Successful Percutaneous Ultrasonic Lithotripsy of Gallstones.

Background: Acute calculous cholecystitis is the obstruction of the cystic duct by a gallstone that leads to inflammation of the gallbladder necessitating cholecystectomy. Case Series: We present the cases of 2 patients with acute calculous cholecystitis who were deemed ineligible candidates for cholecystectomy because of their complicating medical histories. Both patients initially underwent cholecystostomy and drain placement with interventional radiology for management of acute calculous cholecystitis. Their large gallstones remained refractory to attempts at removal by electrohydraulic lithotripsy via the cholecystostomy access. The patients' gallstones were successfully removed via percutaneous ultrasonic lithotripsy during a collaborative procedure with interventional radiology and urology. Conclusion: An interdisciplinary approach using percutaneous cholecystolithotomy with rigid ultrasonic lithotripsy is an effective method for removing challenging gallstones in patients for whom traditional approaches fail.

Factors Associated with Ureteral Stent Failure in Patients with Malignant Ureteral Obstruction.

Introduction: Management of malignant ureteral obstruction (MUO) with ureteral stents remains a clinical challenge, often involving frequent stent exchanges attributable to stent failure or other urological complications. We report our institutional experience with ureteral stents for management of MUO, including analysis of clinical factors associated with stent failure. Methods: We performed a retrospective review of patients treated with indwelling ureteral stents for MUO in nonurothelial malignancies at our tertiary-care institution between 2008 and 2019. Univariate Cox proportional hazards analysis was performed to identify clinical variables associated with stent failure and stent-related complications. Stent failure was defined as need for unplanned stent exchange, placement of percutaneous nephrostomy (PCN), or tandem stents. Results: In our cohort of 78 patients, the median (range) number of stent exchanges was 2 (0-17) during a total stent dwell time of 4.3 (0.1-40.3) months. Thirty-four patients (43.6%) developed a culture-proven urinary tract infection (UTI) during stent dwell time. Thirty-five patients (44.8%) had stent failure. Twenty-two patients (28.2%) underwent unplanned stent exchanges, 23 (29.5%) required PCN after initial stent placement, and 6 (7.7%) required tandem stents. Ten (28.6%) patients with stent failure were treated with upsized stents, which led to resolution in seven patients. Stent failure occurred with 20/44 (45.4%) Percuflex™, 15/27 (55.6%) polyurethane, and 2/3 (66.7%) metal stents. In patients with ≥2 exchanges (N = 45), median time between exchanges was 4.1 (2.0-14.8) months. Bilateral stenting and history of radiation predicted UTI development. Median overall patient survival after initial stent placement was 19.9 months (95% CI 16.5-37.9 months). Conclusions: Ureteral stent failure poses a significant medical burden to patients with MUO. Better methods to minimize stent-related issues and improve patient quality of life are needed. Using a shared decision-making approach, clinicians and patients should consider PCN or tandem stents early in the management of MUO.

Ex Vivo Porcine Model for Robot-Assisted Partial Nephrectomy Simulation at a High-Volume Tertiary Center: Resident Perception and Validation Assessment Using the Global Evaluative Assessment of Robotic Skills Tool.

Introduction: With increased demands on surgeon productivity and outcomes, residency robotics training increasingly relies on simulations. The objective of this study is to assess the validity and effectiveness of an ex vivo porcine training model as a useful tool to improve surgical skill and confidence with robot-assisted partial nephrectomy (RAPN) among urology residents. Methods: A 2.5 cm circular area of ex vivo porcine kidneys was marked as the area of the tumor. Tumor excision and renorrhaphy was performed by trainees using a da Vinci Si robot. All residents ranging from postgraduate year (PGY) 2 to 5 participated in four training sessions during the 2017 to 2018 academic year. Each session was videorecorded and scored using the global evaluative assessment of robotic skills (GEARS) by faculty members. Results: Twelve residents completed the program. Initial mean GEARS score was 16.7 and improved by +1.4 with each subsequent session (p = 0.008). Initial mean excision, renorrhaphy, and total times were 8.2, 13.9, and 22.1 minutes, which improved by 1.6, 2.0, and 3.6 minutes, respectively (all p < 0.001). Residents' confidence at performing RAPN and robotic surgery increased after completing the courses (p = 0.012 and p < 0.001, respectively). Overall, residents rated that this program has greatly contributed to their skill (4/5) and confidence (4.1/5) in robotic surgery. Conclusions: An ex vivo porcine simulation model for RAPN and robotic surgery provides measurable improvement in GEARS score and reduction in procedural time, although significant differences for all PGY levels need to be confirmed with larger study participation. Adoption of this simulation in a urology residency curriculum may improve residents' skill and confidence in robotic surgery.

