Introduction
Urolithiasis is one of the most common health problems with increasing occurrence rate worldwide[1]. In recent years, the number of patients with upper urinary tract calculi has increased significantly, most of them were renal calculi. Among of these patients, 25% of them need surgical intervention when they were diagnosed[2]. At present, minimally invasive surgery is the main treatment for the upper urinary tract stone, which including extracorporeal shock wave lithotripsy(ESWL), laparoscopic ureterolithotomy, percutaneous nephrolithotomy(PCNL), ureteroscopy lithotripsy(URS) and flexible ureteroscopy and laser lithotripsy (FURSL).With advances in endoscopic technology coupled with the development of laser lithotripsy systems and novel endoscopic baskets, flexible ureteroscopy has become an increasingly popular option for the treatment of upper urinary tract stones, especially for renal stones[3-7]. At present, many literatures[8-11] show that flexible ureteroscopy can successfully treat patients with stones > 2 cm with a high stone-free rate and a low complication rate, and show that the efficacy of flexible ureteroscopy can allow an alternative to PCNL. With the continuous improvement and perfection of flexible ureteroscope and associated lithotripsy equipment, especially the development of YAG holmium laser system, it has the advantages of small trauma and high stone free rate (SFR). It has brought a qualitative leap for the minimally invasive treatment of upper urinary tract calculi and is favored by the majority of clinicians. However, in the clinical practices, we found that the actual effect of FURSL is not as good as most literature reports, it will be influenced by many factors and there are some shortcomings and limitations. Base on it, we reviewed the patients treated by FURSL in our unit from January 2015 to October 2020, and analyzed the clinical efficacy of FURSL in the treatment of upper urinary tract calculi.