A population-based retrospective cohort study of surgical trends and outcomes of pediatric urolithiasis in Ontario, Canada (2002-2019).

INTRODUCTION: The worldwide incidence of pediatric urinary stone disease (PUSD) is increasing. However, there is no commensurate data on whether this translates to an increasing need for surgical intervention for PUSD, given the role of conservative management. OBJECTIVE: We aimed to evaluate the trends and outcomes of clinically significant PUSD, using administrative databases to identify patients surgically treated for PUSD. STUDY DESIGN: This retrospective population-based cohort study assessed the incidence and trends of surgically treated PUSD and outcomes in Ontario, Canada in patients <18 years of age who underwent their first PUSD procedure between 2002 and 2019 utilizing administrative databases held at the Institute of Clinical Evaluative Sciences (ICES). We assessed the incidence of surgically treated PUSD, demographics, initial surgical treatment and imaging modality, and risk factors for repeat intervention within 5 years. Statistical analyses summarized demographics, surgical trends, and logistic regression was used to identify risk factors for repeat surgical intervention. RESULTS: We identified 1149 patients (mean age 11.3 years), with 59.6% older than 12 years. There was a decrease in the number of PUSD procedures performed per year that was close to statistical significance (p = 0.059) and a trend towards increased utilization of ureteroscopy (URS) compared with Shockwave Lithotripsy (SWL). In addition, there was a significant increase in the proportion of females surgically treated with PUSD (p = 0.001). In the 706 patients followed for 5 years, 17.7% underwent a repeat procedure within 6 months, while 20.4% underwent a repeat procedure from 6-months to 5 years. Renal stone location (OR 2.79, 95% confidence interval (CI) 1.62-4.80, p = 0.0002) and index SWL (OR 1.66, 95% CI 1.20-2.31, p = 0.0025) were risk factors for repeat surgical intervention within the first 6-months. There was an increasing utilization of ultrasound (US) compared to computerized tomography (CT) (p = 0.0008). DISCUSSION: Despite the literature reporting increasing PUSD incidence, we observed a non-significant decrease in the number of surgical PUSD procedures performed. Exclusion of those treated conservatively may explain our results. The increase in the proportion of females treated reflects the narrowing gender gap in stone disease. A trend towards increased URS utilization was observed and re-intervention rates were similar to previous studies. CONCLUSION: The overall rate of surgically treated PUSD did not show an increasing trend in Ontario, Canada from 2002 to 2019. URS was the most common surgical treatment modality, with a corresponding decline in SWL rates. PUSD was associated with a high surgical re-intervention rate within 6 months.

High-Throughput in vitro Gel-Based Plate Assay to Screen for Calcium Oxalate Stone Inhibitors.

OBJECTIVE: Kidney stones are a common medical condition that is increasing in prevalence worldwide. Approximately, ∼80% of urinary calculi are composed of calcium oxalate (CaOx). There is a growing interest toward identifying therapeutic compounds that can inhibit the formation of CaOx crystals. However, some chemicals (e.g., antibiotics and bacterial metabolites) may directly promote crystallization. Current knowledge is limited regarding crystal promoters and inhibitors. Thus, we have developed an in vitro gel-based diffusion model to screen for substances that directly influence CaOx crystal formation. MATERIALS AND METHODS: We used double diffusion of sodium oxalate and calcium chloride-loaded paper disks along an agar medium to facilitate the controlled formation of monohydrate and dihydrate CaOx crystals. A third disk was used for the perpendicular diffusion of a test substance to assess its influence on CaOx crystal formation. RESULTS: We confirmed that citrates and magnesium are effective inhibitors of CaOx crystals. We also demonstrated that 2 strains of uropathogenic Escherichia coli are able to promote crystal formation. While the other tested uropathogens and most antibiotics did not change crystal formation, ampicillin was able to reduce crystallization. CONCLUSION: We have developed an inexpensive and high-throughput model to evaluate substances that influence CaOx crystallization.

Evaluating the acceptability of an online patient decision aid for the surgical management of lower urinary tract symptoms secondary to benign prostatic hyperplasia.

