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OBJECTIVE: To delineate the role of the urinary metabolome in the genesis of urinary stone disease (USD). METHODS: Untargeted metabolomics was utilized in comparative analyses of calcium-based stones (CBS) and spot urine samples from patients with a history of USD with or without urinary stone activity based on radiologic imaging. Stone and urine metabolomes were stratified by composition and radiographic stone-activity, respectively. Additionally, we quantified highly abundant metabolites that were present in either calcium oxalate (CaOx) or calcium phosphate (CaPhos) stones and also significantly enriched in the urine of active stone formers (SF) compared to non-active SF. These data were used to delineate either a direct involvement of urinary metabolites in lithogenesis or the passive uptake of biomolecules within the stone matrix. RESULTS: Urinary metabolomes were distinct based on radiographic stone-activity and the 2 types of CBS. Stratification by radiologic stone activity was driven by the enrichment of 14 metabolites in the urine of active SF that were also highly abundant in both CaOx and CaPhos stones, indicative of a potential involvement of these metabolites in lithogenesis. Using the combination of these 14 metabolites in total, we generated a model that correctly classified patients as either active vs non-active SF in a prospectively recruited cohort with 73% success. CONCLUSION: Collectively, our data suggest specific urinary metabolites directly contribute to the formation of urinary stones and that active SF may excrete higher levels of lithogenic metabolites than non-active patients. Future studies are needed to confirm these findings and establish the causative mechanisms associated with these metabolites.

Background: Vaginal calculi are rare and can grow quite large if they remain undetected. Vaginal stones are caused by the pooling of urine in the vagina and can be classified as either primary or secondary, depending on the absence or presence, respectively, of a nidus. Primary stones without any urethrovaginal or vesicovaginal fistula are even more uncommon but appear to be more commonly reported in incontinent women with significant physical disabilities. Case Presentation: We present a case of an ∼11 cm primary vaginal stone in a 61-year-old woman with cerebral palsy. This was removed using a nephroscope and an endoscopic ultrasonic lithotrite through the vaginal introitus with subsequent analysis demonstrating a struvite stone composition. Conclusion: This case is unique not only for the large size of the calculi but also for our less invasive approach, using a nephroscope and endoscopic ultrasonic lithotrite to fragment and remove the stone. We hope that this report will assist other providers in the timely and accurate diagnosis and treatment of future vaginal stone patients.

INTRODUCTION AND OBJECTIVE:The American Urological Association guidelines recommend peri-procedural antibiotics for percutaneous nephrolithotomy (PCNL), yet it is not clear which is superior. Given...

INTRODUCTION AND OBJECTIVE:Patients with nephrolithiasis are engaged in shared decision making to determine the most suitable treatment option. This process is inherently accompanied by decisional ...

INTRODUCTION AND OBJECTIVE:Nephrolithiasis is a cause of significant morbidity in patient populations with musculoskeletal abnormalities, spinal cord injury, and multiple sclerosis often requiring ...

Introduction: We sought to assess the accuracy of using stone volume (SV) estimated with a software algorithm as a predictor for stone passage in a trial of medical expulsive therapy (MET). Methods: We identified patients with ureteral stones discharged from the ER on MET. Patients with infection, non-ureteral stones, or needing immediate surgical intervention were excluded. For each stone, longest dimension (LD) was recorded and SV was estimated by a computed tomography (CT)-based region growing (RG) algorithm and standard ellipsoid formula (EF). Stone passage within 30 days was assessed via electronic chart and followup phone call. Results: Fifty-one patients were included for analysis (53±16.7 years, 24% female). The mean LD was 4.85±2.02 mm. The mean SV was similar by EF and RG (0.051±0.057cm3 vs. 0.049± 0.052 cm3; p=0.28). Thirty-three (65%) patients passed their stone, while 18 (35%) did not. The mean LD for passed stones vs. failed passage was 4.1±1.7 mm vs. 6.2±1.8 mm (p=0.0002); the mean EF volume was 0.028±0.035 cm3 vs. 0.093±0.066 cm3 (p=0.00007); and the mean volume by RG was 0.028±0.027cm3 vs. 0.088±0.063 cm3 (p=0.00005). Conclusions: The clinical utility of using SV estimated by software algorithm as a predictor for success of MET has not previously been examined. We demonstrate that spontaneously passed stones had a significantly smaller volume than those requiring intervention. Further prospective studies are needed to validate these findings and establish volume thresholds for probability of stone passage.

