[1] Univ Hlth Sci Porto Alegre UFCSPA, Med Sch Fed, Rua Ciro Gaviao 601,Apt 195, BR-90470020 Porto Alegre, RS, Brazil
[2] UFCSPA, Grad Program Pediat, Porto Alegre, RS, Brazil
[3] Santa Casa de Misericordia Hosp Porto Alegre, Otorhinolaryngol Serv, Porto Alegre, RS, Brazil
[4] Santo Antonio Childrens Hosp Porto Alegre, Pediat Otolaryngol Serv, Porto Alegre, RS, Brazil
[5] Univ Fed Rio Grande do Sul, Med Sch, Porto Alegre, RS, Brazil
[6] Vanderbilt Univ, Med Ctr, Dept Otolaryngol Head & Neck Surg, Nashville, TN USA