Surgical anatomy of the hypoglossal nerve: A new classification system for selective upper airway stimulation

Background Selective upper airway stimulation (UAS) has shown effectiveness in treating patients with obstructive sleep apnea (OSA). The terminating branches of the hypoglossal nerve show a wide complexity, requiring careful discernment of a functional breakpoint between branches for inclusion and exclusion from the stimulation cuff electrode. The purpose of this study was to describe and categorize the topographic phenotypes of these branches. Methods Thirty patients who received an implant with selective UAS from July 2015 to June 2016 were included. All implantations were recorded using a microscope and resultant tongue motions were captured perioperatively for comparison. Results Eight different variations of the branches were encountered and described, both in a tabular numeric fashion and in pictorial schema. Conclusion The examinations showed the complex phenotypic surgical anatomy of the hypoglossal nerve. A schematic classification system has been developed to help surgeons identify the optimal location for cuff placement in UAS.