虚拟手术设计在双颌正颌手术中的精准性研究

目的评估虚拟手术设计在双颌正颌手术中的精准性,以期为临床提供参考。方法纳入需行双颌正颌手术的患者30例,利用CT数据和牙弓平面扫描数据建立复合颅骨模型,在Dolphin Imaging 11.7 Premium软件上模拟上颌骨LeFort I型骨切开术和双侧下颌支矢状骨劈开术,必要时行颏成形术,利用3D打印的手术导板将虚拟手术设计转移到术中。选择3个平面:眶耳平面(FHP)、面中平面(垂直于FHP且通过鼻根点)和冠状面(垂直于FHP且通过蝶鞍点)。选择6个标志点:上、下颌中切牙的近中接触点(UI、LI)以及上下颌第一磨牙的近中颊尖(U6-R、U6-L、L6-R、L6-L)。在虚拟手术模型和真实术后模型上测量选定标志点和对称平面之间的距离,并计算两模型之间的线性差异和总体平均线性差异(UI、LI、U6-R、U6-L、L6-R、L6-L分别与眶耳平面、面中平面和冠状面之间距离的平均差异)。确定由咬合平面、腭平面和下颌平面分别与眶耳平面和面中平面构成的角度值,并计算虚拟手术模型和真实术后模型之间的角度差异和总体平均角度差异。结果借助3D打印手术导板,虚拟手术设计被成功转移至实际手术中,所有患者术后对面型和咬合都很满意。虚拟与真实模型间的总体平均线性差异为0.81 mm(上颌骨0.71 mm,下颌骨0.91 mm);总体平均角度差异为0.95°(相对于眶耳平面的平均角度差异为1.10°,相对于面中平面的平均角度差异为0.83°)。结论虚拟手术设计有助于牙颌面畸形的诊断和治疗计划的制定,可以增加双颌正颌手术中骨块定位的精准性。

Research on the precision of virtual surgical planning in two-jaw orthognathic surgery

ObjectiveTo provide a clinical reference by evaluating the precision of virtual surgical planning in twojaw orthognathic surgery.MethodsThirty consecutive patients who required two-jaw orthognathic surgery were included.A composite skull model was reconstructed using data from spiral computed tomography scan and surface scanning of the dental arch.LeFort I osteotomy of the maxilla and bilateral sagittal split ramus osteotomy of the mandible were simulated using Dolphin Imaging 11.7 Premium.Genioplasty was performed if indicated.Virtual plan was then transferred to operation room using 3 D-printed surgical templates.Frankfort horizontal plane(FHP),midfacial plane(perpendicular to the FHP through the nasion),and coronal plane(perpendicular to the FHP through the sella point) were the selected three symmetry planes.Midpoint of the contact of the maxillary and mandibular central incisors(UI,LI),and the mesio-buccal cusp of the first maxillary and mandibular molars(U6-R,U6-L,L6-R,L6-L) were the six chosen volumetric landmarks.To calculate the linear difference and overall mean linear difference(mean difference of the distance between UI,LI,U6-R,U6-L,L6-R,L6-L to FHP,midfacial and coronal plane) between simulated and postoperative models,the distance between selected landmarks and symmetry planes was measured.To calculate the angular difference and overall mean angular difference,values of the angles constructed by the occlusal,palatal,and mandibular plane to FHP and midfacial plane respectively were determined on simulated and postoperative models.Results The virtual surgical planning was successfully transferred to actual surgery with the help of 3 D-printed surgical templates.All patients were satisfied with the postoperative facial profile and occlusion.The overall mean linear difference was0.81 mm(0.71 mm for maxilla and 0.91 mm for mandible);and the overall mean angular difference was 0.95°(the mean angular difference relative to FHP was 1.10°,and that relative to midfacial plane was 0.83°).ConclusionVirtual surgical planning facilitated the diagnosis,treatment planning,and precise bony segments repositioning in two-jaw orthognathic surgery.