Obstructive sleep apnea (OSA) is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing during sleep. These pauses may last from a few seconds to minutes, and may occur five to thirty times or more an hour. During normal sleep, the throat muscles relax and the airway narrows. During the sleep of a subject with obstructive sleep apnea (OSA), the upper airway narrows significantly more than normal, and during an apneic event, undergoes a complete collapse that stops airflow. In response to a lack of airflow, the subject is awakened at least to a degree sufficient to reinitiate breathing. This disorder understandably limits the quality and duration of a person’s rest, though individuals with sleep apnea are rarely aware of having difficulty breathing. Instead, the compromised rest manifests itself as daytime sleepiness and fatigue associated with the significant levels of sleep disturbance.
Sleepiness is just the tip of the iceberg, however. Further consequences of sleep apnea may include chronic headaches and depression, as well as diminished facilities such as vigilance, concentration, memory, executive function, and physical dexterity. Ultimately, sleep apnea is highly correlated with increased mortality and life threatening comorbidities. Cardiology complications include hypertension, congestive heart failure, coronary artery disease, cardiac arrhythmias, and atrial fibrillation. OSA is a highly prevalent disease condition in the United States, affecting an estimated 18 million Americans to degrees that range from mild to severe, many of whom are undiagnosed, at least in part because the afflicted subjects are often unaware of their own condition.
Treatment for this disorder often begins with behavioral therapy, including sleeping on one’s side, which can prevent the tongue and palate from falling backwards in the throat and blocking the airway. For patients with more serious cases of sleep apnea, use of continuous airway pressure (CPAP) devices are recommended, as are oral mouthpieces that shift the lower jaw forward, opening the airway. For those not helped by CPAP treatment, surgical procedures are available to address anatomical areas of airway obstruction.
These surgical procedures include nasal surgeries, tonsillectomy, adenoidectomy, or reductions in the soft palate or uvula or tongue base. These surgical approaches can be quite invasive and thus have a last-resort aspect to them, and further, simply do not reliably alleviate or cure the condition. There is a need, therefore, for a less invasive procedure that more directly addresses the underlying causes of this disorder.
Scientists at Revent Medical in California offer an innovative solution. The invention relates to devices and methods for reforming tissue surrounding the airway of a subject suffering from obstructive sleep apnea so as to open the airway and alleviate the occurrence of apneic events. The method includes implanting a device at a site in the tissue and bioeroding the bioerodible portion of the device to change its shape and thereby remodel the airway-forming tissue. Through this process, the implanted device is sized and shaped to conform to the airway-forming tissue site in a manner compatible with normal physiological function of the site. This remodeling of the airway-forming tissue results in the airway being unobstructed during sleep, thereby diminishing the frequency of apneic events.