目的

1. 利用数字化技术对眶距增宽症患者头颅模型的解剖标志点和三维评价指标进行测量，分析三维形态学特征，明确其畸形特点，为治疗方案的选择提供依据。

2.探讨数字化技术及三维打印导板定位技术在眶距增宽矫正术中的系统性应用。

3.探讨基于数字化技术的倒U形眶周截骨术在矫正眶距增宽症中的适应症和优势。

4.分析数字化模拟和3D打印截骨导板在眶距增宽矫正手术中的精准性，为数字化技术的应用充实理论基础。

方法

1. 选取2013年6月至2019年8月就诊于中国医学科学院整形外科医院颌面整形中心的先天性眶距增宽症患者，共15例，按病因分为面中裂眶距增宽组（A组）和单侧冠状缝早闭合并眶距增宽组（B组），借助数字化技术，建立新的三维坐标系，对眶距增宽症患者的相关解剖标志点和三维评价指标进行测量，统计分析其畸形特点。

2. 选取2013年6月至2019年8月就诊于中国医学科学院整形外科医院颌面整形中心诊断为先天性眶距增宽症并行数字化技术辅助手术治疗的患儿8例。其中单侧冠状缝合并眶距增宽症患者和面中裂眶距增宽患者各4例。将数字化技术系统应用于手术方案制定，术前模拟，3D打印截骨导板引导截骨，术前畸形以及术后效果定量化评价。

3. 选取2015年1月至2019年12月就诊于中国医学科学院整形外科医院颌面整形中心的单侧冠状缝早闭合并眶距增宽症患儿4例，借助数字化技术行颅内外联合入路倒U形截骨术（一种改良截骨方法）矫正眶距增宽症，观察总结效果，对该改良截骨方式的适应症和优势进行探讨。

4. 选取2015年1月至2019年12月就诊于中国医学科学院整形外科医院颌面整形中心并借助数字化模拟和3D打印截骨导板行手术治疗的先天性眶距增宽患儿6例，分别定量测量其术前、模拟和术后眶内侧壁间距（IOD）,内眦间距（ICD）,额鼻角（FNA）的三维数据，对数字化技术的准确性进行统计分析。

结果

1. A组眶内侧壁到正中矢状面的距离双侧具有统计学差异，双侧眶横径也具有显著性统计学差异；眶内侧壁最内点和眶外侧壁最外点均是在冠状方向上双侧具有统计学差异；双侧视神经角明显增大，但无统计学差异；头颅不对称性指数均值为1.44%，双侧前颅窝蝶骨角双侧无统计学差异。B组眶内侧壁到正中矢状面的距离双侧具有显著性差异，双侧眶横径也具有显著性差异；眶口纵径双侧具有显著性差异，冠状缝早闭侧的眶口纵径较对侧大，双侧视神经角也明显增大；眶上壁最高点在冠状方向、矢状方向和垂直方向双侧均有统计学差异；眶外侧壁最外点在矢状方向和垂直方向双侧有统计学差异；眶内侧壁主要在冠状方向有统计学差异；前颅不对称性指数均值为16.07%，前颅窝蝶骨角患侧为53.15°，健侧为66.08°，双侧具有统计学差异。

2. 应用数字化技术制定手术方案，3D打印截骨导板引导截骨，使得术中截骨时间缩短至1-2小时，未出现任何并发症。术后颅缝早闭组眶距增宽症的IOD由33.20mm减小至23.98mm，ICD由46.83mm减小至37.00mm，前颅不对称性指数由16.07%减小至1.74%，均与术前具有显著性差异；平均颅腔容积由1179.62ml，增大为1241.57ml，较术前增加了5.3%，与术前相比具有显著性差异；患侧平均眶腔容积由18.57ml增加为22.90ml，较术前增加了23.3%，健侧由21.70ml增加为23.65ml，较术前增加了9.0%，均较术前具有显著性差异。术后面中裂眶距增宽组的IOD由30.15mm减小至19.83mm，ICD由50.23mm减小至37.48mm，均与术前具有显著性差异。从解剖标志点坐标变化看，两组双侧的标志点三维坐标差异性变小。

3.  4例病例均按照术前数字化设计方案顺利完成手术，术中截骨时间缩短至2-3 h，术中平均出血量970ml，平均住院时间10天。术后无脑脊液漏、感染、颅内血肿及眼球损伤等并发症。术后患者头颅、眶外形都获得很大改善，患者外斜视获得改善。眶内壁间距减小至正常范围。

