Mayo Clinic Validation of the AUA Risk Groups for Localized Renal Cell Carcinoma.

PURPOSE: The AUA guidelines introduced a new risk group stratification system based primarily on tumor stage and grade to guide surveillance for patients treated surgically for localized renal cell carcinoma (RCC). We sought to evaluate the predictive ability of these risk groups using progression-free survival (PFS) and cancer-specific survival (CSS), and to compare their performance to that of our published institutional risk models. MATERIALS AND METHODS: We queried our Nephrectomy Registry to identify adults treated with radical or partial nephrectomy for unilateral, M0, clear cell RCC, or papillary RCC from 1980 to 2012. The AUA stratification does not apply to other RCC subtypes as tumor grading for other RCC, such as chromophobe, is not routinely performed. PFS and CSS were estimated using the Kaplan-Meier method. Predictive abilities were evaluated using C indexes from Cox proportional hazards regression models. RESULTS: A total of 3191 patients with clear cell RCC and 633 patients with papillary RCC were included. For patients with clear cell RCC, C indexes for the AUA risk groups and our model were 0.780 and 0.815, respectively (P < .001) for PFS, and 0.811 and 0.857, respectively (P < .001), for CSS. For patients with papillary RCC, C indexes for the AUA risk groups and our model were 0.775 and 0.751, respectively (P = .002) for PFS, and 0.830 and 0.803, respectively (P = .2) for CSS. CONCLUSIONS: The AUA stratification is a parsimonious system for categorizing RCC that provides C indexes of about 0.80 for PFS and CSS following surgery for localized clear cell and papillary RCC.

Diagnosis and Management of Non-Metastatic Upper Tract Urothelial Carcinoma: AUA/SUO Guideline.

PURPOSE: The purpose of this guideline is to provide a useful reference on the effective evidence-based diagnoses and management of non-metastatic upper tract urothelial carcinoma (UTUC). MATERIALS/METHODS: The Pacific Northwest Evidence-based Practice Center of Oregon Health & Science University (OHSU) team conducted searches in Ovid MEDLINE (1946 to March 3rd, 2022), Cochrane Central Register of Controlled Trials (through January 2022), and Cochrane Database of Systematic Reviews (through January 2022). The searches were updated August 2022. When sufficient evidence existed, the body of evidence was assigned a strength rating of A (high), B (moderate), or C (low) for support of Strong, Moderate, or Conditional Recommendations. In the absence of sufficient evidence, additional information is provided as Clinical Principles and Expert Opinions (Table 1).[Table: see text]Results:This Guideline provides updated, evidence-based recommendations regarding diagnosis and management of non-metastatic UTUC including risk stratification, surveillance and survivorship. Treatments discussed include kidney sparing management, surgical management, lymph node dissection (LND), neoadjuvant/adjuvant chemotherapy and immunotherapy. CONCLUSION: This standardized guideline seeks to improve clinicians' ability to evaluate and treat patients with UTUC based on available evidence. Future studies will be essential to further support these statements for improving patient care. Updates will occur as the knowledge regarding disease biology, clinical behavior and new therapeutic options develop.

Diagnostic Accuracy of Clinical Lymph Node Staging for Upper Tract Urothelial Cancer Patients: A Multicenter, Retrospective, Observational Study.

