Prospective, Randomized Comparison of Dual-Lumen vs Single-Lumen Flexible Ureteroscopes in Proximal Ureteral and Renal Stone Management.

Introduction: We sought to compare the safety, efficacy, efficiency, and surgeon experience during upper urinary tract stone management with single-lumen (SLFU) vs dual-lumen flexible ureteroscopes (DLFU). Materials and Methods: Seventy-nine patients with proximal ureteral or renal stone burden <2 cm were randomized to a SLFU or DLFU. We recorded times for ureteroscopy (URS), laser lithotripsy, stone basketing, as well as intraoperative and postoperative complications. The rate of stone clearance and stone free status were calculated using CT imaging. Surgeons completed a survey after each procedure rating various metrics regarding ureteroscope performance. Results: Thirty-five patients from the single-lumen group and 44 patients from the dual-lumen group had comparable median URS time (37 vs 35 minutes, p = 0.984) and basketing time (12 vs 19 minutes; p = 0.584). Median lithotripsy time was decreased in the dual-lumen group (single: 6 vs dual: 2 minutes, p = 0.017). The stone clearance rate was superior in the dual-lumen group (single: 3.7 vs dual: 7.1 mm3/min, p = 0.025). The absolute stone-free rate (SFR) was superior for the dual-lumen group (single: 26% vs dual: 48%, p = 0.045). No differences in intraoperative (single: 0% vs dual: 2%; p = 0.375) and postoperative complications (single: 7% vs dual: 11%, p = 0.474) were observed. Surgeons' ratings of the dual-lumen ureteroscope was superior for visibility, comfort, ease of use, and overall performance. Conclusions: The use of the dual-lumen ureteroscope in patients with renal and proximal ureteral stones <2 cm provided shorter lithotripsy time, higher stone clearance rates, improved SFR, and superior surgeon ratings when compared with SLFUs.

Endoscopic Guided Percutaneous Nephrolithotomy.

Percutaneous nephrolithotomy (PCNL) is the treatment of choice for kidney stones >2 cm in size. Obtaining a nephrostomy tract to access the kidney is a key step in this procedure that ultimately determines the patient's outcome. We describe each step of the endoscopic guided approach to PCNL as performed at the University of California, Irvine. Each step of the endoscopic guided PCNL is described and depicted in the video. Surgical steps depicted in the video are from various recorded PCNL procedures from our institution. This guide outlines the indications, preoperative preparation, patient positioning, surgical steps, and postoperative care for patients undergoing PCNL using the endoscopic guided approach. Direct observation of nephrostomy puncture, tract dilation using the balloon, and passing of the Amplatz sheath allow for proper access to the kidney and lower risk of injury. By following this systematic module of endoscopic guided PCNL, a nephrostomy tract can be created and accessed under direct observation, facilitating the routine steps of PCNL.

Crowd-Sourced Assessment of Surgical Skills of Urology Resident Applicants: Four-Year Experience.

OBJECTIVE: To determine a) if surgical skills among urology resident applicants could be reliably assessed via crowdsourcing and b) to what extent surgical skills testing impacts resident selection. DESIGN: Interviewees completed the following surgical skills tasks during their interview day: open knot tying (OKT), laparoscopic peg transfer (LPT), and robotic suturing (RS). Urology faculty and crowd-workers evaluated each applicant's video-recorded performance using validated scoring and were assessed for agreement using Cronbach's alpha. Applicants' USMLE scores, interview scores, and Jefferson Scale of Physician Empathy (JSPE-S) scores were assessed for correlation with skills testing scores and match rank. Additionally, a survey was distributed to interviewees assessing match outcomes. SETTING: University of California Irvine Department of Urology, Surgical Skills Laboratory PARTICIPANTS: All 94 urology residency interviewees at the University of California Irvine Department of Urology from 2015-2018 were invited to complete the three surgical skills tasks on their interview day. RESULTS: Survey responses were received from all 94 interviewees (100%). Crowd and expert agreement was good (α=0.88), fair (α=0.67), and poor (α=0.32) for LPT, RS, and OKT scores, respectively. The skills testing scores did not correlate with match rank, USMLE score, or JSPE-S score. On multivariate analysis, only interview score (r= -0.723; p<0.001) and faculty LPT score (r=-0.262; p=0.001) were significant predictors of match rank. Interviewees who reported matching into a top 3 residency choice had significantly higher faculty LPT scores than those who did not (11.9 vs. 9.7, p=0.03). CONCLUSIONS: Surgical skills overall did not significantly impact match rank. Expert assessment of laparoscopic peg transfer skills and interview performance among urology resident applicants correlated with match rank.

