Retrograde intrarenal surgery for lower pole stones utilizing stone displacement technique yields excellent results.

Objective: To evaluate the long-term stone-free rate (SFR) of retrograde intra-renal surgery (RIRS) in the treatment of lower pole renal calculi using only basket relocation and identify independent predictors of stone-free status. Methods: All consecutive patients undergoing RIRS lower pole renal calculi at a single high-volume tertiary center were analyzed retrospectively. Lower pole stones were relocated to the upper pole, where laser lithotripsy was performed. All patients were followed up in the clinic following the surgery and yearly thereafter. The stone-free status was assessed with a combination of an abdominal ultrasound and abdominal X-ray, or an abdominal non-contrast computed tomography if the stones were known to be radiolucent. Results: A total of 480 consecutive patients who underwent RIRS for treatment of lower pole renal calculi, between January 2012 and December 2018, were analyzed from a prospectively maintained database of 3000 ureteroscopies. With a median follow-up time of 18.6 months, the mean SFR was 94.8%. The procedures were unsuccessful in 26 (5.4%) patients due to unreachable stones. The median stone size of the unreachable stones was 12 mm (range 10-30 mm). Multivariable logistic regression analysis revealed two predictors of SFR for lower pole stones: a small cumulative stone burden (odds ratio [OR]: 0.903, 95% confidence interval [CI]: 0.867-0.941, p<0.0001) and preoperative ureteral stent insertion (OR: 0.515, 95% CI: 0.318-0.835, p=0.007). Conclusion: The long-term SFR of RIRS for the treatment of lower pole stones with basket displacement with appropriate patient selection is high.

Porcine Bladder Replacement with a Bilayer Silk Fibroin Enhanced Prosthetic Reservoir: A Feasibility Study.

Introduction: The creation of synthetic reservoirs for bladder replacement has been limited by challenges of interfacing synthetic materials and native tissue. We sought to overcome this challenge by utilizing a novel bilayer silk fibroin scaffold (BLSF) as an intermediary toward the development of an acellular prosthetic reservoir. Methods: Under institutionally approved protocols, 3D-printed reservoirs were implanted in six juvenile female pigs after cystectomy. BLSF was attached to the in situ prosthetic reservoir serving as an intermediary to native ureteral and urethral tissue anastomoses. Our first protocol allowed four pigs to be survived up to 7 days, and the second protocol allowed two pigs to be survived for up to 1 year. At the first sign of functional decline or the end of the study period, the animals were euthanized, and kidneys, ureters, prosthetic bladder, and urethra were harvested en bloc for histopathology analysis. Results: The first two pigs had anastomotic urine leaks because of design flaws resulting in early termination. The third pig had acute renal failure resulting in early termination. The artificial bladder design was modified in subsequent iterations. The fourth pig survived for 7 days and, upon autopsy, had intact urethral and ureteral anastomoses. The fifth and sixth pigs survived for 11 and 12 weeks, respectively, before they were sacrificed because of failure to thrive. One animal developed an enteric fistula. The other animal had an intact anastomosis, and the BLFS was identified at the ureteral and urethral anastomoses on histopathologic analysis. Conclusions: Replacing the porcine bladder with a prosthetic bladder was achieved for up to 3 months, the second longest survival period for a nonbiologic bladder alternative. BLSF was used for the first time to create an interface between synthetic material and biologic tissue by allowing ingrowth of urothelium onto the acellular alloplastic bladder.

Beyond Efficiency: Surface Electromyography Enables Further Insights into the Surgical Movements of Urologists.

