Hypoglossal nerve stimulator

What is a hypoglossal nerve stimulator?

A hypoglossal nerve stimulator is an implantable medical device used to treat moderate to severe obstructive sleep apnoea (OSA) in adults who are unable to tolerate continuous positive airway pressure (CPAP) therapy.

The device works by stimulating the hypoglossal nerve, which controls movement of the tongue. By gently moving the tongue forward during sleep, it prevents the airway from collapsing and helps maintain normal breathing. The procedure is performed under general anaesthetic.

Why is it done?

Hypoglossal nerve stimulation is recommended for carefully selected patients who:

• Have moderate to severe obstructive sleep apnoea.
• Are unable to tolerate or benefit from CPAP therapy.
• Do not have complete concentric collapse of the airway (confirmed on sleep endoscopy).
• Meet specific body mass index (BMI) criteria.

It is not suitable for patients with central sleep apnoea.

What does it involve?

The procedure involves implanting three components:

• A small pulse generator placed under the skin in the upper chest.
• A stimulation lead connected to the hypoglossal nerve.
• A breathing sensor placed between the ribs to detect respiratory effort.

When switched on at night using a handheld remote control, the system monitors breathing patterns and delivers mild electrical stimulation to the nerve in synchrony with inhalation. This moves the tongue forward and stabilises the airway. The operation typically takes two to three hours.

Preparation for hypoglossal nerve stimulation

Before undergoing hypoglossal nerve stimulator implantation, patients will require a detailed sleep study to confirm the diagnosis and severity of obstructive sleep apnoea. A drug-induced sleep endoscopy (DISE) is also performed to assess the pattern and level of airway collapse during sleep and determine suitability for treatment.

In addition, a general medical assessment is carried out to ensure the patient is fit to undergo a general anaesthetic. Intolerance or inability to comply with CPAP therapy must be clearly documented prior to surgery.

Recovery after the procedure

Most patients are discharged the same day or after one night in hospital. Mild pain, swelling or bruising around the incision sites is common and usually settles within two weeks.

The device is activated approximately four weeks after surgery to allow healing. Fine adjustments are made during follow-up sleep studies to optimise therapy.

Most patients experience a significant reduction in snoring and apnoea episodes, along with improved daytime alertness.

Alternative treatments

Alternative treatments for obstructive sleep apnoea include:

• Continuous positive airway pressure (CPAP).
• Mandibular advancement devices.
• Weight loss and lifestyle modification.
• Upper airway surgery (such as palatal or tongue base procedures).

The most appropriate option depends on individual anatomy, severity of disease and patient preference.