1. Department of Respiratory, Xi’an Children’s Hospital, Xi’an 710003, Shaanxi Province, P.R. China
2. Department of Otolaryngological, Hospital of Northwest Polytechnical University, Xi’an 710072, Shaanxi Province, P.R. China
3. Department of Joint Surgery, Xi’an Hong Hui Hospital, Xi’an Jiaotong University Health Science Center, Xi’an 710054, Shaanxi Province, P.R. China