INTRODUCTION: The growing number of surgical options available to treat benign prostatic hyperplasia (BPH), may overwhelm patients and urologists when deciding on an optimal treatment. Therefore, we developed an online patient decision aid (PtDA) that includes all guideline-approved surgical modalities. The objective of this study was to assess the acceptability of the PtDA among former BPH surgery patients and urologists that treat BPH surgically. METHODS: The International Patient Decision Aids Standards were used to develop a PtDA that includes monopolar transurethral resection of the prostate (TURP), bipolar TURP, GreenLight photovaporization, endoscopic enucleation of the prostate, Rezum, Urolift, Aquablation, open retropubic prostatectomy, and robotic simple prostatectomy as management options. Eleven urologists that regularly treat BPH and 19 patients who received BPH surgery were recruited. Alpha-testing was performed using a validated acceptability scoring system. RESULTS: For all sections of the PtDA, most urologists agreed that the language used was easy to follow (91.9%), that the amount of information provided was adequate (63.6%), that the length of the PtDA was appropriate (63.6%), and that the outcomes reported were correct (81.8%). All 19 patient participants agreed that the language used was easy to follow, and most found that the amount of information provided was adequate (84.2%), that the length of the PtDA was appropriate (84.2%), and that the outcomes reported were well-explained (89.5%). CONCLUSIONS: Our PtDA was found to be acceptable among urologists and patients. These results demonstrate that most of the participants either recommend the use of this tool or plan to incorporate it in their clinical practice.

Point-of-care ultrasonography for the diagnosis of testicular torsion: a practical resident curriculum.

Background: Prompt Doppler ultrasonography to aid in diagnosis is often key to managing testicular torsion, but there may be delays in access; a faster, more widely available alternative is point-of-care ultrasonography (POCUS). The purpose of this study was to develop and evaluate a scrotal POCUS curriculum for urology and emergency medicine residents. Methods: Content experts in urology, emergency medicine and diagnostic imaging collaborated in a modified Delphi method to design a practical didactic curriculum for scrotal POCUS for the identification of testicular torsion. Training included 3 online video teaching modules and a 1-hour hands-on teaching session with standardized adult patients. We evaluated participants' competency in scrotal POCUS using a validated scale. We assessed participants' knowledge, comfort and confidence in performing scrotal POCUS before and after the intervention and at 3 months. Results: Twenty-four urology (n = 12) and emergency medicine (n = 12) residents participated in the curriculum. After hands-on practice, 23 participants (96%) were deemed competent at scrotal POCUS. Pre-post testing showed significant improvement in knowledge (mean score 63% v. 80%, p < 0.001), comfort (mean Likert score 0.6 v. 3.6, p < 0.001) and confidence (mean Likert score 1.0 v. 2.1, p < 0.001) after the intervention. These effects were maintained at the 3-month assessment. Conclusion: The scrotal POCUS curriculum was effective and acceptable to both urology and emergency medicine residents. The findings suggest that scrotal POCUS can be learned effectively through a short hands-on session and didactic instruction.

