0646 Single and combination hypoglossal/ansa cervicalis nerve stimulation increases airflow to airway narrowing in obstructive sleep apnea

Abstract Introduction Hypoglossal nerve stimulation via surgical implantation of a pulse generator and cuff electrode is an effective therapy for many people with obstructive sleep apnea (OSA). However, therapeutic responses vary and are difficult to predict. Recent studies indicate that ansa cervicalis nerve stimulation can also restore airflow via airway stiffening and caudal traction mechanisms. We used a minimally invasive, ultrasound-guided approach to implant a temporary electrode array to stimulate hypoglossal and ansa cervicalis nerves alone and in combination. Methods People with OSA (AHI>15 events/h) had a drug-induced sleep endoscopy (DISE). Ansa cervicalis and hypoglossal nerves were identified via ultrasound to guide percutaneous implantation of temporary multi-electrode arrays. A modified continuous positive airway pressure (CPAP) device attached to a nasal mask and pneumotachograph was used to deliver transient reductions in airflow. Different combinations of electrical stimulation (either nerve alone or both) were then applied and airflow responses were quantified. A sub-sample of participants with improved airflow with stimulation during DISE were then studied overnight during an in-laboratory sleep study. Results Twenty-four participants (8 female; BMI=29±3kg/m2; aged 55±14years; AHI=36±17events/h) across three centres were studied. Peak inspiratory flow (PIF) during transient CPAP reductions was 0.13±0.11L/s. Acute hypoglossal nerve stimulation increased airflow to 0.39±0.26L/s (p< 0.001), similar to PIF achieved at the therapeutic CPAP level, 0.40±0.18L/s (p=0.66). Similarly, ansa cervicalis nerve stimulation increased PIF to 0.36±0.15L/s (p< 0.001). In 5 participants, PIF with ansa stimulation alone was 0.28±0.22L/s which increased to 0.59±0.44L/s with combination stimulation. Similarly, in 2 participants, PIF with hypoglossal stimulation alone was 0.09±0.04L/s which increased to 0.47±0.10L/s with combination stimulation. Of the nine participants who underwent the overnight sleep study, electrode position and stimulation effectiveness was clearly preserved in three participants who demonstrated airflow increases of 150-220% with single or combination nerve stimulation versus pre-stimulation levels without cortical arousal. Conclusion A novel, acute percutaneous stimulation approach targeting hypoglossal and ansa cervicalis nerves improved airflow during airway narrowing/closure under sedation and in some people during natural sleep with preserved stimulation effectiveness after transfer from DISE theatre to the sleep laboratory. Support (if any) Invicta Medical (now Restera)