A retrospective comparison of Sun's tip-flexible semirigid ureterorenoscopy, super-mini percutaneous nephrolithotomy and flexible ureteroscopy applied to treat upper urinary tract calculi.

"Declarations Ethics approval and consent to participateEthical approval was obtained from the institutional review board (No. 2020ZSZY-LLK-148) of the Ethics Committee of Zhongshan Hospital of Traditional Chinese Medicine. All experiments or methods were performed in accordance with the Declaration of Helsinki. The informed consent was obtained from all patients over 16 years of age. For patients under 16 years of age, their respective parents or guardians were fully informed and signed the written informed consent. Consent for publicationNot applicable. Competing interestsThe authors have no conflicts of interest to declare. Competing interests The authors have no conflicts of interest to declare."

"Funding This study was supported by Zhongshan Social Public Welfare Science and Technology Research Special Fund (No. 2017B1045)."