External validation and comparison of magnetic resonance imaging-based risk prediction models for prostate biopsy stratification.

PURPOSE: Magnetic resonance imaging (MRI) is a promising tool for risk assessment, potentially reducing the burden of unnecessary prostate biopsies. Risk prediction models that incorporate MRI data have gained attention, but their external validation and comparison are essential for guiding clinical practice. The aim is to externally validate and compare risk prediction models for the diagnosis of clinically significant prostate cancer (csPCa). METHODS: A cohort of 4606 patients across fifteen European tertiary referral centers were identified from a prospective maintained database between January 2016 and April 2023. Transrectal or transperineal image-fusion MRI-targeted and systematic biopsies for PI-RADS score of ≥ 3 or ≥ 2 depending on patient characteristics and physician preferences. Probabilities for csPCa, defined as International Society of Urological Pathology (ISUP) grade ≥ 2, were calculated for each patients using eight models. Performance was characterized by area under the receiver operating characteristic curve (AUC), calibration, and net benefit. Subgroup analyses were performed across various clinically relevant subgroups. RESULTS: Overall, csPCa was detected in 2154 (47%) patients. The models exhibited satisfactory performance, demonstrating good discrimination (AUC ranging from 0.75 to 0.78, p < 0.001), adequate calibration, and high net benefit. The model described by Alberts showed the highest clinical utility for threshold probabilities between 10 and 20%. Subgroup analyses highlighted variations in models' performance, particularly when stratified according to PSA level, biopsy technique and PI-RADS version. CONCLUSIONS: We report a comprehensive external validation of risk prediction models for csPCa diagnosis in patients who underwent MRI-targeted and systematic biopsies. The model by Alberts demonstrated superior clinical utility and should be favored when determining the need for a prostate biopsy.

The impact of prostate volume estimation on the risk-adapted biopsy decision based on prostate-specific antigen density and magnetic resonance imaging score.

PURPOSE: Utility of prostate-specific antigen density (PSAd) for risk-stratification to avoid unnecessary biopsy remains unclear due to the lack of standardization of prostate volume estimation. We evaluated the impact of ellipsoidal formula using multiparametric magnetic resonance (MRI) and semi-automated segmentation using tridimensional ultrasound (3D-US) on prostate volume and PSAd estimations as well as the distribution of patients in a risk-adapted table of clinically significant prostate cancer (csPCa). METHODS: In a prospectively maintained database of 4841 patients who underwent MRI-targeted and systematic biopsies, 971 met inclusions criteria. Correlation of volume estimation was assessed by Kendall's correlation coefficient and graphically represented by scatter and Bland-Altman plots. Distribution of csPCa was presented using the Schoots risk-adapted table based on PSAd and PI-RADS score. The model was evaluated using discrimination, calibration plots and decision curve analysis (DCA). RESULTS: Median prostate volume estimation using 3D-US was higher compared to MRI (49cc[IQR 37-68] vs 47cc[IQR 35-66], p < 0.001). Significant correlation between imaging modalities was observed (τ = 0.73[CI 0.7-0.75], p < 0.001). Bland-Altman plot emphasizes the differences in prostate volume estimation. Using the Schoots risk-adapted table, a high risk of csPCa was observed in PI-RADS 2 combined with high PSAd, and in all PI-RADS 4-5. The risk of csPCa was proportional to the PSAd for PI-RADS 3 patients. Good accuracy (AUC of 0.69 and 0.68 using 3D-US and MRI, respectively), adequate calibration and a higher net benefit when using 3D-US for probability thresholds above 25% on DCA. CONCLUSIONS: Prostate volume estimation with semi-automated segmentation using 3D-US should be preferred to the ellipsoidal formula (MRI) when evaluating PSAd and the risk of csPCa.

Clinical profile of a Polish cohort of children and young adults with cystinuria.

