The impact of stenting prior to oral chemolysis of upper urinary tract uric acid stones.

ABSTRACT

PURPOSE: To evaluate the impact of ureteral stenting on the success rate of oral chemolysis in the management of suspected uric acid upper urinary tract (UUT) stones. METHODS: Retrospective matched-pair analysis of 172 patients treated with oral chemolysis from 01/2010 to 12/2019. Patients with low density (upon non-contrast enhanced computer tomography [NCCT]), radiolucent (on plain radiography) urinary stones, a low urine pH (< 6) and/or history of uric acid urolithiasis were included. Potassium citrate and/or sodium bicarbonate were used for alkalization (target urine pH 6.5-7.2). Patient 11 matching was performed for the presence of indwelling ureteral stent, stone diameter, stone density, and stone localization. Stone-free status was evaluated after 12 weeks using NCCT. Multivariable logistic regression analysis was used to assess factors affecting the outcome. RESULTS: Mean patient age was 61 years (73% males). Mean stone size was 12 mm. Overall success rates after 12-weeks of chemolysis for stones at any localization in the UUT and ureteral stones were 60.5 and 77.3%, respectively. Smaller stone size (OR = 0.94; CI 0.888-0.992; p = 0.026) and lower pre-treatment urine pH (OR = 0.131; CI 0.023-0.737; p = 0.021) significantly increased the success of oral chemolysis. Ureteral stenting did not have any impact on the efficacy of oral chemolysis. CONCLUSION: Oral chemolysis is an effective treatment modality for patients with UUT stones suspected of uric acid content irrespective of ureteral stenting. Smaller stone diameter and lower urine pH at diagnosis increase its efficacy.