RESUMO
Although it is presumed that both kidneys excrete similar urinary constituents, it is a general observation that the majority of patients present with unilateral stone disease. The aim of this work was to study the laterally of recurrence in calcium stone formers. In a retrospective study of 154 patients treated for recurrent symptomatic nephrolithiasis at our institution between January 1982 and December 2006, the side of stone formation was determined by an analysis of radiographic findings and symptomatic history. Patients with hydronephrosis, major renal anatomic anomalies and non-calcium stones were excluded from the study. The features of unilateral stone forming and bilateral stone forming were compared. Statistical analysis was done using Student's t-test. Of the 154 patients, 102 were males and 52 females with a male-to-female ratio of 1:2. One hundred and fourteen patients had unilateral stones [Group A], 64 [56%] on the left and 50 [44%] on the right side. In 40 patients they were bilateral [Group B]. Comparing Groups A and B, the mean age at the first stone episode was 41.5 versus 38.3 years, the mean interval between the first stone and recurrence was 9.6 versus 9.9 years, and the mean follow-up was 13.3 versus 14.9 years [differences not statistically significant]. In Group A, 101 patients [89%] had unilateral stone recurrence episodes with 86 of these 101 patients [85%] developing stones on the same side as the primary stone. Of the 40 patients with bilateral stone formation, 30 patients [75%] had bilateral stone recurrence episodes. Recurrent stone formers commonly present with calculi on the same side and the etiology of this phenomenon is unclear, but anatomic and external triggers should be considered