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Objective: Our goals were to validate stone comminution with an investigational burst wave lithotripsy (BWL) system in patient-relevant conditions and to evaluate the use of ultrasonic propulsion to move a stone or fragments to aid in observing the treatment endpoint. Materials and Methods: The Propulse-1 system, used in clinical trials of ultrasonic propulsion and upgraded for BWL trials, was used to fragment 46 human stones (5–7 mm) in either a 15-mm or 4-mm diameter calix phantom in water at either 50% or 75% dissolved oxygen level. Stones were paired by size and composition, and exposed to 20-cycle, 390-kHz bursts at 6-MPa peak negative pressure (PNP) and 13-Hz pulse repetition frequency (PRF) or 7-MPa PNP and 6.5-Hz PRF. Stones were exposed in 5-minute increments and sieved, with fragments >2 mm weighed and returned for additional treatment. Effectiveness for pairs of conditions was compared statistically within a framework of survival data analysis for interval censored data. Three reviewers blinded to the experimental conditions scored ultrasound imaging videos for degree of fragmentation based on stone response to ultrasonic propulsion. Results: Overall, 89% (41/46) and 70% (32/46) of human stones were fully comminuted within 30 and 10 minutes, respectively. Fragments remained after 30 minutes in 4% (1/28) of calcium oxalate monohydrate stones and 40% (4/10) of brushite stones. There were no statistically significant differences in comminution time between the two output settings (p = 0.44), the two dissolved oxygen levels (p = 0.65), or the two calyx diameters (p = 0.58). Inter-rater correlation on endpoint detection was substantial (Fleiss' kappa = 0.638, p

INTRODUCTION AND OBJECTIVE:The purpose of the study is to test whether removing small, asymptomatic stones from the kidneys of patients being treated for kidney or ureteral stones will reduce recur...

INTRODUCTION AND OBJECTIVE:The feasibility of ultrasonic propulsion and burst wave lithotripsy (BWL) to noninvasively reposition distal ureteral stones to facilitate passage and relieve pain was te...

INTRODUCTION AND OBJECTIVE:We report stone comminution in the first human subjects by burst wave lithotripsy (BWL), which is the transcutaneous application of focused, cyclic ultrasound pulses.METH...

INTRODUCTION AND OBJECTIVE:In March 2020, the COVID-19 pandemic affected rates of elective patient care; hence graduate medical education was severely impacted. The Urology Collaborative Online Vid...

INTRODUCTION AND OBJECTIVE: Didactic lectures are a commonly used educational tool during urology residency training. Although all residency programs are expected to provide didactic content for their residents, the format of these sessions vary by presenter and institution. Currently, it is not clear which didactic format provides the most educational benefit. Herein, we aimed to evaluate which attributes of didactic education are most preferred by contemporary urology trainees. METHODS: Urology trainees during the 2020-21 academic year were invited to complete an online choice-based conjoint analysis exercise assessing four attributes associated with didactic education: method of delivery, presentation style, presenter credentials, and curriculum design. The survey was distributed via social media platforms and the Urology Collaborative Online Video Didactics (COViD) website. A sensitivity analysis (Sawtooth Software, Inc. Utah USA) was used to determine relative importance of each attribute and predict trainee preferences in didactic format (online/virtual vs. inperson). RESULTS: Of the 431 trainees who received the survey, 73 (17%) completed the conjoint analysis exercise, including 60 participants from the United States and 11 from international training programs. Nearly all trainees (72/73) preferred at least 1 hour of dedicated didactic education per week, with 67% responding that 2-3 hours of didactic time per week is ideal. Overall, the majority of respondents preferred online/virtual presentations (77%, 95% CI 70-84%) compared to in-person presentations. Respondents placed the most importance on presenter credentials, preferring national experts from visiting institutions to faculty members from their local institutions. Conjoint analysis revealed a preference trend toward an online didactic curriculum by increasing PGY year, with senior residents and fellows showing stronger preferences for online didactics compared to more junior trainees (Figure 1). CONCLUSIONS: Contemporary urology trainees prefer didactic education that is available in an online/virtual format, standardized across training institutions, and organized and presented by national experts in the field. This data should inform national educational efforts to standardize didactic learning for urology trainees. (Figure Presented).

