Upper Airway Imaging in Sleep Apnea Syndrome

Obstructive sleep apnea is due to repetitive obstructions of the collapsible pharyngeal airway during sleep. It is therefore natural to search for local anatomical abnormalities to unveil the possible causes of the disease, and to look for potential curative interventions. Up to now, imaging of the upper airway has contributed more to the understanding of the pathophysiology of obstructive sleep apnea than to the identification of individual and solvable problems. The upper airway can be examined in multiple ways beginning with simple clinical observation. Clinical examination can provide the first visual information and can be useful to discard severe craniofacial abnormalities. Predictive morphometric scores have been based on simple clinical measurements, but their clinical utility requires further validation. Computed tomography and magnetic resonance imaging have provided extensive static and dynamic information on the process of obstruction of upper airway. Endoscopy with the Mueller maneuver has also been applied to the study of sleep-related breathing disorders but its predictive value is dubious. Cephalometry has pointed to different anatomical indicators of increased risk for sleep apnea and may be of help in the evaluation of patients submitted to maxillomandibular advancement or treated with oral appliances. Upper airway imaging is a valuable research tool and has provided insight into the pathophysiology of obstructive sleep apnea, thus permitting to improve the medical approach to this syndrome. However, it seems, at present, to have no role in the routine assessment of the patient with sleep-related breathing disorder.