Diagnosis and treatment in patients with asymmetric prominent mandibular angle based on digital design
10.3760/cma.j.cn114453-20210308-00106
- VernacularTitle:基于数字化设计的下颌角不对称肥大的诊断与手术方法
- Author:
Tiecheng SUN
1
;
Kun SHUANG
;
Bowen LEI
;
Bin YANG
Author Information
1. 中国医学科学院北京协和医学院整形外科医院数字化整形外科，北京 100144
- Keywords:
Facial asymmetry;
Osteotomy;
Computers, analog;
Asymmetrical hypertrophy of the mandibular angle;
Digital measurement
- From:
Chinese Journal of Plastic Surgery
2022;38(4):383-391
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the application value of the diagnostic and surgical method for asymmetric prominent mandibular angle assisted by digital surgical design.Methods:The data of the females in Han nationality with prominent mandibular angle from December 2010 to December 2020 in the Department of Digital Plastic Surgery of Plastic Surgery Hospital, Chinese Academy of Medical Sciences were analyzed retrospectively. ProPlan CMF 3.0 software was used to preoperatively mirror the patient’s three-dimensional(3D) model to obtain a diagnosis. The characteristics of bilateral differences of asymmetry of mandible were evaluated, and the surgical method were analyzed. The effect of surgery was objectively evaluated by indicators such as gonion point width (Go-W), condyle apex height (Co-H), and mandibular angle(Ag). SPSS 18.0 was used for statistical analysis, and the data were tested by Kolmogorov-Smirnov test, and the result were in line with the normal distribution. The data were expressed in Mean±SD, and the paired t-test was used to compare the measurement result of the indicators on both sides of the mandible, and P<0.05 was a statistically significant difference. Results:A total of 30 female patients, aged from 18 to 39 years, were included. Preoperative 3D model measurements showed a longer mandibular ascending branch on one side of the mandible (long side) and a more extrusion of the mandibular angle on the other side (prominent side), which was treated with a modified surgical method of mandibular angle osteotomy. The height of the osteotomy line on the long side was the height of the exuberant osteotomy line + the height difference between the two sides, and the thickness of the outer plate grinding on the protrusion side was the thickness of the outer plate grinding on the long side + the width difference between the two sides. Both the preoperative pogonion and menton points were far from the long side of the mandible and biased towards the prominent side. The height, width and mandibular angle of the marker points on both sides of the mandible were compared, and the differences were statistically significant ( P<0.01). Among them, the asymmetrical difference between Go-W, Co-H and Ag was the largest, which could be used to evaluate the effect of surgery. The differences between Go-W, Co-H and Ag before and after surgery on the long side of the mandible were (1.10±2.05) mm, (12.84±2.96) mm, (-17.75±5.16)°, and the differences between the three indicators on the prominent side were (4.24±1.64) mm, (10.95±3.25) mm, (-14.87±5.14)°, respectively, and the differences between preoperative and postoperative comparisons were statistically significant ( P<0.01). The asymmetric differences between the three indicators on both sides of the mandible after surgery were (-0.32±2.30) mm, (-0.02±0.37) mm, (-0.01±1.87)°, respectively, and the differences were not statistically significant ( P>0.05). All patients had no complications such as hematoma and infection after surgery, and the patients were satisfied with the result of the operation. Conclusions:Asymmetric hypertrophy mandibular angle can be reconstructed by the patient’s preoperative 3D model to accurately measure the differences between the two sides of the mandible. This design can effectively guide the surgical method, improve the symmetry of the patient’s bilateral mandible, and achieve better aesthetic effects on the face.