Urinary aquaporin 1 and perilipin 2: Can these novel markers accurately characterize small renal masses and help guide patient management?

OBJECTIVE: To evaluate the role of urine aquaporin 1 and perilipin 2 as biomarkers adjunct to renal mass biopsy in guiding the management of patients with small renal masses. METHODS: Preoperative aquaporin 1 and perilipin 2 levels in 57 patients with small renal masses undergoing partial nephrectomy were analyzed and compared with postoperative tumor histology. An algorithm was created utilizing aquaporin 1 and perilipin 2 in conjunction with renal mass biopsy. Cut-off values were implemented to maximize biomarker sensitivity and specificity. Renal mass biopsy utilization and intervention were then compared with rates in traditional renal mass biopsy algorithms. RESULTS: All clear cell and papillary renal cell carcinomas were correctly identified and assigned to the treatment path. All benign lesions were correctly sorted to a confirmatory renal mass biopsy path. Two chromophobe masses did not have elevated aquaporin 1 and perilipin 2, and would require renal mass biopsy. Compared with protocols that call for all small renal masses to be biopsied, confirmatory renal mass biopsy could have been safely avoided in 74% of patients with elevated aquaporin 1 and perilipin 2. Compared with protocols that do not utilize renal mass biopsy, surgical intervention would have been avoided in 23% of patients with benign masses. CONCLUSIONS: Aquaporin 1 and perilipin 2 possess high sensitivity and specificity for detecting clear cell and papillary renal cell carcinoma. Use of these markers might compliment renal mass biopsy in the characterization of small renal masses.

Partial Nephrectomy for Presumed Renal-Cell Carcinoma: Incidence, Predictors, and Perioperative Outcomes of Benign Lesions.

BACKGROUND: The aim of this study was to investigate the incidence of benign histology after partial nephrectomy (PN) in patients with presumed malignancy from preoperative imaging. Furthermore, preoperative predictors of benign lesions and perioperative outcomes were also assessed. METHODS: A series of patients undergoing PN for renal masses was identified using a prospectively maintained database. Patients were excluded for known genetic conditions, if more than one renal mass was resected, or if standard preoperative imaging was not suspicious for renal-cell carcinoma (RCC). Differences in characteristics between patients with benign and malignant pathology were assessed. RESULTS: A total of 916 patients were identified who underwent PN between 2007 and 2015, including 129 (14.1%) patients with a final diagnosis of benign disease. The most common types of benign pathology were oncocytoma (n = 66, 51.2%), angiomyolipoma (n = 37, 28.7%), and complex cysts (n = 10, 7.8%). Low body mass index (BMI) [0.96 (0.92-0.99) p = 0.02], low R.E.N.A.L. score [0.86 (0.76-0.96) p = 0.007], and low preoperative creatinine [0.37 (0.14-0.91) p = 0.04] predicted benign histology in multivariate analysis. Tumor size was a significant predictor in additional modeling [0.81 (0.69-0.94) p = 0.008]. Patients with benign histology had significantly shorter operative times (p < 0.001) and less estimated blood loss (p < 0.001), and there was no difference in complication (p = 0.93) or blood transfusion (0.24) rates. CONCLUSIONS: In this study, the rate of benign pathology after PN for presumed RCC is 14.1%. BMI, R.E.N.A.L. score, and preoperative creatinine are predictive of benign histology, but the ability of different variables to predict benign lesions may be influenced by the distribution of benign tumor subtypes, reflecting potential unidentified selection bias.

Computed Tomography and Magnetic Resonance Findings of Fat-Poor Angiomyolipomas.

INTRODUCTION: Approximately 5% of angiomyolipomas (AMLs) are classified as "fat poor" due to lack of visually detectable fat on imaging, making them difficult to distinguish from renal cell carcinoma. Recent investigations have proposed CT and MR imaging features suggestive of fat-poor AML (fp-AML). Herein, we determined the frequency of these features in a cohort of fp-AMLs by retrospective review of preoperative imaging. METHODS: A pathology database query from January 2005 to August 2013 identified 49 renal specimens of AML with available imaging. A retrospective review of all CT and MR images of these 49 cases was conducted. Cases with visually detectable fat on imaging were excluded. RESULTS: A total of 26 fp-AMLs were identified. Thirteen lesions had available unenhanced CT images, of which eight (62%) were hyperdense compared to the adjacent renal parenchyma, while five (38%) were isodense. Twenty lesions had enhanced CT images: 14 (70%) and 6 (30%) with homogeneous and heterogeneous enhancement, respectively. Of the nine lesions with enhanced MR sequences, five (56%) were homogeneously enhancing, and four (44%) were heterogeneously enhancing. Eight of nine (89%) lesions had hypointense signal intensity (SI) on T2-weighted MR sequences, while one (11%) had hyperintense SI. None of the eight lesions displayed a decrease in signal on fat-suppressed sequences. CONCLUSIONS: In this study, we confirmed common imaging features of fp-AML: high attenuation on unenhanced CT sequences, homogeneous enhancement on CT, and hypointensity on T2-weighted MR. When these features are present, a renal mass biopsy may be prudent.

