Effects of oropharyngeal neuromuscular stimulation on the volumetric enlarged and reduced tongue base in minipigs

Hypoglossal nerve or tongue protruding muscle stimulation is a current treatment option for obstructive sleep apnea. Thus, the present study analyzed 3D deformations of the volumetric enlarged and reduced tongue base upon oropharyngeal neuromuscular stimulation. Twenty 8‐to‐10‐month‐old Yucatan minipigs were assigned to a control ( n = 8) or one of two experimental groups ( n = 6 each). All minipigs received surgical implantation of eight 2 mm ultrasonic crystals forming a cubic‐shaped array. Distance changes between crystal pairs indicated dimensional deformations for bilateral dorso‐ventral lengths, antero‐posterior thicknesses, and antero‐posterior dorso‐ventral widths. Increased distances indicated elongations while decreased distances indicated shortenings. Bilateral hypoglossal nerves were stimulated at 3–5 V. The genioglossus, styloglossus, thyrohyoid, and middle pharyngeal constrictor were bilaterally stimulated at 20–40 V. Real‐time respiratory airflow parameters were recorded during all stimulations. Nerve stimulation induced lengthening and widening in experimental groups and thinning in controls ( p < 0.05). The stimulated styloglossus showed shortened ventral length in controls and lengthening in experimental groups, and bilateral thinning in controls with thickening in experimental groups ( p < 0.05). The stimulated genioglossus induced widening and thickening in experimental groups and widening in controls. Respiratory airflow parameters increased in both experimental groups as compared to the control group. Neuromuscular stimulation induces distinctive deformations of the normal and volumetric‐altered tongue base that may contribute to understanding irregular changes, and patency or collapse in the oropharyngeal airway due to volumetric alterations of the tongue base.