BACKGROUND: Cystinuria is an inherited disorder that results in increased excretion of cystine in the urine. It accounts for about 1-2% of pediatric kidney stones. In this study, we sought to identify the clinical characteristics of patients with cystinuria in a national cohort. METHODS: This was a retrospective study involving 30 patients from the Polish Registry of Inherited Tubulopathies. Initial data and that from a 6-month follow-up were analyzed. Mutational analysis was performed by targeted Sanger sequencing and, if applicable, MLPA analysis was used to detect large rearrangements. RESULTS: SLC7A9 mutations were detected in 15 children (50%; 10 males, 5 females), SLC3A1 mutations in 14 children (47%; 5 males, 9 females), and bigenic mutations in one male patient. The first clinical symptoms of the disease were detected at a median of 48 months of age (range 3-233 months). When individuals with different mutations were compared, there were no differences identified in gender, age of diagnosis, presence of UTI or urolithiasis, eGFR, calcium, or cystine excretion. The most common initial symptoms were urolithiasis in 26 patients (88%) and urinary tract infections in 4 patients (13%). Urological procedures were performed in 18 out of 30 (60%). CONCLUSIONS: The clinical course of cystinuria is similar among patients, regardless of the type of genetic mutation. Most patients require surgery before diagnosis or soon after it. Patients require combined urological and pharmacological treatment for prevention of stone recurrence and renal function preservation.

Management of urinary stones: state of the art and future perspectives by experts in stone disease.

AIM: To present state of the art on the management of urinary stones from a panel of globally recognized urolithiasis experts who met during the Experts in Stone Disease Congress in Valencia in January 2024. Options of treatment: The surgical treatment modalities of renal and ureteral stones are well defined by the guidelines of international societies, although for some index cases more alternative options are possible. For 1.5 cm renal stones, both m-PCNL and RIRS have proven to be valid treatment alternatives with comparable stone-free rates. The m-PCNL has proven to be more cost effective and requires a shorter operative time, while the RIRS has demonstrated lower morbidity in terms of blood loss and shorter recovery times. SWL has proven to be less effective at least for lower calyceal stones but has the highest safety profile. For a 6mm obstructing stone of the pelviureteric junction (PUJ) stone, SWL should be the first choice for a stone less than 1 cm, due to less invasiveness and lower risk of complications although it has a lower stone free-rate. RIRS has advantages in certain conditions such as anticoagulant treatment, obesity, or body deformity. Technical issues of the surgical procedures for stone removal: In patients receiving antithrombotic therapy, SWL, PCN and open surgery are at elevated risk of hemorrhage or perinephric hematoma. URS, is associated with less morbidity in these cases. An individualized combined evaluation of risks of bleeding and thromboembolism should determine the perioperative thromboprophylactic strategy. Pre-interventional urine culture and antibiotic therapy are mandatory although UTI treatment is becoming more challenging due to increasing resistance to routinely applied antibiotics. The use of an intrarenal urine culture and stone culture is recommended to adapt antibiotic therapy in case of postoperative infectious complications. Measurements of temperature and pressure during RIRS are vital for ensuring patient safety and optimizing surgical outcomes although techniques of measurements and methods for data analysis are still to be refined. Ureteral stents were improved by the development of new biomaterials, new coatings, and new stent designs. Topics of current research are the development of drug eluting and bioresorbable stents. Complications of endoscopic treatment: PCNL is considered the most invasive surgical option. Fever and sepsis were observed in 11 and 0.5% and need for transfusion and embolization for bleeding in 7 and 0.4%. Major complications, as colonic, splenic, liver, gall bladder and bowel injuries are quite rare but are associated with significant morbidity. Ureteroscopy causes less complications, although some of them can be severe. They depend on high pressure in the urinary tract (sepsis or renal bleeding) or application of excessive force to the urinary tract (ureteral avulsion or stricture). Diagnostic work up:  Genetic testing consents the diagnosis of monogenetic conditions causing stones. It should be carried out in children and in selected adults. In adults, monogenetic diseases can be diagnosed by systematic genetic testing in no more than 4%, when cystinuria, APRT deficiency, and xanthinuria are excluded. A reliable stone analysis by infrared spectroscopy or X-ray diffraction is mandatory and should be associated to examination of the stone under a stereomicroscope. The analysis of digital images of stones by deep convolutional neural networks in dry laboratory or during endoscopic examination could allow the classification of stones based on their color and texture. Scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) is another fundamental research tool for the study of kidney stones. The combination of metagenomic analysis using Next Generation Sequencing (NGS) techniques and the enhanced quantitative urine culture (EQUC) protocol can be used to evaluate the urobiome of renal stone formers. Twenty-four hour urine analysis has a place during patient evaluation together with repeated measurements of urinary pH with a digital pH meter. Urinary supersaturation is the most comprehensive physicochemical risk factor employed in urolithiasis research. Urinary macromolecules can act as both promoters or inhibitors of stone formation depending on the chemical composition of urine in which they are operating. At the moment, there are no clinical applications of macromolecules in stone management or prophylaxis. Patients should be evaluated for the association with systemic pathologies. PROPHYLAXIS: Personalized medicine and public health interventions are complementary to prevent stone recurrence. Personalized medicine addresses a small part of stone patients with a high risk of recurrence and systemic complications requiring specific dietary and pharmacological treatment to prevent stone recurrence and complications of associated systemic diseases. The more numerous subjects who form one or a few stones during their entire lifespan should be treated by modifications of diet and lifestyle. Primary prevention by public health interventions is advisable to reduce prevalence of stones in the general population. Renal stone formers at "high-risk" for recurrence need early diagnosis to start specific treatment. Stone analysis allows the identification of most "high-risk" patients forming non-calcium stones: infection stones (struvite), uric acid and urates, cystine and other rare stones (dihydroxyadenine, xanthine). Patients at "high-risk" forming calcium stones require a more difficult diagnosis by clinical and laboratory evaluation. Particularly, patients with cystinuria and primary hyperoxaluria should be actively searched. FUTURE RESEARCH: Application of Artificial Intelligence are promising for automated identification of ureteral stones on CT imaging, prediction of stone composition and 24-hour urinary risk factors by demographics and clinical parameters, assessment of stone composition by evaluation of endoscopic images and prediction of outcomes of stone treatments. The synergy between urologists, nephrologists, and scientists in basic kidney stone research will enhance the depth and breadth of investigations, leading to a more comprehensive understanding of kidney stone formation.

