Evaluating Acetate as a Renoprotective Agent After Kidney Ischemia in a Porcine Model.

Objective: Renoprotection from reperfusion injury appears to be conferred by HIF-2a activation, which can be stimulated by exogenous acetate administration. The study objective was to assess whether administration of acetate in a porcine model can mitigate kidney injury related to ischemia-reperfusion after renal hilar occlusion. Methods: A porcine single-kidney model was created by performing a laparoscopic nephrectomy followed by animal recovery. After 2 days, the animals underwent laparoscopic hilar dissection. Block randomization was used to assign pigs into one of four experimental groups. One treatment block of pigs received 150 mEq of sodium acetate intravenously during 90 minutes of en bloc occlusion of the renal hilum (herein noted as "cross-clamping"). Another block received 0.75 g/kg of oral sodium acetate for 3 days prior to cross-clamping. A third block received no acetate and underwent hilar dissection without cross-clamping (negative control). The final block received no acetate and underwent cross-clamping (positive control). Serum creatinine was used to estimate renal function post-nephrectomy. Results: A total of 16 animals (4 pigs in each group) completed the study protocol. Median pig weight was 34.6 kg. One pig receiving IV acetate was excluded from the final analysis because of unrecoverable renal failure after cross-clamping. There was a significantly lower mean serum creatinine for the IV acetate group compared with the positive control group 72 hours after cross-clamping (p = 0.012). The same effect was not observed for the pigs receiving oral acetate. By day 7, renal function had recovered without significant difference in all groups. Conclusions: We observed that the administration of intravenous acetate conferred a significant renoprotective benefit in our single kidney ischemia-reperfusion porcine model 72 hours after hilar occlusion. This work is hypothesis-generating, and further work in human subjects undergoing renal hilar occlusion during partial nephrectomy is warranted.

Characterization of Demographical Histologic Diversity in Small Renal Masses With the Clear Cell Likelihood Score.

OBJECTIVE: This study aimed to develop a diagnostic model to estimate the distribution of small renal mass (SRM; ≤4 cm) histologic subtypes for patients with different demographic backgrounds and clear cell likelihood score (ccLS) designations. MATERIALS AND METHODS: A bi-institution retrospective cohort study was conducted where 347 patients (366 SRMs) underwent magnetic resonance imaging and received a ccLS before pathologic confirmation between June 2016 and November 2021. Age, sex, race, ethnicity, socioeconomic status, body mass index (BMI), and the ccLS were tabulated. The socioeconomic status for each patient was determined using the Area Deprivation Index associated with their residential address. The magnetic resonance imaging-derived ccLS assists in the characterization of SRMs by providing a likelihood of clear cell renal cell carcinoma (ccRCC). Pathological subtypes were grouped into four categories (ccRCC, papillary renal cell carcinoma, other renal cell carcinomas, or benign). Generalized estimating equations were used to estimate probabilities of the pathological subtypes across different patient subgroups. RESULTS: Race and ethnicity, BMI, and ccLS were significant predictors of histology (all P < 0.001). Obese (BMI, ≥30 kg/m 2 ) Hispanic patients with ccLS of ≥4 had the highest estimated rate of ccRCC (97.1%), and normal-weight (BMI, <25 kg/m 2 ) non-Hispanic Black patients with ccLS ≤2 had the lowest (0.2%). The highest estimated rates of papillary renal cell carcinoma were found in overweight (BMI, 25-30 kg/m 2 ) non-Hispanic Black patients with ccLS ≤2 (92.3%), and the lowest, in obese Hispanic patients with ccLS ≥4 (<0.1%). CONCLUSIONS: Patient race, ethnicity, BMI, and ccLS offer synergistic information to estimate the probabilities of SRM histologic subtypes.

Alkali Citrate Content of Common Over-the-Counter and Medical Food Supplements.