Cerebrovascular Disease and Chronic Obstructive Pulmonary Disease Increase Risk of Complications with Robotic Partial Nephrectomy.

OBJECTIVE: To identify specific comorbidities within the Charlson Comorbidity Index (CCI) that are associated with increased complication rates after robot-assisted partial nephrectomy (RAPN). PATIENTS AND METHODS: After institutional review board approval, a consecutive series of 641 patients undergoing RAPN were retrospectively identified. Perioperative complications were defined and classified using the Clavien grading system. Fisher's exact test or chi-square test was performed to evaluate the association of individual comorbidities with perioperative complications. Logistic regression was used for multivariable analysis to adjust for other non-CCI comorbidities and tumor-specific and patient-specific characteristics. RESULTS: Of the 641 patients undergoing RAPN, complications occurred in 67 patients (10.5%), including 10 (14.9%), 28 (41.8%), 20 (29.9%), 5 (7.5%), and 4 (6.0%) patients with Clavien grade 1, 2, 3a, 3b, and 4 complications, respectively. Cerebrovascular disease [odds ratio 3.01 (95% confidence interval [CI] 1.10, 8.26) p = 0.03] and chronic obstructive pulmonary disease [COPD; 3.12 (1.24, 7.89) p = 0.02] predicted complications in multivariable analysis of clinicopathologic characteristics, including all CCI and non-CCI comorbidities. In additional modeling with only CCI comorbidities, similar results were observed, with cerebrovascular disease [2.93 (1.04, 7.56) p = 0.04] and COPD [2.69 (1.04, 6.28) p = 0.04] as the only two significant variables. No other variables reached statistical significance in either model, including nephrometry score or estimated blood loss (p > .50 for both). COPD predicted major complications (Clavien grade 3 or 4) in multivariable analysis [3.19 (1.07, 9.48) p = 0.04]. CONCLUSIONS: Cerebrovascular disease and COPD predict perioperative RAPN complications after RAPN. Identification of patients with these comorbidities preoperatively may afford improved counseling and risk stratification.

Epithelioid Angiomyolipoma in a Pediatric Patient: Case Report and Review of Literature.

We report a case of a 17-year-old girl with tuberous sclerosis complex who underwent partial nephrectomy for a newly discovered 7.5-cm renal mass subsequently determined to be an epithelioid angiomyolipoma, a rare variant of angiomyolipoma that can be confused clinically, radiographically, and pathologically for renal cell carcinoma. Proper diagnosis and treatment are critical, especially in the pediatric patient. This case report and review of literature serve at increasing the awareness of this renal tumor, with its somewhat unpredictable outcome, reviewing the pertinent literature on the topic of epithelioid angiomyolipoma in the clinical setting of tuberous sclerosis complex.

In vivo evaluation of a reverse thermosensitive polymer for ureteroscopy with laser lithotripsy: porcine model.

PURPOSE: To evaluate the effects of a reverse thermosensitive polymer during ureteroscopy with laser lithotripsy in an in vivo porcine model. MATERIALS AND METHODS: Six pigs underwent general anesthesia followed by bilateral ureteroscopy with laser lithotripsy of stone phantoms while measuring intrapelvic renal pressures through bilateral nephrostomy tubes. The procedures were performed in one ureter with the reverse thermosensitive polymer and in the contralateral, control ureter without the reverse thermosensitive polymer. Stone migration lengths, operative times, laser times, laser energy usage, intrapelvic pressures, and postnecropsy histologic examinations of the ureters were compared between the two groups. RESULTS: Bilateral ureteroscopy with lithotripsy was successfully performed in five of six pigs. In one pig, only the unilateral control was performed, because the ureter was too narrow to complete the contralateral side. The mean laser time was 12.8 minutes shorter with the use of the reverse thermosensitive polymer group than in the controls (P=0.021). The procedure time, laser energy usage, and retropulsion length was shorter in the reverse thermosensitive polymer group, but did not reach significance. Between the two groups, there was no difference in mean renal pelvic pressures, peak renal pelvic pressures, or postprocedure histologic examinations of the ureters. CONCLUSIONS: The use of a reverse thermosensitive polymer during ureteroscopy with lithotripsy may have greater advantages beyond preventing stone retropulsion. Here, the use of a reverse thermosensitive polymer during ureteroscopy with lithotripsy resulted in a significant decrease in laser times. Further clinical investigations could further delineate the advantages of using a reverse thermosensitive polymer during intracorporeal lithotripsy.