Hypoglossal nerve stimulation for obstructive sleep apnea:A review of the literature

Objective:To review the indications and clinical evidence supporting hypoglossal nerve stimulation (HNS) therapy for the treatment of moderate-to-severe obstructive sleep ap-nea (OSA). Methods:Peer reviewed literature on hypoglossal nerve stimulation therapy for obstructive sleep apnea from 2001 to 2016. Results:The only currently FDA-approved HNS device for the treatment of moderate-to-severe OSA is produced by Inspire Medical Systems, which recently published its 36-month outcomes data from its Stimulation Therapy for Apnea Reduction (STAR) trial. HNS therapy is currently indicated for moderate-to-severe OSA patients who are CPAP-intolerant, have a body mass in-dex <32, apnea-hypopnea index <50, and without a concentric pattern of upper airway collapse on sleep endoscopy. Conclusions:Data from the STAR trial suggests that a subset of OSA patients can achieve a sig-nificant therapeutic response from hypoglossal nerve stimulation. However, these results may be limited in their generalizability to the broader OSA population.

Predictors of success in hypoglossal nerve stimulator implantation for obstructive sleep apnea

Objective:Current guidelines for hypoglossal nerve stimulator(HGNS)implantation eligibility include drug-induced sleep endoscopy(DISE)findings and other patient characteristics but lead to highly variable rates of surgical success across institutions.Our objective was to determine whether additional factors seen on preoperative evaluation could be used as predictors of surgical success.Study design:Retrospective chart review.Setting:Single-institution academic tertiary care medical center.Subjects:and Methods:This study included patients with obstructive sleep apnea(OSA)who underwent HGNS implantation between 2015 and 2018.Surgical success was defined as a post-operative apnea-hypopnea index(AHI)of less than 20 events per hour and an AHI reduction of at least 50%.Preoperative polysomnogram(PSG)results,DISE findings,and physical parameters were compared between surgical successes and failures.Results:A total of 68 patients were included in the analysis.The overall surgical success rate was 79.4%(54/68).Elevated preoperative AHI was associated with an increased likelihood of treatment failure,with an AHI of(36.9±16.8)events/hour in the success group compared to(49.4±19.6)events/hour in the failure group(P=0.05).Patients observed to have partial lateral oropharyngeal collapse on DISE was more frequently associated with the treatment failure group than in the success group(P=0.04).Conclusion:Patients who underwent HGNS implantation overall had a very high treatment response rate at our institution.Factors that may predispose patients to surgical failure included the presence of lateral oropharyngeal collapse and a significantly elevated preoperative AHI.These should be considered when determining surgical candidacy for HGNS implantation.