Contexte: Le diagnostic rapide d'une torsion testiculaire à l'aide d'une échographie Doppler est souvent crucial à la prise en charge de ce trouble. Or, comme l'accès à cet examen peut être limité, l'échographie portable constitue une solution de rechange rapide et largement accessible. La présente étude visait la mise au point et l'évaluation d'un programme de formation sur l'échographie portable scrotale destiné aux résidents en urologie et en médecine d'urgence. Méthodes: Des experts en urologie, en médecine d'urgence et en imagerie diagnostique se sont servis d'une méthode Delphi modifiée pour concevoir un programme de formation sur l'échographie portable visant à faciliter le diagnostic de la torsion testiculaire. Ce programme comprenait 3 modules d'apprentissage vidéo en ligne, ainsi qu'une séance pratique d'une heure auprès de patients adultes normalisés. Nous avons évalué les compétences des participants en matière d'échographie portable scrotale au moyen d'une échelle validée. Nous avons également évalué les connaissances, l'aisance et le niveau de confiance des participants à l'égard de cet examen avant et immédiatement après la formation, puis 3 mois plus tard. Résultats: Au total, 24 résidents en urologie (n = 12) et en médecine d'urgence (n = 12) ont suivi le programme de formation. Après la séance pratique, 23 participants (96 %) avaient les compétences nécessaires à la réalisation d'une échographie portable scrotale. La comparaison des résultats obtenus avant et immédiatement après la formation a montré une augmentation significative des connaissances (note moyenne : 63 % c. 80 %; p < 0,001), de l'aisance (moyenne à l'échelle de Likert : 0,6 c. 3,6; p < 0,001) et du niveau de confiance (moyenne à l'échelle de Likert : 1,0 c. 2,1; p < 0,001) des participants. Les effets de la formation étaient toujours présents 3 mois plus tard. Conclusion: Le programme de formation sur l'échographie portable scrotale s'est avéré efficace et acceptable pour les résidents en urologie et en médecine d'urgence. Les résultats obtenus laissent croire qu'une formation pédagogique et une courte séance d'apprentissage pratique permettent l'enseignement efficace de l'échographie portable scrotale.

Population-based assessment of re-treatment and healthcare utilisation after photoselective vaporisation of the prostate or electrosurgical transurethral resection of the prostate.

OBJECTIVE: To compare the healthcare utilisation and repeat surgical treatment rate amongst older men undergoing an electrosurgical-transurethral resection of the prostate (TURP) vs photoselective vaporisation of the prostate (PVP), as the real-world implementation and outcomes of laser-based treatment have not been well studied. PATIENTS AND METHODS: We used administrative data from the province of Ontario, Canada, to identify all men aged >66 years who underwent their first electrosurgical-TURP/PVP between 2003 and 2016. Our primary exposure was type of procedure (PVP or electrosurgical-TURP). Our primary outcome was need for repeat surgical treatment. The primary analysis was an adjusted marginal Cox model approach, which accounted for clustering of patients within surgeons; adjusted hazard ratios (aHRs) or odds ratios (aORs) and 95% confidence intervals (CIs) are reported. RESULTS: We identified 52 748 men: 6838 (13%) underwent PVP, and 45 910 (87%) underwent electrosurgical-TURP. The median age was similar, and PVP became more common with time. Compared to the PVP group, more patients in the electrosurgical-TURP group had prior gross haematuria or urinary retention, and fewer had used anticoagulants, α-blockers, or 5α-reductase inhibitors. The need for repeat surgical treatment was significantly higher amongst men who had PVP (aHR 1.57, 95% CI 1.38-1.78; absolute risk difference +2.3%). PVP was also associated with a slightly higher risk of return to the emergency room within 30 days (aOR 1.11, 95% CI 1.01-1.22) and a significantly lower risk of blood transfusion (aOR 0.24, CI 0.16-0.37); the majority of PVP cases were done with a <24 h stay (73%) vs electrosurgical-TURP (7%). CONCLUSIONS: While some of the expected benefits of PVP (such as reduced transfusion risk and shorter length of stay) were observed, the significantly higher rate of repeat surgical treatment compared to electrosurgical-TURP may represent an important difference in implementation of this technology outside of clinical trials.

Daily therapy with a slow-releasing H2S donor GYY4137 enables early functional recovery and ameliorates renal injury associated with urinary obstruction.

