Management of urinary stones by experts in stone disease (ESD 2026)

The prevalence of urinary stones range between 1 and 14% in different countries around the world. Men account for approximately 67% of cases, but the gender gap is narrowing over time. A study conducted in the Russian Federation showed that 22.2% of subjects interviewed with a questionnaire reported a history of urolithiasis. Stone formation begins with the urinary crystallization of less soluble solutes contained in urine (calcium oxalate and/or calcium phosphate, uric acid, struvite, and cystine), which often depends on urinary pH values. The most common calcium oxalate stones can grow on calcium phosphate plaques (Randall's plaque) that emerge on the surface of the papilla or on calcium oxalate plugs that form in the collecting ducts due to excessive concentrations of calcium or oxalate. Randall's plaques form due to a proinflammatory process initiated by local macrophages with activation of fibroblasts, matrix modeling, and interstitial calcium phosphate deposition. The inhibitory effect of crystallization and crystal aggregation was studied in vitro demonstrating a reduction in the nucleation inhibition index and in aggregation inhibition index in renal stone formers compared to healthy controls (2.15% vs 6.15% and 34.15% vs 62.15%, respectively). Urolithiasis is a cluster of metabolic phenotypes interacting through urinary supersaturation. The metabolic work-up consists in the identification of high-risk patients requiring full metabolic profiling by basic metabolic panel, two 24-hour urine collections, stone analysis (when available), and software assessment of Relative Supersaturation (RSS) for calcium oxalate, calcium phosphate and uric acid. The endpoint of therapy is to reduce RSS not just to achieve "normal" lab values. The most active agents used for the prevention of calcium oxalate stones are phytate, potassium citrate, and magnesium. Phytate stands as the most potent inhibitor of both calcium oxalate and calcium phosphate crystallization exerting its therapeutic effect without modifying urinary pH. It is the ideal inhibitor of calcium oxalate crystallization, particularly in cases of severe hypercalciuria, because it does not increase the risk of secondary calcium phosphate crystallization. Potassium citrate has a weaker direct inhibitory potential at the concentrations achieved in standard clinical practice and tends to increase urinary pH, posing a risk of inducing calcium phosphate precipitation. Magnesium does not affect urinary pH, but its inhibitory effect of calcium oxalate crystallization is negligible at conventional clinical doses. However, it reduces intestinal oxalate absorption and subsequent urinary oxalate excretion, making it a potentially useful agent for stone prevention. The combination of phytate and magnesium represents an ideal synergistic strategy for the prevention of recurrent calcium oxalate urolithiasis. Medical expulsive therapy with alpha-blockers is generally well tolerated, although may be associated with hypotension, dizziness, and ejaculatory dysfunction. Nonsteroidal anti-inflammatory drugs should be used with caution due to the risks of renal impairment and gastrointestinal complications, whereas opioids should be reserved for selected cases because of their potential for adverse gastrointestinal effects and dependency. A proactive strategy focused on prevention, combining lifestyle changes, metabolic assessment, and targeted treatment, offers significant clinical, economic, and ecological advantages. A comprehensive approaches, including increased hydration, dietary modifications, metabolic evaluation and pharmacological treatment can reduce recurrence rates by 60-80% and lower overall costs per each event avoided. However, long-term compliance remains challenging, particularly when lifestyle recommendations are perceived as restrictive or complex. To address this challenge, mobile health applications are emerging as effective tools to support lifestyle modifications and enhance patient engagement. Currently the surgical treatment of urinary stones is based on percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). Recent advancements in PCNL are miniaturized tracts, suction integrated lithotripsy, enhanced ultrasound guided access, and optimized endoscopic combined intrarenal surgery (ECIRS) techniques. Current evidence increasingly favors supine PCNL as a highly efficient technique, demonstrating shorter operative times and lower complication rates compared to the prone approach. Prone positioning remains a valuable option for specific