Where to position osteotomies in genioglossal advancement surgery based on locations of the mental foramen, canine, lateral incisor, central incisor, and genial tubercle.

PURPOSE: The study aimed to provide precise measurements of anterior mandibular structural anatomy and to explore potential osteotomies for genioglossal advancement.
METHODS: Cone beam computed tomography was used to analyze 33 randomly selected patients undergoing surgery for obstructive sleep apnea (OSA) between 2014 and 2016 at an academic surgical hospital. The locations of relevant mandibular structures were measured and statistical modeling was performed.
RESULTS: Mean horizontal distances from midline to the mental foramina and the roots of the canine, lateral incisor, and central incisor were 22.11 ± 1.92, 13.56 ± 3.01, 6.19 ± 1.58, and 2.04 ± 0.87 mm, respectively. Mean vertical distances from the inferior border of the mandible were 15.15 ± 1.77, 17.11 ± 3.28, 20.48 ± 3.10, and 21.81 ± 3.49 mm, respectively. The superior border of the genial tubercle was 15.63 ± 2.75 mm, and the inferior border was 6.87 ± 3.29, from the inferior border of the mandible. The angle of decline of the best-fit line through the important structures was about 18° from the occlusion plane at the midline.
CONCLUSIONS: A straight line estimating the mental foramen, canine, lateral incisor, and central incisor tooth roots crosses at a mean of 22.3-22.6 mm above the inferior border of the mandible at the midline and has an angle of decline of about 18°. Potential osteotomies made parallel to and below this line result in tradeoffs between maximizing capture of the genioglossus muscle attachment and risk of dental/neurovascular injury.