Acoustic rhinometry in the evaluation of congenital choanal malformations

Previous studies have shown that acoustic rhinometry (AR) is well suited to describe the nasal airway dimensions in healthy infants. The technique is quick to perform, non-invasive, without potential hazards and requires minimal cooperation. Due to the small dimensions of the infant nasal airways, the optimized miniprobe (Rhinometrics, Lynge, Denmark) provides abilities superior to those of adult probes. The equipment is portable and examinations can be performed in the maternity ward, out-patient department or at home. Measurements on models simulating the pre- and post-operative nasal geometry were performed to determine the accuracy and resolution of AR and to improve the interpretation of the curves obtained in vivo. Acoustic measurements in five infants with congenital respiratory distress caused by bilateral choanal atresia or stenosis have been compared with CT-scans and the results of the model simulations to evaluate the diagnostic value of the method. We conclude that AR represents a new and valuable tool in the diagnosis of congenital choanal malformations. Despite current technical limitations, it may also be of value in the post-operative evaluation, particularly if the posterior part of the septum is not resected.