Objective: Potassium citrate effectively decreases kidney stone recurrence, but it is costly and associated with side effects. While several over-the-counter supplements and medical foods purport to provide sufficient citrate to prevent recurrent stones, corroborating data on their actual citrate content is limited. Materials and Methods: Nine common nonprescription products were purchased online. Reported citrate content was obtained from packaging, promotional materials, or ingredient labels. Using a single serving of each product, actual citrate, sodium, potassium, calcium, magnesium, and oxalate content was measured using spectrophotometry and chromatography. Total alkali citrate, cost, and amounts of each component per 10 mEq of alkali citrate were also calculated. Results: Nearly all products contained more citrate than advertised, except for Litholyte® powder, Litholyte® Coffee, and Horbäach® potassium citrate. Per serving, Moonstone® powder, LithoBalance™, and KSP tabs™ contained the most citrate (means of 63.9, 33.5, and 26.9 mEq, respectively). Moonstone and LithoBalance had the greatest discrepancy between total citrate and alkali citrate (15.7 and 11.8 mEq per serving, respectively). NOW® potassium citrate was least expensive ($0.04/10 mEq alkali citrate). KSP tabs delivered the most daily sodium (mean 158 mg/10 mEq alkali citrate, Litholyte Coffee provided the most potassium (mean of 13 mEq/10 mEq alkali citrate), and Kidney COP® provided the most calcium (mean 147 mg/10 mEq alkali citrate). Conclusion: Some common over-the-counter products contain sufficient alkali to potentially promote a citraturic response; Moonstone provides the most alkali citrate, but at a higher cost than other products. Sodium, potassium, and calcium from these products must also be considered in daily consumption.

Diet and Stone Disease in 2022.

Diet plays a central role in the development and prevention of nephrolithiasis. Although pharmacologic treatment may be required for some patients who are resistant to dietary measures alone, dietary modification may be sufficient to modulate stone risk for many patients. While there is no single specialized diet for stone prevention, several dietary principles and recommendations for stone prevention are supported by practice guidelines, including adequate fluid intake, modest calcium intake, low dietary sodium, and limited animal protein. In this review, we summarized the evidence supporting these dietary recommendations and reviewed the current literature regarding specific dietary components and comprehensive diets for stone prevention.

Identifying predictors of antispasmodic use following robotic assisted simple prostatectomy.

INTRODUCTION: Anticholinergic or ß-3 agonist use following robotic simple prostatectomy (RASP) is not well described. We describe rates of antispasmodic use following RASP and identify potential predictors of medication use. MATERIALS AND METHODS: A retrospective review of all RASP patients from 2/2016 - 1/2020 was conducted. Patients with no preoperative International Prostate Symptom Score (IPSS) were excluded. Demographics, clinical data, and postoperative medication use were collected by electronic medical record review. Multivariable logistic regression analysis using a priori variables was performed to identify independent factors associated with antispasmodic use. RESULTS: A total of 255 patients underwent RASP at a mean age of 70.0 years ± 7.3 and mean body mass index (BMI) of 28.6 kg/m2 ± 5.0. Median preoperative prostate volume was 132.3 cc ± 45.0. Rates of preoperative diabetes, obstructive sleep apnea (OSA), smoking and alcohol use were 19.6%, 6.3%, 3.1%, and 11.8% respectively; 8.6% of patients (n = 22) initiated antispasmodics at a median of 2.5 months (IQR 1.3-4.2) postoperatively. Median duration of antispasmodic use was 6.5 months (IQR 1.7-14.7). Mirabegron was most commonly prescribed (31.8%). On multivariable logistic regression analysis, OSA was independently associated with postoperative antispasmodic use (OR 8.13, 95% CI 2.02-32.67, p = 0.003); 68.8% of OSA patients were treated with continuous positive airway pressure (CPAP). Treatment was not significantly associated with postoperative antispasmodic use (p = 0.61). CONCLUSION: Patients with OSA are over 8 times more likely to require antispasmodic medications following RASP in the short term. These patients may benefit from more tailored preoperative counseling.

Artificial intelligence in endourology: emerging technology for individualized care.