Interactive Virtual Reality Renal Models as an Educational and Preoperative Planning Tool for Laparoscopic Donor Nephrectomy.

OBJECTIVE: To evaluate the efficacy of interactive virtual reality (iVR) in providing a three-dimensional (3D) experience with the donor's anatomy for surgeons and patients, we present a retrospective, case-controlled study assessing the impact of iVR renal models prior to LDN on both surgical outcomes and patients' understanding of the procedure. MATERIALS AND METHODS: Twenty patients undergoing LDN were prospectively recruited; their contrast-enhanced CT scans were transformed into iVR models. An iVR platform allowed the surgeons to rotate and deconstruct the renal anatomy; patients could also view their anatomy as the procedure was explained to them. Questionnaires assessed surgeons' understanding of renal anatomy after CT alone and after CT+iVR. Surgeons also commented on whether iVR impacted their preoperative plan. Patients assessed their anatomical understanding and anxiety level before and after iVR. Surgical outcomes for the iVR cohort were compared to a retrospectively matched, non-iVR cohort of LDN patients. RESULTS: Surgeons altered their preoperative plan in 18 of 20 LDNs after viewing iVR models. Patients reported better understanding of their anatomy (5/5) and noted decreased preoperative anxiety (5/5) after viewing iVR. When compared to the non-iVR group, the iVR group had a 25% reduction in median operative time (P < .001). In terms of surgical outcomes, patients in the iVR group had a 40% lower median relative change in postoperative creatinine (P < .001). CONCLUSION: Preoperative viewing of iVR models altered the operative approach, decreased the operative time, and improved donor patient outcomes. iVR models also reduced patients' preoperative anxiety.

Comparison of Conventional and Triple Bolus Computerized Tomographic Urography Protocols for Radiation Dose Reduction in Hematuria Evaluation: A Randomized Controlled Trial.

PURPOSE: Computerized tomographic urography is the diagnostic tool of choice for evaluating hematuria. In keeping with the ALARA (As Low As Reasonably Achievable) principle, we evaluated a triple bolus computerized tomography protocol designed to reduce radiation exposure. MATERIALS AND METHODS: Patients with macroscopic or microscopic hematuria were prospectively randomized to conventional computerized tomography (100) or triple bolus computerized tomography (100). The triple bolus computerized tomography protocol entails 2 scans: pre-contrast scan followed by 3 contrast injections at 40 seconds, 60 seconds and 20 minutes prior to the second scan to capture all 3 phases. The conventional computerized tomography protocol requires 4 scans: pre-contrast scan, and 3 post-contrast scans at the corticomedullary, nephrographic and excretory phases. Radiation exposure and the detection of urological pathology were recorded based on radiology reports. RESULTS: There were no differences in patient demographics or body mass index between the 2 groups. Triple bolus computerized tomography exposed patients to 33% less radiation (1,715 vs 1,145 mGy*cm for conventional vs triple bolus computerized tomography; p <0.001). For macroscopic hematuria, the pathology detection rates were 70% for triple bolus and 73% for conventional computerized tomography (p=0.72). For microscopic hematuria, the detection rates were 59% for triple bolus and 50% for conventional computerized tomography (p=0.68). In both groups, the rates of detection of urolithiasis, renal cysts, urological masses, bladder pathology and prostate pathology were no different between triple bolus and conventional computerized tomography. CONCLUSIONS: In both the settings of macroscopic and microscopic hematuria evaluation, triple bolus computerized tomography significantly reduces radiation exposure while providing equivalent detection of genitourinary pathology compared to conventional computerized tomography. The ability to detect upper tract filling defects was not specifically tested.

Evaluation of a Novel Female Gender Flexible Ureteroscope: Comparison of Flow and Deflection to a Standard Flexible Ureteroscope.

