经缝牵引成骨术治疗唇腭裂患者面中部发育不全的临床研究与三维有限元分析

Clinical study and finite element analysis of trans-sutural distraction osteogenesis for midfacial hypoplasia in cleft lip and palate patients

目的通过临床研究和三维有限元分析,探讨经缝牵引成骨术治疗唇腭裂患者的生物力学机制,为临床应用该方法纠正面中部发育不足提供理论依据。方法通过对1例单侧完全性唇裂患者经缝牵引前后头颅三维CT影像进行重建,生成头颅骨骼三维模型影像,然后将其注册进入同一空间坐标体系进行拟合配准,分析并测量骨缝在三维方向上的形态学改变。同时采用三维有限元法,建立患者颅上颌复合体模型,模拟经缝牵引成骨,获取骨缝应力分布。结果牵引结束后,患者面部形态获得显著改善,面中部凹陷畸形消失。骨缝在三维方向上不等量移位,在前后向上,翼颌缝有着最大前移量;在垂直向上,鼻旁区的鼻颌缝、额颌缝标志点表现为明显的上移,而靠近上颌骨下方的翼颌缝表现为明显的下移;在左右向上,各骨缝标志点位移较小。在健侧,Von Mises应力最大值出现在颧颌缝,患侧Von Mises应力比健侧Von Mises应力更大,最大值位于蝶颌缝及颧颌缝。结论经缝牵引成骨术可以实现整个面中部骨骼的生长前移。各缝区生长潜能的不同,造成了面中部骨骼群自上而下的渐进式不等量前移。

Objective To investigate the biomechanic properties of trans-sutural distraction osteogenesis(STDO)for midfacial hypoplasia in patients with cleft lip and palate through clinical study and three-dimensional finite element analysis(3D-FEA). Methods The skull skeleton 3D model images were generated by reconstructing the skull 3D CT images of a patient with unilateral complete cleft lip before and after STDO,then registered it into the same spatial coordinate system for fitting and registration, and the morphological changes of the suture in the 3D direction were analyzed and measured. At the same time, 3D-FEA method was used to establish the patient’s craniomaxillary complex model to simulate STDO and obtain the stress distribution of suture. Results The patient achieved improved facial appearance.The 3D quantitative measurement showed differential advancement of each landmark of midfacial sutures. In the sagittal plane,maximum forward displacements were observed at the pteryomaxillary suture. In the vertical plane,nasomaxillary suture and frontomaxillary suture on both sides showed the maximum upward displacements,and the maximum downward displacement at pteryomaxillary suture. In the transverse plane,each landmark of midfacial sutures had a smaller displacement. The maximum Von Mises stress was at zygomaticomaxillary suture on the normal side. The stress level on the cleft side was higher than that on the normal side,and the maximum Von Mises stresses were at sphenomaxillary suture and zygomaticomaxillary suture. Conclusion TSDO allows the growth and advancement of the whole midfacial skeleton. The different growth potential of midfacial sutures lead to the unequal advancement in different regions.