Three-dimensional analysis of changes in pharyngeal airway space after mandibular setback surgery

Abstract

Purpose

The purpose of this study was to assess the quantitative three-dimensional (3-D) effects of orthognathic surgery on skeletal and pharyngeal airway morphology.

Methods

The patients were 22 Japanese females with mandibular prognathism. Ten patients underwent bilateral sagittal split ramus osteotomy and 12 underwent bilateral intraoral vertical ramus osteotomy without reduction glossoplasty. Spiral/helical computed tomography (CT) was performed before treatment and after orthognathic surgery. A volume-rendering technique was used to create 3-D CT images.

Results

The antero-posterior width, lateral width, cross-sectional area of the soft palate plane, and upper volume of the oropharyngeal airway decreased significantly following mandibular setback surgery. Significant positive correlations were found between changes in ANB, FH-NB angle, mandibular plane angle, Y-axis, the amount of mandibular setback and change in total height of the pharyngeal airway, and between changes in Co width and changes in distance and vertical height between the hyoid bone and the 3rd cervical vertebra. There was no significant correlation between surgical changes and the volume of the PAS after surgery.

Conclusions

Combined orthognathic–orthodontic treatment improved skeletal 3 deformities. Orthognathic surgery reduced the volume and the antero-posterior width of the pharyngeal airway of patients with such deformities.

Keywords:

• Computed tomography
• Three-dimensional
• Skeletal class III
• Setback surgery
• Pharyngeal airway space

Acknowledgments

This study supported by Grant-in-Aids 19390531 and 18791561 from the Ministry of Science, Sports, Education, and Culture, Japan, and 19659542 from the Japan Society for the Promotion of Science.