OBJECTIVES: To assess the effects of slow-releasing H2S donor GYY4137 on post-obstructive renal function and injury following unilateral ureteral obstruction (UUO) by using the UUO and reimplantation (UUO-R) model in rats and to elucidate potential mechanisms by using an in vitro model of epithelial-mesenchymal transition (EMT). METHODS: Male Lewis rats underwent UUO at the left ureterovesical junction. From post-operative day (POD) 1-13, rats received daily intraperitoneal (IP) injection of phosphate buffered saline (PBS, 1 mL) or GYY4137 (200 µmol/kg/day in 1 mL PBS, IP). On POD 14, the ureter was reimplanted back into the bladder, followed by a right nephrectomy. Urine and serum samples were collected to monitor renal function. On POD 30, the left kidney was removed and tissue sections were stained with H&E, TUNEL, CD68, CD206, myeloperoxidase, and Masson's trichrome to determine cortical thickness, apoptosis, inflammation, and fibrosis. In our in vitro model of EMT, NRK52E cells were treated with 10 ng/mL TGF-ß1, 10 µM GYY4137 and/or 50 µM GYY4137. Western blot analysis was performed to determine the expression of E-cadherin, vimentin, Smad7 and TGF-ß1 receptor II (TßRII). RESULTS: GYY4137 led to a moderate decrease in post-obstructive serum creatinine, cystatin C and FENa. We also observed a trend towards a decrease in post-obstructive proteinuria following GYY4137 treatment. Histologically, we observed a significant decrease in apoptosis, inflammation, and fibrosis. Furthermore, our in vitro studies demonstrate that in the presence of TGF-ß1, GYY4137 significantly decreases vimentin and TßRII and significantly increases E-cadherin and Smad7. CONCLUSIONS: H2S may help to accelerate the recovery of renal function post-obstruction and attenuates renal injury associated with UUO. It is possible that H2S mitigates fibrosis by regulating the TGF-ß1-mediated EMT pathway. Taken together, our data suggest that H2S may be a potential novel therapy for improving renal function and limiting renal injury associated with obstructive uropathy.

Stones in special situations.

There are several special situations in which urinary lithiasis presents management challenges to the urologist. An in-depth knowledge of the pathophysiology, unique anatomy, and treatment options is crucial in order to maintain good health in these patients. In this review, we summarize the current literature on the management of the following scenarios: bladder stones, stones in bowel disease, during pregnancy, in association with renal anomalies, with skeletal deformities, in urinary diversions, and in children.

Retained Digital Flexible Ureteroscopes.

This report documents two instances of retained flexible ureteroscopes at the time of ureteroscopy and laser lithotripsy in a healthy 37-year-old male and a 53-year-old male with a pelvic kidney. We describe maneuvers to remove the ureteroscope endoscopically in the first case, while the second case required conversion to open surgery for ureteroscope extrication.

Questions and challenges associated with studying the microbiome of the urinary tract.

Urologists are typically faced with clinical situations for which the microbiome may have been a contributing factor. Clinicians have a good understanding regarding the role of bacteria related to issues such as antibiotic resistance; however, they generally have a limited grasp of how the microbiome may relate to urological issues. The largest part of the human microbiome is situated in the gastrointestinal tract, and though this is mostly separated from the urinary system, bacterial dissemination and metabolic output by this community is thought to have a significant influence on urological conditions. Sites within the urogenital system that were once considered "sterile" may regularly have bacterial populations present. The health implications potentially extend all the way to the kidneys. This could affect urinary tract infections, bladder cancer, urinary incontinence and related conditions including the formation of kidney stones. Given the sensitivity of the methodologies employed, and the large potential for contamination when working with low abundance microbiomes, meticulous care in the analyses of urological samples at various sites is required. This review highlights the opportunities for urinary microbiome investigations and our experience in working with these low abundance samples in the urinary tract.

KIM-1 Is a Potential Urinary Biomarker of Obstruction: Results from a Prospective Cohort Study.