clinical scenarios requiring complex puncture strategies or multitract access. Modified or intermediate positions remain a valuable tactical option in challenging scenarios, such as significant anatomical deformities or developmental renal anomalies, where a personalized approach is required. True supine position without bolster or tilting can be facilitated by using the "Dixit Line" as anatomical landmark for safe planning of calyceal puncture. RIRS innovations are related to new lasers for stone dusting, suction integrated access sheaths, slim digital flexible ureteroscopes, and pressure controlled systems that improve efficiency and safety. The ultra-slim HU-30S ureteroscope enables retrograde intrarenal surgery (RIRS) without pre-stenting and is easily manipulated through a 9 or 10 F sheath providing greater infusion space and preventing pressure and temperature rise during laser lithotripsy, Flexible and navigable suction ureteral access sheaths (FANS) represent one of the most significant recent innovations in RIRS combining active suction with distal flexibility and navigability to the target calyx and allowing direct evacuation of stone dust and fragments during laser lithotripsy. RIRS is also a safe and effective solution in selected anomalous kidneys such as horseshoe kidneys, ectopic pelvic kidneys, calyceal diverticular stones and selected nephrocalcinosis cases for reducing intraductal pressure or removing obstructive stones. PCNL remains the first option for staghorn calculi with stone-free rates ranging from 70% to 90% although it has come limitations as bleeding, sepsis, and the possible need for multiple access tracts or staged procedures. Mini-PCNL provides stone-free rates comparable to standard PCNL, with reduced hemoglobin drop and transfusion risk, although operative time may be longer. The integration of suction systems and the simultaneous retrograde approach can potentially shorten operative time and perioperative morbidity as well as increasing the stone-free rates. Retrograde intrarenal surgery as monotherapy has a limited role for staghorn stones. Complications of surgical treatment of kidney stones are related to increased intrarenal pressure and temperature resulting from irrigation and laser use, and the risk of intraoperative bleeding. All the minimally invasive treatments for stone removal still imply a risk of kidney damage, with mechanisms and extent varying across methods. ESWL can cause self-limiting kidney injury by mechanical and vascular trauma although repeated high-energy shocks could cause fibrosis and hypertension. Major damage (hematoma, steinstrasse) is rare. RIRS carries risks of kidney damage from high intrarenal pressure (above 40 cm of water) and heat from high-power lasers whereas PCNL is the more invasive procedure being associated with risks of trauma, vascular injury and infectious complications. Anticoagulant and antiplatelet therapy increase the risk of bleeding complications during stone removal procedures. The risk is moderate to high for extracorporeal shock wave lithotripsy (ESWL), low to moderate for ureteroscopy, and high for percutaneous nephrolithotomy. Ureteroscopy should be preferred whenever possible in patients on anticoagulant and/or antiplatelet therapy. ESWL requires discontinuing therapeutic low-molecular-weight heparin and careful evaluation of risk-benefit for aspirin. Percutaneous nephrolithotomy requires discontinuation of warfarin, direct oral anticoagulants, and clopidogrel. Routine bridging is no longer recommended for most patients. Stent encrustation represents a clinically significant adverse event, leading to complex management scenarios and increased healthcare costs. Prolonged indwelling time is commonly associated with encrustation with rates up to 75% at >12 weeks. Minimizing indwelling time, following strict follow-up protocols, optimizing stent material selection, and modifying the urinary environment are essential to prevent stent encrustation. Administration of L-methionine, phytate and theobromine was associated with 95% lower odds of stent encrustation compared to a placebo group. Urinary acidification is also a non-antibiotic strategy for managing recurrent urinary tract infections in women. L-methionine can reduce urinary pH to around 5.0 creating a hostile environment for bacterial survival. It also enhances the effectiveness of certain antibiotics as fosfomycin which increases its activity at lower pH levels. Phytate can be used in conjunction to acidification to reduce bacterial proliferation and persistence in the urinary tract by multiple antimicrobial effects.