Abstract
Objective: Compared to traditional OSA surgeries that modify skeletal and soft tissues, hypoglossal nerve stimulation alters physiology to maintain upper airway patency. To evaluate long-term stability of CN XII stimulation, AHI and nerve stimulation parameters were assessed and compared.
Method: Data were reviewed from a prospective multicenter feasibility trial of an implantable hypoglossal nerve stimulation device (Inspire, Inspire Medical) that includes both stimulation and sensing leads and a programmable stimulation generator. Polysomnographic and device outcomes were available in 24 of 36 subjects at 12-month follow-up.
Results: Six- to 12-month responder rate (a priori = 50% reduction in AHI) improved (10/24 to 12/24). AHI (baseline, 6, and 12 month) remained constant in responder (33.8, 8.8, 10.0 events/h, P < .01) and nonresponder (48.9, 60.3, 44.1 events/hr, P < ns) groups. Three subjects were reclassified as responders and 2 as nonresponders from 6 to 12 months. Average nerve stimulation thresholds (sensation, function, and subdiscomfort) did not change from baseline to 12 months. Stimulation parameters (frequency, pulse duration, stimulation intensity but not amplitude (2.2 [0.7] vs 1.5 [0.4] Volt, P = .01)) were similar in responder groups. No additional device-related adverse events were recorded at 12 months.
Conclusion: Polysomnographic measures recorded at 6 months are maintained at 12 months following CN XII implant in the majority of patients. Average stimulation thresholds remain constant over 1 year. Results support that clinically significant improvements in AHI are maintained over the 6 to 12 month interval.
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