Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea
Hypoglossal nerve stimulation (upper airway stimulation) is the primary implantable treatment available for obstructive sleep apnea in carefully selected patients who cannot tolerate or have failed CPAP therapy. 1
How the Device Works
The hypoglossal nerve stimulator is an implantable pacemaker-like device that includes a pulse generator, sensing lead, and stimulation lead. 2 The sensing lead detects inspirations and expirations during sleep, and at end-expiration, the stimulation lead triggers the hypoglossal nerve to contract and stiffen the tongue, preventing airway obstruction. 2 This mechanism directly addresses the diminished neuromuscular activity of upper airway dilating muscles that occurs during sleep in OSA patients. 1
Strict Patient Selection Criteria
You must verify ALL of the following criteria before considering hypoglossal nerve stimulation: 1
- Age ≥18 years 1
- BMI <32-40 kg/m² (guidelines vary: Veterans Affairs/DoD recommend <32 kg/m², while other guidelines allow up to <40 kg/m²) 1
- AHI between 15-65 to 15-100 events/hour (moderate to severe OSA) 1
- Documented CPAP failure or intolerance 1
- Polysomnography performed within 24 months 1
- Drug-induced sleep endoscopy (DISE) confirming appropriate anatomy 1
- No complete concentric collapse at the soft palate level on DISE 1, 3
The selection criteria are intentionally restrictive—only about 10% of screened patients typically meet all criteria, emphasizing the need for careful evaluation. 1
Treatment Algorithm Position
Hypoglossal nerve stimulation is a second-line therapy, not first-line treatment. 1 The treatment hierarchy is:
- CPAP remains the gold standard first-line therapy for moderate to severe OSA 1
- For CPAP-intolerant patients with mild-to-moderate OSA: Consider mandibular advancement devices first 4, 1
- For CPAP-intolerant patients with moderate-to-severe OSA meeting strict criteria: Hypoglossal nerve stimulation is appropriate 1
- Multilevel surgery: Reserved as salvage procedure with unpredictable results, should not be considered before hypoglossal nerve stimulation in appropriate candidates 1
Clinical Effectiveness
The device demonstrates significant efficacy in properly selected patients. In clinical studies, responders (those with BMI ≤32, AHI ≤50, and no complete concentric palatal collapse) showed improvement in AHI from 38.9 ± 9.8 to 10.0 ± 11.0 at 6 months post-implant. 3 Adherence to hypoglossal nerve stimulation is superior to CPAP. 5
Important Caveats and Considerations
MRI incompatibility is a critical issue. 6 MRI incompatibility is one of the documented reasons for device explantation, so future need for MRI or chest wall surgery should be considered during patient evaluation. 6 Other reasons for explantation include surgical site infection and poor cosmesis. 6
Prior tongue trauma may not be an absolute contraindication. Case reports demonstrate successful implantation even in patients with previous severe penetrating tongue trauma with contracture, though this requires careful individual assessment. 7
The device requires surgical implantation with an average operative time of approximately 163 minutes for explantation (implantation times are similar). 6 Since FDA approval in 2014, over 18,000 patients have been implanted. 2
Other Implantable Options (Historical Context)
Palatal implants are mentioned in older surgical classifications for OSA but are not recommended in current evidence-based guidelines. 8 Early studies of apnea-triggered neurostimulation showed conflicting results on clinical efficacy. 1 Tracheotomy, while technically an implantable bypass procedure, is reserved for extreme cases and is not a practical modern treatment option. 8