ABSTRACT
Objective@# To establish a three-dimensional coordinate system that can accurately measure the recurrence rate after orthognathic surgery, and evaluate and analyze the degree of recurrence.@*Methods @#Data from patients who underwent orthognathic surgery in a hospital were selected to reconstruct three-dimensional images with spiral CT. The two researchers used the multiplane assisted positioning method to fix the points three times and screened them using intra-andintreclass correlation coefficients (ICC). Reproducible and accurate landmark points were drawn to establish different coordinate systems and calculate the facial asymmetry index (AI) to determine the coordinate system with the best mid-sagittal plane symmetry. This coordinate system and lateral radiographs were used to separately measure the recurrence rate, and evaluate and analyze the three-dimensional recurrence degree of orthognathic surgery.@*Results @#Ten landmark points that may be repeatedly fixed were obtained, including N (nasion), K (K point), ANS(anterior nasal spine), PNS (posterior nasal spine), Ptm(pterygomaxillary fissure), Gn (gnathion), IZ(IZ point), MZ (MZ point), Ms (mastoideale), Cor (coronion) and and Go (gonion). Three coordinate systems were established, and the most suitable coordinate system was the upper edge point of the left infraorbital foramen. The inner upper edge of the right infraorbital foramen and both sides of the midpoint of the ear points constituted the horizontal plane (HP), which passed through the outermost point of the left zygomatic frontal suture and the outermost point of the right zygomatic frontal suture and was perpendicular to the horizontal plane to constitute the coronal plane (CP). It was perpendicular to the two planes to form a sagittal plane (SP). Two-dimensional and three-dimensional measurements of recurrence were performed on 112 patients, and new three-dimensional recurrence evaluation results were obtained. Less than 40% had low recurrence, 40% to 61% had moderate recurrence, and greater than 61% had high recurrence.@*Conclusion@#This study established a three-dimensional coordinate system suitable for measuring the recurrence rate after orthognathic surgery, obtained a new three-dimensional recurrence evaluation result, and provided a clinical experimental basis for evaluating the effect of orthognathic surgery and improving stability.
ABSTRACT
Objective @#To explore the clinical effect of simultaneous distraction osteogenesis of the maxilla and affected mandible combined with second-stage orthognathic surgery for the treatment of adult hemifacial microsomia to provide a reference for clinical practice.@*Methods@#Twelve adult patients with hemifacial microsomia who underwent simultaneous distraction osteogenesis and second-stage orthognathic surgery from 2006 to 2013 were enrolled. Distraction osteogenesis of the maxilla and malformed lateral mandible and second-stage orthognathic surgery were performed according to each patient’s specific conditions. The height ratio of the mandibular ramus of the affected side to the contralateral side, the shift distance of the chin point and the inclination angle of the screw plane were measured before and after the operation, and the therapeutic effect was evaluated with clinical photographs.@*Results @#No patients had obvious complications after the operation, the postoperative aesthetic effect was good, and the relationship between the facial shape and occlusion was significantly improved. The cephalometric measurement showed that the height ratio of the mandibular ramus of the affected side to the contralateral side was increased by 23.83% (t=11.658, P<0.001), the deviation distance of the chin was corrected, and the chin point moved back to the midline by 6.63 mm (t=13.042, P<0.001) on average, and the inclination angle of the occlusal plane was improved and returned to the horizontal plane by 8.83° (t=15.358, P<0.001) on average.@*Conclusion @#The application of simultaneous distraction osteogenesis of the maxilla and mandible combined with secondary orthognathic surgery for the treatment of adult hemifacial microsomia can obtain satisfactory clinical and aesthetic results and has clinical value.