Author(s): Fedrigon, Donald; Alshara, Luay; Monga, Manoj | Abstract: INTRODUCTION:Two automated irrigation systems have been released for use during endoscopic procedures such as ureteroscopy: the Cogentix RocaFlow® (CRF) and Thermedx FluidSmart® (TFS). Accurate pressure control using automated systems may help providers maintain irrigation pressures within a safe range while also providing clear visualization. Our objective was to directly compare these systems based on their pressure accuracy, pressure-flow relationships, and fluid heating capabilities in order to help providers better utilize the temperature and pressure settings of each system. MATERIALS AND METHODS:An in vitro ureteroscopy model was used for testing, consisting of a short semirigid ureteroscope (6/7, 5F, 31cm Wolf 425612) connected to a continuous digital pressure transducer (Meriam m1550). Each system pressure output and flow-rate, via 100mL beaker filling time, was measured using multiple trials at pressure settings between 30 and 300mmHg. Output fluid temperature was monitored using a digital thermometer (Omega DP25-TH). RESULTS:The pressure output of both systems exceeded the desired setting across the entire tested range, a difference of 15.7±2.4mmHg for the TFS compared to 5.2±1.5mmHg for the CRF (p l 0.0001). Related to this finding, the TFS also had slightly higher flow rates across all trials (7±2mL/min). Temperature testing revealed a similar maximum temperature of 34.0⁰C with both systems, however, the TFS peaked after only 8 minutes and started to plateau as early as 4-5 minutes into the test, while the CRF took over 18 minutes to reach a similar peak. CONCLUSIONS:Our in vitro ureteroscopy testing found that the CRF system had better pressure accuracy than the TFS system but with noticeably slower fluid heating capabilities. Each system provided steady irrigation at safe pressures within their expected operating parameters with small differences in performance that should not limit their ability to provide steady irrigation at safe pressures.

INTRODUCTION AND OBJECTIVE:Recurrence of urinary stone disease (USD) is typically assessed through imaging, which can expose patients to unhealthy levels of radiation. We aimed to use the urinary m...

Introduction: This study sought to characterize delays and estimate resulting costs during nephrolithiasis surgery. Methods: Independent observers documented delays during ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) procedures. Fifty index cases over a period of three months was considered sufficient to observe the generalizable trends. Operating room staff, excluding the surgeons, were blinded. Time-related metrics and delays preventing case progression were recorded using a smartphone-accessible data collection instrument. Delays were categorized as: 1) missing equipment; 2) missing personnel; 3) equipment malfunction; or 4) delay due to case complexity. The first two categories were regarded as preventable and the latter two non-preventable. Results: Forty URS and 18 PCNL cases were included. There was a total of 56 delays in 35 (65%) cases. Twelve (67%) PCNLs and 23 (58%) URSs had delays (p=0.57). The mean cumulative delay per case was 3.5±3.2 minutes. Pre-start delays (n=17) were 4.5±3.5 minutes on average while intraoperative delays (n=39) were 3.1±2.9 minutes (p=0.167). Delays were evenly spread among the four categories. Thirty-one (55%) delays were preventable (mean 3.7±3.2 minutes) while 25 (45%) were non-preventable (mean 3.2±3.2 minutes) (p=0.58). This translates to $137 per case in preventable costs. Conclusions: Preventable operative delays are encountered frequently in nephrolithiasis surgery, translating to significant additional charges and costs. We demonstrate a rationale for the development of improved communication and workflow protocols to increase efficiency in endourological surgeries. Key limitations are the observational nature of the study and sample size.

Introduction: We aimed to characterize current practice patterns among endourologists on medical expulsive therapy (MET) for treatment of ureteral calculi.Methods: An online survey was administered to Endourological Society members. Respondents’ MET usage, index case management, and awareness of recent guidelines and literature were compared based on international status, practice setting, interval since training, and endourological fellowship training.Results: Of the 237 complete responses, 65% were international, 61% were academic, 66% had >10 years in practice, and 71% were endourology fellowship-trained. MET was used by 88%, with no differences between international, academic, practice length, and fellowship-trained groups. MET was used more frequently for