[1] Univ Penn, Childrens Hosp Philadelphia, Dept Surg, Philadelphia, PA 19104 USA
[2] Univ Penn, Perelman Sch Med, Philadelphia, PA 19104 USA
[3] Univ Penn, Childrens Hosp Philadelphia, Dept Pediat, Philadelphia, PA 19104 USA
[4] Univ Penn, Childrens Hosp Philadelphia, Pediat Thyroid Ctr, Philadelphia, PA 19104 USA
[5] Univ Penn, Childrens Hosp Philadelphia, Div Pediat Otolaryngol, Philadelphia, PA 19104 USA