Three-dimensional Upper Airway Computed Tomography in Obstructive Sleep Apnea: A Prospective Study in Patients Treated by Uvulopalatopharyngoplasty

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Abstract
The success of uvulopalatopharyngoplasty in treating obstructive sleep apnea varies considerably. Some of this variability may be accounted for by differences in the site of upper airway narrowing. To determine whether preoperative awake upper airway and soft tissue volumes predict the response to uvulopalatopharyngoplasty, preoperative awake computed tomograms (CT) of the upper airway were performed on 60 consecutive patients with symptomatic obstructive sleep apnea. Tracings were made from the CT scans of upper airway, tongue, and soft palate. Computer software was used to determine the cross-sectional area and volume of the upper airway, tongue, and soft palate. Patients underwent overnight polysomnograms before and 3 months after uvulopalatopharyngoplasty. Tongue volume was larger (p < 0.02) and both upper airway to tongue volume (p < 0.0005) and oropharynx to soft palate volume ratios (p < 0.01) were smaller in obese patients. A good response to uvulopalatopharyngoplasty as defined by a postoperative apnea index of < 5 apneas/h or a reduction in apnea index ⩾ 50% was seen in 50 patients (83%). Patients who had a good response had a smaller oropharyngeal cross-sectional area (p < 0.01), a smaller upper airway volume (p < 0.05), a smaller upper airway to tongue volume ratio (p < 0.01), and a smaller oropharynx to soft palate volume ratio (p < 0.05). Obese patients with obstructive sleep apnea have larger tongues and smaller upper airways relative to tongue and soft palate size. Patients with smaller upper airways, particularly relative to tongue and soft palate size, have a good response to uvulopalatopharyngoplasty.