PURPOSE: Treatment options for the management of upper tract urothelial cancer are based on accurate staging. However, the performance of conventional cross-sectional imaging for clinical lymph node staging (N-staging) remains poorly investigated. This study aims to evaluate the diagnostic accuracy of conventional cross-sectional imaging for upper tract urothelial cancer N-staging. MATERIALS AND METHODS: This study was a multicenter, retrospective, observational study. We included 865 nonmetastatic (M0) upper tract urothelial cancer patients treated with curative intended surgery and lymph node dissection who had been staged with conventional cross-sectional imaging before surgery. We compared clinical (c) and pathological (p) N-staging results to evaluate the concordance of node-positive (N+) and node-negative (N0) disease and calculate cN-staging's diagnostic accuracy. RESULTS: Conventional cross-sectional imaging categorized 750 patients cN0 and 115 cN+. Lymph node dissection categorized 641 patients pN0 and 224 pN+. The cN-stage was pathologically downstaged in 6.8% of patients, upstaged in 19%, and found concordant in 74%. The sensitivity and specificity of cN-staging were 25% (95% CI 20; 31) and 91% (95% CI 88; 93). Positive and negative likelihood ratios were 2.7 (95% CI 2.0; 3.8) and 0.83 (95% CI 0.76; 0.89). The area under the receiver operating characteristics curve (0.58, 95% CI 0.55; 0.61) revealed low diagnostic accuracy. CONCLUSIONS: Conventional cross-sectional imaging had low sensitivity in detecting upper tract urothelial cancer pN+ disease. However, cN+ increased the likelihood of pN+ by almost threefold. Thus, conventional cross-sectional imaging is a rule-in but not a rule-out test. Lymph node dissection should remain the standard during extirpative upper tract urothelial cancer surgery to obtain accurate N-staging. cN+ could be a strong argument for early systemic treatment.

Environmental impact of single-use and reusable flexible cystoscopes.

OBJECTIVES: To compare the carbon footprint and environmental impact of single-use and reusable flexible cystoscopes. MATERIALS AND METHODS: We analysed the expected clinical lifecycle of single-use (Ambu aScope™ 4 Cysto) and reusable (Olympus CYF-V2) flexible cystoscopes, from manufacture to disposal. Performance data on cumulative procedures between repairs and before decommissioning were derived from a high-volume multispecialty practice. We estimated carbon expenditures per-case using published data on endoscope manufacturing, energy consumption during transportation and reprocessing, and solid waste disposal. RESULTS: A fleet of 16 reusable cystoscopes in service for up to 135 months averaged 207 cases between repairs and 3920 cases per lifecycle. Based on a manufacturing carbon footprint of 11.49 kg CO2 /kg device for reusable flexible endoscopes and 8.54 kg CO2 /kg device for single-use endoscopes, the per-case manufacturing cost was 1.37 kg CO2 for single-use devices and 0.0017 kg CO2 for reusable devices. The solid mass of single-use and reusable devices was 0.16 and 0.57 kg, respectively. For reusable devices, the energy consumption of reusable device reprocessing using an automated endoscope reprocessor was 0.20 kg CO2 , and per-case costs of device repackaging and repair were 0.005 and 0.02 kg CO2 , respectively. The total estimated per-case carbon footprint of single-use and reusable devices was 2.40 and 0.53 kg CO2 , respectively, favouring reusable devices. CONCLUSION: In this lifecycle analysis, the environmental impact of reusable flexible cystoscopes is markedly less than single-use cystoscopes. The primary contributor to the per-case carbon cost of reusable devices is energy consumption of reprocessing.

Healthcare system contact following ureteroscopy: does discharge instruction readability matter?

INTRODUCTION: We aimed to assess the impact of discharge instruction (DCI) readability on 30-day postoperative contact with the healthcare system. MATERIALS AND METHODS: Utilizing a multidisciplinary team, DCI were modified for patients undergoing cystoscopy, retrograde pyelogram, ureteroscopy, laser lithotripsy, and stent placement (CRULLS) from a 13th grade to a 7th grade reading level. We retrospectively reviewed 100 patients including 50 consecutive patients with original DCI (oDCI) and 50 consecutive patients with improved readability DCI (irDCI). Clinical and demographic data collected including healthcare system contact (communications [phone or electronic message], emergency department [ED], and unplanned clinic visits) within 30 days of surgery. Uni/multivariate logistic regression analyses used to identify factors, including DCI-type, associated with increased healthcare system contact. Findings reported as odds ratios with 95% confidence intervals and p values (< 0.05 significant). RESULTS: There were 105 contacts to the healthcare system within 30 days of surgery: 78 communications, 14 ED visits and 13 clinic visits. There were no significant differences between cohorts in the proportion of patients with communications (p = 0.16), ED visits (p =1.0) or clinic visits (p = 0.37). On multivariable analysis, older age and psychiatric diagnosis were associated with significantly increased odds of overall healthcare contact (p = 0.03 and p = 0.04) and communications (p = 0.02 and p = 0.03). Prior psychiatric diagnosis was also associated with significantly increased odds of unplanned clinic visits (p = 0.003). Overall, irDCI were not significantly associated with the endpoints of interest. CONCLUSIONS: Increasing age and prior psychiatric diagnosis, but not irDCI, were significantly associated with an increased rate of healthcare system contact following CRULLS.

