The three dimensional analysis of volumetric airway change in orthognathic surgery of mandibular prognathism

ABSTRACT

Orthognathic surgery changes patient's mandibular position and environment of related anatomic structures. Many clinicians were interested in these changes and studied about this problem. However, most of them were based on two dimensional cephalogram. According to the development of image and computer system, it would be possible that the airway change is analyzed with three dimensional CT. So we tried to measure the volumetric change of airway and analyzed the relationship between the airway structure and volumetric change. Nineteen patients who experienced orthognathic surgery due to mandibular prognathism were analyzed with 3D CT data (preoperative and postoperative 6 months) and 2D lateral cephalometry. Volumetric change was measured and 3 dimensional change of related structure was assessed with simulation program (V-works., 4.0 Cybermed, Korea). Ten patients showed the decrease of airway volume change and nine showed the increase of airway volume change. Volumetric change was determined by dimensional change of mandible and hyoid bone. The dimensional positions of mandible and hyoid bone were the key factor for determining the airway change after surgery. Airway change is also predictable with the dimensional change of mandible and hyoid bone.