4. 术前患者的平均眶内测壁间距是35.1mm，术前手术设计的眶内测壁间距是23.9mm，术后实际的眶内测壁间距是23.4mm，术前设计的眶内侧壁间距与术后实际的眶内测壁间距没有统计学差异，然而，术后眶内侧壁间距和术前眶内侧壁间距具有明显统计学差异。术前患者的平均内眦间距是50.5mm，术前手术设计的内眦间距是40.7mm，术后实际的内眦间距是43.6mm，术前设计的内眦间距与术后实际的内眦间距有统计学差异，术后内眦间距和术前内眦间距具有明显统计学差异。术前患者的平均额鼻角是168.4°术后实际的额鼻角是148.5°，术前额鼻角和术后额鼻角具有统计学差异。色温图显示，手术模拟效果和术后实际效果具有较大程度上的一致性。

结论

1. 建立了新的三维测量坐标系对眶距增宽畸形特点进行定量化评价，面中裂眶距增宽畸形特点主要表现在冠状方向的双眼眶非对称性外扩；单侧冠状缝早闭合并眶距增宽的畸形特点不仅表现为双侧眼眶在冠状方向非对称性外扩，还在矢状方向和垂直方向存在不对称畸形，表现为患侧眼眶眶口横向变窄，纵向变长，并向上，向后倾斜。

2. 将数字化技术贯穿于眶距增宽外科整复治疗的术前设计、术中截骨及术后评估的整个过程中，并将其系统化、规范化、流程化，能够缩短手术时间，提高截骨准确性，定量化评估术后外形效果和颅眶发育功能形成有力反馈，便于对眶距增宽症的治疗更深一步研究。

3. 倒U型截骨适用于双眼眶上缘不在同一水平的眶距增宽症患者，尤其是冠状缝早闭合并眶距增宽症的患者，优点是手术创伤小，手术时间短，矫正效果好。

数字化技术在模拟手术，设计导板引导截骨等方面具有较高的准确性，能够保证术中对手术设计的精准执行，为数字化技术的进一步应用提供理论依据。

Objective

1. Using digital technology to measure the anatomical landmarks and three-dimensional evaluation indexes of head modeling in patients with hypertelorism, analyze the three-dimensional morphological characteristics, and clarify the deformity characteristics, so as to provide the basis for the selection of treatment stratege.

2. To explore the systematic application of digital technology and three-dimensional cutting guides in the correction of hypertelorism.

3. To explore the indications and advantages of inverted U-shaped periorbital osteotomy based on digital technology in correcting hypertelorism.

4. Analyze the accuracy of digital simulation and 3D printing cutting guides in the correction of hypertelorism, and to enrich the theoretical basis for the application of digital technology.

Methods

A total of 15 patients with congenital hypertelorism were selected from June 2013 to August 2019 in Maxillofacial Plastic Center, Plastic Surgery Hospital, Chinese Academy of Medical Sciences. They were divided into midface cleft hypertelorism group (Group A) and unilateral coronal craniosynostosis group (Group B) according to the etiology. With the help of digital technology, a new three-dimensional coordinate system was established to measure the related anatomical landmarks and three-dimensional evaluation indexes of patients with hypertelorism.

From June 2013 to August 2019, 8 children with congenital hypertelorism diagnosed and received surgical treatment in  maxillofacial plastic surgery center of Plastic Surgery Hospital of Chinese Academy of Medical Sciences were selected. Among them, there were 4 patients with hypertelorism caused by unilateral coronal craniosynostosis and 4 patients were midface cleft hypertelorism. The digital technology system was applied to the design of surgical plan, preoperative simulation, osteotomy guided by 3D printing cutting guides, preoperative deformity and quantitative evaluation of postoperative effect.

From January 2015 to December 2019, 4 children with hypertelorism caused by unilateral coronal craniosynostosis in Maxillofacial Plastic Center of Plastic Surgery Hospital of Chinese Academy of Medical Sciences were selected, and inverted U-shaped osteotomy (an modified osteotomy method) through combined intracranial and extracranial approaches was performed to correct hypertelorism, and the surgical results were observed and summarized.

From January 2015 to December 2019, 6 children with congenital hypertelorism who were treated in maxillofacial plastic surgery center of plastic surgery hospital of Chinese academy of medical sciences and operated with digital simulation and 3D printing cutting guides were selected. the data of IOD, ICD and FNA were measured quantitatively, and the accuracy of digital technology was statistically analyzed.