Biological and prognostic implications of biopsy upgrading for high-grade upper tract urothelial carcinoma at nephroureterectomy.

OBJECTIVES: Technical limitations of ureteroscopic (URS) biopsy has been considered responsible for substantial upgrading rate in upper tract urothelial carcinoma (UTUC). However, the impact of tumor specific factors for upgrading remain uninvestigated. METHODS: Patients who underwent URS biopsy were included between 2005 and 2020 at 13 institutions. We assessed the prognostic impact of upgrading (low-grade on URS biopsy) versus same grade (high-grade on URS biopsy) for high-grade UTUC tumors on radical nephroureterectomy (RNU) specimens. RESULTS: This study included 371 patients, of whom 112 (30%) and 259 (70%) were biopsy-based low- and high-grade tumors, respectively. Median follow-up was 27.3 months. Patients with high-grade biopsy were more likely to harbor unfavorable pathologic features, such as lymphovascular invasion (p < 0.001) and positive lymph nodes (LNs; p < 0.001). On multivariable analyses adjusting for the established risk factors, high-grade biopsy was significantly associated with worse overall (hazard ratio [HR] 1.74; 95% confidence interval [CI], 1.10-2.75; p = 0.018), cancer-specific (HR 1.94; 95% CI, 1.07-3.52; p = 0.03), and recurrence-free survival (HR 1.80; 95% CI, 1.13-2.87; p = 0.013). In subgroup analyses of patients with pT2-T4 and/or positive LN, its significant association retained. Furthermore, high-grade biopsy in clinically non-muscle invasive disease significantly predicted upstaging to final pathologically advanced disease (≥pT2) compared to low-grade biopsy. CONCLUSIONS: High tumor grade on URS biopsy is associated with features of biologically and clinically aggressive UTUC tumors. URS low-grade UTUC that becomes upgraded to high-grade might carry a better prognosis than high-grade UTUC on URS. Tumor specific factors are likely to be responsible for upgrading to high-grade on RNU.

Effect of Dataset Size and Medical Image Modality on Convolutional Neural Network Model Performance for Automated Segmentation: A CT and MR Renal Tumor Imaging Study.

The aim of this study is to investigate the use of an exponential-plateau model to determine the required training dataset size that yields the maximum medical image segmentation performance. CT and MR images of patients with renal tumors acquired between 1997 and 2017 were retrospectively collected from our nephrectomy registry. Modality-based datasets of 50, 100, 150, 200, 250, and 300 images were assembled to train models with an 80-20 training-validation split evaluated against 50 randomly held out test set images. A third experiment using the KiTS21 dataset was also used to explore the effects of different model architectures. Exponential-plateau models were used to establish the relationship of dataset size to model generalizability performance. For segmenting non-neoplastic kidney regions on CT and MR imaging, our model yielded test Dice score plateaus of [Formula: see text] and [Formula: see text] with the number of training-validation images needed to reach the plateaus of 54 and 122, respectively. For segmenting CT and MR tumor regions, we modeled a test Dice score plateau of [Formula: see text] and [Formula: see text], with 125 and 389 training-validation images needed to reach the plateaus. For the KiTS21 dataset, the best Dice score plateaus for nn-UNet 2D and 3D architectures were [Formula: see text] and [Formula: see text] with number to reach performance plateau of 177 and 440. Our research validates that differing imaging modalities, target structures, and model architectures all affect the amount of training images required to reach a performance plateau. The modeling approach we developed will help future researchers determine for their experiments when additional training-validation images will likely not further improve model performance.

Incidence, prevalence and mortality of chronic periaortitis: a population-based study.

