Medicine:Hypoglossal nerve stimulator

The hypoglossal nerve stimulator is a novel strategy for the treatment of obstructive sleep apnea. It has been gaining popularity over the last few decades and was approved in Europe in 2013 and the Food and Drug Administration (FDA) in April 2014. The purpose of the hypoglossal nerve stimulator is to relieve tongue base obstruction during sleep by stimulating the tongue to protrude during inspiration (i.e., inhale).

Eligibility criteria

Certain patients with obstructive sleep apnea who are deemed eligible candidates may be offered the hypoglossal nerve stimulator as an alternative. FDA-approved hypoglossal nerve neurostimulation is considered medically reasonable and necessary for the treatment of moderate to severe obstructive sleep apnea when all of the following criteria are met:

1. Age is 22 years of age or older; and
2. Body mass index is less than 35 kg/m2; and
3. A polysomnography is performed within 24 months of first consultation for hypoglossal nerve stimulator implant; and
4. Beneficiary has predominantly obstructive events (defined as central and mixed apneas less than 25% of the total apnea–hypopnea index; and
5. Apnea–hypopnea index is 15 to 65 events per hour; and
6. Beneficiary has documentation that demonstrates continuous positive airway pressure failure (defined as apnea–hypopnea index greater than 15 despite continuous positive airway pressure usage) or continuous positive airway pressure intolerance (defined as less than 4 hours per night, 5 nights per week or the continuous positive airway pressure has been returned) including shared decision making that the patient was intolerant of continuous positive airway pressure despite consultation with a sleep expert: and
7. Absence of complete concentric collapse at the soft palate level as seen on a drug-induced sleep endoscopy procedure; and
8. No other anatomical findings that would compromise performance of device (e.g., tonsil size 3 or 4 per standardized tonsillar hypertrophy grading scale).

Procedure details

In this procedure, an electrical stimulator lead is placed around branches of the hypoglossal nerve that control tongue protrusion (e.g., genioglossus) via an incision in the neck. A sensor lead is then placed in the chest between the ribs in the layer between the internal intercostal muscles and external intercostal muscles. The stimulator and sensory lead are then connected via a tunneled wire to an implantable pulse generator. When turned on during sleep, the sensory lead in the chest detects the respiratory cycle. During inspiration (i.e., inhale), an electrical signal is fired via the stimulator lead in the neck, stimulating the hypoglossal nerve, and causing the tongue to protrude, thereby alleviating obstruction.

Post-operative and long term care

Once implanted, the hypoglossal nerve stimulator is typically activated in clinic approximately 4 weeks afterwards. The implant may be configured to best accommodate the patient's comfort and sleeping habits (e.g., set a delay based on sleep latency).

The hypoglossal nerve stimulator implantable pulse generator battery life typically lasts 8–12 years, after which the implantable pulse generator may be safely replaced with another surgery.

External links

• Video demonstrating the procedure in detail (viewer discretion is advised): Hypoglossal Nerve Stimulator Implantation for Obstructive Sleep Apnea.