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.

INTRODUCTION AND OBJECTIVE:Meaningful and timely resident feedback is an essential component for developing resident competency. With a department of more than two dozen clinical faculty, 5 trainin...

INTRODUCTION AND OBJECTIVE:Clinical errors almost resulting in adverse patient events, also known as near misses, are common and can serve as warning signs of unsafe practices. They are routinely u...

INTRODUCTION AND OBJECTIVE:Our goals were to validate stone comminution with an investigative clinical burst wave lithotripsy (BWL) system and to evaluate the use of ultrasonic propulsion to move t...

INTRODUCTION AND OBJECTIVE:Artificial stone models are used in lithotripsy research. While the value of models is their availability and reproducibility in shape and characteristics, a challenge re...

OBJECTIVE To determine if obtaining a 24-hour urine collection (24HU) in stone formers is associated with decreased recurrent stone episodes. METHODS Using the MarketScan database, adults 17-62 years old with nephrolithiasis were identified between 2007 and 2017 with a minimum of 3-year follow up. High-risk stone formers, those undergoing stone surgery, and those with history of recurrent stones were identified. The exposure was a 24HU within 6 months of primary diagnosis. The outcome was recurrent stone episodes—defined by stone-related emergency room visits, hospitalizations, or stone surgery 90 days to 3 years after diagnosis. Logistic regression was used to estimate recurrence risk by 24HU exposure for the overall cohort and sub-cohorts limited to known recurrent stone formers, high-risk subjects, and those having stone surgery. RESULTS Of 434,055 subjects analyzed, 30,153 (6.9%) had a 24HU. An annual decline in 24HU utilization was seen (7.5%-5.8%). Regional variation in usage rate was also observed. On multivariate analysis, completing a 24HU was not associated with risk of recurrence in any of the following cohorts: recurrent stone formers (OR 0.98, 95% CI 0.9-1.07), both high risk and recurrent stone formers (OR 0.95 [0.8-1.13]), those undergoing surgery (OR 1.02 [0.97-1.07]); a positive association with 24HU and recurrence was seen in those labeled high-risk (OR 1.08 [1.01-1.16]) and in all-comers (OR 1.15 [1.12-1.19]). CONCLUSION The 24HU was not associated with decreased recurrence rates in the overall population nor in higher risk sub-cohorts.

It is hypothesized a 2.6-mm stone was too small to break with 390-kHz burst wave lithotripsy (BWL). In clinical trial NCT03873259, a 2.6-mm stone failed to break after 10 min of 390-kHz BWL and was removed intact. Ex vivo, the stone failed to break after another 30 min at 390 kHz but broke into four pieces in 4 min at 650 kHz. A linear elastic model was used to calculate the stress created inside stones of different sizes, shapes, and compositions by shock wave lithotripsy (SWL) and different BWL frequencies. The model predicts above a threshold frequency proportionate to wave speed over stone length, the maximum principal stress inside a stone increases to more than five times the acoustic pressure applied. Thus, smaller stones may fragment at higher but not lower frequency. Amplification remains with irregularly shaped stones but is not seen with an SWL waveform. Ex vivo, stones smaller than 3 mm broke fastest at 830 kHz while larger stones broke fastest with 390 kHz followed by 830 kHz. For small stones and fragments, increasing BWL frequency many produce, amplified stress in the stone causing the stone to break to smaller fragments to pass. [Work supported by NIH-P01-DK04331 and NIH-K01-DK104854.]