OBJECTIVES: To evaluate the epidemiology, presentation and outcomes of patients with chronic periaortitis from 1998 through 2018. METHODS: An inception cohort of patients with incident chronic periaortitis from January 1, 1998 through December 31, 2018, in Olmsted County, Minnesota was identified based on comprehensive individual medical record review utilising the Rochester Epidemiology Project medical record linkage system. Inclusion required radiographic and/or histologic confirmation of periarterial soft tissue thickening around at least part of the infra-renal abdominal aorta or the common iliac arteries. Data were collected on demographic characteristics, clinical presentation, renal and radiographic outcomes, and mortality. Incidence rates were age and sex adjusted to the 2010 United States white population. RESULTS: Eleven incident cases of chronic periaortitis were identified during the study period. Average age at diagnosis was 61.8±13.4 years. The cohort included 9 men (82%) and 2 women (18%). Age- and sex-adjusted incidence rates per 100,000 population were 0.26 for females, 1.56 for males and 0.87 overall. Overall prevalence on January 1, 2015 was 8.98 per 100,000 population. Median (IQR) length of follow-up was 10.1 (2.5, 13.8) years. Overall mortality was similar to the expected age, sex, and calendar estimates of the Minnesota population with standardised mortality ratio (95% CI) for the entire cohort 2.07 (0.67, 4.84). CONCLUSIONS: This study reports the first epidemiologic data on chronic periaortitis in the United States. In this cohort of patients with chronic periaortitis, men were 4 times more commonly affected than women. Mortality was not increased compared to the general population.

The Impact of Upper Tract Urothelial Carcinoma Diagnostic Modality on Intravesical Recurrence after Radical Nephroureterectomy: A Single Institution Series and Updated Meta-Analysis.

PURPOSE: Diagnostic ureteroscopic biopsy for upper tract urothelial carcinoma (UTUC) has been hypothesized to increase intravesical recurrence of urothelial carcinoma after radical nephroureterectomy (RNU). Moreover, the impact of ureteroscopy without biopsy or percutaneous biopsy on intravesical recurrence remains unknown. Herein, we compared post-RNU intravesical recurrences across UTUC diagnostic modalities. MATERIALS AND METHODS: Patients undergoing RNU at our institution between 1995 and 2019 were categorized by UTUC diagnostic modality: 1) no ureteroscopy or percutaneous biopsy; 2) percutaneous biopsy; 3) ureteroscopy without biopsy; 4) ureteroscopic biopsy. Intravesical recurrences were compared using Kaplan-Meier analyses and Cox-proportional hazard models. Results of group 4 vs 1 were pooled with the literature using a fixed effects meta-analysis. RESULTS: In a cohort of 834 RNU patients, 210 (25.2%) had undergone no ureteroscopy, 57 (6.6%) percutaneous biopsy, 125 (15.0%) ureteroscopy without biopsy, and 442 (53.0%) ureteroscopic biopsy. Two-year intravesical recurrence rates were 15.0%, 12.7%, 18.4%, and 21.9% for groups 1 through 4, respectively (p=0.09). Multivariable analysis found that group 4 had increased intravesical recurrences (HR 1.40, p=0.04) relative to group 1 while group 2 (HR 1.07, p=0.87) and group 3 (HR 1.15, p=0.54) did not. Group 4 remained associated with intravesical recurrence on subset analyses accounting for post-RNU surveillance cystoscopy frequency. On meta-analysis including 11 other series, ureteroscopic biopsy was associated with intravesical recurrence (HR 1.47, p <0.01). CONCLUSIONS: Ureteroscopic biopsy before RNU, but not percutaneous biopsy or ureteroscopy without biopsy, was associated with increased intravesical recurrence. Clinical trials of intravesical chemotherapy after ureteroscopic biopsy are warranted to reduce intravesical recurrences.

Partial versus radical nephrectomy in clinical T2 renal masses.