PURPOSE OF REVIEW: Artificial intelligence in medicine has allowed for efficient processing of large datasets to perform cognitive tasks that facilitate clinical decision-making, and it is an emerging area of research. This review aims to highlight the most pertinent and recent research in artificial intelligence in endourology, where it has been used to optimize stone diagnosis, support decision-making regarding management, predict stone recurrence, and provide new tools for bioinformatics research within endourology. RECENT FINDINGS: Artificial neural networks (ANN) and machine learning approaches have demonstrated high accuracy in predicting stone diagnoses, stone composition, and outcomes of spontaneous stone passage, shockwave lithotripsy (SWL), or percutaneous nephrolithotomy (PCNL); some of these models outperform more traditional predictive models and existing nomograms. In addition, these approaches have been used to predict stone recurrence, quality of life scores, and provide novel methods of mining the electronic medical record for research. SUMMARY: Artificial intelligence can be used to enhance existing approaches to stone diagnosis, management, and prevention to provide a more individualized approach to endourologic care. Moreover, it may support an emerging area of bioinformatics research within endourology. However, despite high accuracy, many of the published algorithms lack external validity and require further study before they are more widely adopted.

Clinical Outcomes of Robotic Assisted Partial Nephrectomy for Pathologic T3a Renal Masses With Venous Tumor Thrombus.

OBJECTIVE: To evaluate the safety, efficacy, and early oncologic outcomes of pathologic T3a (pT3a) renal cell carcinoma with venous involvement treated with robotic partial nephrectomy (RPN), given that experience and outcomes in this group is limited. METHODS: A retrospective chart review of patients undergoing RPN from September 2009 to July 2020 was performed. Outcomes were captured from patients with pT3a disease with vein involvement. Clinical characteristics were analyzed using SPSS (IBM, Armonk, NY). Local recurrence-free survival and metastasis-free survival at 2 years were calculated from Kaplan-Meier survival curves. RESULTS: For 45 included patients, mean operative and warm ischemia times were 199.6 ± 47.3 minutes and 30.5 ± 10.5 minutes, with mean estimated blood loss of 324.9 ± 209.5 cc. Rates of transfusion, embolization, re-admission, and re-operation at 30 days were 8.9% (4/45), 2.2% (1/45), 11.1% (5/45), and 6.7% (3/45; cystoscopic stent placement), respectively. All tumors were malignant on pathology, with clear cell renal cell carcinoma being the most common (91.0%, n = 41). The positive margin rate was 6.7% (n = 3). Local recurrence occurred in 4.4% (n = 2) at a mean time of 5.2 ± 2.3 months. Four patients (8.9%) progressed to metastatic disease at a mean of 22.2 ± 23.0 months. At 2 years, local recurrence-free survival was 95.4% and metastasis-free survival was 95.3%. CONCLUSION: We present the largest known series of patients RPN for pT3a renal masses with venous tumor involvement. We found it both feasible and safe in the appropriate hands. Short term oncologic outcomes for these patients appear more favorable than historic literature suggested.

MRI Features Associated with Histology of Benign Prostatic Hyperplasia Nodules: Generation of a Predictive Model.

Background: Histologic phenotypic variation of benign prostatic hyperplasia (BPH) has been hypothesized to underlie response to medical therapy. We evaluate preoperative MRI of robot-assisted simple prostatectomy (RASP) specimens and determine imaging features associated with histologic phenotype. Materials and Methods: All patients undergoing RASP from November 2015 to November 2019 with a multiparametric MRI ≤1 year before RASP were included. Patients without identifiable BPH nodules on histologic specimens were excluded. Histology slides were obtained from whole mount adenoma specimens and corresponding MRI were reviewed and graded independently by a blinded expert in BPH histopathology (D.W.S.) and an experienced radiologist specializing in prostate imaging (D.N.C.), respectively. Each nodule was assigned a phenotypic score on a 5-point Likert scale (1 = predominantly glandular; 5 = predominantly stromal) by each reviewer. Scores were compared using the sign test and univariate analysis. Signal intensity relative to background transition zone and nodule texture were noted on T2, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging sequences. Univariate and multivariate stepwise linear regression analysis were conducted to identify MRI features associated with histology score. All analyses were performed using Statistical Analysis System (version 9.4). Results: A total of 99 prostate nodules in 29 patients were included. Median phenotypic scores by histology and MRI were comparable (2, interquartile range [IQR] 2-3 vs 2, IQR 2-4, respectively; p = 0.63). Histology scores were positively correlated with MRI scores (Pearson's correlation 0.84, p < 0.0001). Multivariate stepwise linear regression analysis showed that low apparent diffusion coefficient (ADC) signal intensity (p < 0.001) and DCE wash-in (p = 0.03) were positively associated with more stromal histology, whereas ADC standard deviation (p = 0.03), DCE wash-out (p = 0.001), and heterogeneous T2 texture (p = 0.003) were associated with more glandular histology. Conclusion: There is a strong correlation between MRI features and the histologic phenotype of BPH nodules. MRI may provide a noninvasive method to determine underlying BPH nodule histology.