Transperineal or Transrectal Magnetic Resonance Imaging-targeted Biopsy for Prostate Cancer Detection.

BACKGROUND AND OBJECTIVE: A notable paradigm shift has emerged in the choice of prostate biopsy approach, with a transition from transrectal biopsy (TRBx) to transperineal biopsy (TPBx) driven by the lower risk of severe urinary tract infections. The impact of this change on detection of clinically significant prostate cancer (csPCa) remains a subject of debate. Our aim was to compare the csPCa detection rate of TRBx and TPBx. METHODS: Patients who underwent magnetic resonance imaging (MRI)-targeted and systematic biopsies for clinically localized PCa at 15 European referral centers from 2016 to 2023 were included. A propensity score matching (PSM) analysis was performed to minimize selection biases. Logistic regression models were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). KEY FINDINGS AND LIMITATIONS: Of 3949 patients who met the study criteria, 2187 underwent TRBx and 1762 underwent TPBx. PSM resulted in 1301 matched pairs for analysis. Patient demographics and tumor characteristics were comparable in the matched cohorts. TPBx versus TRBx was associated with greater detection of csPCa, whether defined as International Society of Urological Pathology grade group ≥2 (51% vs 45%; OR 1.37, 95% CI 1.15-1.63; p = 0.001) or grade group ≥3 (29% vs 23%; OR 1.38, 95% CI 1.13-1.67; p = 0.001). Similar results were found when considering MRI-targeted biopsy alone and after stratifying patients according to tumor location, Prostate Imaging-Reporting and Data System score, and clinical features. Limitations include the retrospective nature of the study and the absence of centralized MRI review. CONCLUSIONS: Our findings bolster existing understanding of the additional advantages offered by TPBx. Further randomized trials to fully validate these findings are awaited. PATIENT SUMMARY: We compared the rate of detection of clinically significant prostate cancer with magnetic resonance imaging (MRI)-guided biopsies in which the sample needle is passed through the perineum or the rectum. Our results suggest that the perineal approach is associated with better detection of aggressive prostate cancer.