OBJECTIVE: To report perioperative, renal functional and oncologic outcomes for patients undergoing partial or radical nephrectomy for cT2 renal masses. METHODS: Retrospective review of patients who underwent partial (n = 72) or radical nephrectomy (n = 379) for cT2 renal masses from 2000 to 2016. After propensity adjustment using inverse probability weighting, the following were compared by surgery (partial or radical nephrectomy): complications, renal function measured by estimated glomerular filtration rate as continuous and as <60 mL/min/1.73 m2 at 1 and 3 years postoperatively and overall, metastases-free survival and cancer-specific survival in patients with renal cell carcinoma. RESULTS: After propensity adjustment, clinical and radiographic features were well-balanced between groups. Overall and severe complications were more common for partial compared with radical nephrectomy, although not statistically significant (19 vs 13%, P = 0.14 and 4 vs 2%, P = 0.3, respectively). Estimated glomerular filtration rate change at 1 and 3 years was more pronounced in radical compared with partial nephrectomy (median -16 vs -5 and -14 vs -2, respectively, P < 0.001). A greater proportion of radical nephrectomy patients had an estimated glomerular filtration rate <60 at 1 and 3 years (55 vs 17% and 48 vs 17%, respectively, P < 0.01). In renal cell carcinoma patients, overall, metastases-free and cancer-specific survival were not significantly different between groups (median survivor follow up 7.1 years, interquartile range 3.6-11.4). CONCLUSIONS: Partial nephrectomy appears to be a relatively safe and a potentially effective treatment for cT2 renal masses, conferring better renal functional preservation compared with radical nephrectomy. These data support continued use of partial nephrectomy for renal masses >7 cm in appropriately selected patients.

Catheterization alters bladder ecology to potentiate Staphylococcus aureus infection of the urinary tract.

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of catheter-associated urinary tract infection (CAUTI), which frequently progresses to more serious invasive infections. We adapted a mouse model of CAUTI to investigate how catheterization increases an individual's susceptibility to MRSA UTI. This analysis revealed that catheterization was required for MRSA to achieve high-level, persistent infection in the bladder. As shown previously, catheter placement induced an inflammatory response resulting in the release of the host protein fibrinogen (Fg), which coated the bladder and implant. Following infection, we showed that MRSA attached to the urothelium and implant in patterns that colocalized with deposited Fg. Furthermore, MRSA exacerbated the host inflammatory response to stimulate the additional release and accumulation of Fg in the urinary tract, which facilitated MRSA colonization. Consistent with this model, analysis of catheters from patients with S. aureus-positive cultures revealed colocalization of Fg, which was deposited on the catheter, with S. aureus Clumping Factors A and B (ClfA and ClfB) have been shown to contribute to MRSA-Fg interactions in other models of disease. We found that mutants in clfA had significantly greater Fg-binding defects than mutants in clfB in several in vitro assays. Paradoxically, only the ClfB- strain was significantly attenuated in the CAUTI model. Together, these data suggest that catheterization alters the urinary tract environment to promote MRSA CAUTI pathogenesis by inducing the release of Fg, which the pathogen enhances to persist in the urinary tract despite the host's robust immune response.

Timing and distribution of early renal cell carcinoma recurrences stratified by pathological nodal status in M0 patients at the time of nephrectomy.

OBJECTIVES: To evaluate the timing and distribution of first renal cell carcinoma metastasis after nephrectomy stratified by nodal status. METHODS: We evaluated patients treated with nephrectomy for sporadic, unilateral renal cell carcinoma between 1970 and 2011 who subsequently developed distant metastasis to three or fewer sites. Site-specific metastases-free 2-year survival rates were estimated using the Kaplan-Meier method. Associations of nodal status with time to metastasis were evaluated using multivariable Cox regression models. RESULTS: A total of 1049 patients met the inclusion criteria (135 pN1, 914 pN0/x patients). The median time to identification of first distant metastasis for pN1 patients was 0.4 years (interquartile range 0.2-1.1 years) versus 2.2 years (interquartile range 0.6-6.0 years) in pN0/x patients. The most common site of metastasis was to the lung, but this occurred earlier in pN1 patients (median 0.3 years vs 2.0 years). pN1 was associated with significantly lower site-specific 2-year metastases-free survival when compared with pN0/x for lung (37% vs 70%, P < 0.001), bone (63% vs 87%, P < 0.001), non-regional lymph nodes (60% vs 96%, P < 0.001) and liver metastases (79% vs 91%, P < 0.001). On multivariable analysis, pN1 status remained significantly associated with lung, bone, and non-regional lymph node (all P < 0.001) metastases, but it was no longer associated with liver metastases (P = 0.3). CONCLUSIONS: pN1 nodal status in M0 patients treated with nephrectomy for renal cell carcinoma is associated with more frequent early metastasis to sites conferring poor prognosis when compared with pN0/x. Our findings highlight the importance of rigorous, early surveillance though the multimodal use of a comprehensive history, physical, laboratory and radiological studies, as outlined in societal guidelines.

