Staghorn nephrolithiasis represents one of the most complex forms of urolithiasis, with treatment approaches remaining a subject of ongoing debate among specialists. This study aims to assess the effectiveness and safety of oral chemolysis using citrate mixtures in treating staghorn urate nephrolithiasis. A prospective, multicenter cohort study was conducted from January 2023 to October 2024 among patients with CT-diagnosed staghorn stones of presumed urate composition (average urine pH ≤ 5.8, average stone density ≤ 650 HU, radiolucent on urogram or topogram) who received oral chemolysis with a citrate mixture containing citric acid, potassium bicarbonate, and sodium citrate («Blemaren»). Patients were recruited from outpatient clinics and hospitals in Moscow.
Results: Of the 49 patients included in the study, 2 were excluded within the first 2 months. Complete stone dissolution was achieved in 30 patients (63.8%), while 17 patients (36.2%) eventually required surgical intervention. Among these, 4 patients (8.5%) achieved complete stone dissolution within 1 month of therapy, 18 patients (38%) within 3 months, and 8 patients (17%) within 6 months. Of the stones removed surgically, 12 (70.6%) were calcium oxalate, and 5 (29.4%) were uric acid stones. Consequently, the proportion of patients with non-calcium oxalate stones who did not achieve complete stone dissolution was 14.3%. Stone density was the only parameter that significantly influenced the likelihood of stone dissolution and the risk of surgical intervention (p<0.05). According to regression analysis, the likelihood of stone dissolution decreased by a factor of 1.012 with each unit increase in stone density, while the risk of surgery increased by a factor of 1.008 under the same conditions.
Conclusions: The results of this study demonstrate that oral chemolysis for staghorn uric acid nephrolithiasis is an effective method and may serve as a viable alternative to surgical treatment, potentially reducing the associated risks of anesthesia and surgery for this patient group.

Keywords: oral chemolysis, staghorn uric acid stones, citrate mixtures, urolithiasis