Radiofrequency Ablation of Small Renal Masses.

Although the incidence of localized renal cell carcinoma has increased in recent decades due to greater use of imaging, the treatment has shifted to less invasive, nephron-sparing approaches. Radiofrequency ablation (RFA) is one accepted treatment modality for patients with small renal masses, and it has the advantage of being minimally invasive and highly nephron sparing, with the additional benefits of reduced blood loss and complication rates. We describe our experience with RFA with an accompanying instructional video outlining the procedure's key components.

Irreversible Electroporation for the Treatment of Small Renal Masses: 5-Year Outcomes.

Introduction: Irreversible electroporation (IRE) is a nonthermal ablative technology that applies high-voltage short-pulse electrical current to create cellular membrane nanopores and ultimately results in apoptosis. This is thought to overcome thermal limitations of other ablative technologies. We report 5-year oncologic outcomes of percutaneous IRE for small renal masses. Patients and Methods: A single-institution retrospective review of cT1a renal masses treated with IRE from April 2013 to December 2019 was performed. Those with <1 month follow-up were excluded. IRE was performed with the NanoKnife© System (Angiodynamics, Latham, NY). Renal mass biopsy was obtained before or during ablation in most circumstances; biopsy was excluded in some patients because of concern for IRE probe displacement. Postablation guideline-based surveillance imaging was performed. Initial treatment failure was defined as persistent tumor enhancement on first post-treatment imaging. Survival analysis was performed through the Kaplan-Meier method for effectively treated tumors (SPSS; IBM, Armonk, NY). Results: IRE was used to treat 48 tumors in 47 patients. Twenty-two per 48 tumors (45.8%) were biopsy-confirmed renal cell carcinoma (RCC). No complications ≥ Clavien Grade III occurred and 36 patients (76.6%) were discharged the same day. Initial treatment success rate was 91.7% (n = 44/48); three treatment failures were managed with salvage radiofrequency ablation and one with robotic partial nephrectomy. Median follow-up was 50.4 months (interquartile range 29.0-65.5). The 5-year local recurrence-free survival was 81.4% in biopsy-confirmed RCC patients and 81.0% in all patients. Five-year metastasis-free survival was 93.3% and 97.1%, respectively, and 5-year overall survival was 92.3% and 90.6%, respectively. Five-year cancer-specific survival was 100% for both biopsy-confirmed RCC and all patient groups. Conclusions: IRE has low morbidity, but suboptimal intermediate-term oncologic outcomes compared with conventional thermal ablation techniques for small low-complexity tumors. Use of IRE should be restricted to select cases.

Use of Pre-operative Pharmacologic Venous Thromboembolism Prophylaxis for Robotic Partial Nephrectomy.

OBJECTIVE: To determine whether a single dose of preoperative enoxaparin for venous thromboembolism (VTE) prophylaxis impacts rates of thrombotic and bleeding events after robotic partial nephrectomy (RPNx). METHODS: A retrospective cohort study of RPNx patients from 2009 to 2020 was performed. Clinical characteristics and perioperative outcomes were compared between patients receiving a single dose of preoperative enoxaparin and those who did not. The primary outcome was 30-day hemorrhagic complications (transfusion ≥2 units, embolization, or reoperation for bleeding). Secondary outcomes were 30-day VTE events. Multivariable logistic regression was performed to control for significant differences between groups and to identify predictors of hemorrhagic complications among patients. RESULTS: Among 945 RPNx procedures, 794 (84%) received preoperative enoxaparin (PPx) and 151 (16%) did not (NPPx). The PPx cohort was older (P = .004), had lower BMI (P = .03), lower ASA class (P = .049), and fewer smokers (P = .03). Warm ischemia time was longer for PPx patients (P < .001). 4.9% and 2.6% of the PPx and NPPx cohorts, respectively, developed postoperative hemorrhagic complications (P = .29). After adjustment for potential covariates, pharmacologic prophylaxis was not associated with 30-day hemorrhagic complications (P = .39). On multivariable regression, longer warm ischemia time (OR 1.05, 95% CI 1.01-1.10, P = .02) and greater tumor size (OR 1.27, 95% CI 1.03-1.56, P = .02) were predictors of hemorrhagic complications. 30-day readmissions, VTE events, and mortality were similar between groups (all P> 0.05). CONCLUSION: Similar rates of thrombotic and bleeding events occurred between patients receiving pharmacologic prophylaxis and those who did not. Single dose of preoperative enoxaparin did not significantly alter perioperative outcomes after RPNx.