Introduction: The advent of single-use disposable flexible ureteroscopes allows for rapid prototyping of novel endoscopes. In this regard, we sought to develop a female-specific ureteroscope, with a shorter working length, to account for the female anatomy. We hypothesized that the shorter, female-specific single-use flexible ureteroscope would engender higher irrigation flow at a given pressure than that of the standard-length ureteroscope. Methods: An in vitro analysis of a standard 65 cm Dornier Axis™ ureteroscope and a shorter, 45 cm female-specific Dornier Axis ureteroscope was performed. All other aspects of the endoscopes were identical. Each ureteroscope was oriented vertically and connected to a Thermedx® irrigation system to provide uniform pressurized flow. The average flow rate was computed over five, 2-minute periods at pressure settings of 50, 100, 150, and 200 mm Hg. Data were collected with the working channel unoccupied, after placement of a 200 µm (0.6F) holmium laser fiber and after passage of a 1.7F stone basket. The procedure was then repeated with the endoscopes at maximum deflection. Results: The female gender ureteroscope had significantly higher irrigation flow rates than the standard-length ureteroscope under all conditions by an average of 11% (p < 0.02). The highest average percent increase, 17% (p < 0.001), was seen with the 1.7F NGage® basket in the working channel with the endoscope straight. The maximum angle of deflection was not significantly different between the female gender and standard ureteroscopes with an open working channel (314° vs 315°, p = 0.86), with the 1.7F NGage basket in place (314° vs 315°, p = 0.15), and with the 200 µm holmium laser in place (316° vs 309°, p = 0.09). Conclusions: A 45 cm female gender ureteroscope allows for a higher irrigation flow rate than the standard-length ureteroscope under all test conditions. There is no added benefit with regard to deflection capabilities.

Long-Term Antibiotic Treatment Prior to Laparoscopic Nephrectomy for Xanthogranulomatous Pyelonephritis Improves Postoperative Outcomes: Results from a Multicenter Study.

PURPOSE: Xanthogranulomatous pyelonephritis is a destructive bacterial infection typically necessitating nephrectomy. We hypothesized that long-term preoperative antibiotics would facilitate laparoscopic nephrectomy by reducing the renal inflammation. MATERIALS AND METHODS: We reviewed the records of all patients with histologically confirmed xanthogranulomatous pyelonephritis at 3 University of California institutions between 2005 and 2018. Patients were stratified by antibiotic treatment duration and surgical approach. Patients treated with long-term preoperative antibiotics (28 days or more of continuous treatment until surgery) were compared to patients treated with short-term antibiotics (less than 28 days) and those who only received single-dose prophylactic antibiotics before surgery. Patient demographics and operative outcomes were analyzed. Complications were assigned by Clavien-Dindo classification. RESULTS: Among the 61 patients, 51 (84%) were female and mean age was 50 years. There were 21 (34%) open procedures and 40 (66%) laparoscopic procedures. Median duration of antibiotic treatment was 5 days in those who received a short-term treatment and 87 days in those who received long-term treatment. Eleven patients received only prophylactic single-dose antibiotics. Using multivariate analysis among patients undergoing laparoscopic nephrectomy, controlling for preoperative drainage, long-term antibiotics resulted in a 6.5-day shorter length of stay (p=0.023) and less overall as well as milder postoperative complications (p <0.001). CONCLUSIONS: Greater than or equal to 4 weeks of preoperative antibiotics before laparoscopic nephrectomy for xanthogranulomatous pyelonephritis was associated with shorter length of stay and fewer, less severe postoperative complications.

Analysis of Ureteral Diameter and Peristalsis in Response to Irrigant Fluid Temperature Changes in an In Vivo Porcine Model.

Objective: It has been previously reported that warming irrigation fluid higher than body temperature may decrease ureteral spasm and thereby facilitate ureteroscopic access to the proximal ureter. Our objective was to examine the effects on ureteral peristalsis and ureteral diameter if the irrigant was warmed to just under the biological threshold for injury. Materials and Methods: Two female adult Yorkshire pigs were studied in this pilot study. In the first pig, a dilute mixture of contrast and irrigation fluid at 37°C and then at 43°C was instilled for 30 minutes into each renal pelvis through a ureteral catheter at 40 mm Hg. Retrograde pyelogram images were captured for each trial and the caliber of the ureter was measured using Vitrea® software. In the second pig, a lumbotomy was performed, and a magnetic sensor was placed on the extraluminal surface of the ureter to monitor ureteral peristalsis while repeating the aforedescribed regimen. Thirty minutes after the first regimen, the force exerted during placement of a 16F ureteral access sheath (UAS) was recorded at both temperatures using the University of California, Irvine Ureteral Force Sensor. Results: There was no statistically significant difference in ureteral caliber along the length of the ureter at 43°C (p = 0.87, p = 0.32, p = 0.66 for proximal, middle, and distal ureter, respectively). Indeed, there was an increase in peristalsis from baseline with fluid irrigation at 37°C and at 43°C (59% and 65%, respectively). There was no significant difference in the force exerted for UAS placement at either temperature. On histologic analysis, there were no significant changes in ureteral histology or luminal diameter. Conclusions: In a porcine model, warming irrigation fluid to just under the biological threshold for injury did not increase ureteral caliber, decrease ureteral peristalsis, or facilitate UAS placement. As such, during ureteroscopy, we continue to warm our irrigation fluid just to body temperature.