Background The application of crowdsourcing to surgical education is a recent phenomenon and adds to increasing demands on surgical residency training. The efficacy, range, and scope of this technology for surgical education remains incompletely defined. Objective A systematic review was performed using the PubMed database of English-language literature on crowdsourced evaluation of surgical technical tasks up to April 2017. Methods Articles were reviewed, abstracted, and analyzed, and were assessed for quality using the Medical Education Research Study Quality Instrument (MERSQI). Articles were evaluated with eligibility criteria for inclusion. Study information, performance task, subjects, evaluative standards, crowdworker compensation, time to response, and correlation between crowd and expert or standard evaluations were abstracted and analyzed. Results Of 63 unique publications initially identified, 13 with MERSQI scores ranging from 10 to 13 (mean = 11.85) were included in the review. Overall, crowd and expert evaluations demonstrated good to excellent correlation across a wide range of tasks (Pearson's coefficient 0.59–0.95, Cronbach's alpha 0.32–0.92), with 1 exception being a study involving medical students. There was a wide range of reported interrater variability among experts. Nonexpert evaluation was consistently quicker than expert evaluation (ranging from 4.8 to 150.9 times faster), and was more cost effective. Conclusions Crowdsourced feedback appears to be comparable to expert feedback and is cost effective and efficient. Further work is needed to increase consistency in expert evaluations, to explore sources of discrepant assessments between surgeons and crowds, and to identify optimal populations and novel applications for this technology.

Greater visual contrast between calculi and tissue would improve ultrasound (US) imaging of urolithiasis and potentially expand clinical use. The color Doppler twinkling artifact has been suggested to provide enhanced contrast of stones compared with brightness mode (B-mode) imaging, but results are variable. This work provides the first quantitative measure of stone contrast in humans for B-mode and color Doppler mode, forming the basis to improve US for the detection of stones.Using a research ultrasound system, B-mode imaging was tuned for detecting stones by applying a single transmit angle and reduced signal compression. Stone twinkling with color Doppler was tuned by using low-frequency transmit pulses, longer pulse durations, and a high-pulse repetition frequency. Data were captured from 32 subjects, with 297 B-mode and Doppler images analyzed from 21 subjects exhibiting twinkling signals. The signal to clutter ratio (i.e., stone to background tissue) (SCR) was used to compare the contrast of a stone on B-mode with color Doppler, and the contrast between stone twinkling and blood-flow signals within the kidney.The stone was the brightest object in only 54% of B-mode images and 100% of Doppler images containing stone twinkling. On average, stones were isoechoic with the tissue clutter on B-mode (SCR = 0 dB). Stone twinkling averaged 37 times greater contrast than B-mode (16 dB, p 0.0001) and 3.5 times greater contrast than blood-flow signals (5.5 dB, p = 0.088).This study provides the first quantitative measure of US stone to tissue contrast in humans. Stone twinkling contrast is significantly greater than the contrast of a stone on B-mode. There was also a trend of stone twinkling signals having greater contrast than blood-flow signals in the kidney. Dedicated optimization of B-mode and color Doppler stone imaging could improve US detection of stones.

Background With increasing public awareness of and greater coverage for gender-confirming surgery by insurers, more transgender patients are likely to seek surgical transition. The degree to which plastic surgery and urology trainees are prepared to treat transgender patients is unknown. Objective We assessed the number of hours dedicated to transgender-oriented education in plastic surgery and urology residencies, and the impact of program director (PD) attitudes on provision of such training. Methods PDs of all Accreditation Council for Graduate Medical Education–accredited plastic surgery (91) and urology (128) programs were invited to participate. Surveys were completed between November 2015 and March 2016; responses were collected and analyzed. Results In total, 154 PDs (70%) responded, and 145 (66%) completed the survey, reporting a yearly median of 1 didactic hour and 2 clinical hours of transgender content. Eighteen percent (13 of 71) of plastic surgery and 42% (31 of 74) of urology programs offered no didactic education, and 34% (24 of 71) and 30% (22 of 74) provided no clinical exposure, respectively. PDs of programs located in the southern United States were more likely to rate transgender education as unimportant or neutral (23 of 37 [62%] versus 39 of 105 [37%]; P = .017). PDs who rated transgender education as important provided more hours of didactic content (median, 1 versus 0.75 hours; P = .001) and clinical content (median, 5 versus 0 hours; P Conclusions A substantial proportion of plastic surgery and urology residencies provide no education on transgender health topics, and those that do, provide variable content. PD attitudes toward transgender-specific education appear to influence provision of training.

INTRODUCTION AND OBJECTIVES:Burst wave lithotripsy (BWL) is a preclinical technology that uses focused ultrasound bursts to fragment stones. Unlike shock wave lithotripsy, stones fracture into spec...

