Hypoglossal nerve stimulation and airway changes under fluoroscopy.
OBJECTIVE
To characterize the changes in the anteroposterior dimensions of both the retropalatal and retrolingual airway spaces of the pharynx and hyoid bone position during hypoglossal nerve stimulation under general anesthesia in subjects with obstructive sleep apnea.


METHODS
Cross-sectional.


METHODS
Academic center.


METHODS
Cross-table fluoroscopic images obtained during hypoglossal nerve stimulation were studied in 26 subjects enrolled in the Apnex Medical Hypoglossal Nerve Stimulation (HGNS) system feasibility trials. Changes in the anteroposterior dimensions (2-dimensional) of the retropalatal and retrolingual airway spaces and hyoid bone position were recorded. Measurements were estimated in millimeters and standardized to each subject's C3 vertebral height. Opening of the pharyngeal airspace was examined relative to body mass index.


RESULTS
During hypoglossal nerve stimulation, all subjects demonstrated anterior displacement of the tongue base on fluoroscopy. The average retrolingual airway opening was 0.71 ± 0.23 C3 vertebral body heights (9 ± 3 mm). Opening of the retropalatal airway with stimulation occurred in 65% (15/23) of subjects. When present, the average opening was 0.42 ± 0.14 vertebral heights (5 ± 3 mm). Anterior displacement of the hyoid occurred in 92% (23/25) of subjects. Retrolingual airway opening was independent of baseline body mass index.


CONCLUSIONS
Unilateral hypoglossal nerve stimulation results in anterior tongue base displacement and an increase in the anterior-posterior retrolingual airway dimensions of the pharynx, independent of body mass index. Opening of the retropalatal airway occurred in a majority of subjects and had a trend toward correlation with body mass index.
Department of Otolaryngology, University of Minnesota-Minneapolis, Minneapolis, Minnesota 55455, USA. godin001@umn.edu
George S
GS
Goding
Wondimeneh
W
Tesfayesus
Eric J
EJ
Kezirian
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004558:Electric Stimulation; D005240:Feasibility Studies; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D006928:Hyoid Bone / Q000000981:diagnostic imaging*; D007002:Hypoglossal Nerve; D008297:Male; D008875:Middle Aged; D010159:Palate / Q000000981:diagnostic imaging; D010614:Pharynx / Q000000981:diagnostic imaging*; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging* / Q000628:therapy*; D055815:Young Adult