Introduction: Surgical skill evaluation while performing minimally invasive surgeries is a highly complex task. It is important to objectively assess an individual's technical skills throughout surgical training to monitor progress and to intervene when skills are not commensurate with the year of training. The miniaturization of wireless wearable platforms integrated with sensor technology has made it possible to noninvasively assess muscle activations and movement variability during performance of minimally invasive surgical tasks. Our objective was to use electromyography (EMG) to deconstruct the motions of a surgeon during robotic suturing (RS) and distinguish quantifiable movements that characterize the skill of an experienced expert urologic surgeon from trainees. Methods: Three skill groups of participants, novice (n = 11), intermediate (n = 12), and expert (n = 3), were enrolled in the study. A total of 12 wireless wearable sensors consisting of surface EMGs and accelerometers were placed along upper extremity muscles to assess muscle activations and movement variability, respectively. Participants then performed a RS task. Results: EMG-based parameters, total time, dominant frequency, and cumulative muscular workload, were significantly different across the three skill groups. We also found nonlinear movement variability parameters such as correlation dimension, Lyapunov exponent trended differently across the three skill groups. Conclusions: These findings suggest that economy of motion variables and nonlinear movement variabilities are affected by surgical experience level. Wearable sensor signal analysis could make it possible to objectively evaluate surgical skill level periodically throughout the residency training experience. Clinical Trial Registration Number: HS# 2018-4407.

Multidisciplinary Approach and Outcomes of Pretreatment Small (cT1a) Renal Mass Biopsy: Single-Center Experience.

Purpose: We evaluated our experience of a multidisciplinary approach to renal mass biopsy (RMB) for small renal masses (SRMs) employing in-office ultrasound (US)-guided biopsy by urology (24%), CT, or US biopsy by interventional radiology (IR) (79%), and endoscopic ultrasound (EUS)-guided biopsy by gastroenterology (GI) (4%). Materials and Methods: A single-institution retrospective review of patients who underwent RMB for SRM from May 2013 to August 2019 was conducted. Data regarding patient demographics, tumor characteristics, biopsy technique, histopathology, and management were collected. Diagnostic rates, concordance with final pathology, complications, and outcomes were analyzed. Results: Of the 192 biopsies reviewed, 63% biopsies were malignant, 20% were benign, and 17% were nondiagnostic. Based on biopsy results, 71 patients (37%) elected active surveillance. Thirty-eight (20%) patients underwent cryoablation, 56 (29%) underwent partial nephrectomy, 14 (7%) underwent radical nephrectomy, and the remaining patients were treated elsewhere. The rate of surgery for benign pathology after pretreatment RMB was 3%. The concordance rate between biopsy and final pathology was 99% for malignancy, 96% for specific pathology subtype, and 85% for renal cell carcinoma grade. Median time from diagnosis to definitive treatment was 97 days (urology: 76, IR: 110 and GI: 54, p = 0.002). Three (1.6%) Clavien I complications were reported. Conclusion: Our multidisciplinary approach to RMB for clinical stage T1a demonstrated favorable safety and diagnostic rates, which effectively directed management strategies and minimized surgery for benign disease. Urologist-performed office biopsies significantly shortened the time from diagnosis to definitive treatment. Our experience with GI EUS biopsy has demonstrated feasibility and safety for tumors that were otherwise not accessible percutaneously.

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.

Can preoperative renal mass biopsy change clinical practice and reduce surgical intervention for small renal masses?

INTRODUCTION: The role of renal biopsy prior to surgical intervention for a renal mass remains controversial despite the fact that for all other urological organs except the testicle, biopsy inevitably precedes treatment as is true for all other specialties dealing with solid masses (e.g. thyroid, breast, colon, liver, etc.). Accordingly, we sought to determine the impact of a routine biopsy regimen on the course of patients with cT1a lesions in comparison with a contemporary series of cT1a individuals who went directly to treatment without a preoperative biopsy. METHODS: We analyzed a multi-institutional, prospectively maintained database of patients who underwent an office-based, ultrasound-guided, renal mass biopsy (RMB) for a cT1a renal mass (i.e. ≤4cm in largest dimension). Controls were selected from all patients in the database who had a cT1a renal lesion but did not undergo RMB. Both groups were analyzed for differences in treatment modality and surgical pathology results. RESULTS: A total of 72 RMB and 73 control patients were analyzed. The groups were similar in regards to their baseline characteristics. Overall RMB diagnostic rate was 75%. Surgical pathology revealed that excision of benign tumors was eight-fold less in the RMB cohort compared to the control group (3% vs. 23%; P < 0.001). Additionally, the rate of active surveillance in the RMB cohort was nearly three times higher at 35% vs. 14% for the controls (P < 0.001). Biopsy was concordant with surgical pathology in 97% of cases for primary histology (i.e. benign vs. malignant), 97% for histologic subtype, and 46% for low (I or II) vs. high (III or IV) grade. On multivariate analysis patients who underwent surgical intervention without preoperative RMB were 6.7 times more likely to have benign histopathology compared to patients who underwent preoperative RMB (OR 6.7, 95% CI = 0.714 - 63.626, P = 0.096). There were no procedural or post-procedural RMB complications. CONCLUSIONS: For patients with cT1a lesions, the implementation of routine office-based RMB led to a significant decrease in the rate of surgical intervention for benign tumors. This practice also resulted in a higher rate of active surveillance for the management of renal cortical neoplasms with benign histopathology compared to a control group.

