Biomechanics of the upper airway: changing concepts in the pathogenesis of obstructive sleep apnea

A selection of abstracts of clinically relevant papers from other journals. The abstracts on this page have been chosen and edited by John R. Radford.

Abstract

Disorders in central nervous system regulation may have a role in obstructive sleep apnoea (OSA).

Main

Susarla SM, Thomas RJ et al. Int J Oral Maxillofac Surg 2010; 39: 1149–1159

Not only does OSA result in daytime somnolence, but it has been linked with high impact medical events such as myocardial infarction and stroke. The authors of this paper ask the question why 10-20% of patients with OSA do not respond to surgical maxillomandibular advancement? They argue that, in addition to the usual links of obesity with OSA, myoneural factors (nerve endings in muscles) are important in maintaining upper airway patency. For example, disorders of the hypoglossal nerve, that innovates the genioglossus muscle, compromise pharyngeal integrity. The engineering concept of loop-gain ('magnitude of the system response relative to the magnitude of the disturbance') is also discussed. A high gain system responds disproportionately to hypoxia/hypercarbia, whereas a low-gain system stabilises the condition.