[The study about the characteristics of upper airway in obstructive sleep apnea syndrome].

OBJECTIVE: To investigate the upper airway (UA) characteristics of the patient's with obstructive sleep apnea syndrome (OSAS) and analyses the value of computer assisting fiberoptic pharyngoscopy with müller's maneuver (CFPMM) in topodiagnosis of OSAS. METHODS: The pharyngxes of 30 cases with OSAS and 30 controls were examined by CFPMM. The cross-section area at velo- and tongue-pharyngeal, pharyngeal collapsibility, sites of UA obstructive and their anatomical factors were measured and calculated and the correlation between the anatomical abnormalities of UA and outcomes of polysomnography (PSG) were analysed. RESULTS: 1. CFPMM can accurately measure and calculate the cross-section area of the upper airway. 2. mean areas of velopharyngeal and tongue-pharyngeal were significantly less than those in control subjects (all P < 0.05). OSAS patient's also showed relatively much larger collapsibility at sach site of the UA than controls. 3. At müller's maneuver, all the areas of OSAS patient's were below 40 mm2 and 60% cases appeared complete occlusion in pharyngeal. 4. All patient's had obstruction at velopharymx and airway collapses at multiple sites in 40% of cases. 5. At velopharyngeal the anatomical factors causing obstruction mainly were posterior displacement of soft palate, thicken and collapse of the pharyngeal wall. Besides the redundant lymph tissue at tongue base and posterior displacement of the tongue base, enlarged inferior pole of tonsil and collapse of pharyngeal wall played an important role at tongue-pharyngeal obstruction. 6. Diminished pharyngeal apertures and collapsibility were associated with increased rates of apnea and hypopnea index (P < 0.05). CONCLUSION: 1. CFPMM is able to measure and calculate UA's cross-section area and collapsibility, determine the site of obstruction, and helping the treatment. 2. Complete occlusion of UA at müller's maneuver is the criterion to determine site of UA obstruction in OSAS patient's during waking hours. 3. The anatomical abnormalities of UA of patients is reflects the severity of the OSAS.