Role of CT Scan before Snoring and OSA Surgery

Snoring is associated with typical changes that can be revealed by CT scanning. Greater retropalatal and pharyngeal narrowing is the most important factor. The key structure in snoring is the soft palate, it causes a constriction and is sucked into vibrating by negative pressure that develops at this site. Its repetitive closures present an obstruction to breathing, producing the snoring sound, and should therefore be the target for surgical treatment of snoring. Obstacles in the upper airway that increase negative inspiratory pressure could not be confirmed as important for the development of snoring, although they may increase its loudness.

Using CT images, the antero posterior and transversal distances of the pharyngeal space at different levels, and the thickness and length of the soft palate and uvula and their angle against the hard palate were measured; evidence of impaired nasal passages was noted; the extent of pharyngeal inspiratory narrowing was the ratio between the area at the hard palate level and most narrow area; and expiratory narrowing was the ratio between the area behind the root of the tongue and the most narrow area.

Soft palate-tongue contact and automatically calculated pharyngeal narrowing ratio (PNR), defined as a ratio between the airway cross-section at the hard palate level and the narrowest cross-section from the hard palate to the epiglottis, could assist in earlier identification of potential obstructive sleep apnea syndrome (OSA) patients even on awake individuals.

CT imaging of retropalatal airway and a felxible fibre optic examination of the upper airway is more important and useful in planning Laser/Coblator surgery for OSA, than a PSG(sleep study).This helps surgeon to plan his surgery beforehand to get adequate airway and better result.