Objective: 

This observational retrospective cross-sectional study aimed to investigate the morphological characteristics of the temporomandibular joint (TMJ) in type IIa hemifacial microsomia (HFM).

Methods: 

We recruited 88 patients with unilateral type IIa HFM. Data relating to the length, distance, and angle of the TMJ, were measured on 3-dimensional models created by the analysis of computed tomography data. Normality analysis was performed by using the Shapiro-Wilk test. Data were compared with the paired t test and Wilcoxon signed-rank test.

Results: 

The height, long axis, and short axis of the affected condyle were significantly shorter than the unaffected side (P<0.001); the ratios were 0.41±0.15, 0.75±0.20, and 0.95±0.24, respectively. The spaces between the condyle and the glenoid fossa were significantly larger in affected TMJs (P<0.001). The ratio between the ipsilateral and contralateral anterior space in the sagittal plane was 4.62±2.59; this was significantly different than the ratio of inner space (1.50±1.70), superior space (1.70±0.97), and lateral space (1.28±0.62) in the coronal plane (P<0.001) and the ratio of superior space (1.43±1.05) and posterior space (1.47±0.98) in the sagittal plane (P<0.001); there were no statistical differences between the 5 spaces (P>0.05). The breadth and depth of the glenoid fossa were significantly shorter in affected TMJs (P<0.001), the ratio of the breadth in the affected and unaffected glenoid fossa was between 0.5 and 1 and the depth of the affected glenoid fossa was almost half of that on the unaffected side. The ratio between the ipsilateral and contralateral height of the condyle was significantly different when compared with the length of the mandibular ramus (P<0.001). The ratio between the ipsilateral height of the condyle and the length of the mandibular ramus was significantly different when compared with that of the contralateral side (P<0.001). The height of the affected condyle were significantly different (P=0.005) among different ages.

Conclusions: 

We found that hypoplasia was more severe in terms of the height of the condyle than the long axis and short axis of the condyle. The degree of condyle deformity was more severe than the mandible. And the affected condyle still had growth potential in the vertical direction with age.

中文翻译：

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Pruzansky-Kaban IIa 型半面小儿颞下颌关节的三维测量

客观的： 

这项观察性回顾性横断面研究旨在调查IIa 型半面小儿畸形 (HFM) 患者的颞下颌关节(TMJ) 的形态学特征。

方法： 

我们招募了 88 名单侧 IIa 型 HFM 患者。与 TMJ 的长度、距离和角度相关的数据是在通过计算机断层扫描数据分析创建的 3 维模型上测量的。使用 Shapiro-Wilk 检验进行正态性分析。数据与配对t检验和 Wilcoxon 符号秩检验进行比较。

结果： 

患侧髁突高度、长轴、短轴均显着短于健侧（P <0.001）；比率分别为0.41±0.15、0.75±0.20和0.95±0.24。受影响的 TMJ 的髁突和关节窝之间的空间明显更大（P <0.001）。矢状面同侧前间隙与对侧前间隙之比为4.62±2.59；与冠状面内间隙(1.50±1.70)、上间隙(1.70±0.97)、侧间隙(1.28±0.62)比值和上间隙比( 1.43 ± 1.05)和矢状面后间隙(1.47±0.98)( P <0.001); 5个空间之间没有统计差异（P > 0.05）。患侧颞下颌关节盂的宽度和深度均显着缩短（P <0.001），患侧和未患侧关节窝宽度之比在0.5~1之间，患侧关节窝深度几乎是其一半。在未受影响的一侧。同侧和对侧髁突高度与下颌升支长度的比值差异有统计学意义（P <0.001）。同侧髁突高度与下颌升支长度之比与对侧比较差异有统计学意义（P <0.001）。受影响的髁突高度有显着差异（P=0.005) 不同年龄段。

结论： 

我们发现，就髁突的高度而言，发育不全比髁突的长轴和短轴更为严重。髁突畸形程度较下颌骨严重。并且随着年龄的增长，受影响的髁突仍有垂直方向的生长潜力。