Dehong Cao1, Liangren Liu1, Liang Gao1, Qiang Wei2. 1. Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China. 2. Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China. Electronic address: weiqiang339@126.com.