Adenoid-nasopharyngeal ratio may predict otitis media with effusion in adenoid hypertrophy patients

The study found that when the A/N ratio reaches 0.815, patients are at a higher risk for otitis media with effusion (OME), so it could predict OME in patients with adenoid hypertrophy.

Adenoid hypertrophy (AH) is an obstructive condition in which the size of the adenoids increases; it is present in about 19%–70% of children and could cause mouth breathing, hypoplasia of mid-face, snoring, and is always complicated with otitis media with effusion. About 90% of patients with OME could self-cure in three months. Still, a small proportion would develop cholesteatoma, irreversible hearing loss, and concerns such as delays in speech development and behavioural disorders.

Fujioka introduced the adenoid-nasopharyngeal (A/N) ratio; it means the adenoid size takes the proportion of the nasopharyngeal. It is a classical index for evaluating the extent of AH that can reflect the obstruction ratio of the nasopharyngeal. It is noted that patients with adenoid hypertrophy with OME have a higher A/N ratio than AH without OME.

Against the above background, Ping Li, Department of Otolaryngology-Head and Neck Surgery, Shandong University, Jinan, P. R. China, and colleagues explored the associated factors of OME and analyzed the diagnostic value of the A/N ratio to OME.

For this purpose, the authors collected patients with adenoid hypertrophy recently in 2 years, including age, sex, duration, with/without rhinosinusitis, and examination results, including pure tone audiometry (PTA), CBCT (Cone Beam Computerized Tomography) sinus imaging, allergen detection, and blood test. Patients were categorized into two groups based on Liden/Jerger's classification as Type B and type C, which was defined as the tympanometry abnormal group (TAG). The rest were put in the tympanometry normal group (TNG). The study included a total of 316 children.

The authors reported the following findings:

• Age and duration were significantly younger and shorter in TAG (6.0 vs.5.0); 12.0 vs 6.0).
• Compared to TNG, the allergen test results of fx5 (protein, milk, cod, wheat, peanut, and soybean) in TAG were higher (0.09 vs 0.14), but eosinophilia in blood was lower (count: 0.21 vs 0.18; ratio: 3.10 vs 2.50).
• The A/N ratio and Visual obstruction ratio had a statistical difference (Z = −3.770), but the two ratios didn't have too much disparity (0.82 VS 0.80), and they had a positive correlation (r = 0.345).
• The A/N ratio of TAG was higher than TNG (0.78 vs 0.86) and had a positive correlation with increasing negative middle ear pressure (r = −3.777).
• A/N ratio was an associated factor of OME (OR:1355.611), the cut-off value of A/N ratio was 0.815(sensitivity: 75.3%, specificity: 64.3%, area under the curve (AUC): 0.747).

Patients in the tympanometry abnormal group with higher A/N ratio and Lund-Mackay scores showed negative correlations with Negative Middle Ear Pressure. It suggests that children with larger adenoid sizes are more likely to get OME and AH with OME children more easily have chronic rhinosinusitis than AH children without OMR.

"A/N ratio was an associated factor of OME, and can be used as an index to predict OME in children with adenoid hypertrophy when A/N ratio reaches up to 0.815," the researchers wrote.

Reference:

Li P, Li T, Yu L, et al. Predictive Value of Adenoid-Nasopharyngeal Ratio in the Diagnosis of Secretory Otitis Media. Ear, Nose & Throat Journal. 2022;0(0). doi:10.1177/01455613221144496