Baek Chaehwan, Paeng Jun-Young, Lee Janice S, Hong Jongrak
Department of Oral and Maxillofacial Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
J Oral Maxillofac Surg. 2012 May;70(5):1161-9. doi: 10.1016/j.joms.2011.02.135. Epub 2011 Jul 16.
A systematic classification is needed for the diagnosis and surgical treatment of facial asymmetry. The purposes of this study were to analyze the skeletal structures of patients with facial asymmetry and to objectively classify these patients into groups according to these structural characteristics.
Patients with facial asymmetry and recent computed tomographic images from 2005 through 2009 were included in this study, which was approved by the institutional review board. Linear measurements, angles, and reference planes on 3-dimensional computed tomograms were obtained, including maxillary (upper midline deviation, maxilla canting, and arch form discrepancy) and mandibular (menton deviation, gonion to midsagittal plane, ramus height, and frontal ramus inclination) measurements. All measurements were analyzed using paired t tests with Bonferroni correction followed by K-means cluster analysis using SPSS 13.0 to determine an objective classification of facial asymmetry in the enrolled patients. Kruskal-Wallis test was performed to verify differences among clustered groups. P < .05 was considered statistically significant.
Forty-three patients (18 male, 25 female) were included in the study. They were classified into 4 groups based on cluster analysis. Their mean age was 24.3 ± 4.4 years. Group 1 included subjects (44% of patients) with asymmetry caused by a shift or lateralization of the mandibular body. Group 2 included subjects (39%) with a significant difference between the left and right ramus height with menton deviation to the short side. Group 3 included subjects (12%) with atypical asymmetry, including deviation of the menton to the short side, prominence of the angle/gonion on the larger side, and reverse maxillary canting. Group 4 included subjects (5%) with severe maxillary canting, ramus height differences, and menton deviation to the short side.
In this study, patients with asymmetry were classified into 4 statistically distinct groups according to their anatomic features. This diagnostic classification method will assist in treatment planning for patients with facial asymmetry and may be used to explore the etiology of these variants of facial asymmetry.
面部不对称的诊断和外科治疗需要一个系统的分类方法。本研究的目的是分析面部不对称患者的骨骼结构，并根据这些结构特征将这些患者客观地分为不同组。
本研究纳入了2005年至2009年期间有面部不对称且有近期计算机断层扫描图像的患者，该研究获得了机构审查委员会的批准。在三维计算机断层扫描上获得线性测量值、角度和参考平面，包括上颌骨（上颌中线偏移、上颌骨倾斜和牙弓形态差异）和下颌骨（颏点偏移、下颌角至正中矢状面、升支高度和额升支倾斜度）测量值。所有测量值均使用配对t检验并进行Bonferroni校正，然后使用SPSS 13.0进行K均值聚类分析，以确定所纳入患者面部不对称的客观分类。进行Kruskal-Wallis检验以验证聚类组之间的差异。P < 0.05被认为具有统计学意义。
本研究纳入了43例患者（18例男性，25例女性）。根据聚类分析，他们被分为4组。他们的平均年龄为24.3±4.4岁。第1组包括因下颌体移位或侧向化导致不对称的受试者（占患者的44%）。第2组包括左右升支高度有显著差异且颏点向短侧偏移的受试者（占39%）。第3组包括具有非典型不对称的受试者（占12%），包括颏点向短侧偏移、较大侧的下颌角/下颌角突出以及上颌反向倾斜。第4组包括具有严重上颌倾斜、升支高度差异且颏点向短侧偏移的受试者（占5%）。
在本研究中，不对称患者根据其解剖特征被分为4个统计学上不同的组。这种诊断分类方法将有助于面部不对称患者的治疗规划，并可用于探索这些面部不对称变体的病因。