The Added Value of Side-specific Systematic Biopsy in Patients Diagnosed by Magnetic Resonance Imaging-targeted Prostate Biopsy.

BACKGROUND: Systematic biopsy (SB) combined with magnetic resonance imaging (MRI)-targeted biopsy is still recommended considering the risk of missing clinically significant prostate cancer (csPCa). OBJECTIVE: To evaluate the added value in csPCa detection on side-specific SB relative to MRI lesion and to externally validate the Noujeim risk stratification model that predicts the risk of csPCa on distant SB cores relative to the index MRI lesion. DESIGN, SETTING, AND PARTICIPANTS: Overall, 4841 consecutive patients diagnosed by MRI-targeted biopsy and SB for Prostate Imaging Reporting and Data System score ≥3 lesions were identified from a prospectively maintained database between January 2016 and April 2023 at 15 European referral centers. A total of 2387 patients met the inclusion criteria and were included in the analysis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: McNemar's test was used to compare the csPCa detection rate between several biopsy strategies including MRI-targeted biopsy, side-specific SB, and a combination of both. Model performance was evaluated in terms of discrimination using area under the receiver operation characteristic curve (AUC), calibration plots, and decision curve analysis. Clinically significant prostate cancer was defined as International Society of Urological Pathology grade group ≥2. RESULTS AND LIMITATIONS: Overall, the csPCa detection rate was 49%. Considering MRI-targeted biopsy as reference, the added values in terms of csPCa detection were 5.8% (relative increase of 13%), 4.2% (relative increase of 9.8%), and 2.8% (relative increase of 6.1%) for SB, ipsilateral SB, and contralateral SB, respectively. Only 35 patients (1.5%) exclusively had csPCa on contralateral SB (p < 0.001). Considering patients with csPCa on MRI-targeted biopsy and ipsilateral SB, the upgrading rate was 2% (20/961) using contralateral SB (p < 0.001). The Noujeim model exhibited modest performance (AUC of 0.63) when tested using our validation set. CONCLUSIONS: The added value of contralateral SB was negligible in terms of cancer detection and upgrading rates. The Noujeim model could be included in the decision-making process regarding the appropriate prostate biopsy strategy. PATIENT SUMMARY: In the present study, we collected a set of patients who underwent magnetic resonance imaging (MRI)-targeted and systematic biopsies for the detection of prostate cancer. We found that biopsies taken at the opposite side of the MRI suspicious lesion have a negligible impact on cancer detection. We also validate a risk stratification model that predicts the risk of cancer on biopsies beyond 10 mm from the initial lesion, which could be used in daily practice to improve the personalization of the prostate biopsy.

Olbert's Balloon Dilatation as a Minimally Invasive Possibility of Treating Ureteral Stricture After Complicated URS-L in Children.

Olbert's balloon dilatation is a surgical technique used for the treatment of ureteral stricture. Although it is more frequently used in adults, due to the advancing miniaturization of the equipment, this technique has become possible in children. We would like to present five cases of Olbert's balloon dilatation carried out in children with ureteral stricture, aged 12-17 years. All of these children were diagnosed for at least 6 months. Ureteral stricture has been noticed in those patients with a time of a stone residence in the ureter longer than 6 months. The duration of the stone in the ureter varied from 6 to 18 months. The symptoms were abdominal pain, renal colic pain, UTI, fever, vomiting, and nausea. Ultrasound (US) revealed hydronephrosis and ureter dilatation above the stone. All of these children had grade-3 hydronephrosis based on the Onen grading system during admission to the hospital. The lack of renal function on the DMSA scan was observed with an average of 22%. JJ-stent was inserted as a first-line treatment. A retrograde pyelogram revealed ureteral stricture at a length from 1 to 1.7 cm in the place where the stone was ingrown. Olbert's balloon dilatation under fluoroscopy was performed successfully in all children. We achieved an efficacy of 60% in our series. Renal function increased to an average of 36% on DMSA 3 months after surgery. The level of creatinine is shaped at an average of 0.6. On US, two children had no hydronephrosis while one child had grade-1 hydronephrosis. The longest follow-up is now 4 years, with the same good results. In conclusion, Olbert's balloon dilatation is an effective, safe, and minimally invasive tool for ureteral stricture in the hands of the endourological experienced pediatric urologist. But more prospective, randomized trials are still needed.

