Characterization of Upper Airway Obstruction by Fiber-Optic Nasolaryngoscopy and MRI in Preoperative OSAHS Patients

OBJECTIVE: To investigate changes in the upper airway and its surrounding soft tissue and to characterize the extent and severity of upper airway obstruction in 136 obstructive sleep apnea/hypopnea syndrome (OSAHS) patients who were awake. METHODS: OSAHS patients and healthy controls were evaluated by fiber-optic nasolaryngoscopy and MRI. The cross-sectional area and pharyngeal wall thickness of the retropalatal, retroglossal and epiglottic region were determined. RESULTS: Ninety-five percent of the mild OSAHS subjects had single-plane obstruction (vs. severe OSAHS, p < 0.05), 5.0% of the mild OSAHS subjects had two-plane obstruction (p < 0.05) and none of them had three-plane obstruction (p < 0.05). The cross-sectional area of the retropalatal, retroglossal and epiglottic region progressively declined as the severity of OSAHS increased (severe OSAHS vs. controls, p < 0.05). The lateral pharyngeal wall was significantly thicker in OSAHS subjects than in healthy controls (p < 0.05). The cross-sectional area of the soft palate in moderate and severe OSAHS subjects was markedly larger than that of the healthy controls (p < 0.05) and positively correlated with the apnea/hypopnea index (p < 0.05). CONCLUSION: Moderate and severe OSAHS patients exhibit multi-plane obstruction of the upper airway, particularly in the retropalatal and retroglossal region. The severity of OSAHS negatively correlates with the thickness, length and cross-sectional area size of the soft palate.