Increased soft tissue around the airway, often resulting from obesity, though not seen in all patients with OSA.Some otorhinolaryngologists believe the risk factors to be structural features that give rise to a narrowed airway, such as enlarged tonsils, an enlarged posterior tongue or fat deposits in the neck. Further factors leading to OSA can be impaired nasal breathing, floppy soft palate or a collapsible epiglottis. Some oral and maxillofacial surgeons believe the risk factors to be a number of primary forms of mandibular hypoplasia, which offers a primary anatomical basis to the development of OSA through glossoptosis. Some maxillofacial surgeons who offer orthognathic surgery for treatment of OSA believe that their treatments offer superior guarantees of cure of OSA. Risk factors
Obesity
It is well known that children, adolescents or adults with OSA are often obese. Obese people show an increase in neck fat tissue which potentiate respiratory obstruction during sleep.However, people of all ages and sex with normal body mass indices (BMIs) can also demonstrate OSA – and these people do not have significant measures of subdermal or intra neck fat as shown on DEXA scans. It is speculated that they may have increased muscle mass, or alternatively have a tendency to decreased muscle tone potentiating airway collapse during sleep.However, loss of muscle tone is a key feature of deep sleep anyway, and whilst obesity seems a common association, it is not an invariable state of OSA. Sleeping supine (on ones back) is also represented as a risk factor for OSA.
In much the same way, a narrow upper jaw will also contribute to OSA due to its relation to airway volume. A more narrow upper jaw results in more narrow nasal passages and a more narrow throat, this also appears to be why so many OSA patients experience nasal congestion especially while lying down. Maxillofacial surgeons see many effects of small lower jaws, including crowded teeth, malocclusions, as well as OSA – all of which are treatable by surgical operations that increase and normalise jaw size. Operations such as custom BIMAX, GenioPaully, and IMDO (in adolescence) offer a valid medical option that replaces all traditional forms of OSA treatment – including CPAP, Mandibular Advancement Splints, tonsillectomy and UPPP. There are patterns of unusual facial features that occur in recognizable syndromes. Some of these craniofacial syndromes are genetic, others are from unknown causes. In many craniofacial syndromes, the features that are unusual involve the nose, mouth, and jaw, or resting muscle tone, and put the individual at risk for OSA syndrome. Down syndrome is one such syndrome. In this chromosomal abnormality, several features combine to make the presence of obstructive sleep apnea more likely. The specific features of Down syndrome that predispose to obstructive sleep apnea include relatively low muscle tone, narrow nasopharynx, and large tongue. Obesity and enlarged tonsils and adenoids, conditions that occur commonly in the western population, are much more likely to be obstructive in a person with these features than without them.