Abstract
A-mode ultrasound examination was used as a screening test for 442 children (4–10 years) undergoing adenoidectomy or adenotonsillectomy. In 85 sinuses of 65 (15 %) children the A-scan showed a back wall echo indicating retained secretion in the sinus. Antral lavage yielded discharge from 81 (95 %) of these sinuses. After ten days treatment with amoxicillin and decongestant the ultrasonography demonstrated the disappearance of fluid retention in 67 (83 %) of the sinuses. Thirty days afterwards A-scan was positive in only two cases. All initial radiologic findings of these 65 children were abnormal. After 30 days treatment still 47 per cent of the radiographs were abnormal mostly due to a slight mucosal thickening in the sinuses.