Retroperitoneal access for robotic renal surgery.

INTRODUCTION AND OBJECTIVE: Retroperitoneal access for robotic renal surgery is an effective alternative to the commonly used transperitoneal approach. We describe our contemporary experience and technique for attaining retroperitoneal access. MATERIALS AND METHODS: We outline our institutional approach to retroperitoneal access for the instruction of urologists at the beginning of the learning curve. The patient is placed in the lateral decubitus position. The first incision is made just inferior to the tip of the twelfth rib as described by Hsu, et al. After the lumbodorsal fascia is traversed, the retroperitoneal space is dilated with a round 10 millimeter AutoSutureTM (Covidien, Mansfield, MA) balloon access device. The following trocars are used: A 130 millimeter KiiR balloon trocar (Applied Medical, Rancho Santa Margarita, CA), three robotic, and one assistant. Key landmarks for the access and dissection are detailed. RESULTS: 177 patients underwent a retroperitoneal robotic procedure from 2007 to 2015. Procedures performed include 158 partial nephrectomies, 16 pyeloplasties, and three radical nephrectomies. The robotic fourth arm was utilized in all cases. When compared with the transperitoneal approach, the retroperitoneal approach was associated with shorter operative times and decreased length of stay (1). Selection bias and surgeon preference accounted for the higher proportion of patients who underwent partial nephrectomy off-camp via the retroperitoneal approach. CONCLUSIONS: Retroperitoneal robotic surgery may confer several advantages. In patients with previous abdominal surgery or intra-abdominal conditions, the retroperitoneum can be safely accessed while avoiding intraperitoneal injuries. The retroperitoneum also provides a confined space that may minimize the sequelae of potential complications including urine leak. Moreover, at our institution, retroperitoneal robotic surgery is associated with shorter operative times and a decreased length of stay when compared with the transperitoneal approach (2). In selected patients, the retroperitoneal approach is a viable alternative to the transperitoneal approach for a variety of renal procedures.

Lymphoepithelioma-like carcinoma of the ureter: a rare presentation, synchronous with conventional urothelial carcinoma.

Lymphoepithelioma-like carcinoma (LELC) is a rare finding in the upper urinary tract. The presenting clinical findings mimic those of other more common upper-tract tumors, such as urothelial carcinoma. Preoperative imaging has not been shown to reliably predict the diagnosis of LELC. This tumor can be misdiagnosed as a reactive inflammatory lesion or lymphoma if the proper immunohistochemical stains for cytokeratin are not used.

Validation of preoperative variables and stratification of patients to help predict benefit of cytoreductive nephrectomy in the targeted therapy ERA.

OBJECTIVES: To further elucidate which patients with metastatic renal cell carcinoma (mRCC) may benefit from cytoreductive nephrectomy (CN) before targeted therapy (TT), and to assess the overall survival of patients undergoing CN and TT versus TT alone. MATERIALS AND METHODS: We identified 88 patients who underwent CN at our institution prior to planned TT and 35 patients who received TT without undergoing CN. Preoperative risk factors described in the literature were assessed in our patient population (serum albumin, liver metastasis, symptomatic metastasis, clinical ≥T3 disease, retroperitoneal and supradiaphragmatic lymphadenopathy). Patients were stratified by number of pretreatment risk factors and overall survival (OS) was compared. RESULTS: TT patients had significantly more risk factors compared to CN patients (3.06 vs. 2.11, p<0.01). Patients who received TT alone had median OS of 5.8 months. All but one patient receiving TT alone had two or more risk factors. A comparison of the CN and TT groups was performed by constructing Kaplan-Meier curves. There was no significant difference in median OS for those patients with exactly two risk factors (447 vs. 389 days, p=0.24), and those with three or more risk factors (184 vs. 155 days, p=0.87). CONCLUSIONS: Using previously described pretreatment risk factors we found that patients with two or more risk factors derived no significant survival advantage from CN in the TT era. These risk factors should be incorporated in the assessment of patients for CN.

