Surgical Maxillary Advancement Increases Upper Airway Volume in Skeletal Class III Patients: A Cone Beam Computed Tomography-Based Study

Abstract

Study objectives: Although volumetric changes of the upper airway occur following surgical advancement of the maxilla, few studies investigated these changes using three-dimensional imaging techniques. Thus, the goal of this study was to verify whether the surgical advancement of the maxilla affects the volume of the upper airway and to determine any association of these volume changes with sex and age.

Methods: Preoperative and postoperative cone-beam computed tomography (CBCT) scans of 14 patients (8 male and 6 female) who underwent maxillary advancement to correct skeletal class III deformities were assessed to determine the postoperative volumetric changes in the upper airway. Preoperative and postoperative airway volume measurements were compared by means of paired t-test, which was also used to compare airway volume between genders. Pearson correlation coefficient was used to verify whether a correlation between age and upper airway volume was present.

Results: Maxillary advancement produced significant upper airway volume increases (mean 20.94%, p < 0.05) on nearly half of our sample. However, sex and age did not seem to influence upper airway volume in our sample of skeletal class III patients.

Conclusions: Surgical advancement of the maxilla may produce significant volume increases in the upper airway of skeletal class III patients regardless of sex and age.

Keywords: airway obstruction; diagnosis; orthognathic surgery; sleep apnea.

Figure 1

(A) Delimitation of the pharyngeal space in the sagittal view: the upper limit includes the glandular soft palate, the region above the adenoid pad and the choanae, representing the roof of the nasopharynx (a), the anterior limit is defined as a plane perpendicular to the sella-nasion line passing through the point of transition between the hard and the soft palate (b), the inferior limit was a horizontal plane passing from the most anterior and inferior point of C3 (c), and the posterior limit was a plane perpendicular to the sella-nasion tangential to the posterior pharyngeal wall (d). (B) and (C) show the corresponding limits in the axial and coronal views, respectively.

Figure 2

Sagittal (A) and axial (B) views of the DICOM image in 2-mm increments, which enables finer delimitation of the pharyngeal contour (C).

Figure 3

Three-dimensional reconstruction of the airway in the software window, which shows the numerical information for the volume of interest.