INTRODUCTION: Partial or complete obstruction of the urinary tract is a common and challenging urological condition that may occur in patients of any age. Serum creatinine is the most commonly used method to evaluate global renal function, although it has low sensitivity for early changes in the glomerular filtration rate or unilateral renal pathology. Hence, finding another measurable parameter that reflects the adaptation of the renal physiology to these circumstances is important. Several recent studies have assessed the use of new biomarkers of acute kidney injury (AKI), but the information among patients with stone disease and those with obstructive uropathy is limited. MATERIAL AND METHODS: A prospective cohort study was conducted to determine the urinary levels of kidney injury molecule-1 (KIM-1), Total and Monomeric neutrophil gelatinase-associated lipocalin (NGAL) in patients with hydronephrosis secondary to renal stone disease, congenital ureteropelvic junction obstruction or ureteral stricture. Comparison between patients with hydronephrosis and no hydronephrosis was carried out along with correlation analysis to detect factors associated with biomarker expression. RESULTS: Urinary levels of KIM-1 significantly decreased after hydronephrosis treatment in patients with unilateral obstruction (1.19 ng/mL vs 0.76 ng/mL creatinine, p = 0.002), additionally KIM-1 was significantly higher in patients with hydronephrosis compared to stone disease patients without radiological evidence of obstruction (1.19 vs 0.64, p = 0.006). Total and Monomeric NGAL showed a moderate correlation with the presence of leukocyturia. We found that a KIM-1 value of 0.735 ng/mg creatinine had a sensitivity of 75% and specificity of 67% to predict the presence of hydronephrosis in preoperative studies (95% CI 0.58-0.87, p = 0.006). CONCLUSION: Our results show that KIM-1 is a promising biomarker of subclinical AKI associated with hydronephrosis in urological patients. NGAL values were influenced by the presence of leukocyturia, limiting its usefulness in this population.

Natural History of Residual Fragments After Percutaneous Nephrolithotomy: Evaluation of Factors Related to Clinical Events and Intervention.

OBJECTIVE: To determine the natural history of residual fragments (RF) after percutaneous nephrolithotomy in long-term patient follow-up and to identify possible predictive factors for future intervention. MATERIALS AND METHODS: We assessed all patients from 2006 to 2013 with postoperative computed tomography scan revealing RF, who did not undergo second-look nephroscopy or immediate ancillary procedures, and with at least 12 months of clinical follow-up. We evaluated factors associated with clinical, radiological, and surgical outcomes. Kaplan-Meier curves were used to calculate the proportion of asymptomatic and treatment-free patients during follow-up. RESULTS: From 781 percutaneous nephrolithotomies performed, 202 patients underwent postoperative computed tomography scan and 44 patients with residual stones were included in the analysis. Mean follow-up was 57.9 months. A total of 24 patients (54.5%) developed at least 1 clinical outcome, and 32 (72.7%) patients had a surgical intervention. Only 4 patients had radiological evidence of stone passage. Multivariate analysis found that RF >4 mm and struvite or apatite stones were significant predictors for surgical intervention. The 5-year estimated probability to remain intervention free was 29%. CONCLUSION: Despite the size of the RF, the vast majority of patients required an intervention during long-term follow-up. We identified that RFs of diameter >4 mm associate with the need for a surgical therapy, but the rate of clinical events was not affected by the size or location of the stones. Struvite or apatite composition stones had an increased risk of intervention during follow-up. Spontaneous passage was an uncommon event in this cohort.

Multicenter External Validation and Comparison of Stone Scoring Systems in Predicting Outcomes After Percutaneous Nephrolithotomy.

BACKGROUND AND PURPOSE: Several scoring systems have recently emerged to predict stone-free rate (SFR) and complications after percutaneous nephrolithotomy (PCNL). We aimed to compare the most commonly used scoring systems (Guy's stone score, S.T.O.N.E. nephrolithometry, and CROES nomogram), assess their predictive accuracy for SFR and other postoperative variables, and develop a risk group stratification based on these scoring systems. MATERIALS AND METHODS: We performed a retrospective review of patients who have had a PCNL at four academic institutions between 2006 and 2013. Primary outcome was SFR within 3 weeks of the surgery and secondary outcomes were operative time (OT), complications, and length of stay (LOS). We performed chi-squared, t-test, logistic, linear, and Poisson regressions, as well as receiver operating characteristics curve with area under the curve (AUC) calculation. RESULTS: We identified 586 patients eligible for analysis. Of these, 67.4% were stone free. Guy's, S.T.O.N.E., and CROES score were predictive of SFR on multivariable logistic regression (odds ratio [OR]: 1.398, 95% confidence interval [CI]: 1.056, 1.852, p = 0.019; OR: 1.417, 85% CI: 1.231, 1.631, p < 0.001; OR: 0.993, 95% CI: 0.988, 0.998, p = 0.004) and have similar predictive accuracy with AUCs of 0.629, 0.671, and 0.646, respectively. On multivariable linear regression, only S.T.O.N.E. was an independent predictor of longer OT (ß = 14.556, 95% CI: 12.453, 16.660, p < 0.001). None of the scores were independent predictors of postoperative complications or a longer LOS. Poisson regression allowed for risk group stratification and showed the S.T.O.N.E. score and CROES nomogram to have the most distinct risk groups. CONCLUSIONS: The three evaluated scoring systems have similar predictive accuracy of SFR. S.T.O.N.E. has additional value in predicting OT. Risk group stratification can be used for patient counseling. Further research is needed to identify whether or not any is superior to the others with regard to clinical usefulness and predictive accuracy.

