Analysis of Failure Factors in Flexible Ureteroscopy for Upper Ureteral Stones and Comparison with Ureterolithotomy: Development of a Simple Predictive Model - SHAH, ARSALAN IKRAM; yong, Wang; Ahamad, Pathan Iliyash; AMIN, HAMZA; KHAN, SALMAN (International Journal of Advance Research and Innovative Ideas In Education, 2025)