Office-Based Renal Tumor Biopsy: a Paradigm Change in the Management of a Small Renal Mass?

PURPOSE OF REVIEW: The goal of this paper is to evaluate the use of an office-based renal mass biopsy (RMB), whose feasibility could represent a paradigm shift in clinical practice. RECENT FINDINGS: Despite the earlier diagnosis of patients with renal masses, the lack of evidence showing a reduction in cancer-specific mortality warrants an examination in treatment practices. RMB is underutilized when compared to biopsy practice for all other neoplasms in every other solid organ (except testis), and the majority of RMB performed are outsourced to interventional radiologists. Performing an ultrasound-guided, office-based RMB is safe, reproducible, and has a meaningful impact on management decisions. The use of percutaneous RMB in clinical practice is growing, and the use of RMB has meaningful impact on management decisions for renal masses. Incorporating ultrasound-guided biopsy of a renal mass into clinical practice is feasible, and in contemporary practice, the urologist has the skill set to perform the procedure reliably, with low morbidity, and with minimal patient discomfort.

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.

Determining the Safety Threshold for the Passage of a Ureteral Access Sheath in Clinical Practice Using a Purpose-Built Force Sensor.

PURPOSE: Ureteral injury is a frequent complication of ureteral access sheath deployment. We sought to define the safe threshold of force for the passage of a ureteral access sheath using a novel ureteral access sheath force sensor. MATERIALS AND METHODS: Ureteral access sheath-force sensor measurements were recorded in 210 renal units. A 16Fr ureteral access sheath was deployed initially based on a prior porcine study. If 6 N was reached, the surgeon was advised to downsize the 16Fr ureteral access sheath. In each case, a post-ureteroscopic lesion scale was recorded. Regression models were used to estimate the impact of adjusted variables on post-ureteroscopic lesion scale grade, 16Fr ureteral access sheath deployment, and peak force. RESULTS: A 16Fr ureteral access sheath was deployed in 127 (61%) renal units with a mean peak force of 5.7 N. Two high-grade ureteral injuries occurred; in both cases >6 N of force was recorded. Post-ureteroscopic lesion scale grade correlated directly with peak insertion force (p <0.01). Bacteriuria within 60 days of the procedure (OR 2.009, p=0.034), combination of preoperative stent plus oral tamsulosin (OR 2.998, p=0.045), and prior ipsilateral stone surgery (OR 2.13, p=0.01) were independent predictors of successful 16Fr ureteral access sheath deployment. Among patients with neither prior ipsilateral stone surgery nor preoperative stent, preoperative tamsulosin facilitated passage of a 16Fr ureteral access sheath (OR 2.750, p=0.034). CONCLUSIONS: Ureteral access sheath associated ureteral injury can be averted by limiting the insertion force to ≤6 N. Prior stone surgery, preoperative indwelling ureteral stent plus oral tamsulosin, and recently treated bacteriuria favored passage of a 16Fr ureteral access sheath. In the naïve, unstented patient, preoperative tamsulosin favored deployment of a 16Fr ureteral access sheath.

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.

The impact of the number of lifetime stone events on quality of life: results from the North American Stone Quality of Life Consortium.

