Usefulness of adenotonsillar size for prediction of severity of obstructive sleep apnea and flow limitation

Objective. Adenotonsillar hypertrophy is considered the most common cause of pediatric obstructive sleep apnea syndrome (OSAS). This study aimed to evaluate the relationships between tonsil/adenoid size, parameters of polysomnography, and subjective sleep symptoms. Study Design. Case-control studies. Setting. Tertiary care center. Subjects and Methods. A 4-point tonsil grading method and adenoid-nasopharynx (AN) ratio were used to categorize tonsil and adenoid size, respectively. Sleep questionnaires (Korean version of the Obstructive Sleep Apnea-18 [KOSA-18]) and full-attended polysomnography were performed. Results. The subjects (n = 70) were divided into a control group (n = 31, apnea-hypopnea index [AHI] <1) and an OSAS group (n = 39, AHI ≥1), which was subdivided into mild and moderate to severe groups. Tonsil/adenoid size showed a statistically significant difference between control and OSAS groups, but these differences had no clinical significance. In addition, tonsil/adenoid size did not differ significantly among 2 OSAS severity subgroups. Only adenoid size in the total and OSAS groups was related to quality of life (QOL) by the KOSA-18. The AN ratio was related to lowest oxygen saturation only in the OSAS group, especially in the moderate to severe OSAS group, but tonsil size was related to flow limitation in total and supine positions in the control group. In the control group, flow limitation was not associated with QOL. Conclusion. Tonsil/adenoid size did not predict the severity of AHI. Nevertheless, adenoid size might be related to lowest oxygen saturation, which is thought to be related to subjective symptoms. Although flow limitation was related to tonsil size but not to QOL in the control group, further research will be needed to understand the importance of flow limitation and upper airway resistance syndrome in the pediatric population.