Encrustation of the ureteral double-J Stents made of styrene/ethylene/butylene and polyurethane before and after implantation.

PURPOSE: The aim of this study was to determine the affinity to crystal, calculi and biofilm deposition on ureteral double-J stents (DJ stents) after ureterorenoscopic-lithotripsy procedure (URS-L). The analysis was performed in two aspects: to determine which material used for fabricating ureteral stents promotes encrustation and which part of the DJ stents is the most vulnerable for blockage. METHODS: One hundred and twenty patients with an indwelling DJ stent duration between 7 and 78 days were included in this study. The encrustation of DJ stents was characterized by scanning electron microscopy (SEM), and the mechanical properties of DJ stents were examined using the standard MTS Micro Bionix tensile test. RESULTS: This study showed that polyurethane catheters have a much higher affinity for encrustation than styrene/ethylene/butylene block copolymer. Obtained results indicated the proximal (renal pelvis) and distal (urinary bladder) part is the most susceptible to post-URS-L fragments and urea salt deposition. Both the DJ ureteral stents' outer and inner surfaces were completely covered even after 7 days of implantation. CONCLUSIONS: Performed analysis pointed out that polyurethane DJ stents have a much higher affinity for encrustation of calculi and NaCl crystals compared to the silicone-based copolymer. The surface of the ureteral stents needs improvement to minimize salt and kidney stone deposition, causing pre-biofilm formation and the occurrence of defects and cracks.

Spectrum of Bacterial Pathogens from Urinary Infections Associated with Struvite and Metabolic Stones.

OBJECTIVE: The purposes of this multi-center study were to evaluate the rate of infection stones and to evaluate the urine cultures of patients with infection stones. MATERIALS: Charts of adulpatients with urinary stones were reviewed and data on stone analyses and urine cultures were collected. RESULTS: In total, 1204 renal stone formers (RSFs) from 10 countries were included (776 males, 428 females). Fifty-six patients (4.6%) had struvite stones. The highest frequency of struvite stones was observed in India (23%) and Pakistan (18%). Lower rates were reported in Canada (2%), China (3%), Argentina (3%), Iraq (3%), Italy (3.5%) and Poland (3%), and intermediate rates in Egypt (5.5%) and Bulgaria (5.4%). Urine cultures were retrieved from 508 patients. Patients with struvite stones had a positive culture in 64.3% of the samples and patients with other stones, in 26.7%. In struvite stones, the most common isolates were Escherichia coli (27.7%) and Proteus spp. (27.7%), followed by Klebsiella spp. (16.7%); in other types of stone, it was Escherichia coli (47.6%), followed by Gram-positive bacteria (14.0%) Conclusions: The struvite stone composition was associated with a urinary infection, although an infection was not demonstrable with a conventional midstream urine culture in about 30%.

Surface analysis of ureteral stent before and after implantation in the bodies of child patients.

The aim of this work was to determine which part of a double-J ureteral stent (DJ stents) showed the highest tendency to crystal, calculi, and biofilm deposition after ureterorenoscopic-lithotripsy procedure (URS-L) to treat calcium oxalate stones. Additionally, the mechanical strength and the stiffness of DJ stents were evaluated before and after exposure to urine. Obtained results indicated that the proximal (renal pelvis) and distal (urinary bladder) part is the most susceptible for post-URS-L fragments and urea salt deposition. Both, the outer and inner surfaces of the DJ ureteral stents were completely covered even after 7 days of implantation. Encrustation of DJ stents during a 31-day period results in reducing the Young's modulus by 27-30%, which confirms the loss of DJ stent elasticity and increased probability of cracks or interruption. Performed analysis pointed to the need to use an antibacterial coating in the above-mentioned part of the ureteral stent to prolong its usage time and to prevent urinary tract infection.

Endourology Methods in Pediatric Population for Kidney Stones Located in Lower Calyx: FlexURS vs. Micro PCNL (MicroPERC®).