Novel Methods of Determining Urinary Calculi Composition: Petrographic Thin Sectioning of Calculi and Nanoscale Flow Cytometry Urinalysis.

Accurate determination of urinary stone composition has significant bearing on understanding pathophysiology, choosing treatment modalities and preventing recurrence. A need exists for improved methods to determine stone composition. Urine of 31 patients with known renal calculi was examined with nanoscale flow cytometry and the calculi collected during surgery subsequently underwent petrographic thin sectioning with polarized and fluorescent microscopy. Fluorescently labeled bisphosphonate probes (Alendronate-fluorescein/Alendronate-Cy5) were developed for nanoscale flow cytometry to enumerate nanocrystals that bound the fluorescent probes. Petrographic sections of stones were also imaged by fluorescent and polarized light microscopy with composition analysis correlated to alendronate +ve nanocrystal counts in corresponding urine samples. Urine samples from patients with Ca(2+) and Mg(2+) based calculi exhibited the highest alendronate +ve nanocrystal counts, ranging from 100-1000 nm in diameter. This novel urine based assay was in agreement with composition determined by petrographic thin sections with Alendronate probes. In some cases, high alendronate +ve nanocrystal counts indicated a Ca(2+) or Mg(2+) composition, as confirmed by petrographic analysis, overturning initial spectrophotometric diagnosis of stone composition. The combination of nanoscale flow cytometry and petrographic thin sections offer an alternative means for determining stone composition. Nanoscale flow cytometry of alendronate +ve nanocrystals alone may provide a high-throughput means of evaluating stone burden.

The Effect of Renal Cysts on the Fragmentation of Renal Stones During Shockwave Lithotripsy: A Comparative In Vitro Study.

PURPOSE: To assess the potential effect of simple renal cysts (SRC) on stone fragmentation during shockwave lithotripsy (SWL) in an in vitro model. MATERIALS AND METHODS: The in vitro model was constructed using 10% ordnance gelatin (OG). Models were created to mimic four scenarios: Model A-with an air-filled cavity (suboptimal for stone fragmentation); model B-without a cavity (normal anatomy); model C-with a 3-cm serum filled cavity (to represent a small SRC); model D-with a 4-cm serum filled cavity (to represent a larger SRC). SWL was applied to 24 standardized phantom stones (weight of 2±0.1 g) in each model using a standardized protocol. Stone fragments were retrieved, then dried overnight at room air temperature. Fragmentation coefficient (FC) was calculated for each stone, for fragments<4 mm and <2 mm. RESULTS: The OG in vitro model was robust enough for the proposed research. There was no fragmentation evident in model A as expected. The mean FC was 29.7 (±20.5) and 39.7 (±23.7) for <4 mm fragments (P=0.069) and 7.6 (±4.1) and 10.6 (±6.7) for <2 mm fragments (P=0.047), for noncystic and cystic models, respectively. The mean FC was 29.7 (±20.5), 38.8 (±26.2) and 40.7 (±21.3) for <4 mm fragments (P=0.213) and 7.6 (±4.1), 11.1 (±8) and 10.2 (±5.3) for <2 mm fragments (P=0.138), for models B, C, and D, respectively. CONCLUSION: Our in vitro experiment confirms better stone fragmentation associated with SWL in the presence of adjacent SRC.

Combining Mean and Standard Deviation of Hounsfield Unit Measurements from Preoperative CT Allows More Accurate Prediction of Urinary Stone Composition Than Mean Hounsfield Units Alone.

