Obstructive sleep apnoea syndrome (OSAS) is characterized by repeated episodes of pharyngeal obstruction during sleep, including airway collapse or narrowing resulting in recurrent airflow cessation.
Identified risk factors include obesity, male sex, Craniofacial and upper airway anomalies, increasing age, and alcohol consumption.
Traditional approach to treating OSAS focused on weight reduction (occasionally easy to prescribe, but hard to comply with), removal of obstructive airway lesions (adenotonsillectomy), palatal implants, mandibular advancement surgery (for retrognathia), our own UPPP (uvulopalatopharyngoplasty) and of course the popular (GPs) option - the CPAP. The interesting fact is compliance rate with CPAP is just about 40-60% (can you stand mask and tubes coming between you and your spouse while on bed?).
Recent interest in OSAS focuses on genioglossus muscle as therapeutic target, for simple reason: if you get the tongue out of the way, the oropharyngeal airway blockage is removed.
Devices that stimulate this muscle directly were demonstrated to improve disease severity in OSAS sufferers. However, the interesting aspect is that such direct stimulation would often arouse the patient!!!
This led to the choice of targeted electrical stimulation of the hypoglossal nerve which is directly motor to the genioglossus fibers, with little or no sensory innervation.
The Hypoglossal Nerve Stimulation (HNS) system is currently undergoing trials in several countries and may be the next interesting toy for treatment of OSAS, though its current cost puts it far beyond the reach of all but very endowed OSAS cases with mild to moderate ( not severe) OSAS. Maybe for severe OSAS, we are stuck with CPAP for some time to come!!!
References:
1. Health Policy Advisory Committee on Technology - Technology Brief: hypoglossal nerve stimulation for sleep apnoea. http://health.qld.gov.au/healthpact/docs/briefs/WP097.pdf
2. Cure Opin Pulm Med. 2011;17(6):419-424
No comments:
Post a Comment