Kidney stone disease in children is always a therapeutic challenge. It is a multifactorial condition and it should be approached, diagnosed and treated as such. One of the biggest challenges is kidney stones located in the lower renal calyx. There are currently three main surgical techniques to treat this condition: ESWL-Extracorporeal Shock Wave Lithotripsy, RIRS-Retrograde IntraRenal Surgery, and PCNL-PerCutaneous Nephro-Lithotripsy. In pediatric population, the most frequently used method is ESWL, and in the event of failure, endoscopic procedures are the second-best choice. In this article, a sample of 53 children admitted to a tertiary medical center was examined. Thirty-eight of those children underwent flexible URS, while the remaining 15-micro PCNL. The average size of the deposit in the former group was 12.2 mm, against 13.5 mm in the latter. The full Stone Free Rate (SFR) was achieved in RIRS at 84.21 and 86.7% in percutaneous nephrolithotripsy. Flexible ureterorenoscopy and MicroPERC are two comparably effective methods for treating lower calyx stones of any size. However, according to our data, flexible ureterorenoscopy carries a lower risk of complications and inpatient care (with the mean of 3 days). The learning curve for these procedures in pediatric urology is long and relies on a limited number of patients. The number of pediatric patients qualifying for these procedures is restricted also due to the high efficacy of extracorporeal shock wave lithotripsy in pediatric population. Radiation exposure is an important factor in every endoscopy procedure and should never exceed the limits set in the ALARA protocol. ESWL remains to this day the treatment of choice for stone disease in children and can be performed under ultrasound control. For many parents, it is a first-choice treatment preference for their child due to its greater apparent safety, although data on this remains insufficient. Prospective, randomized, multicenter trials are definitely needed.

Stone composition of renal stone formers from different global regions.

OBJECTIVE: To study urinary stone composition patterns in different populations around the world. MATERIALS AND METHODS: Data were collected by reviewing charts of 1204 adult patients of 10 countries with renal or ureteral stones (> 18 years) in whom a stone analysis was done and available. Any method of stone analysis was accepted, but the methodology had to be registered. RESULTS: In total, we observed 710 (59%) patients with calcium oxalate, 31 (1%) with calcium phosphate, 161 (13%) with mixed calcium oxalate/calcium phosphate, 15 (1%) with carbapatite, 110 (9%) with uric acid, 7 (< 1%) with urate (ammonium or sodium), 100 (9%) with mixed with uric acid/ calcium oxalate, 56 (5%) with struvite and 14 (1%) with cystine stones. Calciumcontaining stones were the most common in all countries ranging from 43 to 91%. Oxalate stones were more common than phosphate or mixed phosphate/oxalate stones in most countries except Egypt and India. The rate of uric acid containing stones ranged from 4 to 34%, being higher in Egypt, India, Pakistan, Iraq, Poland and Bulgaria. Struvite stones occurred in less than 5% in all countries except India (23%) and Pakistan (16%). Cystine stones occurred in 1% of cases. CONCLUSIONS: The frequency of different types of urinary stones varies from country to country. Calcium-containing stones are prevalent in all countries. The frequency of uric acid containing stones seems to depend mainly on climatic factors, being higher in countries with desert or tropical climates. Dietary patterns can also lead to an increase in the frequency of uric acid containing stones in association with high obesity rates. Struvite stones are decreasing in most countries due to improved health conditions.

Obesity rates in renal stone formers from various countries.