INTRODUCTION AND OBJECTIVES: The mineral composition of a urinary stone may influence its surgical and medical treatment. Previous attempts at identifying stone composition based on mean Hounsfield Units (HUm) have had varied success. We aimed to evaluate the additional use of standard deviation of HU (HUsd) to more accurately predict stone composition. METHODS: We identified patients from two centers who had undergone urinary stone treatment between 2006 and 2013 and had mineral stone analysis and a computed tomography (CT) available. HUm and HUsd of the stones were compared with ANOVA. Receiver operative characteristic analysis with area under the curve (AUC), Youden index, and likelihood ratio calculations were performed. RESULTS: Data were available for 466 patients. The major components were calcium oxalate monohydrate (COM), uric acid, hydroxyapatite, struvite, brushite, cystine, and CO dihydrate (COD) in 41.4%, 19.3%, 12.4%, 7.5%, 5.8%, 5.4%, and 4.7% of patients, respectively. The HUm of UA and Br was significantly lower and higher than the HUm of any other stone type, respectively. HUm and HUsd were most accurate in predicting uric acid with an AUC of 0.969 and 0.851, respectively. The combined use of HUm and HUsd resulted in increased positive predictive value and higher likelihood ratios for identifying a stone's mineral composition for all stone types but COM. CONCLUSIONS: To the best of our knowledge, this is the first report of CT data aiding in the prediction of brushite stone composition. Both HUm and HUsd can help predict stone composition and their combined use results in higher likelihood ratios influencing probability.

Clinical Research Office of the Endourological Society Global GreenLight Laser Study: Outcomes from a contemporary series of 713 patients.

OBJECTIVE: To evaluate the outcome in patients undergoing photoselective vaporization of the prostate for benign prostatic obstruction as part of the Clinical Research Office of the Endourological Society Global GreenLight Laser Study. METHODS: Data were collected on 713 patients with lower urinary tract symptoms suggestive of benign prostatic obstruction undergoing photoselective vaporization of the prostate at 25 centers worldwide, between April 2010 and April 2012. Three types of GreenLight laser powers were used: 80 W, 120 W or 180 W. Intraoperative and postoperative complications were recorded. Outcome parameters measured at baseline, 6-12 weeks, 6 months and 12 months were: uroflow measurements, International Prostate Symptom Score; prostate-specific antigen and International Index of Erectile Function. RESULTS: Operating time was shortest with the 180-W laser at 53.8 min. Intraoperatively, bleeding occurred in 3.1% of patients. Statistically significant changes were reported in maximum flow rate, postvoid residual urine, International Prostate Symptom Score, quality of life score and prostate-specific antigen (P < 0.01) at each time-point assessed for the 80- and 120-W lasers as well as for the 180-W laser, with the exception of prostate-specific antigen at 6 months and 12 months. There were 14 Clavien-Dindo grade III-A complications and two grade III-B. The incontinence rate at 12 months was 6.3%, 4.5%, and 2.6% for the 80, 120 and 180 W lasers, respectively. The overall blood transfusion rate was 0.4%. CONCLUSIONS: Objective and subjective improvement after GreenLight laser treatment worldwide was significant at 1-year follow up. Morbidity and complications were low. Although not a randomized control study, the data can provide an indication of the outcome of the different GreenLight laser powers.

Risk Factors for Postoperative Complications of Percutaneous Nephrolithotomy at a Tertiary Referral Center.

