快速成型技术——三维头颅模型的制作及在颅颌面创伤修复中初步应用一例

FABRICATION OF 3-DIMENSIONAL SKULL MODEL WITH RAPID PROTOTYPING TECHNIQUE AND ITS PRIMARY APPLICATION IN REPAIRING ONE CASE OF CRANIOMAXILLOFACIAL TRAUMA

目的探讨利用电子束CT(e lectron beam CT,EBCT)数据、快速成型技术制作三维头颅模型的方法,以及在颅颌面创伤后骨缺损修复中的应用。方法EBCT连续薄层容积扫描提取层面轮廓数据,所得数据以计算机辅助设计软件构建曲面模型,模型数据输入AFS-320 QZ激光快速成型机,运用液态光敏树脂选择固化法,以光敏树脂为成型材料获得仿真三维头颅实体模型,在实体模型上进行手术模拟并预制个体化骨缺损修复体。应用于外伤后二期额骨缺损修复1例,患者术前左侧额部凹陷,鼻根低平,鼻梁左侧歪斜;EBCT扫描左额骨缺损4 cm×6 cm。结果EBCT数据和快速成型技术结合制作的三维仿真头颅实体模型,能详尽、直观地显示颅颌面创伤后骨骼的三维解剖结构及相互关系。患者利用模型预制的修复体与缺损适配性好,术后左额骨缺损达解剖意义修复,鼻梁塌陷歪鼻畸形获得矫正。随访1年5个月,医患双方均满意。结论三维头颅模型能真实再现病体原形,为准确诊断、手术计划及模拟提供真实的虚拟空间,在颅颌面创伤修复中具有重要的意义。

Objective To investigate the methods of establishing 3-dimensional skull model using electron beam CT （EBCT） data rapid prototyping technique, and to discuss its application in repairing crainomaxillofacial trauma. Methods The data were obtained by EBCT continuous volumetric scanning with 1.0 mm slice at thickness. The data were transferred to work-station for 3-dimensional surface reconstruction by computer-aided design software and the images were saved as STL file. The data can be used to control a laser rapid-prototyping device（AFS-320QZ） to construct geometric model. The material for the model construction is a kind of laser-sensitive resin power, which will become a mass when scanned by laser beam . The design and simulation of operation can be done on the model. The image data were transferred to the device slice by slice. Thus a geometric model is constructed according to the image data by repeating this process. Preoperative analysis, surgery simulation and implant of bone defect could be done on this computer-aided manufactured 3D model. One case of craniomaxillofacial bone defect resulting from trauma was reconstructed with this method. The EBCT scanning showed that the defect area was 4 cm × 6 cm. The nose was flat and deviated to left. Results The 3-dimensional skull was reconstructed with EBCT data and rapid prototyping technique. The model can display the structure of 3-dimenstional anatomy and their relationship. The prefabricated implant by 3-dimensional model was well-matched with defect . The deformities of flat and deviated nose were corrected. The clinical result was satisfactory after a follow-up of 17 months. Conclusion The 3-dimensional model of skull can replicate the prototype of disease and play an important role in the diagnosis and simulation of operation for repairing craniomaxillofacial trauma.