INTRODUCTION AND OBJECTIVES:The American Urologic Association Guidelines recommends obtaining a 24-hour urine (24HU) in recurrent stone formers, patients high-risk for stone recurrence, and interested first-time stone formers. However, the advantage of selective therapy based on 24HU results over empiric treatment is unclear. We aimed to determine if obtaining a 24HU in high risk stone formers is associated with decreased recurrent stone episodes in a contemporary cohort exemplifying real-world clinical practice.METHODS:We used the MarketScan database to identify insured, employed subjects, 18 to 64 years old with a primary diagnosis of kidney and/or ureteral stones based on ICD-9 and ICD-10 diagnosis codes from 2008 to 2014. Subjects at high risk for infectious stones or with cystinuria were excluded. High risk stone formers (based on AUA guidelines), those undergoing stone surgery, and those with previous stone diagnoses one year prior to the date of inclusion were characterized with CPT and ICD codes, ...

INTRODUCTION AND OBJECTIVES:Burst wave lithotripsy (BWL) is a preclinical method developed to noninvasively fragment kidney stones with low-amplitude focused bursts of ultrasound. In this study, we...

Rationale & Objective Although maintaining high fluid intake is an effective low-risk intervention for the secondary prevention of urinary stone disease, many patients with stones do not increase their fluid intake. Study Design We describe the rationale and design of the Prevention of Urinary Stones With Hydration (PUSH) Study, a randomized trial of a multicomponent behavioral intervention program to increase and maintain high fluid intake. Participants are randomly assigned (1:1 ratio) to the intervention or control arm. The target sample size is 1,642 participants. Setting & Participants Adults and adolescents 12 years and older with a symptomatic stone history and low urine volume are eligible. Exclusion criteria include infectious or monogenic causes of urinary stone disease and comorbid conditions precluding increased fluid intake. Interventions All participants receive usual care and a smart water bottle with smartphone application. Participants in the intervention arm receive a fluid intake prescription and an adaptive program of behavioral interventions, including financial incentives, structured problem solving, and other automated adherence interventions. Control arm participants receive guideline-based fluid instructions. Outcomes The primary end point is recurrence of a symptomatic stone during 24 months of follow-up. Secondary end points include changes in radiographic stone burden, 24-hour urine output, and urinary symptoms. Limitations Periodic 24-hour urine volumes may not fully reflect daily behavior. Conclusions With its highly novel features, the PUSH Study will address an important health care problem. Funding National Institute of Diabetes and Digestive and Kidney Diseases. Trial Registration Registered at ClinicalTrials.gov with study number NCT03244189 .

Ultrasonic propulsion is a new technology using focused ultrasound energy applied transcutaneously to reposition kidney stones. We report what are to our knowledge the findings from the first human investigational trial of ultrasonic propulsion toward the applications of expelling small stones and dislodging large obstructing stones.Subjects underwent ultrasonic propulsion while awake without sedation in clinic, or during ureteroscopy while anesthetized. Ultrasound and a pain questionnaire were completed before, during and after propulsion. The primary outcome was to reposition stones in the collecting system. Secondary outcomes included safety, controllable movement of stones and movement of stones less than 5 mm and 5 mm or greater. Adverse events were assessed weekly for 3 weeks.Kidney stones were repositioned in 14 of 15 subjects. Of the 43 targets 28 (65%) showed some level of movement while 13 (30%) were displaced greater than 3 mm to a new location. Discomfort during the procedure was rare, mild, brief and self-limited. Stones were moved in a controlled direction with more than 30 fragments passed by 4 of the 6 subjects who had previously undergone a lithotripsy procedure. The largest stone moved was 10 mm. One patient experienced pain relief during treatment of a large stone at the ureteropelvic junction. In 4 subjects a seemingly large stone was determined to be a cluster of small passable stones after they were moved.Ultrasonic propulsion was able to successfully reposition stones and facilitate the passage of fragments in humans. No adverse events were associated with the investigational procedure.

INTRODUCTION AND OBJECTIVE:American Urological Association (AUA) guidelines recommend low dose (

INTRODUCTION AND OBJECTIVE:Burst wave lithotripsy (BWL) is a new method to noninvasively fragment stones in the urinary tract with focused ultrasound. This is a case report on the first two human s...