PURPOSE: We sought to describe and evaluate the complications related to percutaneous nephrolithotomy and identify risk factors of morbidity according to the modified Clavien scoring system. We also sought to specify which perioperative factors are associated with minor and major complications. MATERIALS AND METHODS: We retrospectively analyzed data on patients who underwent percutaneous nephrolithotomy from 1990 to 2013. Descriptive statistics were used to analyze patient characteristics, medical comorbidities and perioperative features. Complications were categorized according to the Clavien score for percutaneous nephrolithotomy. The Mann-Whitney and Fisher exact tests were used as appropriate. Logistic regression analysis was performed to look for prognostic factors associated with major complications. RESULTS: A total of 2,318 surgeries were evaluated. Mean age of the population was 53.7 years. The stone-free rate at hospital discharge was 81.6%. The overall complication rate was 18.3%. Two deaths occurred. Patients with any postoperative complications were older, had more comorbidities, were more likely to have staghorn calculi and had longer operative time and hospital stay on univariate analysis (p<0.05). Age 55 years or older and upper pole access were independent predictors of major complications on multivariate analysis. Other factors such as a history of urinary tract infections, body mass index, stone composition, previous percutaneous nephrolithotomy and multiple tracts were not associated with a major complication. CONCLUSIONS: At our center percutaneous nephrolithotomy is an excellent option for complex kidney stone management with a low overall complication rate. Older patient age and upper pole access are significantly associated with an increased risk of a major complication.

A comparison of outcomes after percutaneous nephrolithotomy in children and adults: a matched cohort study.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) has surpassed open stone surgery as the operation of choice for large and complex stone burdens (figure). Although the procedure was developed in adults, its principles have been extrapolated to children. There is a paucity of literature comparing outcomes of PCNL in adults and children for similar stone burdens. OBJECTIVE: The purpose of this study was to evaluate outcomes following PCNL among children and adults with similar stone burdens. PATIENTS AND METHODS: Data on patient characteristics and outcomes for 2196 consecutive patients undergoing PCNL at a single institution were collected prospectively from January 1992 to July 2013. Thirty-one pediatric patients undergoing 39 PCNLs were identified. Each pediatric PCNL was matched in a ratio of 1:4 to adult PCNLs by year of surgery and stone burden characteristics (staghorn, partial staghorn, number of stones). All PCNLs were performed by two fellowship-trained endourologists who operate on both adult and pediatric patients. Ultrasonic lithotripsy was used primarily. The primary outcome measure was stone-free rate (SFR) at hospital discharge. Secondary outcomes included the need for second-look nephroscopy, length of hospital stay, complication rate, and blood transfusion rate. The Student t test was used for continuous variables and the Fisher exact for categorical variables. RESULTS: The median age for the pediatric group was 13.9 ± 4.30 years and for the adult group was 55.4 ± 15.1 years. Pediatric patients tended to present with metabolic stones, with no difference in rates of infection stones. No difference was found in SFR at time of hospital discharge (86.1% vs. 86.4%, p = 0.2). More pediatric patients required a second access tract than adult patients (15.4% vs. 4.52%, p = 0.02). There was no significant difference in the need for second-look nephroscopy, length of stay, or complication rates (overall and by Clavien classification subgroup) between both groups. The rates of blood transfusion were low in both groups (0% vs. 0.6%, p = 0.80). DISCUSSION: There was no difference in primary and secondary outcomes among children compared with adults undergoing PCNL in our study. The outcomes reported in this study were similar to published literature. A limitation of this study is the low number of pediatric patients. However, it is unique to have a single-center study that compares PCNL outcomes in both adult and pediatric patient and accounts for stone burden characteristics. CONCLUSIONS: Although principles of PCNL were developed in adults, this study affirms the safety and efficacy of PCNL in both pediatric and adult patients.

The microbiome of the urinary tract--a role beyond infection.

Urologists rarely need to consider bacteria beyond their role in infectious disease. However, emerging evidence shows that the microorganisms inhabiting many sites of the body, including the urinary tract--which has long been assumed sterile in healthy individuals--might have a role in maintaining urinary health. Studies of the urinary microbiota have identified remarkable differences between healthy populations and those with urologic diseases. Microorganisms at sites distal to the kidney, bladder and urethra are likely to have a profound effect on urologic health, both positive and negative, owing to their metabolic output and other contributions. Connections between the gut microbiota and renal stone formation have already been discovered. In addition, bacteria are also used in the prevention of bladder cancer recurrence. In the future, urologists will need to consider possible influences of the microbiome in diagnosis and treatment of certain urological conditions. New insights might provide an opportunity to predict the risk of developing certain urological diseases and could enable the development of innovative therapeutic strategies.