OBJECTIVE: To collect evidence on the rate of obesity in renal stone formers (RSFs) living in different climatic areas and consuming different diets. MATERIALS AND METHODS: Data of adult renal stone formers were retrospectively collected by members of U-merge from 13 participant centers in Argentina, Brazil, Bulgaria (2), China, India, Iraq (2), Italy (2), Nigeria, Pakistan and Poland. The following data were collected: age, gender, weight, height, stone analysis and procedure of stone removal. RESULTS: In total, 1689 renal stone formers (1032 males, 657 females) from 10 countries were considered. Average age was 48 (±14) years, male to female ratio was 1.57 (M/F 1032/657), the average body mass index (BMI) was 26.5 (±4.8) kg/m2. The obesity rates of RSFs in different countries were significantly different from each other. The highest rates were observed in Pakistan (50%), Iraq (32%), and Brazil (32%), while the lowest rates were observed in China (2%), Nigeria (3%) and Italy (10%). Intermediate rates were observed in Argentina (17%), Bulgaria (17%), India (15%) and Poland (22%). The age-adjusted obesity rate of RSFs was higher than the age-adjusted obesity rate in the general population in Brazil, India, and Pakistan, whereas it was lower in Argentina, Bulgaria, China, Italy, and Nigeria, and similar in Iraq and Poland. CONCLUSIONS: The age-adjusted obesity rate of RSFs was not higher than the age-adjusted obesity rate of the general population in most countries. The relationship between obesity and the risk of kidney stone formation should be reconsidered by further studies carried out in different populations.

Interest of URS-L in the Treatment of Ureterolithiasis in Preschool Children.

Urolithiasis can affect all children even preschool ones. Diagnostic difficulties in the youngest children are due to the problems in locating pain and determining its character and severity. In keeping with the ALARA (As Low As Reasonably Achievable) protocol, the number of imaging tests possible to perform is very limited. Ultrasound is the first line exam of choice. After diagnosis of the presence of a stone, ESWL (Extracorporeal Shock Wave Lithotrypsy) should always be considered and offered to parents due to its high effectiveness and minimal invasiveness. If ESWL is contraindicated or not well-accepted by parents, authors suggest another minimal invasive approach: URS-L (Uretherorenoscopy-Lithotrypsy). Our study clinically analyzes 87 children, which were treated between 2009 and 2017 using the URS-L procedure. URS-L treatments were performed using Lithoclast until 2009, and after that time, using the holmium laser Ho:YAG. The overall effectiveness of treatments was 93.3%. There was no failure in the access to the stones. A macroscopic hematuria (Clavien-Dindo I grade) was observed through the second post-operative day in 9.2% of treated patients. No urosepsis was observed. Full metabolic evaluation was performed on all patients. Children remained under constant urological and nephrological observation. A recurrence of urolithiasis was observed in 35.6% of the cases. Treating ureteral lithiasis in young infants remains a big challenge. Our series shows that modern minimal invasive techniques used by very experienced pediatric urologists in high volume centers gives excellent results. In most cases, surgery should no longer need to be an option.

Dent disease in Poland: what we have learned so far?

PURPOSE: Dent disease (DD) is a rare tubulopathy characterized by proximal tubular dysfunction leading to chronic kidney disease (CKD). The aim of the study was to characterize patients with DD in Poland. METHODS: A retrospective analysis of a national cohort with genetically confirmed diagnosis. RESULTS: Of 24 males, all patients except one carried mutations in the CLCN5 gene; in one patient a mutation in the OCRL gene was disclosed. Molecular diagnosis was delayed 1 year on average (range 0-21 years). The most common features were tubular proteinuria (100%), hypercalciuria (87%), and nephrocalcinosis (56%). CKD (≤stage II) and growth deficiency were found in 45 and 22% of patients, respectively. Over time, a progression of CKD and persistence of growth impairment was noted. Subnephrotic and nephrotic proteinuria (20%) was found in most patients, but tubular proteinuria was assessed in only 67% of patients. In one family steroid-resistant nephrotic syndrome prompted a genetic testing, and reverse phenotyping. Five children (20%) underwent kidney biopsy, and two of them were treated with immunosuppressants. Hydrochlorothiazide and angiotensin-converting enzyme inhibitors were prescribed for a significant proportion of patients (42 and 37.5%, respectively), while supplemental therapy with phosphate, potassium, vitamin D (12.5% each), and alkali (4.2%) was insufficient, when compared to the percentages of patients requiring repletion. CONCLUSIONS: We found CLCN5 mutations in the vast majority of Polish patients with DD. Proteinuria was the most constant finding; however, tubular proteins were not assessed commonly, likely leading to delayed molecular diagnosis and misdiagnosis in some patients. More consideration should be given to optimize the therapy.