Acoustic rhinometry, used as a method to demonstrate changes in the volume of the nasopharynx after adenoidectomy.

Acoustic rhinometry is a method of investigating the geometry of the nasal cavity and the nasopharynx. An acoustic impulse is transferred to the nasal cavity and the reflected signal is analysed expressing the cross-sectional area in the nasal cavity and the nasopharynx as a function of the distance from the nostril. The method provides an accurate and objective measurement of the geometry of the nasal cavity and the nasopharynx in a non-invasive way. In a series of 20 children, age range 4-16 years, it has been possible to demonstrate the changes in the volume of the nasopharynx after adenoidectomy. The relation between the volume of the adenoid and the calculated change of volume in the nasopharynx is found to be proportional and highly significant (P = 0.0005). It is concluded that acoustic rhinometry, which is very easy to perform, gives a reliable, objective measurement of the amount of adenoid tissue in the nasopharynx. The results from these and future studies may help reduce the number of unnecessary adenoidectomies.