Yutian Lai1, Xinyi Ye2, Xin Wang3, Yang Hu4. 1. Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China. 2. Department of Endoscopy Center, West China Hospital, Sichuan University, Chengdu, China. 3. Department of Thoracic Surgery, Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China. 4. Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China. Electronic address: huyangthoracic@126.com.