[1] Qingdao Univ, Weihai Maternal & Child Hlth Hosp, Dept Otolaryngol Head & Neck Surg, Affiliated Weihai Hosp, Weihai, Peoples R China
[2] Dongying Dist Peoples Hosp, Dept Internal Med 1, Dongying, Peoples R China
[3] Qingdao Univ, Blood Purifying Ctr, Affiliated Qingdao Cent Hosp, Qingdao, Peoples R China
[4] Shandong First Med Univ, Dept Outpatient, Affiliated Hosp 2, Tai An, Peoples R China
[5] Laiyang Cent Hosp, Dept Otolaryngol, Yantai, Peoples R China
[6] Laiyang Cent Hosp, Dept Otolaryngol, 119 Changshan Rd, Yantai 265200, Peoples R China