Our goal is an office-based, handheld ultrasound system to target, detach, break, and/or expel stones and stone fragments from the urinary collecting system to facilitate natural clearance. Repositioning of stones in humans (maximum 2.5 MPa, and 3-second bursts) and breaking of stones in a porcine model (maximum 50 cycles, 20 Hz repetition, 30 minutes, and 7 MPa peak negative pressure) have been demonstrated using the same 350-kHz probe. Repositioning in humans was conducted during surgery with a ureteroscope in the kidney to film stone movement. Independent video review confirmed stone movements (≥ 3 mm) in 15 of 16 kidneys (94%). No serious or unanticipated adverse events were reported. Experiments of burst wave lithotripsy (BWL) effectiveness on breaking human stones implanted in the porcine bladder and kidney demonstrated fragmentation of 8 of 8 stones on post mortem dissection. A 1-week survival study with the BWL exposures and 10 specific-pathogen-free pigs, showed all findings were within normal limits on clinical pathology, hematology, and urinalysis. These results demonstrate that repositioning of stones with ultrasonic propulsion and breaking of stones with BWL are safe and effective.

Non-invasive kidney stone treatments such as shock wave lithotripsy (SWL) and burst wave lithotripsy (BWL) rely on the delivery of pressure waves through tissue to the stone. In both SWL and BWL, the potential to hinder comminution by exciting cavitation proximal to the stone has been reported. To elucidate how different stones alter prefocal cavitation in BWL, different natural and synthetic stones were treated in vitro using a therapy transducer operating at 350 kHz (peak negative pressure 7 MPa, pulse length 20 cycles, pulse repetition frequency 10 Hz). Stones were held in a confined volume of water designed to mimic the geometry of a kidney calyx, with the water filtered and degassed to maintain conditions for which the cavitation threshold (in the absence of a stone) matches that from in vivo observations. Stone targeting and cavitation monitoring were performed via ultrasound imaging using a diagnostic probe aligned coaxially with the therapy transducer. Quantitative differences in the extent and location of cavitation activity were observed for different stone types—e.g., stones (natural and synthetic) that are known to be porous produced larger prefocal cavitation clouds. Ongoing work will focus on correlation of such cavitation metrics with stone fragmentation.

Shock wave lithotripsy (SWL), ureteroscopy, and percutaneous nephrolithotomy all have an important role in the management of patients with kidney and ureteral stones. SWL remains popular with providers and is preferred by many patients. This review describes the pros and cons of these procedures, the appropriate conditions for SWL, indicators for successful outcomes for SWL, effective SWL technique, and adverse effects. Also reported are the imaging and therapeutic research to improve SWL effectiveness. This may expand the use of SWL by addressing some of SWL’s current limitations and lead to improved patient outcomes. This review contains 5 highly rendered figures, 3 tables, and 85 references Key words: burst wave lithotripsy, cavitation, comminution, coupling, endourology, kidney injury, kidney stones, minimally invasive, nephrolithiasis, shock wave lithotripsy, stone-free rate, ultrasonic propulsion, urolithiasis

Focused ultrasonic propulsion is a new noninvasive technique designed to move kidney stones and stone fragments out of the urinary collecting system. However, to our knowledge the extent of tissue injury associated with this technique is not known. We quantitated the amount of tissue injury produced by focused ultrasonic propulsion under simulated clinical treatment conditions and under conditions of higher power or continuous duty cycles. We compared those results to extracorporeal shock wave lithotripsy injury.A human calcium oxalate monohydrate stone and/or nickel beads were implanted by ureteroscopy in 3 kidneys of live pigs weighing 45 to 55 kg and repositioned using focused ultrasonic propulsion. Additional pig kidneys were exposed to extracorporeal shock wave lithotripsy level pulse intensity or continuous ultrasound exposure 10 minutes in duration using an ultrasound probe transcutaneously or on the kidney. These kidneys were compared to 6 treated with an unmodified Dornier HM3 lithotripter (Dornier Medical Systems, Kennesaw, Georgia) using 2,400 shocks at 120 shock waves per minute and 24 kV. Histological analysis was performed to assess the volume of hemorrhagic tissue injury created by each technique according to the percent of functional renal volume.Extracorporeal shock wave lithotripsy produced a mean ± SEM lesion of 1.56% ± 0.45% of functional renal volume. Ultrasonic propulsion produced no detectable lesion with simulated clinical treatment. A lesion of 0.46% ± 0.37% or 1.15% ± 0.49% of functional renal volume was produced when excessive treatment parameters were used with the ultrasound probe placed on the kidney.Focused ultrasonic propulsion produced no detectable morphological injury to the renal parenchyma when using clinical treatment parameters but produced injury comparable in size to that of extracorporeal shock wave lithotripsy when using excessive treatment parameters.

