Ureteroscopy has been considered the best approach when treating renal stones smaller than 2 cm. This procedure is usually performed together with ureteral access sheaths, which helps protect the ureter mucosa and lowers intrarenal pressure. Recently, a new vacuum-assisted ureteral access sheath called ClearPetra has entered US market and allows for continuous stone fragmentation and aspiration. Because there is little information on comparing this device with traditional approach (no sheath or non-vacuum-assisted sheath) in American population, we aim to compare those devices in terms of their ability to clear the kidney from kidney stones, as well as reduce infection rates postoperatively.