Introduction to Hypoglossal Nerve Stimulation

Obstructive sleep apnea (OSA) is characterized by repetitive collapse of the upper airway during sleep, resulting in intermittent hypoxia, sleep fragmentation, and significant cardiovascular and metabolic consequences. While continuous positive airway pressure therapy remains the standard treatment, poor long-term adherence severely limits its clinical efficacy. Recently, hypoglossal nerve stimulation (HNS) has emerged as a physiological, neuromodulatory therapy that activates the tongue protrusor muscles to maintain airway patency during sleep. The objective of this review is to summarize the therapeutic rationale for upper airway stimulation therapy, elucidate the neurophysiological mechanisms underlying tongue muscle activation, and trace the historical development and current clinical indications of HNS. In conclusion, HNS represents a paradigm shift in OSA management, offering functional restoration of upper airway tone rather than structural modification. Ongoing advances in bilateral stimulation, targeted activation, and adaptive closed-loop systems are expected to broaden its indications and enhance therapeutic precision.