The Inspire Upper Airway Stimulation (UAS) system offers an alternative treatment for individuals with Obstructive Sleep Apnea (OSA) who have not found success with Continuous Positive Airway Pressure (CPAP) therapy. This implanted device stimulates the hypoglossal nerve, controlling the tongue and upper airway muscles to keep the breathing passage open during sleep. However, this therapy is highly selective. Patients must meet specific criteria for safety and effectiveness, meaning many individuals will not qualify due to physical measurements, diagnostic results, or existing health concerns.
Physical and Anatomical Limitations
A patient’s body composition is a common reason for disqualification from UAS therapy. Body Mass Index (BMI) is used to identify a maximum threshold beyond which the device’s efficacy is significantly reduced. While the U.S. Food and Drug Administration (FDA) has expanded the indication to include patients with a BMI up to 40 kg/m², many providers and insurance plans maintain a stricter limit, often at or below 32 kg/m² or 35 kg/m².
Excess weight increases soft tissue and fat deposits around the neck and pharynx. This reduces the space in the upper airway, making it difficult for nerve stimulation to effectively open the passage during sleep. Patients exceeding established BMI cutoffs are not suitable candidates because the mechanical obstruction is too severe for the electrical stimulation to overcome.
Beyond general body size, the specific structure of the airway must be assessed through an endoscopic procedure. The most definitive anatomical exclusion criterion is the presence of a “complete concentric collapse” of the soft palate. This means the airway closes completely in a 360-degree fashion at the level of the soft palate.
The Inspire mechanism pushes the tongue forward, but it is not effective against a complete collapse involving all sides of the palate. Any anatomical finding that compromises the proper function of the upper airway stimulation, such as an unusually large tonsil or an abnormal position of the epiglottis, can also lead to disqualification. The device relies on a specific, non-concentric pattern of collapse to be successful.
Sleep Apnea Severity and Diagnosis Type Requirements
The severity of a patient’s sleep apnea, measured by the Apnea-Hypopnea Index (AHI), must fall within a specific range determined during a formal sleep study. The AHI is the average number of apnea (complete pauses in breathing) and hypopnea (partial reductions in breathing) events per hour of sleep. Adult patients must have moderate to severe OSA, typically falling within the range of 15 to 100 events per hour.
Patients with an AHI under 15 events per hour are excluded because their condition is considered mild and may be better managed with less invasive interventions. Patients with an AHI significantly higher than 65 may be approached with caution due to potentially decreased treatment efficacy in very severe cases. The therapy targets a specific degree of airway obstruction responsive to nerve stimulation.
A fundamental exclusion criterion relates to the type of sleep apnea diagnosed. Inspire UAS treats Obstructive Sleep Apnea (OSA), which occurs when the airway is physically blocked by soft tissue. It is not intended for use in individuals with predominant Central Sleep Apnea (CSA) or Mixed Sleep Apnea.
CSA occurs when the brain fails to send proper signals to the muscles that control breathing. Mixed Sleep Apnea is a combination of both obstructive and central events. If central and mixed apneas constitute more than 25% of the patient’s total AHI, they are not candidates. Hypoglossal nerve stimulation cannot correct a problem stemming from the central nervous system, making the device ineffective for these breathing disturbances.
Existing Health Conditions and Compliance Factors
Certain existing medical conditions unrelated to breathing can preclude a patient from receiving the implant due to safety concerns.
Neurological Impairment
Any condition or prior procedure resulting in compromised neurological control of the upper airway, such as severe nerve damage or paralysis, disqualifies a patient. The device relies on the hypoglossal nerve being intact and responsive to electrical stimulation to move the tongue. Damage to this pathway renders the therapy useless.
Other Implanted Devices and Imaging
Patients with other implanted medical devices, such as pacemakers, defibrillators, or certain neurostimulators, may face exclusion due to the risk of unintended electromagnetic interaction. The Inspire system could interfere with the function of these other devices, creating a safety hazard. Additionally, patients who require frequent Magnetic Resonance Imaging (MRI) scans may be disqualified, especially if they have an older, non-MR Conditional model.
Compliance Requirements
Behavioral and cognitive factors also play a significant role in determining eligibility. The patient must consistently and correctly operate the external sleep remote to turn the device on before sleep and off upon waking. Individuals unable or unwilling to comply with the long-term use and maintenance schedule are not considered appropriate candidates. This requirement ensures the patient can maximize the device’s benefit and maintain its functionality over time.