Muscle fiber area distribution of musculus uvulae in obstructive sleep apnea and non-apneic snorers

OBJECTIVE: To determine whether differences exist in the morphology of upper airway muscles between apneic and non-apneic snorers DESIGN: Muscle characteristic analysis in patients undergoing upper airway surgery in a tertiary sleep center. SUBJECTS: 10 non-apneic snorers and 10 sleep apnea hypopnea syndrome (SAHS). MEASUREMENTS: Frequency distribution of musculus uvulae (MU) muscle fiber area determined from 475 +/- 207 (mean +/- s.d.) and 697 +/- 165 type IIA fibers and 92 +/- 32 and 68 +/- 45 type I fibers in snorers and SAHS, respectively. RESULTS: Histochemical analyses of MU revealed as expected that type IIA fibers occupied a significantly larger area within that muscle in SAHS compared to Snorers (89.4 +/- 5.8% and 76.1 +/- 15.1% respectively, P= 0.01), No difference was found in the frequency distribution of type I and type IIA fiber areas between the two groups comparing the between-groups and within-group variance of individual area distributions found in snorers and SAHS. CONCLUSION: There is no difference in muscle fiber area frequency distribution between non-apneic snorers and SAHS patients, This suggests that musculus uvulae of these groups of patients does not have a specific prevalence of atrophic or hypertrophic muscle fibers.