Eufinger H, Wehmöller M
Department of Oral and Maxillofacial Surgery, Regional Plastic Surgery, Knappschaftskrankenhaus-University Hospital Bochum, and Ruhr-University, Germany.
Plast Reconstr Surg. 1998 Aug;102(2):300-8. doi: 10.1097/00006534-199808000-00002.
The reconstruction of craniofacial bone defects by intraoperative modeling of implants restricts the choice of material and its biocompatibility and also reduces the predictability of the aesthetic result. These shortcomings go hand in hand with a prolonged surgical procedure time and increased stress on the patient. In contrast, modern industrial computer-aided design and computer-aided manufacturing systems allow the prefabrication of titanium implants, i.e., individual computer-based three-dimensional models of the bone defect are generated after acquisition, transfer, and evaluation of helical computed tomographic data. Based on these data, the individual shape of the implant is designed using freeform-surfaces geometries and is fabricated by a numerically controlled milling machine in a direct fashion. The conical margins of this implant are designed with a precision of 0.25 mm to the borders of the defect, and the surface contours are generated harmonically to the nonaffected neighboring contours with a constant thickness of 1.5 mm. Individual constructions for fixation with the dimensions of microplates are integrated in this process if screw holes cannot be drilled in thin overlapping implant margins. The reconstruction of 22 posttraumatic, postoperative, or primary cranial and craniofacial defects measuring up to 18 cm was performed using this new method. Wound healing was uneventful in all but one case, although some of the patients had been operated on several times before. The result was always predictable and constant using this highly precise technique, and duration of surgery was reduced dramatically.
通过术中对植入物进行建模来重建颅面骨缺损，限制了材料的选择及其生物相容性，也降低了美学效果的可预测性。这些缺点还伴随着手术时间延长和患者压力增加。相比之下，现代工业计算机辅助设计和计算机辅助制造系统允许预制钛植入物，即通过获取、传输和评估螺旋计算机断层扫描数据后生成基于计算机的骨缺损个体三维模型。基于这些数据，使用自由曲面几何形状设计植入物的个体形状，并通过数控铣床直接制造。该植入物的锥形边缘设计为与缺损边界精确到0.25毫米，表面轮廓与未受影响的相邻轮廓和谐生成，厚度恒定为1.5毫米。如果在薄的重叠植入物边缘无法钻孔，则在此过程中集成尺寸为微型钢板的个体固定结构。使用这种新方法对22例创伤后、术后或原发性颅骨和颅面缺损进行了重建，缺损大小达18厘米。除1例患者外，所有患者伤口愈合均顺利，尽管其中一些患者此前已接受过多次手术。使用这种高精度技术，结果始终是可预测和恒定的，手术时间也大幅缩短。
