Application of novel burst wave lithotripsy and ultrasonic propulsion technology for the treatment of ureteral calculi in a bottlenose dolphin (Tursiops truncatus) and renal calculi in a harbor seal (Phoca vitulina).

Marine mammals may develop kidney stones, which can be challenging to treat. We describe burst wave lithotripsy (BWL) and ultrasonic propulsion to treat ureteral calculi in a 48-year-old female bottlenose dolphin (Tursiops truncatus) and to reduce renal stone burden in a 23-year-old male harbor seal (Phoca vitulina). BWL and ultrasonic propulsion were delivered transcutaneously in sinusoidal ultrasound bursts to fragment and reposition stones. Targeting and monitoring were performed with real-time imaging integrated within the BWL system. Four dolphin stones were obtained and fragmented ex vivo. The dolphin case received a 10-min and a 20-min BWL treatment conducted approximately 24 h apart to treat two 8-10 mm partially obstructing right mid-ureteral stones, using oral sedation alone. For the harbor seal, while under general anesthesia, retrograde ureteroscopy attempts were unsuccessful because of ureteral tortuosity, and a 30-min BWL treatment was targeted on one 10-mm right kidney stone cluster. All 4 stones fragmented completely to < 2-mm fragments in < 20 min ex vivo. In the dolphin case, the ureteral stones appeared to fragment, spread apart, and move with ultrasonic propulsion. On post-treatment day 1, the ureteral calculi fragments shifted caudally reaching the ureteral orifice on day 9. On day 10, the calculi fragments passed, and the hydroureter resolved. In the harbor seal, the stone cluster was observed to fragment and was not visible on the post-operative computed tomography scan. The seal had gross hematuria and a day of behavior indicating stone passage but overall, an uneventful recovery. BWL and ultrasonic propulsion successfully relieved ureteral stone obstruction in a geriatric dolphin and reduced renal stone burden in a geriatric harbor seal.

Development and external validation of a machine learning-based model to classify uric acid stones in patients with kidney stones of Hounsfield units < 800.

The correct diagnosis of uric acid (UA) stones has important clinical implications since patients with a high risk of perioperative morbidity may be spared surgical intervention and be offered alkalization therapy. We developed and validated a machine learning (ML)-based model to identify stones on computed tomography (CT) images and simultaneously classify UA stones from non-UA stones. An international, multicenter study was performed on 202 patients who received percutaneous nephrolithotomy for kidney stones with HU < 800. Data from 156 (77.2%) patients were used for model development, while data from 46 (22.8%) patients from a multinational institution were used for external validation. A total of 21,074 kidney and stone contour-annotated CT images were trained with the ResNet-18 Mask R-convolutional neural network algorithm. Finally, this model was concatenated with demographic and clinical data as a fully connected layer for stone classification. Our model was 100% sensitive in detecting kidney stones in each patient, and the delineation of kidney and stone contours was precise within clinically acceptable ranges. The development model provided an accuracy of 99.9%, with 100.0% sensitivity and 98.9% specificity, in distinguishing UA from non-UA stones. On external validation, the model performed with an accuracy of 97.1%, with 89.4% sensitivity and 98.6% specificity. SHAP plots revealed stone density, diabetes mellitus, and urinary pH as the most important features for classification. Our ML-based model accurately identified and delineated kidney stones and classified UA stones from non-UA stones with the highest predictive accuracy reported to date. Our model can be reliably used to select candidates for an earlier-directed alkalization therapy.

Innovations in Endourologic Stone Surgery: Contemporary Practice Patterns from a Global Survey.

Objective: The purpose of this study is to evaluate the current availability of technology for urolithiasis treatment and ureteroscopy (URS). Perioperative practice patterns, availability of ureteroscopic technologies, pre- and poststenting practices, and methods to alleviate stent-related symptoms (SRS) were assessed via a survey of members of the Endourological Society. Methods: We distributed a 43-question survey online via the Qualtrics platform to members of the Endourological Society. The survey consisted of questions pertaining to the following topics: general (6), equipment (17), preoperative URS (9), intraoperative URS (2), and postoperative URS (9). Results: A total of 191 urologists responded to the survey and 126 completed all questions of the survey (66%). Fifty-one percent (65/127) of urologists were fellowship trained and dedicated an average of 58% of their practice to stone management. In terms of procedures, most urologists performed URS most commonly (68%), followed by percutaneous nephrolithotomy (23%) and extracorporeal shockwave lithotripsy (11%). Ninety percent (120/133) of respondent urologists purchased a new ureteroscope within the last 5 years (16% single-use scopes, 53% reusable, and 31% purchased both). Fifty-three percent (70/132) of the respondents stated that they would be interested in a ureteroscope that can sense intrarenal pressure, with an additional 28% (37/132) stating they would be interested depending on the cost. Seventy-four percent (98/133) of responders purchased a new laser within the last 5 years, and 59% (57/97) changed their lasering technique due to the new laser. Urologists are performing primary ureteroscopy for obstructing stones in 70% of cases, and prefer prestenting patients for subsequent URS in 30% (on average after 21 days). Seventy-one percent (90/126) of responders insert a ureteral stent after uncomplicated URS, which is removed, on average, after 8 days in uncomplicated cases and 21 days after complicated URS. Most urologists give analgesics, alpha-blockers, and anticholinergics for SRS and <10% prescribe opioids. Conclusion: Our survey revealed urologists' eagerness for the early adoption of novel technologies and adherence to conservative practice patterns focused on patient safety.

