Pulling on Hyoid Reduces Airway Collapse in Human Cadavers

Abstract

Objective: This study examined the changes in upper airway dimensions and collapsibility associated with force applied to the hyoid bone using a suture and a novel magnetic system (internal magnet secured to the hyoid and external magnet) in un-fixed human cadavers.

Method: Eight cadavers were tested with traction on the hyoid using 1) suture around the hyoid to apply 0.5-5 Newtons of force and 2) a novel magnetic system. Changes in airway dimensions were measured with fluoroscopy and 3-dimensional computed tomography reconstructions. Airway collapsibility was measured using a previously-described flow-based model.

Results: A 2N (0.5 lb) force applied to the hyoid bone increased airway dimensions, with greatest effect in the retrolingual region. The anterior direction of traction was more effective than inferior or superior. There was a linear association between the magnitude of force and critical airflow, at 1.5L/min/N (R² = 0.75). All magnitudes of pull increased the critical airflow (P < .001). At 2N, the hyoid was advanced 1cm, and the critical airflow was increased 3-fold (3.0 ± 1.71L/min). The magnet system showed similar airway effects to the direct 2N applied force. An increase in upper airway dimensions occurred with inter-magnet distances of 2cm.

Conclusion: Forces applied to the hyoid improve upper airway dimensions and collapsibility in the human un-fixed cadaver model. A novel magnet system may represent a promising therapy for treatment of upper airway obstruction in disorders such as obstructive sleep apnea.