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.

A naked-eye comparison of image quality between a portable versus a fixed camera system for digital flexible ureterorenoscopy - A single centre experience.

OBJECTIVE: To assess the image quality using the portable OTV-SI (Olympus, Southend, UK) light source system compared to a dedicated fixed standard stack system for flexible ureterorenoscopy (URS) as judged by the human eye. METHODS: We compared two differing flexible URS set-ups. The first was our normal completely digital fixed set-up, comprising a flexible ureteroscope and matching digital stack system (CLV-S40 PRO-6E, Olympus). The second set-up comprised the same digital ureteroscope but with a conventional non-digital stack system and the OTV-SI portable light source. Seven experienced urologists were asked to subjectively assess the quality of the video sequences with the naked eye. The image qualities assessed were as follows: colour, distortion, graininess, depth perception, contrast, and glare. Finally, they were asked to guess whether they were observing images from the normal fixed set-up or the portable set-up. Fisher's exact test was used to compare the two sets of nominal variables. RESULTS: There were no significant differences in the observation ratings between the fixed and portable systems, independent of observer or image settings. Also, the surgeons were not able to correctly guess which stack system had been used. CONCLUSION: For flexible URS imaging, the combination of a digital ureteroscope with a conventional non-digital stack system together with the OTV-SI portable light source was subjectively found not to be inferior to the completely digital fixed set-up. Thus, the cheaper and smaller portable system could be considered as an economical option without substantial loss of image quality, especially useful in developing countries.

Renal Pseudoaneurysm after Flexible Ureterorenoscopy - An Unusual Complication.

Pseudoaneurysm following flexible ureterorenoscopy has not been reported so far. The etiology remains unclear as high intra-renal pressure, direct laser damage and damage through stiff guidewire puncture had all been avoided. We like to share this case to make urologists aware of this unusual complication and discuss possible causes and therapeutic approaches.

Current Trends in Urolithiasis Treatment in Various European Health Systems.

OBJECTIVE: In spite of readily available evidence-based guidelines on urolithiasis treatment, practical applications of treatments vary from country to country, or even within countries. The choice of treatment depends not only on the evidence, but often on general non-medical decision factors such as infrastructure, expertise, trends, patient demands, industry drive and reimbursement levels. In turn, many of these factors are interdependent and a result of the individual National Health System. METHOD: In an attempt to get a crude picture of trends and practices in stone treatment across Europe, a group of well-renowned international experts in the field were asked to reply to a set of standard questions relating to stone treatments, health systems and adherence to guidelines (level of evidence D = expert opinion). RESULTS: The above-mentioned interdependencies showed a varying picture in different countries. Overall, there is a trend away from lithotripsy and toward ureterorenoscopy. However, the choice of treatment is largely dependent on the affordability of infrastructure. Urologists may make choices based on the national reimbursement system, too. CONCLUSION: Without claiming to represent a scientifically sound study, this survey represents an interesting insight into a representative cross-section of European urological current practices and trends in urolithiasis treatment.

Laparoscopic varicocelectomy in the management of chronic scrotal pain.

BACKGROUND AND OBJECTIVES: To evaluate the usefulness of laparoscopic varicocelectomy in the management of chronic scrotal pain. METHODS: Between 2009 and 2011, 48 patients in total were treated with laparoscopic varicocelectomy for dull scrotal pain that worsened with physical activity and was attributed to varicoceles. All patients were followed up at 3 and 6 months and biannually thereafter with a physical examination, visual analog scale score, and ultrasonographic scan in selected cases. RESULTS: The mean age was 38.2 years (range, 23-54 years). The mean follow-up period was 19.6 months (range, 6-26 months). Bilateral varicoceles were present in 7 patients (14.6%), and a unilateral varicocele was present in 41 (85.4%). The varicocele was grade 3 in 27 patients (56.3%), grade 2 in 20 (41.6%), and grade 1 in 1 (2.1%). The mean preoperative visual analog scale score was 4.8 on a scale from 0 to 10. The mean postoperative visual analog scale score at 3 months was 0.8. After the procedure, 42 patients (87.5%) had a significant improvement in the visual analog scale score (P<.001); 5 (10.4%) had symptom improvement, although it was not statistically significant; and 1 (2.1%) remained unchanged. During follow-up, we observed 5 recurrences (10.4%) whereas de novo hydrocele formation was identified in 4 individuals (8.3%). CONCLUSION: Laparoscopic varicocelectomy is efficient in the treatment of symptomatic varicoceles with a low complication rate. However, careful patient selection is necessary because it appears that individuals presenting with sharp, radiating testicular pain and/or a low-grade varicocele are less likely to benefit from this procedure.

A self-expanding thermolabile nitinol stent as a minimally invasive treatment alternative for ureteral strictures in renal transplant patients.

BACKGROUND AND PURPOSE: Ureteral obstruction in renal transplant allografts secondary to strictures can pose a challenging problem. Its incidence is reported between 0.5% and 4.7%. Usually, open surgical repair is performed. We present a series of patients in whom a metal Memokath™ 051 stent has been used as a minimally invasive treatment alternative. METHODS: We analyzed our data on the use of thermo-expandable metallic Memokath 051 stents for ureteral strictures in renal transplant patients. RESULTS: Between 2003 and 2010, eight male kidney recipients with a mean age of 49 years and obstructed ureters after kidney transplantation were treated with ureteral Memokath insertion. In six patients, the obstruction was at the level of the anastomosis, and in two, at the pelviureteral junction. After a mean follow-up of 4 years, half of the stents are in situ providing a good graft function. The average indwelling time is 4 years. Spontaneous resolution of the stricture without the need for further stent insertion was seen in three patients after a mean indwelling time of 7.3 months. There was one treatment failure in a patient with an obstructed, dilated, and convoluted ureter that was unable to withhold the stent in situ. No perioperative complications were recorded in this series. The overall success rate was 87%. CONCLUSION: Ureteral stent placement with the Memokath 051 is a safe minimally invasive treatment alternative for ureteral strictures in renal transplant recipients.