Relation between CT axial cross-sectional area of the oropharynx and obstructive sleep apnea syndrome in adults.

PURPOSE To look for correlation between obstructive sleep apnea syndrome (OSAS) and axial cross-sectional area of the narrowed oropharyngeal lumen. METHODS Thirty-six men with OSAS and 10 control subjects underwent polysomnography with registration of oxygen saturation and number of sleep apnea episodes and their duration. Nine of them underwent uvulopalatopharyngoplasty and repeated polysomnography. Each polysomnography was followed by high-resolution CT scan with reconstructions in sagittal and coronal planes. Measurements of the axial cross-sectional area of the oropharyngeal lumen were taken at the level of the narrowing. RESULTS Twenty-seven patients with severe OSAS (high number and prolonged episodes of OSAS and 22% or greater decrease in oxygen saturation) had a narrowed oropharyngeal cross-sectional area less than 50 mm2 wide. The control subjects and 6 patients who had uvulopalatopharyngoplasty without OSAS had a minimal pharyngeal cross-sectional area of 110 mm2. Eight patients with moderate OSAS and 3 patients who had uvulopalatopharyngoplasty and diagnoses of OSAS had intermediate values of the narrowest pharyngeal level--between 60 mm2 and 100 mm2. CONCLUSION The measurement of the axial cross-sectional area of the pharyngeal lumen can play an important role in evaluation of OSAS and indications for surgery.