Fibrinogen Release and Deposition on Urinary Catheters Placed during Urological Procedures.

PURPOSE: Catheter associated urinary tract infections account for approximately 40% of all hospital acquired infections worldwide with more than 1 million cases diagnosed annually. Recent data from a catheter associated urinary tract infection animal model has shown that inflammation induced by catheterization releases host fibrinogen, which accumulates on the catheter. Further, Enterococcus faecalis catheter colonization was found to depend on EbpA (endocarditis and biofilm-associated pilus), a fibrinogen binding adhesin. We evaluated this mechanism in a human model. MATERIALS AND METHODS: Urinary catheters were collected from patients hospitalized for surgical or nonsurgical urological procedures. Catheters were subjected to immunofluorescence analyses by incubation with antifibrinogen antibody and then staining for fluorescence. Fluorescence intensity was compared to that of standard catheters. Catheters were incubated with strains of Enterococcus faecalis, Staphylococcus aureus or Candida to assess binding of those strains to fibrinogen laden catheters. RESULTS: After various surgical and urological procedures, 50 catheters were collected. In vivo dwell time ranged from 1 hour to 59 days. All catheters had fibrinogen deposition. Accumulation depended on dwell time but not on surgical procedure or catheter material. Catheters were probed ex vivo with E. faecalis, S. aureus and Candida albicans, which bound to catheters only in regions where fibrinogen was deposited. CONCLUSIONS: Taken together, these data show that urinary catheters act as a binding surface for the accumulation of fibrinogen. Fibrinogen is released due to inflammation resulting from a urological procedure or catheter placement, creating a niche that can be exploited by uropathogens to cause catheter associated urinary tract infections.

Urinary fistula after robot-assisted partial nephrectomy: a multicentre analysis of 1 791 patients.

OBJECTIVE: To evaluate the incidence of and risk factors for a urine leak in a large multicentre, prospective database of robot-assisted partial nephrectomy (RPN). PATIENTS AND METHODS: A database of 1 791 RPN from five USA centres was reviewed for urine leak as a complication of RPN. Patient and tumour characteristics were compared between patients with and those without postoperative urine leaks. Fisher's exact test was used for qualitative variables and Wilcoxon sum-rank tests were used for quantitative variables. A review of the literature on PN and urine leak was conducted. RESULTS: Urine leak was noted in 14/1 791 (0.78%) patients who underwent RPN. The mean (sd) nephrometry score of the entire cohort was 7.2 (1.9), and 8.0 (1.9) in patients who developed urine leak. The median (range) postoperative day of presentation was 13 (3-32) days. Patients with urine leak presented in delayed fashion with fever (two of the 14 patients, 14%), gastrointestinal complaints (four patients, 29%), and pain (five patients, 36%). Eight of the 14 patients (57%) required admission, while eight (57%) and nine (64%) had a drain or stent placed, respectively. Drains and stents were removed after a median (range) of 8 (4-13) days and 21 (8-83) days, respectively. Variables associated with urine leak included tumour size (P = 0.021), hilar location (P = 0.025), operative time (P = 0.006), warm ischaemia time (P = 0.005), and pelvicalyceal repair (P = 0.018). Upon literature review, the historical incidence of urine leak ranged from 1.0% to 17.4% for open PN and 1.6-16.5% for laparoscopic PN. CONCLUSION: The incidence of urine leak after RPN is very low and may be predicted by some preoperative factors, affording better patient counselling of risks. The low urinary leak rate may be attributed to the enhanced visualisation and suturing technique that accompanies the robotic approach.