with lower SW doses targeted to a specific renal calyx, which would be more applicable to patient treatment. A swine model of metabolic syndrome (MetS) was employed as such pigs produce acidic urine, which may better allow the detection of an acidification defect. METHODS: Adult female Ossabaw pigs were fed a hypercaloric diet to induce obesity and MetS. An upper pole renal calyx was treated with 2000 SWs (n1⁄45) or 4000 SWs (n1⁄47) using the HM3 lithotripter (24 kV, 120 SWs/min). Sixty days after SWL, the pigs were anesthetized for assessment of bilateral renal function including bulk (entire renal unit) urine pH. The urine pH value from the SW-treated (T) kidney of pigs was compared to their corresponding contralateral, nontreated (CNT) kidney urine pH value to assess for an acidification defect. Adult female farm pigs fed a normal chow diet were included in the study to confirm that both kidneys ordinarily produce urine of similar pH (n1⁄410). RESULTS: Both kidneys from untreated farm pigs produced urine with similar pH. MetS pig kidneys produced acidic urine with 2000 SW-treated kidneys producing less acidic urine than CNT kidneys, whereas 4000 SW-treated kidneys had a similar urine pH to CNT kidneys. CONCLUSIONS: Measuring the bulk urine pH difference between SW lithotripsy-treated and nontreated kidneys does not appear to be a reliable method to detect a focal urine acidification defect within the SW-treated kidney.

Background: Hyperparathyroidism is associated with hypercalciuria and nephrolithiasis. Urine calcium excretion decreases after parathyroidectomy, but whether there is a differential decrease between stone and nonstone formers remains controversial. We evaluated differences between stone formers and non-stone formers in serum and urinary parameters before and after parathyroidectomy. Methods: 90 patients, 40 with and 50 without a history of nephrolithiasis underwent parathyroidectomy for hyperparathyroidism; 24-hour urine samples were collected before and after parathyroidectomy. Overall, 92% of patients provided samples before parathyroidectomy and 63% after parathyroidectomy. Preoperative, postoperative and changes in urinary parameters were evaluated. Results: Preoperative hypercalciuria was present in ∼65% in both groups (P =.68). Parathyroidectomy decreased serum levels of calcium, parathyroid hormone, and urinary calcium, but there were no differences between stone formers and nonstone formers. Stone formers were 12-fold (P =.001) more likely to resolve an increase in supersaturation of calcium oxalate (SSCaOx), and after adjustment for age, sex, and BMI were 46-fold (P =.002) more likely to resolve an increase in SSCaOx. After parathyroidectomy, the rate of stone recurrence was 23% and male sex (aOR 20, P =.032) and increasing BMI (aOR 1.23, P =.038) were the only independent predictors of stone recurrence after adjusting for age. No other factor evaluated preoperatively, postoperatively, or the change after parathyroidectomy differentiated stone and nonstone formers or predicted stone recurrence. Conclusion: Metabolic evaluation did not differentiate stone formers from nonstone formers reliably. Stone formers were more likely to resolve an increase in SSCaOx after parathyroidectomy. Male sex and increasing BMI were independently associated with stone recurrence after parathyroidectomy. © 2012 Mosby, Inc. All rights reserved.

