“…The placement of flexible ureteroscope into the ureter and renal pelvis had been proved minimally invasive, safe, and highly effective for the treatment of ureter and renal stones. As compared with flexible ureteroscope, the other available treatment techniques, such as ESWL and PCNL, were difficult to perform and had poor therapeutic effects [5] . The management of nephrolithiasis in patients with the characteristics of gravel, multiple renal calculi, bleeding tendency, obesity, anomalous kidneys (horseshoe kidney, ectopic kidney, and kidney transplant), pregnant women, and other special patients imparted a special challenge to the treating urologist.…”