Women in Leadership in Urology: The Case for Increasing Diversity and Equity.

There is a persistent male gender predominance in urology, especially with respect to female representation in leadership. We review the current status of women in urology leadership, discuss challenges women face in leadership positions, present the case for adopting inclusive practices that increase diversity and gender equity in urology leadership, and review the potential benefits of such an expansion. We discuss practical strategies to grow the role of women in urologic leadership, including increasing mentorship, modifying academic promotion criteria, and addressing implicit bias, while presenting a roadmap toward achieving equity and diversity at the highest ranks of urologic leadership.

Nephrolithiasis in Pregnancy: Treating for Two.

OBJECTIVES: To review the literature regarding the epidemiology of stone disease and develop a management algorithm based on current evidence and societal guidelines. METHODS: A structured literature review was performed to determine highest quality of evidence guiding care for pregnant patients with symptomatic nephrolithiasis. PUBMED and EMBASE databases were searched using terms "pregnancy," "nephrolithiasis," or "pregnancy" and "renal colic" alone and in combination with "stone", "kidney stone," "ultrasound," "MRI," "CT," "percutaneous nephrostomy," "ureteral stent," or "ureteroscopy." All English-language abstracts were reviewed for relevance and full-length articles were reviewed for content. Articles published prior to 1990 were excluded, and priority for inclusion was given to multi-institutional studies and larger institutional studies, reflecting the highest level of current available evidence and most contemporaneous practice patterns. RESULTS: Symptomatic nephrolithiasis affects less than 1% of pregnancies but poses unique diagnostic challenges due to the physiologic changes of pregnancy and risks of ionizing radiation exposure to the fetus. Ultrasound remains the imaging modality of choice. Most patients may be managed non-operatively, but drainage with percutaneous nephrostomy or ureteral stent may be performed if warranted. Growing evidence also supports the safety and efficacy of definitive stone treatment. CONCLUSIONS: Though rare, symptomatic nephrolithiasis poses significant clinical challenges due to the need to minimize risk for both mother and fetus with diagnostic and therapeutic interventions. A multi-disciplinary approach is paramount, as is shared decision making with the patient at each step of care.

National Imaging Trends in Nephrolithiasis-Does Renal Ultrasound in the Emergency Department Pave the Way for Computerized Tomography?

INTRODUCTION: Concern regarding radiation exposure has led to increased interest in the use of ultrasound for the initial imaging of suspected renal colic in the emergency department. It is unknown whether such an approach simply defers computerized tomography to outpatient followup. We analyzed national imaging patterns to explore this relationship. METHODS: Using the MarketScan® insurance claims database we reviewed adult patients newly diagnosed with nephrolithiasis in U.S. emergency departments between 2007 and 2015. Patients were excluded if they had been diagnosed with or undergone treatment for nephrolithiasis in the preceding 180 days. RESULTS: From 2007 to 2015, 830,785 emergency department nephrolithiasis encounters met inclusion criteria. The ultrasound-only rate increased from 2.7% to 6.9%, while the computerized tomography-only rate remained stable at 85.8%. A history of computerized tomography in the 30 days before emergency department presentation increased the rate of ultrasound-only imaging from 4.6% to 8.9%. The mean cumulative computerized tomography scans from the emergency department visit to 90 days after was significantly lower in those imaged with emergency department ultrasound (0.82±0.77) compared to those imaged with emergency department computerized tomography (1.2±0.51, p <0.001). CONCLUSIONS: Patients who undergo ultrasonography in the emergency department for evaluation of renal colic undergo fewer cumulative computerized tomography scans in the 90 days following their visit than do patients initially imaged with computerized tomography. Ultrasound use for the evaluation of renal colic has increased while computerized tomography rates have remained stable.