To evaluate the impact of chronic stone recurrence on an individual's quality of life using the validated Wisconsin Stone Quality of Life (WISQOL) questionnaire. We collected cross-sectional data on patients with kidney stones from 14 institutions in North America. A stone event was defined as renal colic, stone-related procedure or emergency department visit. The regression analyses using general linear models and pairwise comparison determined the impact of the number of stone events on quality of life. The median number of stone events among the 2205 patients who completed the questionnaire was 3 (IQR 1-6). The mean total score was 107.4 ± 28.7 (max 140 points). The number of lifetime stone events was an independent predictor of lower quality of life (p < 0.001), specifically, score declined significantly beyond five events. Compared with patients who experienced a single stone event, there was a 0.4, 2.5, and 6.9 point decline in the adjusted mean WISQOL score after 2-5, 6-10, or > 10 events, respectively. The cumulative number of lifetime stone events was associated with a lower quality of life when more than five stone events were occurred. These findings underscore the importance of efforts to determine the underlying metabolic etiology of urolithiasis in the recurrent stone former, and the institution of a regimen to place their stone disease in remission.

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.

Metabolic diagnoses of recurrent stone formers: temporal, geographic and gender differences.

BACKGROUND: Metabolic factors underlying the recent increase in stone prevalence over the past decades are not well understood. Herein, we evaluate temporal, geographic and gender-specific trends in metabolic risk factors in recurrent kidney stone formers. PATIENTS AND METHODS: A systematic literature review of metabolic risk factors for stone formation was conducted, inclusive of the last four decades. Studies with inadequate 24 h urine metabolic data, pediatric or those with less than 50 patients were excluded. The primary outcome was prevalence of each metabolic risk factor, compared between studies published prior to the year 2000 vs those following. Geographic and gender differences were secondary outcomes. RESULTS: Twenty-eight articles met inclusion criteria, of which 10 (n = 1578) were published prior to the year 2000 and 18 (n = 8747) were published thereafter. Comparing these groups, an increase in hyperoxaluria (29% vs 33%; p = 0.002), hypercalciuria (35 vs 36%; p = 0.446), hyperuricosuria (17% vs 22%; p < 0.0001), low urine volume (28 vs 38%; p < 0.0001) and hypocitraturia (23% vs 44%; p < 0.0001) was observed. The prevalence of hyperoxaluria, hypercalciuria, hyperuricosuria and hypocitraturia were significantly higher in males. There were also significant geographical differences, with higher prevalence of hyperoxaluria and hypocitraturia in non-Western countries and higher prevalence of hypercalciuria in Western countries. Prevalence of hyperoxaluria is increasing in the US. CONCLUSION: Prevalence of metabolic risk factors for nephrolithiasis significantly increased in recent years. These findings are hypothesis-generating and may provide valuable insight into the epidemiology, prevention and management of recurrent stone disease. Dietary modifications and innovative medical therapies are needed to decrease metabolic risk factors underlying nephrolithiasis.

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.

Ureteroscopic Doppler Ultrasonography: Mapping Renal Blood Flow from Within the Collecting System.

Introduction: Herein we provide the first report regarding in vivo porcine renal forniceal, papillary, and infundibular blood flow at the urothelial level using a novel ureteroscopic Doppler transducer. Materials and Methods: Nephroureteroscopy was performed on 11 female Yorkshire pigs to map the forniceal, papillary, and infundibular blood flow. A Doppler transducer was mounted to a 3F 120 cm catheter; the probe was passed through the working channel of a flexible ureteroscope. Blood flow was categorized from 0 (no flow) to 3 (highest flow) based on auditory intensity. At each site, a holmium laser probe was activated until it penetrated ∼1 cm into each of the examined areas; bleeding times were recorded. Results: The frequency of the Doppler transducer signal was proportional to the blood velocity within the vessel with expected increased bleeding times confirmed after puncture with a holmium laser. Analysis demonstrated that the 6 o'clock position of the fornix had significantly greater blood flow than any other forniceal location (p < 0.001). The center of each papilla had the least blood flow (p < 0.001). Blood flow was significantly higher at the infundibular level compared with the caliceal fornices at all locations (anterior, posterior, upper pole, midkidney, and lower pole) (p < 0.001). Conclusions: In a porcine model, a miniaturized Doppler ultrasound probe used during ureteroscopy demonstrated that the renal papilla had the least amount of blood flow whereas the infundibula had the highest blood flow. These data may serve to inform site selection during percutaneous nephrostomy placement.

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.