1. Department of Urinary Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
2. Center of Science Experiments, China Medical University, Shenyang, Liaoning 110122, P.R. China
3. Department of Urinary Surgery, General Hospital of Northern Theater Command, Shenyang, Liaoning 110001, P.R. China