In-Office Ultrasound Facilitates Timely Clinical Care at a Multidisciplinary Kidney Stone Center.

INTRODUCTION: A considerable publication record exists comparing sensitivity and specificity of radiological ultrasound (including point of care ultrasound) to computerized tomography for stone disease. However, the practical application of in-office ultrasound to support the growing number of kidney stone centers around the world represents a nuanced topic that is ripe for study and discussion. METHODS: We provide a descriptive analysis of how in-office ultrasound is being used as an adjunct to clinical care based on our experience during 50 days in clinic at an institutionally affiliated, multidisciplinary kidney stone center. Clinic subjects gave consent and underwent ultrasound as part of research studies. Ultrasonograms were shared with and verified by the treating physician before the patient was discharged from care. We counted the number of times research imaging altered the care plan. RESULTS: Of the 60 patients enrolled the clinician used the information obtained from the studies in 20 (33%) to determine the course of clinical care that resulted in a change in treatment or process. CONCLUSIONS: Ultrasound has the potential to be a cost-effective and valuable tool that can provide more efficient workflow within a kidney stone center or urology clinic.

Perspectives on Priapism Education in Emergency Medicine.

INTRODUCTION: Priapism is a urologic emergency managed by both emergency medicine (EM) providers and urologists. Attitudes regarding its management and understanding of education of non-urology trainees in this area are poorly defined. AIM: The aim of this study was to describe attitudes toward priapism management among multiple stakeholders and define the current state of priapism education among EM residency programs. METHODS: Surveys were developed and distributed online to EM residency leadership, EM residents, and urology providers. Each solicited attitudes and preferences regarding independent priapism management by EM providers. EM residents were further queried about their educational and clinical experiences in priapism management, and EM residency leadership were surveyed about their educational curricula. Responses among all 3 groups were compared using Fisher's exact tests. MAIN OUTCOME MEASURE: Quantitative and descriptive responses were solicited regarding EM providers' management of acute ischemic priapism and current priapism curricula for EM residents. RESULTS: 91 EM residency program directors and assistant program directors (31.6% of programs), 227 EM residents (14.7% of programs), and 94 urologists (6.3% of survey recipients) responded. All geographic regions and all years of EM training were represented. Over 90% of all surveyed groups felt that EM providers should independently manage priapism in practice. 17% of senior EM residents felt "not at all" confident in managing priapism; and 25.5% had never primarily managed this entity in training. 81% of programs had a formalized priapism curriculum, of which 19% included treatment simulation. However, 36% of residents felt that current curricula were insufficient. CLINICAL IMPLICATIONS: Widespread approval from both EM providers and urologists support EM-based management for uncomplicated cases of acute ischemic priapism. Current educational curricula for EM trainees may not be sufficient to prepare them to manage this entity in practice. STRENGTHS & LIMITATIONS: This is the first study to examine provider attitudes toward EM-based management of priapism and assess the current state of education in this area with input from all key stakeholders. This survey was limited in its scope and the response rate was lower than desired. CONCLUSION: Urologists support independent priapism management by EM providers, but an educational gap remains for EM trainees who do not feel adequately trained to manage this independently in practice. Dai JC, Franzen DS, Lendvay TS, et al. Perspectives on Priapism Education in Emergency Medicine. J Sex Med 2020;17:159-162.

Strategies for Attracting Women and Underrepresented Minorities in Urology.

PURPOSE OF REVIEW: This article summarizes the current state of underrepresented minorities (URM) and women within urology. Specific strategies to promote the recruitment and retention of URM and women within urology are discussed. RECENT FINDINGS: Minorities and women remain underrepresented within urology, a disparity that has roots as early as medical school and persists throughout residency and practice. This is likely due to implicit and explicit bias, lack of role models, and persistent disparities in compensation and promotion. Strategies to improve recruitment and retention of these individuals should focus on increasing early exposure to urology, opportunities for mentorship, and support in professional development. Creation of a supportive institutional culture, consideration of alternative career advancement paths, and intentional diversity-focused recruitment efforts are also critical. Successful recruitment and retention of URM and women in urology requires specific, directed efforts to increase opportunities for exposure, mentorship, and career promotion at a programmatic, institutional, and national level.

