Adenoid hypertrophy: Correlation of radiographic parameters to postoperative adenoid volume among children at Moi Teaching and Referral Hospital, Eldoret.

Abstract

Background: Adenoid hypertrophy is a common clinical condition especially in the paediatric population. Postnasal space (PNS) x-rays are the imaging modality frequently used to assess the adenoids. Various objective parameters of assessing adenoid size on PNS x-ray have been proposed with no agreement on which is most suitable. In this study, the correlation of two radiographic parameters: adenoidal-nasopharyngeal ratio (ANR) and antroadenoid diameter (AA diameter) to the volume of adenoid tissues measured postoperatively will be compared, in order to determine which is more suitable in assessing the adenoids on postnasal space x-ray. Objective: To determine and compare the correlation of ANR and AA diameter to postoperative adenoid volume in order to establish which of the two parameters of assessing adenoid size on postnasal space x-ray is more suitable. Methods: This was a cross-sectional study carried out at the Moi Teaching and Referral Hospital (MTRH) between September 2017 and August 2018. 107 patients aged below 15 years diagnosed with adenoid hypertrophy and scheduled to undergo adenoidectomy were enrolled. All the x-rays were reviewed by the principal investigator and findings verified by two consultant radiologists. The postoperative volume of the adenoid tissues was measured by a trained research assistant. Data were analysed using STATA version 13E. Descriptive statistics were summarized using tables and graphs. Correlation of ANR and AA diameter to the postoperative adenoid volume was calculated using Pearson‟s correlation coefficient. Correlation was calculated controlling for the number of days between the x-ray and surgery which was a potential confounding factor. Comparison of the two correlation coefficients was carried out using Steiger‟s Z-test. Results: The age of the participants ranged from 11 months to 11 years; mean of 3.4 years. The mean ANR was 0.70, mean AA diameter was 3.10mm while the mean postoperative adenoid volume was 2.83mL. Correlation of the ANR to the postoperative adenoid volume was 0.661(p<0.001) while that of the AA diameter was -0.222 (p=0.022). Null hypothesis was tested using Steiger‟s Z-test and the difference between the two correlation coefficients found to be significant; the ANR was determined to have a stronger correlation to adenoid volume than the AA diameter. Conclusions: The correlation of ANR to postoperative adenoid volume was moderately positive and statistically significant at 0.661 while that of AA diameter to postoperative adenoid volume was weak and negative but statistically significant at -0.222. Comparing the correlation of the two radiographic parameters, the ANR is determined to have a stronger correlation to the adenoid volume and the difference between the two is significant. Thus, the ANR is a better predictor of adenoid volume than the AA diameter. Recommendation: Use of the ANR when reporting PNS x-rays at MTRH.