic stone fragmentation.Displacement and velocity profiles were measured for 1-mm and 2-mm probes using a laser beam aimed at a photo detector. For the percutaneous model, 2-mm probes fragmented 10-mm spherical BegoStone phantoms until the fragments passed through a 4-mm mesh sieve. The ureteroscopic model used 1-mm probes and compared the pneumatic and electrokinetic devices to a 200-μm holmium laser fiber. Cylindrical (4-mm diameter, 4-mm length) BegoStone phantoms were placed into silicone tubing to simulate the ureter; fragmented stones passed through a narrowing in the tubing.For both 1-mm and 2-mm probes, the electrokinetic device had significantly higher tip displacement and slower tip velocity, P0.01. In the percutaneous model, the electrokinetic device needed an average of 484 impulses over 430 seconds to fragment one BegoStone, while the pneumatic device needed 29 impulses over 122 seconds to fragment one stone. Both clearance times and number of impulses needed for percutaneous stone clearance were significantly different at P0.01. Ureteroscopically, the mean clearance time was 97 seconds for the electrokinetic lithotripter, 145 seconds for the pneumatic lithotripter, and 304 seconds for the laser. Comparing the pneumatic device with the electrokinetic device ureteroscopically, there was no significant difference in clearance time, P=0.55. Both the pneumatic and electrokinetic lithotripters, however, demonstrated decreased clearance times compared with the laser, P=0.027.The portable electrokinetic lithotripter may be better suited for ureteroscopy instead of percutaneous nephrolithotomy. It appears to be comparable to the portable pneumatic device in the ureter. Further clinical studies are needed to confirm these findings in vivo.

Background and Purpose: Topical chemotherapy for urothelial cancer is dependent on adequate contact time of the chemotherapeutic agent with the urothelium. To date, there has not been a reliable method of maintaining this contact for renal or ureteral urothelial carcinoma. We evaluated the safety and feasibility of using a reverse thermosensitive polymer to improve dwell times of mitomycin C (MMC) in the upper tract.Using a porcine model, four animals were treated ureteroscopically with both upper urinary tracts receiving MMC mixed with iodinated contrast. One additional animal received MMC percutaneously. The treatment side had ureteral outflow blocked with a reverse thermosensitive polymer plug. MMC dwell time was monitored fluoroscopically and intrarenal pressures measured. Two animals were euthanized immediately, and three animals were euthanized 5 days afterward.In control kidneys, drainage occurred at a mean of 5.3±0.58 minutes. Intrarenal pressures stayed fairly stable: 9.7±14.0 cm H20. In treatment kidneys, dwell time was extended to 60 minutes, when the polymer was washed out. Intrarenal pressures in the treatment kidneys peaked at 75.0±14.7 cm H20 and reached steady state at 60 cm H20. Pressures normalized after washout of the polymer with cool saline. Average washout time was 11.8±9.6 minutes. No histopathologic differences were seen between the control and treatment kidneys, or with immediate compared with delayed euthanasia.A reverse thermosensitive polymer can retain MMC in the upper urinary tract and appears to be safe from our examination of intrarenal pressures and histopathology. This technique may improve the efficacy of topical chemotherapy in the management of upper tract urothelial carcinoma.