骨水泥堆积法导向模板技术辅助微创逆向耻骨上支髓内拉力螺钉置钉的研究

目的 观察利用骨水泥堆积导向模板技术和3D打印制作的个体化微创逆向耻骨上支髓内拉力螺钉导向模板的可行性。 方法 回顾性选择2015年7月-2016年7月于宁波市第二医院就诊的5例骨盆骨折患者,其中男性3例,女性2例,平均年龄49岁,分型为LCⅡ型骨折4例,LCⅢ型骨折1例,左侧耻骨上支外侧骨折3例,右侧耻骨上支外侧骨折2例。应用Pro/E软件制作模拟1.5 mm克氏针,选择基准平面,通过Pro/E软件的拉伸功能绘制模拟克式针,以STL格式进行保存。在Mimics软件Medcad模块中运用配准工具进行螺钉的虚拟置入。通过布尔计算将克式针和患侧模型融为一体。根据CT薄层扫描数据,通过图像筛选,蒙板编辑,阈值精确提取,图像填充和分割,光顺处理和缩减三角面片建立完整的骨盆三维重建模型,将骨盆的三维重建数据和虚拟克氏针的数据以STL格式进行保存导入3D打印机打印1:1骨盆模型3D模型及虚拟克氏针,利用骨水泥堆积技术制作反向导向模板,虚拟克氏针截断后将导向模板置于患侧耻骨结节置入1.5 mm直径长度80 mm的克氏针,观察克氏针是否位于患侧耻骨上支骨性钉道内。 结果 3D打印的骨盆模型及数字化个性化导向定制的骨水泥堆积导向模板能够满足耻骨上支骨折置钉的要求,定位导针均位于患侧耻骨上支的骨性钉道内,克氏针置入后经X线及CT证实与手术设计一致,导板与耻骨联合骨性标志贴合良好。 结论 基于3D打印技术的个性化骨水泥堆积导向模板可实现微创逆向耻骨上支外侧髓内拉力螺钉的精确置入,节省手术时间、手术费用并减少患者及医护人员的射线暴露次数。 

Preliminary design of 3D patient-specific drill template based on bone cement accumulation for lag screw placement in minimal invasive retrograde intramedullary fixation of the superior pubic ramus

Objective To investigate the feasibility of 3D patient-specific drill template based on bone cement accumulation for lag screw placement in minimal invasive retrograde intramedullary fixation of the superior pubic ramus. Methods The clinical data of 5 cases of pelvic fracture were reviewed retrospectively, including 3 males and 2 females, with average age of 49. According to the Young & Burgess classification, the type of pelvic fracture was 4 cases of LC Ⅱ and 1 case of LC Ⅲ. Three cases were left lateral superior pubic fracture and 2 cases were right. Pro/E software was used to simulate the 1.5 mm Kirschner wire, selected the base plane, drew the 1.5 mm Kirschner wire through the stretching function of Pro/E software, and saved it in STL format. The virtual screw placement was inserted by using the registration tool in Medcad module of the Mimics software. The Kirschner wire and the model were integrated by Boolean calculation. According to CT scan images, 3D reconstruction model of the pelvis were established by image screening, mask editing, threshold extraction, image filling and segmentation, smoothing and reduction triangular facets. The pelvic reconstructed data and the virtual Kirschner's data were processed in STL format to print 1:1 three dimensional model, The screw channel and the individual drill template was designed by bone cement accumulation technique to observe if the Kirschner wires were located in the bone canal. Results Three dimensional pelvic model and digital, individual drill template confirmed the effectiveness of superior ramus of pubis fracture, all of Kirschner wires were located in the bone canal. Kirschner was placed and the accuracy of screw placement was confirmed with X-ray and CT scanning. Template and the corresponding anatomical landmark fitted well. Conclusion By means of individual bone cement technique and 3D printing technology, accurate and minimal invasive placement of superior ramus of lateral pubis fracture screws can be finished. This technology is helpful to reduce the operation time and X-rays exposure of the patient and staff.