Long-term stability of hypoglossal nerve stimulation for the treatment of obstructive sleep apnea in children with Down syndrome

Importance: Obstructive sleep apnea (OSA) occurs in 55-97% of people with Down syndrome (DS). Even after adenotonsillectomy, residual OSA often persists into adulthood due, in part, to tongue base collapse. Implantable hypoglossal nerve stimulators are being investigated in children and young adults with DS and persistent, moderate to severe OSA. However, the long-term necessity for such an intervention-especially as patients mature and voltage adjustment becomes warranted-has not been previously reported in the pediatric DS population. Objective: To assess the long-term need for implantable hypoglossal nerve stimulators and the necessity for voltage adjustment in children and young adults with Down syndrome. Design: This is a case series from an ongoing clinical trial assessing safety and efficacy of hypoglossal nerve stimulation among 42 children and young adults with DS and persistent OSA, despite adenotonsillectomy and trialed positive airway pressure (PAP) therapy. We focus here on the first 4 participants who have undergone implantation by age 13 and have completed at least 44 months of follow-up. Participants: 4 participants (2 male, 2 female; ages 10-13 years) with DS and persistent, severe OSA (AHI > 10 events/h) underwent hypoglossal nerve stimulator implantation and were followed for 44-58 months. Setting: Participants completed in-lab sleep studies at baseline (before implantation), 1 year postoperatively, and 44-58 months postoperatively. During their most recent follow-up, 2 participants completed split-night sleep studies in which assessment was done with the device both on and off. Interventions: Hypoglossal nerve stimulator implantation. Main outcomes and measures: Stability in titrated and untitrated OSA as measured by the apnea-hypopnea index (AHI); growth measures including BMI; and quality of life as measured by the OSA-18 questionnaire. Results: Compared to baseline, all 4 participants maintained reductions of at least 50% in AHI over the course of follow-up. At recent follow-up, two participants had persistent, moderate OSA despite stimulation therapy. The other two participants achieved 100% reductions in AHI with stimulation therapy; when they underwent splitnight sleep studies, the severe OSA persisted with the device turned off. Improvement in OSA-18 quality of life scores was observed in three of the four participants. Conclusion: and Relevance: Hypoglossal nerve stimulation continues to effectively control OSA in children with DS as they mature, while their underlying untitrated OSA appears to persist into adulthood. Trial registration: clinicaltrials.gov Identifier: NCT2344108.