[The terminal hypoglossal nerve and its anatomical variability]

Area of Science:

• Neurology
• Otolaryngology
• Biomedical Engineering

Background:

• Obstructive sleep apnea (OSA) is increasingly treated with upper airway stimulation targeting the hypoglossal nerve (N. XII).
• The N. XII is a motor nerve controlling tongue muscles essential for airway patency.

Purpose of the Study:

• To highlight the importance of N. XII anatomy and intraoperative neuromonitoring for successful upper airway stimulation.
• To emphasize the need for precise electrode placement for selective N. XII stimulation.

Main Methods:

• Review of anatomical variations of the N. XII.
• Application of intraoperative neuromonitoring techniques.
• Assessment of muscle contractions and tongue movements during electrode placement.

Main Results:

• Anatomical variants of the N. XII significantly influence surgical implantation of stimulation systems.
• Intraoperative neuromonitoring aids in accurate electrode placement.
• Selective stimulation of individual nerve fibers requires precise assessment of tongue muscle responses.

Conclusions:

• Successful upper airway stimulation for OSA hinges on detailed knowledge of N. XII anatomy.
• Intraoperative neuromonitoring and precise assessment of muscle function are critical for effective treatment.
• Optimizing electrode placement ensures selective N. XII fiber stimulation and airway opening.