National Trends in CT Utilization and Estimated CT-related Radiation Exposure in the Evaluation and Follow-up of Stone Patients.

OBJECTIVE: To describe trends in computed tomography (CT) use and estimate the radiation exposure among stone formers using a national insurance claims database. METHODS: Within MarketScan, adult stone patients from 2007 to 2013 were identified using International Classification of Diseases-Revision 9, International Classification of Diseases-Revision 10, and Current Procedural Terminology codes. Patients were classified as "active" (≥2 diagnosis codes for nephrolithiasis, or receipt of stone surgery) or "inactive" (1 stone diagnosis) and compared to age- and gender-matched controls. CT utilization was tracked over 3 years for each group. Annual CT-related radiation exposure was estimated using previously published dose values and compared using Kruskal-Wallis and χ2 tests. Demographic factors associated with greater CT exposure were identified on multivariate logistic regression. RESULTS: Of active stone patients, 112,140 underwent surgery and 215,376 were managed nonoperatively. There were 175,228 inactive stone patients and 502,744 controls. On average, active stone patients received nearly 10 times as many CTs as controls at 3 years (P <.001), and more acute imaging (P <.001). About 25% and 15% of operative and nonoperative patients, respectively, received ≥3 CTs in 3 years. This was associated with female gender. For nonoperative patients, this was also associated with age, residence in the North-Central or South regions, and inversely associated with metropolitan residence (all P <.01). Over 10% of active stone patients are estimated to receive >20 mSv in the first year alone. CONCLUSION: CT use and nonsurgical radiation exposure for active stone patients is significant. Over 10% are estimated to exceed occupational limits in the first year. Judicious CT imaging and low-dose protocols are critical for stone patients.

Quantitative Assessment of Effectiveness of Ultrasonic Propulsion of Kidney Stones.

Purpose: Ultrasonic propulsion is an investigative modality to noninvasively image and reposition urinary stones. Our goals were to test safety and effectiveness of new acoustic exposure conditions from a new transducer, and to use simultaneous ureteroscopic and ultrasonic observation to quantify stone repositioning. Materials and Methods: During operation, ultrasonic propulsion was applied transcutaneously, whereas stone targets were visualized ureteroscopically. Exposures were 350 kHz frequency, ≤200 W/cm2 focal intensity, and ≤3-second bursts per push. Ureteroscope and ultrasound (US) videos were recorded. Video clips with and without stone motion were randomized and scored for motion ≥3 mm by independent reviewers blinded to the exposures. Subjects were followed with telephone calls, imaging, and chart review for adverse events. Results: The investigative treatment was used in 18 subjects and 19 kidneys. A total of 62 stone targets were treated ranging in size from a collection of "dust" to 15 mm. Subjects received an average of 17 ± 14 propulsion bursts (per kidney) for a total average exposure time of 40 ± 40 seconds. Independent reviewers scored at least one stone movement ≥3 mm in 18 of 19 kidneys (95%) from the ureteroscope videos and in 15 of 19 kidneys (79%) from the US videos. This difference was probably because of motion out of the US imaging plane. Treatment repositioned stones in two cases that would have otherwise required basket repositioning. No serious adverse events were observed with the device or procedure. Conclusions: Ultrasonic propulsion was shown to be safe, and it effectively repositioned stones in 95% of kidneys despite positioning and access restrictions caused by working in an operating room on anesthetized subjects.

Innovations in Ultrasound Technology in the Management of Kidney Stones.

This article reviews new advances in ultrasound technology for urinary stone disease. Recent research to facilitate the diagnosis of nephrolithiasis, including use of the twinkling signal and posterior acoustic shadow, have helped to improve the use of ultrasound examination for detecting and sizing renal stones. New therapeutic applications of ultrasound technology for stone disease have emerged, including ultrasonic propulsion to reposition stones and burst wave lithotripsy to fragment stones noninvasively. The safety, efficacy, and evolution of these technologies in phantom, animal, and human studies are reviewed herein. New developments in these rapidly growing areas of ultrasound research are also highlighted.