PurposeSerum calcium and parathyroid hormone levels are the primary means of evaluating patients for hyperparathyroidism. Whether there are differences in urinary parameters between stone formers with and those without hyperparathyroidism is controversial. In this study we identify urinary parameters that predict primary hyperparathyroidism.Materials and methodsFrom 2001 to 2010 a total of 1,190 adult, noncystine stone forming patients underwent urinary metabolic stone evaluation. Of these patients 34 (3%) underwent parathyroidectomy for primary hyperparathyroidism. Urinary parameters were evaluated as predictors of primary hyperparathyroidism. The most accurate combination of serum and urinary tests and their cutoffs were determined.ResultsStone forming patients with primary hyperparathyroidism were more likely to be women and had higher urinary calcium excretion. Hypercalciuria (aOR 4.38), supersaturation calcium oxalate greater than 10 (aOR 4.27), supersaturation calcium phosphate greater than 2 (aOR 3.64), calcium per kg greater than 4 mg/kg (aOR 8.03) and calcium-to-creatinine ratio greater than 150 mg/gm (aOR 7.07) were significant predictors of primary hyperparathyroidism in separate multivariate models after adjustment. The best accuracy was determined using serum calcium and parathyroid hormone levels with our laboratory cutoffs (AUC 0.984) with a sensitivity of 87%, specificity of 99%, positive predictive value of 79% and negative predictive value of 99.5%. No other factor(s) improved diagnostic accuracy or could replace parathyroid hormone level.ConclusionsGreater urinary calcium excretion predicted primary hyperparathyroidism. Serum calcium with parathyroid hormone level was the most accurate test for primary hyperparathyroidism. No other serum or urinary parameter improved diagnostic accuracy or could replace parathyroid hormone. There were no obvious cutoffs for any of the urinary parameters that reliably differentiated cases of hyperparathyroidism.

UNLABELLED Study Type - Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Technetium-99m MAG3 renography can be used to quantify relative renal function (RRF). Deterioration of renal function occurs with chronic obstruction. Small studies have previously shown that RRF is not improved in adult patients after pyeloplasty. Some studies have suggested that patients with higher preoperative RRF are more likely to improve. To our knowledge, these data represent the largest review of cases related to this subject. This study verifies past studies' assertions that RRF does not improve after relief of chronic renal obstruction. Using multivariable analysis, we identify lower age and lower preoperative RRF as predictors of >7% improvement in RRF. These data suggest that the aim of relieving obstruction should be to maintain RRF and alleviate symptoms, but not to seek improvement in overall renal function. OBJECTIVE To determine the change in relative renal function (RRF) after relief of chronic obstruction in adults. PATIENTS AND METHODS We retrospectively identified 85 adult patients who underwent scintigraphic diuretic renography before and after an intervention to relieve chronic unilateral renal obstruction. Patients were stratified into groups of low ( 40%) preoperative RRF in the obstructed kidney. Each group was assessed for change in RRF after relief of obstruction. We performed multivariable logistic regression analysis to determine whether age and pre-procedural RRF predicted a >7% improvement in RRF, controlling for medical comorbidities and type of obstruction. RESULTS The mean (sd) patient age was 43.6 (16.8) years and 66% of patients were female. The mean (sd) pre- and postoperative RRF values were not significantly different (37.6 [12.3] % vs 38.4 [13.6] %; P = 0.31). Patients stratified by low, medium and high preoperative function showed no significant change in postoperative RRF (P = 0.53, 0.39 and 0.77, respectively). In multivariable logistic regression analysis, younger age (odds ratio [OR] 0.90, 95% confidence interval [CI] 0.83-0.98) and lower preoperative RRF (OR 0.90, 95% CI 0.83-0.97) predicted improvement in RRF of >7%, after adjustment. CONCLUSIONS RRF does not significantly increase after relief of chronic obstruction. The goals of relieving chronic renal obstruction should be to maintain renal function and relieve symptoms, but not to regain renal function.

To improve in vitro lithotripsy models, we investigated the effects of multiple experimental variables on stone fragmentation. We performed timed burst wave lithotripsy (BWL) and shock wave lithotripsy (SWL) exposures in a water tank with the following variable parameters: water gas content (60, 30, and 15% O2), temperature (20 and 37°C), stone holder degree of enclosure (open wire basket, polyvinyl chloride (PVC) open-ended gel, and similar material anatomically accurate artificial kidney), and stone type (Begostone at 2 mixture ratios, calcite, calcium oxalate monohydrate (COM), and uric acid). At least 3 stones were treated for each condition, with fragmentation defined as percent stone mass