The incidence of variation in the subglottic size was investigated in 3304 infants and children. A mild degree of congenital subglottic stenosis was found in 0.91% and a moderate degree of stenosis in 0.06% of the patients. A mild degree of congenital subglottic enlargement was noted in 0.7% and moderate enlargement in 0.06% of the patients.
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