Acoustic Rhinometry in the Pre-operative Assessment of Adenoidectomy Candidates

Abstract

Claims have been made for the potential of acoustic rhinometry (AR) in the evaluation of adenoidectomy patients. Little evidence has been presented to support such claims, and evidence is accumulating that AR is inaccurate in reflecting anatomical reality in the nasopharynx. We set out to establish whether acoustic rhinometry studies could predict operative decision-making sufficiently for it to be of assistance to the clinician, despite these theoretical and practical obstacles. A total of 101 patients aged 2-13 years were examined by AR using the impulse technique. Parameters were chosen from the area-distance function to indicate nasopharyngeal volumes and areas (decongested and non-decongested). This information was compared with findings at EUA (examination under anaesthesia-obstruction categories: A-'good airway' to D-'severe obstruction'), operative decision (2 categories-'obstructive' = remove, versus 'non obstructive' = leave in situ) and parents' symptom scores. Twenty-one patients were also evaluated post-operatively. There was considerable overlap between the AR parameters in the groups classified at EUA as 'obstructive' or 'non obstructive', but this overlap diminished after decongestion. Logistic regression demonstrated that the decongested volume and area parameters were of significant predictive value with respect to operative decision (odds ratio for unit change in volume = 0.82; 95% C.I. = 0.70-0.97; p = 0.018). Parents' analogue scores for snoring and for [snoring+obstruction+ mouthbreathing] were also of significant predictive value. The presence of rhinitis diminishes the predictive value of AR. Acoustic rhinometry has potential as a pre-operative evaluation of the nasopharyngeal airway in adenoidectomy candidates, but the predictive value is low unless combined with clinical factors.

The role of acoustic rhinometry in the diagnosis of adenoidal hypertrophy in pre-school children

“…The accuracy of this technique for measuring nasopharyngeal cross-sectional areas may be re®ned, to some extent, using topical nasal decongestant solutions prior to acoustic measurements [5]. Some investigators have reported improved acoustic measurements of the nasal cavity using contoured nasal adapters.…”

The influence of birch pollination on the adenoid size in children with intermittent allergic rhinitis

“…In this examination, the mean change of value of nasopharyngeal volume (NPV) was estimated. In accordance with the literature, it was assumed that the most representative section of the rhinometric curve is a 4 cm section situated at a distance of 6-12 cm from the front nostril [4][5][6][7][8].…”

Avaliação da cavidade nasal e nasofaringe através da rinometria acústica antes e após adenoidectomia

“…Fisher et al 12 referem que a RA não tem acurácia para evidenciar pequenas alterações de volume na nasofaringe e conclui que a RA tem pouco valor preditivo se usada isoladamente para avaliar a presença de adenóide hipertrófica; terá maior poder preditivo se avaliarmos conjuntamente com o quadro clínico.…”

“…Embora a RA tenha menor precisão para medir as dimensões da nasofaringe devido à existência de obstruções severas anteriores causando subestimação de regiões posteriores, aos movimentos voluntários e involuntários do palato mole, ao escape sonoro para a fossa nasal oposta e às próprias limitações físicas da técnica 5,12,14,15 , ela foi capaz de evidenciar o ganho de ASTM e volume pérveo na nasofaringe após a cirurgia.…”