Objective: To three-dimensionally calculate the craniofacial parameters of midface of patients with Treacher Collins syndrome (TCS) in China, in order to understand the changes in the spatial position relationship between the various anatomical structures of the midface.
Methods: CT imaging data of TCS patients and age- and gender-matched normal populations between January 2013 and July 2020 was retrospectively analyzed. A total of 33 cases met the selection criteria for inclusion in the study, including 14 cases in the TCS group and 19 cases in the control group. ProPlan CMF 3.0 software was used to perform three-dimensional digital reconstruction of the craniofacial bone, measure the anatomical parameters of the midface, and analyze its morphological structure; at the same time perform three-dimensional digital reconstruction of the upper airway for morphological analysis (measure upper airway volume).
Results: CT images analysis revealed that all 14 patients with TCS presented the typical features with downward slanting of the palpebral fissures and different degrees of zygomatico-orbital complex dysplasia. Cephalometric and morphological analysis of the midface revealed that, multiple transverse diameters of the midface of TCS patients were significantly decreased when compared with the control group ( P<0.05), such as the width of the maxillary base, the length of the maxillary complex, and some distances related to the nasal morphology; but the distance between bilateral orbitales increased in TCS group ( P<0.05). Several anteroposterior distances in TCS group were decreased significantly when compared to control group and the distance between the skull base point and the posterior nasal spine was the most shortened ( P<0.05). But there was no significant difference of the distance between nasion and anterior nasal spine, which represented anterior midface height, between groups ( P>0.05). The skull base angle and SNB angle (the angle between the sella point-nose root point-inferior alveolar seat point) of the TCS group both decreased when compared with the control group ( P<0.05), but there was no significant difference in SNA angle (the angle between the sella point-nose root point-upper alveolar seat point) between the two groups ( P>0.05). The total volume of the upper airway was (24 621.07±8 476.63) mm 3 in the TCS group, which was significantly lower than that of the control group [(32 864.21±13 148.74) mm 3] ( t=2.185, P=0.037).
Conclusion: The transverse distances, anteroposterior distances, and multiple craniofacial angles measurement of TCS patients were significantly decreased when compared to the control group, presented with different degrees of zygomatico-orbital complex dysplasia, nasal and maxillary dysplasia, but there was no obvious restriction in face height development. Reduced internal diameters of the upper airway maybe responsible for the decreased upper airway volume of patients with TCS.
目的: 研究国人 Treacher Collins 综合征（Treacher Collins syndrome，TCS）患者的面中部形态结构及解剖学参数，以了解面中部各解剖结构之间的空间位置关系变化。.
方法: 回顾分析 2013 年 1 月—2020 年 7 月就诊的 TCS 患者及年龄和性别相匹配的正常人群 CT 影像学资料，共 33 例符合选择标准纳入研究，其中 TCS 组 14 例，对照组 19 例。通过 ProPlan CMF 3.0 软件对其颅面骨进行三维数字化重建，测量面中部解剖学参数并分析其形态结构；同时行上呼吸道三维数字化重建进行形态分析（测量上呼吸道容积）。.
结果: CT 检测示，14 例 TCS 患者均表现为睑裂下斜，且合并不同程度的颧骨复合体发育不良。面中部形态分析显示，与对照组比较，TCS 组患者面中部横向径线长度下降，如上颌骨基底宽度、上颌复合体长度及鼻骨相关横径（ P<0.05），但眶下点距离较对照组增高（ P<0.05）；TCS 组患者面中部多处矢状径线长度下降，其中颅底点-后鼻棘点的距离缩短程度最严重（ P<0.05），但两组间比较代表前面中部高度的鼻根点-前鼻棘点距离，差异无统计学意义（ P>0.05）。TCS 组患者颅底角及 SNB 角（蝶鞍点-鼻根点-下齿槽座点之间的夹角）较对照组明显下降（ P<0.05），但两组间 SNA 角（蝶鞍点-鼻根点-上齿槽座点之间的夹角）差异无统计学意义（ P>0.05）。上呼吸道形态分析示，TCS 组患者上呼吸道容积为（24 621.07±8 476.63）mm 3，与对照组（32 864.21±13 148.74）mm 3相比显著下降，差异有统计学意义（ t=2.185， P=0.037）。.
结论: TCS 患者面中部横径、矢状前后径及多个颅面骨角度明显小于正常人群，表现为不同程度颧骨缺失、鼻骨及上颌骨显著横向发育不良，但高度发育无明显受限。TCS 患者上呼吸道容积小于正常人群可能与上呼吸道内部径线缩短相关。.
Keywords: Treacher Collins syndrome; midface morphology; three-dimensional measurement; upper respiratory obstruction.