Combined Hypoglossal Nerve and Ansa Cervicalis Stimulation During Drug-induced Sleep Endoscopy in Patients With Obstructive Sleep Apnea

Rationale: Ansa cervicalis stimulation (ACS) has been proposed as a novel neurostimulation treatment for obstructive sleep apnea (OSA). ACS enhances pharyngeal patency by mimicking the caudal tracheal traction effect. Previous studies have demonstrated that ACS decreases airway collapsibility more effectively at the palatal, oropharyngeal lateral wall, and epiglottic levels than at the tongue base, whereas hypoglossal nerve stimulation (HNS) is expected to alleviate tongue-driven sources of airway obstruction at the tongue base and velopharynx. We hypothesized that ACS combined with hypoglossal nerve stimulation (HNS) would relieve airway obstruction to a greater level than the isolated HNS alone. This study aimed to quantify the effect of combined HNS and ACS on metrics of airway collapsibility in patients with OSA. Methods: Twenty-nine participants (Age: 54.2±11.8 years; Male: 18; BMI: 31.9±3.1kg/m2; AHI: 42.0±17.2 events/hour) with moderate-to-severe OSA underwent unilateral HNS with and without bilateral ACS via hook-wire percutaneous electrodes during drug-induced sleep endoscopy. Maximum inspiratory airflow was assessed with a pneumotachometer during flow-limited breathing across varying levels of positive airway pressure support. Pressure-flow relationships were constructed to quantify changes in pharyngeal critical closing (PCRIT) and opening pressures (POPEN) for each stimulation regimen. A linear mixed-effect model analysis was performed on a per-breath basis to characterize the effect of stimulation regimen on airflow. Results (see Figure): Combined HNS+ACS (n=22) significantly decreased PCRIT (median [Q1, Q3]: 3.1 [2.1, 5.8] cmH2O) and POPEN (5.8 [3.3, 9.8] cmH2O) from baseline (p<0.001). The decrease was greater than that of isolated HNS (n=26) in POPEN (-3.0 [-5.6, -0.9] cmH2O, p =0.02) and PCRIT (-1.7 [-4.3, -1.3] cmH2O, p=0.22) (Figure 1A). In 7 patients, ACS+HNS completely abolished flow limitation, dropping PCRIT and POPEN well below atmospheric pressure. The mixed-effect model demonstrated combined stimulation had a significantly greater effect on increasing airflow compared to HNS per unit increment of airway pressure (β = 25 mL/s/cmH2O, p=0.02), resulting in a greater reduction in POPEN (ΔΔPOPEN = -2.8 [95% CI: -4.0, -1.6] cmH2O, p < 0.001, Figure 1B). Conclusions: Combined HNS+ACS reduced pharyngeal collapsibility to a greater degree than isolated HNS, highlighting its potential as a neurostimulation strategy for OSA.

Duke Scholars

Author Christopher Lindsell Biostatistics & Bioinformatics, Division of Biostatistics