基于三维打印及三维数据校正的骨折复原技术在股骨近端骨折治疗中的应用

目的 探讨三维(3D)打印的股骨近端骨折复原模型在术前规划与术中的应用,研究3D数据校正方案临床应用的可行性。方法 纳入2015年10月—2017年9月江苏省溧阳市人民医院骨科47例股骨近端骨折患者,按照左右两侧股骨自身配对方案,采用三层面长短轴对照方法进行前瞻性研究。所有病例行双侧股骨全长的CT扫描,获取DICOM数据,通过Mimics 15.0软件将双侧股骨远端距离膝关节髁间隆突凹5、10、15 cm处分别做3个横截面,记录符号为DF5、DF10、DF15。测量对比左右侧长轴与左右侧短轴。对于Mimics软件中股骨解剖轴线与冠状面和矢状面同时存在夹角的数据,进行3D数据校正。对47例股骨远端的左右侧3个层面(DF5、DF10、DF15)的长短轴(6对)进行数据汇总,通过Mimics 15.0软件生成3D模型的STL文件,打印出实际尺寸的股骨近端骨折模型和健侧股骨近端镜像模型,该镜像模型作为术前演练及手术解剖复位的参考,术中使用预演选取的置入物并术后摄片对比。结果 成对样本的相关系数均＞0.97;左右两侧股骨远端距离髁间隆突5 cm处的右侧短轴(28.20±3.41) mm,左侧短轴(28.54±3.51) mm,差异有统计学意义(t=3.404, P＜0.01),其余5对左右侧差异无统计学意义(P值均＞0.05)。47例患者均进行了手术治疗,术后复查X线,显示置入物选择与螺钉长度与术前设计符合,长度偏差在容许范围,内固定满意。结论 采用“三层面长短轴对照”进行左右股骨对称性判断,偏差小于5%者,术中直接采用镜像模型预演的置入物,固定效果满意,达到了术前规划,术中应用的预期目的。“三维数据校正方案”扩充了“三层面长短轴对照”的数据选取范围,有效避免了因肢体倾斜导致的数据失效问题。

The application of fracture recovery techniques based on 3D printing and three-dimensional data correction scheme in fractures of the proximal femur

Objective To explore a 3D printing model of fracture restoration which can be used in preoperative planning and design for proximal femur fractures. To study the feasibility of clinical application of three-dimensional data correction scheme.Methods An analysis of the 47 patients with proximal femur fracture treated from October 2015 to September 2017 in Department of Orthopaedics of Liyang People's Hospital was conducted. Bilateral femur CT scan was performed in all the cases to obtain DICOM data. Using Mimics 15.0 software, cross sections were created at 5 cm, 10 cm and 15 cm above the knee joint at the bilateral distal femur and marked as DF5, DF10 and DF15. The long and short axles on the left and right sides were measured and compared. If the femur was tilted, the correction data would be used. All the data were collected of the long and short axles on the 3 cross-sections (DF5, DF10 and DF15) of the left and right sides of the distal femur. After the STL files for 3D models were generated by using Mimics 15.0 software, a real-sized 3D model of the proximal femur fracture and a mirror model of the contralateral femur were printed. The preoperative manoeuvre was performed on the mirror 3D printed model. The real operation used the implants preoperatively designed, and compared radiographically with those designed in the preoperative manoeuvre.Results There were significant differences between the short axis of the left and right femoral condyle 5 cm from the intercondylar keel (28.54±3.51) mm vs. (28.20±3.41) mm, t=3.404, P＜0.01)]. There was no significant difference between the left and right sides in the other groups. The differences between the left and right sides showed no statistically significance in paired samples of LL-LS and RL-RS groups on DF5, DF10 and DF15 cross-sections(all P values＞0.05). All the 47 patients received surgical operation. The postoperative X-ray review showed fine agreement between actual surgery and preoperative design in terms of screw length and accuracy. The deviations were in an allowable range, leading to satisfactory internal fixation.Conclusions Symmetry of the bilateral femur can be judged by the “comparison of long axis and short axis of three equidistant transverse sections” methods. If the deviation is less than 5%, the preoperative implants would be directly used. It is satisfactory for postoperative radiography validation. “Three-dimensional data correction scheme” expands the “Comparison of long axis and short axis of three equidistant transverse sections” data selection range, which can effectively avoid the data failure because of limb tilt .