The Fate of Residual Fragments After Percutaneous Nephrolithotomy: Results from the Endourologic Disease Group for Excellence Research Consortium.

Background: Residual fragments (RFs) after percutaneous nephrolithotomy (PCNL) have a significant impact on patients' quality of life and clinical course. There is a paucity of studies that evaluate the natural history of RFs after PCNL. The objective of this study is to compare rates of reintervention, complications, stone growth, and passage in patients with RFs >4, ≤4, and ≤2 mm after PCNL. Methods: Sites from the Endourologic Disease Group for Excellence (EDGE) research consortium examined data of PCNL patients from 2015 to 2019 with at least 1-year follow-up. RF passage, regrowth, reintervention, and complications were recorded and RFs were stratified into >4 and ≤4 mm groups, as well as >2 and ≤2 mm groups. Potential predictors for stone-related events after PCNL were determined using multivariable logistic regression analysis. It was hypothesized that larger RF thresholds would result in lower passage rates, faster regrowth, and greater clinically significant events (complications and reinterventions) than smaller RF thresholds. Results: A total of 439 patients with RFs >1 mm on CT postoperative day 1 were included in this study. For RFs >4 mm, rates of reintervention were found to be significantly higher and Kaplan-Meier curve analysis showed significantly higher rates of stone-related events. Passage and RF regrowth were not found to be significantly different compared with RFs ≤4 mm. However, RFs ≤2 mm had significantly higher rates of passage, and significantly lower rates of fragment regrowth (>1 mm), complications, and reintervention compared with RFs >2 mm. On multivariable analysis, older age, body mass index, and RF size were found to be predictive of stone-related events. Conclusions: With the largest cohort to date, this study by the EDGE research consortium further confirms that clinically insignificant residual fragment is problematic for patients after PCNL, particularly in older more obese patients with larger RFs. Our study underscores the importance of complete stone clearance post-PCNL and challenges the use of Clinically insignificant residual fragment (CIFR).

Preoperative patient optimization for endourological procedures: the current best clinical practice.

PURPOSE OF REVIEW: Despite technological advancements in endourological surgery, there is room for improvement in preoperative patient optimization strategies. This review updates recent best clinical practices that can be implemented for optimal surgical outcomes. RECENT FINDINGS: Outcome and complication predictions using novel scoring systems and techniques have shown to assist clinical decision-making and patient counseling. Innovative preoperative simulation and localization methods for percutaneous nephrolithotomy have been evaluated to minimize puncture-associated adverse events. Novel antibiotic prophylaxis strategies and further recognition of risk factors that attribute to postoperative infections have shown the potential to minimize perioperative morbidity. Accumulating data on the roles of preoperative stenting and selective oral alpha-blockers adds evidence to the current paradigm of preventive measures for ureteral injury. SUMMARY: Ample tools and technologies exist that can be utilized preoperatively to improve surgical outcomes. The combination of these innovations, along with validation in larger-scale studies, presents the cornerstone of future urolithiasis management.

Prospective randomized trial of 2 versus 12-weeks of postoperative antibiotics after percutaneous nephrolithotomy in complex patients with infection-related kidney stones.

PURPOSE: Treatment of struvite kidney stones requires complete surgical stone removal combined with antibiotic therapy to eliminate urinary tract infections and preventive measures to reduce stone recurrence. The optimal duration of antibiotic therapy is unknown. We sought to determine if 2- or 12-weeks of antibiotics post percutaneous nephrolithotomy (PNL) for infection stones resulted in better outcomes for stone recurrence and positive urine cultures. MATERIAL AND METHODS: This multi-center, prospective randomized trial evaluated patients with the clinical diagnosis of infection stones. Patients were randomized to 2- or 12-weeks of postoperative oral antibiotics (nitrofurantoin or culture-specific antibiotic) and included if residual fragments were ≤4 mm on computed tomography imaging after PNL. Imaging and urine analyses were performed at 3-, 6-, and 12-months post-procedure. RESULTS: Thirty-eight patients were enrolled and randomized to either 2-weeks (n = 20) or 12-weeks (n = 18) of antibiotic therapy post-PNL. Eleven patients were excluded due to residual fragments >4 mm, and 3 patients were lost to follow-up. The primary outcome was the stone-free rate (SFR) at 6 months post-PNL. At 3-, 6-, and 12-months follow-up, SFRs were 72.7% versus 80.0%, 70.0% versus 57.1%, 80.0% versus 57.1% (p = ns), between 2- and 12-week-groups, respectively. At 3-, 6-, and 12-months follow-up, positive urine cultures were 50.0% versus 37.5%, 50.0% versus 83.3%, and 37.5% versus 100% between 2- and 12-week groups, respectively (p = ns). CONCLUSIONS: For patients with stone removal following PNL, neither 2-weeks nor 12-weeks of postoperative oral antibiotics is superior to prevent stones and recurrent positive urine cultures.

