Future advances in neurostimulation for obstructive sleep apnea

Over the past several decades, extensive clinical and investigative efforts have been directed toward the development of hypoglossal nerve stimulation (HNS) as an alternative treatment option for patients with obstructive sleep apnea (OSA) who are intolerant to positive airway pressure. Nevertheless, HNS is ultimately effective only for a subpopulation of individuals with OSA and a need exists for additional neuromodulation strategies to better replicate the complex interactions that exist between upper airway muscles in the awake, patent state. Two additional neuromodulation strategies have recently emerged from a reappraisal of pharyngeal mechanics: ansa cervicalis stimulation (ACS) and glossopharyngeal nerve stimulation (GNS). ACS is designed to generate active caudal traction through infrahyoid strap muscle contraction, and GNS is intended to impose a lateral stabilizing vector on the oropharyngeal wall through activation of the stylopharyngeus muscle and potentially related pharyngeal plexus motor components. This chapter reviews the mechanistic basis for these approaches and outlines key priorities for future translational and clinical research.