At univariate logistic regression , middle ureteral stone ( OR 3.33 , p = 0.04 ) , distal ureteral stone ( OR 4.4 , p = 0.02 ) , LL ( OR 3.05 , p = 0.04 ) and Hounsfield units ( HUs ) ( OR 1.07 , p = 0.03 ) were significantly predictive factors of a SF status .