Quality of Life of Urolithiasis Patients During the COVID-19 Pandemic: A Multi-Institutional Cross-Sectional Study.

Purpose: The coronavirus disease 2019 (COVID-19) pandemic is an unprecedented global event that has caused significant fear and anxiety across all populations. To date, there have been no studies on how major health crises have affected the stone-related quality of life (QOL) of urolithiasis patients. In this multi-institutional study, we investigated the association between fear of COVID-19 and the QOL of urolithiasis patients during the COVID-19 pandemic using the Fear of COVID-19 Scale (FCV-19S) and the Wisconsin Stone Quality of Life (WISQOL) questionnaires. Materials and Methods: Patient-reported data collection occurred between April and October 2020 during the COVID-19 pandemic where many procedures (radiologic or surgical) and visits were either delayed or cancelled. The scores generated from patient-reported responses to questionnaires were correlated and then further subanalyzed dependent on categorical responses related to procedural delays or care and were analyzed via the Student's t-test. A single factor analysis of variance (ANOVA) was performed to analyze varying QOL scores across the FCV-19S quartiles. Results: Four hundred respondents participated in this study. Overall mean total standardized FCV-19S and WISQOL scores (both transformed to min-max 0-100) were 34.3 and 70.3, respectively. A significant inverse correlation (r = -0.265, p < 0.0001) demonstrated that suggesting greater COVID-19 fear may result in lower stone-related QOL. A significant difference in fear and QOL scores was observed between the sexes, with women having more COVID-19 fear (35.8 vs 28.6, p < 0.01) and lower stone-related QOL (64.2 vs 75.2, p < 0.01). Quartile ANOVA analysis revealed significant mean difference in WISQOL scores across all FCV-19S score quartiles (p < 0.05). Conclusions: Using two validated questionnaires (FCV-19S and WISQOL) and correlating patient-reported responses, we found that greater fear for COVID-19 was associated with lower stone-related QOL in urolithiasis patients.

Evaluation of a Single-Use Flexible Cystoscope: A Multi-Institutional International Study.

Introduction: Acquisition costs and prohibitively expensive technical support for endoscope maintenance, repair, and reprocessing have deterred adoption of flexible cystoscopes by many urologists internationally. This study evaluated the performance of a novel single-use digital cystoscope that can directly connect to a laptop or computer monitor for visualization, obviating the need for a tower. Materials and Methods: The performance characteristics of flexible single-use cystoscopes (NeoScope) were prospectively evaluated vs a reusable flexible cystoscope (Olympus) in three clinical cases and two independent benchtop testing episodes in Canada. Cystoscope maneuverability, imaging, deflection, irrigation, and ease of use of instrumentation were investigated. Additional investigations were performed during clinical use in Zimbabwe (7 patients), Egypt (10 patients), and Dominica (5 patients). Results: Bench testing revealed smaller tip diameter (4.06 vs 6.09 mm) and shorter (35.4 vs 38 cm) single-use cystoscopes vs reusable cystoscopes. Deflection of the single-use scope was superior with an empty working channel (230 up/220 down) vs the reusable (195 up/95 down) but showed a more substantial decrease in deflection on placement of instruments including a grasper. Clinical use revealed satisfactory maneuverability, ease of use of instruments, deflection, and visualization. Conclusions: Benchtop testing performance of the single-use digital flexible cystoscopes was inferior compared with reusable digital cystoscopes. However, these single-use endoscopes offer adequate illumination, imaging, and maneuverability. Direct connection to any computer monitor allowed truly portable use, allowing for treatment of patients in a variety of clinical settings without the need for ancillary equipment.

Ureteral stents: the good the bad and the ugly.

PURPOSE OF REVIEW: Ureteral stents are necessary in the routine practice of an urologist. Choosing the correct stent and being aware of the options available will allow urologists to provide the best possible care for patients and value to the healthcare system. This review seeks to educate urologists regarding improvements in stent technology currently available or in development. RECENT FINDINGS: Research from around the world is underway to discover an ideal stent - one that is comfortable for patients, resists infection and encrustation and is affordable for hospital systems. Stent design alterations and stent coatings are revealing reductions in encrustation and bacterial colonization. Biodegradable stents and magnetic stents are being tested to prevent the discomfort of cystoscopic removal. Intraureteral stents are proving efficacious while eliminating an irritating coil from the bladder and the symptoms associated with it. SUMMARY: The studies highlighted in this review provide encouraging results in the pursuit of the ideal stent while opening discussion around new concepts and further areas of research.