Results

1. In group A, the distance from the medial orbital wall to the median sagittal plane is statistically different on both sides, and the lateral orbital diameter on both sides is also statistically different. The innermost point of orbital medial wall and the outermost point of orbital lateral wall have statistical differences on both sides in coronal direction. Bilateral optic nerve angle increased obviously, but there was no statistical difference. The mean value of ACVAI was 1.44%, and there was no significant difference between the sphenoid angle of the anterior cranial fossa. In group B, the distance from the medial orbital wall to the median sagittal plane was significantly different on both sides, and the lateral orbital diameter was also significantly different on both sides The longitudinal diameter is significantly different on both sides. The longitudinal diameter on the affected side is larger than that on the opposite side, and the optic nerve angle on both sides is also significantly increased. The highest point of supraorbital wall has statistical differences in coronal direction, sagittal direction and vertical direction The outermost point of orbital lateral wall has statistical difference in sagittal direction and vertical direction; There are statistical differences in the medial orbital wall mainly in the coronal direction; The mean ACVAI was 16.07%, the affected side of sphenoid angle of anterior cranial fossa was 53.15°, and the healthy side was 66.08°.

2. Using digital technology to make the operation plan and 3D printing osteotomy guide plate to guide osteotomy can shorten the osteotomy time to 1-2 hours without any complications. In unilateral coronal craniosynostosis group, IOD, ICD and ACVAI decreased from 33.20mm to 23.98mm, 46.83mm to 37.00mm and 16.07% to 1.74% respectively, which were significantly different from those before operation. The average cranial cavity volume increased from 1179.62ml to 1241.57ml, an increase of 5.3% compared with that before operation, with significant difference compared with that before operation. The mean orbital cavity volume of the affected side increased from 18.57ml to 22.90ml, which was 23.3% higher than that before operation, and that of the healthy side increased from 21.70ml to 23.65ml, which was 9.0% higher than that before operation. In midface cleft hypertelorism group, IOD and ICD decreased from 30.15mm to 19.83mm and 50.23mm to 37.48mm respectively, which were significantly different from those before operation. From the coordinate changes of anatomical landmarks, the difference of three-dimensional coordinates of landmarks on both sides of the two groups became smaller.

3. The 4 cases were successfully operated according to the digital design plan, the osteotomy time was shortened to 2-3 h, the average blood loss was 970ml, and the average hospitalization time was 10 days. There were no complications such as cerebrospinal fluid leakage, infection, intracranial hematoma and eyeball injury. After operation, the shape of the head and orbit of the patients were greatly improved, and the exotropia of the patients was improved. The interorbital distance decreased to normal range.

4. The average IOD of patients before operation is 35.1mm, the designed IOD is 23.9mm, and the actual IOD after operation is 23.4 mm. There is no statistical difference between the designed IOD before operation and the actual IOD after operation. The average ICD of patients before operation is 50.5mm, the designed ICD before operation is 40.7mm, and the actual ICD after operation is 43.6 mm. There is  statistical difference between the designed ICD before operation and the actual ICD after operation. The average FNA of patients before operation is 168.4°, and the actual FNA after operation is 148.5°. There is statistical difference between preoperative and postoperative FNA. Color temperature diagram showed that the  surgical simulated effect was consistent with the actual effect after surgery to a great extent.

Conclusion

A new three-dimensional measurement coordinate system is established to quantitatively evaluate the morphological characteristics of hypertelorism. The deformity characteristics of midface cleft hypertelorism are mainly manifested in the asymmetric expansion of double orbits in the coronal direction; The deformity of hypertelorism caused by unilateral coronal craniosynostosis is characterized by asymmetric outward expansion of bilateral orbitals in coronal direction, and asymmetric deformity in sagittal and vertical directions, showing that the orbital diameter of the affected side narrows laterally, lengthens longitudinally, and the whole orbit inclines upward and backward.

Applying digital technology to the whole process of preoperative design, intraoperative osteotomy and postoperative evaluation of hypertelorism correction can shorten the operation time, improve the accuracy of osteotomy, quantitatively evaluate the postoperative effect and cranio-orbital development function.

Inverted U-shaped osteotomy is suitable for patients with hypertelorism whose orbital upper edges are not at the same level, especially those with coronal craniosynostosis and hypertelorism. Its advantages are less surgical trauma, shorter operation time and better correction effect.

4. Digital technology has high accuracy in surgical simulating, designing cutting guides, which can ensure the accurate implementation of surgical design during operation. It can provide theoretical basis for further application of digital technology.