Keller EX, et al. - Researchers assessed the data related to adults with upper urinary tract stones to analyze the association of the size of spontaneously passed stones (SPS) with clinical parameters. They found 4.1 mm and 11.5 mm³, overall mean maximal stone diameter (MSD) and stone volume (SV) for 18,029 spontaneously passed stones (SPS), respectively. They recorded the lowest mean MSD and SV for calcium oxalate monohydrate ie, 3.6 mm and 9.0 mm³, respectively whereas the highest mean MSD and SV were observed for struvite ie, 7.9 mm and 61.0 mm³, respectively. They also noted stone composition and increasing age, the independent predictors of MSD ≥ 6 mm but no role of sex differentiation was observed.