<b>Introduction</b>: Cystinuria is a genetic disorder marked by elevated urinary cystine excretion and recurrent cystine nephrolithiasis. Interestingly, despite seemingly similar contralateral renal anatomy, a subset of cystinuric patients consistently form stones in only one kidney. The aim of this study is to evaluate clinical outcomes in unilateral versus bilateral cystine stone formers. <b>Methods</b>: We performed a retrospective case-control study of cystinuric patients evaluated and treated at the University of California, San Francisco between 1994 and 2015 and categorized patients as either unilateral or bilateral stone formers. Clinical presentation, baseline patient demographics, stone procedures, medical therapy regimens, and long term renal function were compared between the two groups. <b>Results</b>: 42 cystine stone patients (22 female, 20 male) were included in the analysis. The median age at first presentation was 18.5 years and median age at study conclusion was 45.5 years. Two-thirds of patients (n=28) had a history of bilateral stones while one-third (n=14) had unilateral stones. Medical therapy regimens were similar between groups. Despite an increased average number of lifetime surgeries (7.5 sessions for bilateral vs 3.7 sessions for unilateral, p < 0.05), there was no significant difference in medians of the most recent glomerular filtration rate when compared to unilateral stone formers (81.5 versus 95 ml/min, respectively; p = 0.28). <b>Conclusions</b>: The majority of cystinuric patients within our cohort will form stones bilaterally during their lifetime, and require more surgical interventions than unilateral stone formers. Despite this, overall renal function is well preserved in unilateral and bilateral cystinuric stone formers treated with minimally invasive stone extraction procedures.
Journal of endourology. 2017 Nov 27 [Epub ahead of print]
Manint Usawachintachit, Benjamin Sherer, Matthew Hudnall, David T Tzou, Kazumi Taguchi, Ryan S Hsi, Marshall Stoller, Thomas Chi
University of California San Francisco, Urology , 400 Parnassus Avenue , San Francisco, California, United States , 94143 ; ., University of California San Francisco, Urology, San Francisco, California, United States ; ., San Francisco, California, United States ; ., University of California San Francisco, 8785 , 400 Parnassus Avenue , San Francisco, California, United States , 94143 ; ., University of California San Francisco, 8785, Urology , 400 parnassus, suite A634 , San Francisco, California, United States , 94122., Vanderbilt University Medical Center, 12328, Urologic Surgery , A-1302 Medical Center North , Nashville, Tennessee, United States , 37232 ; ., University of California San Francisco, Urology, San Francisco, California, United States ; ., University of California San Francisco, Urology , 400 Parnassus Ave , 6th floor Urology Clinics A638 , San Francisco, California, United States , 94143 ; .