Evidence for persistence of upper airway narrowing during sleep, 12 years after adenotonsillectomy

Aims: To establish whether subjects with previous evidence of sleep apnoea prior to adenotonsillectomy continue to have evidence of narrower upper airways during sleep, 12 years later. Methods: Twenty subjects (median age 16 years) underwent repeat sleep studies at home, 12 years after such studies had shown significant sleep apnoea in many of them prior to an adenotonsillectomy. Twenty control subjects, also studied 12 years ago, underwent repeat home sleep studies as well. The sleep studies provided information on snoring, hypoxia, and inspiratory effort (from measures of pulse transit time). A questionnaire was also administered, the subjects were weighed, and their heights measured. Results: There was more reported snoring in the previous adenotonsillectomy group (50% versus 20%) and also during the sleep study (80 versus 31 snores per hour). The measure of inspiratory effort overnight was higher in the previous adenotonsillectomy group (15.6 versus 12.3 ms). Allowance for potentially confounding variables (obesity and nasal congestion) partially reduced the statistical significance of the difference in snoring, but not that of the measure of inspiratory effort. Conclusion: Results suggest that a narrower upper airway during sleep, to the point of snoring, persists 12 years after adenotonsillectomy, and may partly account for the occurrence earlier of preoperative sleep apnoea while adenotonsillar hypertrophy was present. It is not known if this narrowing is one of the risk factors for later development of adult sleep apnoea.