Ideal Time of Stenting Prior to Ureteral Access Sheath for Stone Disease , Two vs Four Weeks Prospective Study

The miniaturization of endourological instruments and improvements in laser lithotripsy have revolutionized the approach to renal stones . - Flexible URS has become popular with urologists, as it is easy to learn, is associated with high stone-free rates, and is acceptable to patients. Firstly described in 1964 by Marshall, the uretroscope was only passively deflectable and did not include working channel. - Although the first successful procedure in humans with a ureteroscope integrating active deflection has been reported by Takayasu, it was not until 1987 that Demetrius Bagley introduced flexible ureteroscopy as we know it today ).] - two types of flexible uretroscopy can be distinguished : fiberoptic and digital flexible URS. The difference between them is the image relay and light transmission. - Now either to use ureteral access sheath (AS) or not , but usage of AS decrease intrarenal pressure and clear vision by drainage of dust , so , for access of AS stent better to be inserted prior to the procedure ) So, there are little publications regarding the optimal timing of the stent In this study we will assess the feasibility of passage AS after two versus four weeks from stent insertion