3D Volumetric Analysis of Pharyngeal Airway of 50 Individuals Who Underwent Maxillary Advancement

3D volumetric analysis of pharyngeal airway of 50 individuals who underwent maxillary advancement.

Authors: Gonçales ES, Tieghi Neto V, Palmieri Jr C, Ghali GE. 

Introduction: Dentofacial deformities (DFD) can be defined as defects in the growth and development of facial bones, mainly in the maxilla and mandible. It may affect the function or development of other structures, organs and related systems. Orthognathic surgery is the procedure of choice for the treatment of DFDs and it may affect some related systems such as the pharyngeal airway. Objective: The aim of this study was to evaluate, through a 3D retrospective analysis of cone beam computed tomographic images (CBCT), the changes in the dimensions of the pharyngeal airway space after maxillary advancement. Materials and Method: Pre and post-operative 3D volumetric measurements were done with the use of CBCT and Dolphin Imaging 11.5 of 50 individuals who underwent isolated maxillary advancement by Le Fort I osteotomy. The data were analyzed by the ANOVA Test. Results: Preoperative and postoperative CBCTs of 50 individuals that underwent maxillary advancement by Le Fort I osteotomy were studied. Fourteen of them were male and 36 were female. The average age and the standard deviation (SD) at the time of the surgery was 24.82 (11.21) years old and the average and the standard deviation (SD) of the postoperative period was 57.24(43.19) days. The average maxillary advancement was 3.44mm and it was shown by the A-Na Perp (average of 2.75mm at the preoperative time and average of 6.19mm at the postoperative time) and by the SNA, being 78.88⁰ at the preoperative time and  83.25⁰ at the postoperative time. The average volume of the oropharyngeal airway space had a statistically significant increase of 4020.49mm³ and this increase seemed to be higher at the upper portion of the oropharyngeal airway between the Posterior Nasal Spine (PNS) and the Uvula (U). Conclusion: Isolated maxillary advancement increased the volume of the oropharyngeal airway space, what would benefit patients which the site of obstruction is located at that upper level (Fujita Type I). For Fujita type II patients, where the site of obstruction is located at the oropharynx and hypopharynx, which are the majority of the OSA patients, the bi-maxillary advancement would be a more appropriate procedure.

References: 

Gonçales ES, Rocha JF, Gonçales AG, Yaedú RY, Sant'Ana E. Computerized cephalometric study of the pharyngeal airway space in patients submitted to orthognathic surgery. J Maxillofac Oral Surg. 2014 Sep;13(3):253-8. doi: 10.1007/s12663-013-0524-5. Epub 2013 May 3.

Gonçales ES, Duarte MA, Palmieri C Jr, Zakhary GM, Ghali GE. Retrospective analysis of the effects of orthognathic surgery on the pharyngeal airway space. J Oral Maxillofac Surg. 2014 Nov;72(11):2227-40. doi: 10.1016/j.joms.2014.04.006. Epub 2014 Apr 13.

Key words: Orthognathic Surgery. Cone Beam Computed Tomographic. Pharyngeal Airway Space.

Thanks to Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP.