Comparison of Different Orthognathic Surgeries Impact on Pharyngeal Airway Space in CL III Patients

This study sought to compare the changes in the pharyngeal airway space, hyoid bone position, tongue, soft palate, and retro-lingual soft tissues following three different orthognathic surgeries on class III patients.

This quasi-experimental study was conducted on 75 skeletal class III patients. The predictor variable was the type of orthognathic surgery namely mandibular setback, maxillary impaction & mandibular setback and maxillary advancement & mandibular setback (25 patients in each group). The primary outcome variables were the dimensions of the pharyngeal airway space and retrolingual region, measured preoperatively and at least one year postoperatively. Cephalometric landmarks were also measured. Pre- and post-operative cephalograms were superimposed based on the S-N line with registration at the S-point.

When considering the changes in the whole sample (75 cases), significant changes were found in oropharyngeal length (UMPW, VLPW), tongue height (H-VT), horizontal position of vallecula (V_C3) and horizontal position of the hyoid bone. The only significant difference noted, was the tongue height and vertical position of hyoid between the three groups.

Orthognathic surgery significantly affects the oropharyngeal space and position of the tongue and hyoid bone. The three types of Orthognathic surgeries on class III patients caused different effects on oropharyngeal space, tongue and hyoid position with a significant impact on tongue height in maxillary advancement plus mandibular setback.