Postoperative Urinary Retention in Patients Who Undergo Joint Arthroplasty or Spine Surgery.

Postoperative urinary retention (POUR) may result from orthopaedic procedures and potentially lead to bacteremia and chronic voiding difficulties. Risk factors for POUR include age, undergoing joint arthroplasty, male sex, intraoperative intravenous fluid administration, operative time, and history of benign prostatic hyperplasia. Indwelling catheterization is the preferred management strategy for patients at risk for developing POUR. A consistent definition of POUR is needed in order to draw conclusions from future studies.

Evaluation of Interactive Virtual Reality as a Preoperative Aid in Localizing Renal Tumors.

Introduction: A detailed understanding of renal tumor anatomy is required to perform partial nephrectomy. We evaluated the utility of a CT-based interactive virtual reality (iVR) display to assist surgeons' understanding of the precise location of the renal tumor. Methods: CT scans and iVR models of 11 patients with a mean R.E.N.A.L. nephrometry score of 6.9 were evaluated. Seven faculty urologists and six urology residents reviewed CT scans and positioned each tumor onto a digital three-dimensional model of the same kidney, although without the tumor present. A week later, participants repeated the session using both iVR models and CT scans. For both time points, the overlap between the surgeon-inserted tumor and the actual tumor location was calculated. Participants answered a 1 to 10 Likert scale survey to gauge their understanding of renal and tumor anatomy based on CT alone vs CT+iVR. Results: Median tumor overlap for the entire cohort was 28% after CT review and 42% after CT+iVR (p = 0.05); among faculty urologists, for CT+iVR vs CT alone, percentage overlap improved (47% vs 33%, p = 0.033) and the incidence of 0% overlap decreased (19%-4%, p = 0.024), respectively. Among residents, there was no significant difference for either percentage overlap or 0% overlap for CT vs CT+iVR. The percentage overlap for the two tumors with high R.E.N.A.L. nephrometry scores (i.e., 10) increased from 51% to 67% after using CT+iVR (p = 0.039). The combination of CT+iVR was an independent predictor of improved overlap vs CT alone (odds ratio 2.22, 95% confidence interval 1.04-4.78, p = 0.039). Faculty surgeons' survey responses showed an improved understanding of the tumor location and shape with the addition of iVR (p < 0.05). Conclusions: The addition of patient-specific iVR models to standard CT imaging improved the ability of faculty urologists to accurately configure the location of a renal tumor, and improved their understanding of tumor anatomy.

Evaluation of a Diuresis Enhanced Non-Contrast Computed Tomography for Kidney Stones Protocol to Maximize Collecting System Distention.

Purpose: In urolithiasis patients, preoperative non-contrast computed tomography (NCCT) commonly fails to provide sufficient distention of the renal collecting system to allow reliable preoperative planning for how best to approach a stone. Our objective was to evaluate the effect of a novel protocol, including oral hydration and an oral diuretic, on the distention of the renal collecting system. Patients and Methods: Twenty patients with a prior NCCT, who were scheduled to undergo a subsequent NCCT for urolithiasis assessment, were enrolled. Each patient was instructed to ingest 1 L of water and 20 mg of oral furosemide 30 to 60 minutes before their scan (DRINK [DiuResIs Enhanced Non-contrast Computed Tomography for Kidney Stones] protocol). Patients' prior NCCT scan (non-DRINK) was used for comparison. Three-dimensional (3D) reconstruction of DRINK and non-DRINK NCCT studies was performed to determine the volume and surface area of the collecting system. In addition, three faculty endourologists measured the width of the upper and lower pole infundibula and renal pelvis in the axial, coronal, and sagittal views. Results: Among the 20 patients, 13 completed the DRINK protocol as specified. For these 13 patients, 3D reconstruction of the DRINK study collecting systems showed a 63% and a 36% increase in collecting system volume and surface area, respectively (p = 0.02 and p < 0.01, respectively). Also, measurements of the CT images demonstrated a significant (p < 0.05) increase in the collecting system widths in 67% of measurements. Conclusion: The DRINK protocol significantly increased the visible collecting system volume and surface area; in the majority of cases, the upper and lower pole infundibular widths and the width of the renal pelvis were also expanded.

Stone Culture Positive Veillonella in Analysis of Calcium-Based Stones: A Case Report.

Background: Calcium-based urinary stones rarely grow bacteria on stone culture. The presence of an anaerobic bacteria is even more uncommon. We present a case of Veillonella growth from a primarily calcium phosphate-based urinary stone culture. Case Presentation: A 56-year-old Caucasian woman presented with urosepsis and bilateral nephrolithiasis. A nephrostomy tube was emergently placed in the left kidney. After resolution of her urosepsis, she underwent a left percutaneous nephrolithotomy. The stone culture grew Veillonella, a gram-negative anaerobe. Conclusion: Growth of anaerobic bacteria, such as Veillonella, on stone culture of a calcium-based stone is a rare occurrence; the mechanism of this association remains unexplained.

The role of transient receptor potential vanilloid 2 channel in cardiac aging.

BACKGROUND: The aging heart is characterized by cellular and molecular changes leading to a decline in physiologic function and cardiac remodeling, specifically the development of myocyte hypertrophy and fibrosis. Transient receptor potential vanilloid 2 (TRPV2), a stretch-mediated channel and regulator of calcium homeostasis, plays a key role in the function and structure of the heart. TRPV2 also plays an important role in the adaptive and maladaptive compensatory mechanisms of the heart in response to pathologic and exercise-induced stress. Our current study seeks to elucidate the potential role of TRPV2 channels in the regulation of cardiac function in aging. METHODS: Wild-type (WT) and TRPV2 functional knockout (FKO) mice were aged out to various time points, and their cardiac function was measured using advanced echocardiography. Furthermore, we histologically analyzed the heart morphology to determine myocyte hypertrophy, the development of fibrosis and the relative expression of TRPV2. RESULTS: Our results demonstrate that even though TRPV2-FKO mice have impaired function at baseline, their cardiac function as measured via standard and advanced echocardiographic parameters (ejection fraction, cardiac output and circumferential strain) decreased less with aging in comparison with the WT group. Furthermore, there was less fibrosis and hypertrophy in the TRPV2-FKO group with aging in comparison with the WT. The expression of TRPV2 in the WT group did not significantly change with aging. CONCLUSIONS: TRPV2 functional deletion is compatible with aging and associated with a decreased development of myocyte hypertrophy and fibrosis. It may be an important target for prevention of age-induced cardiac remodeling.

Transient receptor potential vanilloid 2 function regulates cardiac hypertrophy via stretch-induced activation.

OBJECTIVE: Hypertension (increased afterload) results in cardiomyocyte hypertrophy leading to left ventricular hypertrophy and subsequently, heart failure with preserved ejection fraction. This study was performed to test the hypothesis that transient receptor potential vanilloid 2 subtype (TRPV2) function regulates hypertrophy under increased afterload conditions. METHODS: We used functional (pore specific) TRPV2 knockout mice to evaluate the effects of increased afterload-induced stretch on cardiac size and function via transverse aortic constriction (TAC) as well as hypertrophic stimuli including adrenergic and angiotensin stimulation via subcutaneous pumps. Wild-type animals served as control for all experiments. Expression and localization of TRPV2 was investigated in wild-type cardiac samples. Changes in cardiac function were measured in vivo via echocardiography and invasive catheterization. Molecular changes, including protein and real-time PCR markers of hypertrophy, were measured in addition to myocyte size. RESULTS: TRPV2 is significantly upregulated in wild-type mice after TAC, though not in response to beta-adrenergic or angiotensin stimulation. TAC-induced stretch stimulus caused an upregulation of TRPV2 in the sarcolemmal membrane. The absence of functional TRPV2 resulted in significantly reduced left ventricular hypertrophy after TAC, though not in response to beta-adrenergic or angiotensin stimulation. The decreased development of hypertrophy was not associated with significant deterioration of cardiac function. CONCLUSION: We conclude that TRPV2 function, as a stretch-activated channel, regulates the development of cardiomyocyte hypertrophy in response to increased afterload.

Transient Receptor Potential Vanilloid 2 Regulates Myocardial Response to Exercise.

The myocardial response to exercise is an adaptive mechanism that permits the heart to maintain cardiac output via improved cardiac function and development of hypertrophy. There are many overlapping mechanisms via which this occurs with calcium handling being a crucial component of this process. Our laboratory has previously found that the stretch sensitive TRPV2 channels are active regulators of calcium handling and cardiac function under baseline conditions based on our observations that TRPV2-KO mice have impaired cardiac function at baseline. The focus of this study was to determine the cardiac function of TRPV2-KO mice under exercise conditions. We measured skeletal muscle at baseline in WT and TRPV2-KO mice and subjected them to various exercise protocols and measured the cardiac response using echocardiography and molecular markers. Our results demonstrate that the TRPV2-KO mouse did not tolerate forced exercise although they became increasingly exercise tolerant with voluntary exercise. This occurs as the cardiac function deteriorates further with exercise. Thus, our conclusion is that TRPV2-KO mice have impaired cardiac functional response to exercise.