[1] HCPA, Div Otolaryngol Head & Neck Surg, Porto Alegre, RS, Brazil
[2] HCPA, Div Otolaryngol, Porto Alegre, RS, Brazil
[3] HCPA, Div Radiol, Porto Alegre, RS, Brazil
[4] Univ Fed Rio Grande do Sul, Grad Program Epidemiol, Porto Alegre, RS, Brazil
[5] Univ Fed Rio Grande do Sul, Dept Surg, Porto Alegre, RS, Brazil
[6] HCPA, Div Craniomaxillofacial Surg, Porto Alegre, RS, Brazil
[7] Univ Fed Rio Grande do Sul, Dept Otolaryngol & Ophthalmol, Porto Alegre, RS, Brazil