髋臼后表面解剖形态测量及新型解剖锁定钢板的设计

摘要

Objective To design a new type of anatomical locking plate which fits better the shape of posterior acetabular surface in Chinese population and presets reasonable directions of locking screws according to the measurements of the posterior acetabular surface in three dimensional (3D) reconstruction models of normal Chinese acetabulum.Methods Included in this study were CT scan data of the normal pelvis of 171 patients,100 males and 71 females with a mean of age 45.9 years (range,from 18 to 60 years).The imaging data at the.dicom format were imported into the Materiaise' s interactive medical image control system (Mimics,version 10.0) for 3D reconstruction and editing before they were saved as the STL files.Next the STL files were imported into the IMAGEWARE software (Imageware V12.1,US EDS Corporation) to set up standard points and surface of the posterior acetabular surfac e.Based on the database,we designed a new type of anatomical locking plate which could fit the shape of bone surface and preset directions of lock screws.Finally,the data were entered into a computerized numerical control digital milling machine to manufacture a real plate and screws.Results The mean acetabular diameters were 57.6 ± 2.9 mm and 52.6 ± 2.6 mm and the mean widths of the posterior acetabular wall were 40.7 ± 2.9 mm and 38.4 ± 2.4 mm for men and women,respectively,with significant differences between men and women (P ＜ 0.05).After one-tenth of the diameter (d) of the acetabulum (d/10) was chosen as the measurement unit of the new coordinate system,the mean widths of the acetabular wall were 7.10 ±0.52 d/10 and 7.16 ±0.47 d/10 for men and women,respectively,with no significant difference between men and women (P ＞ 0.05).The IMAGEWARE software showed that the anatomic shape of our self-designed new type of locking plate was in complete agreement of that of the posterior acetabular surface.The mean deviation of the plate from the bone surface was 3.2 ± 1.0 mm.The locking directions of screws preset completely avoided the acetabulum.Conclusion The new type of anatomical locking plate we designed provides a new choice for the treatment of acetabular fractures,because it perfectly fits the anatomic shape of the posterior acetabular wall and presets reasonable directions of the locking screws to ensure better stability and safety of the fixation.%目的 基于髋臼后表面的三维重建解剖形态数据库,自行设计符合髋臼后表面形态且具有成角稳定作用的新型解剖锁定钢板. 方法 共纳入171例全骨盆,男100例,女71例;年龄18 ～ 60岁,平均45.9岁;将所有骨盆.dicom格式的影像学资料导入Mimics 10.0版软件进行三维重建及编辑,并保存为.stl格式文件,再导入Imageware V12.1软件,设立髋臼表面标准点、标准平面后进行图像分割和测量,得到髋臼后表面的点云数据库,并通过该点云数据库拟合形成髋臼后表而曲面,以设计锁定钢板形态和角度锁定螺钉系统最后,将设计好的钢板和螺钉数据输入数码铣床获得实体钢板. 结果 男、女髋臼直径平均分别为(57.6±2.9) mm、(52.6 ±2.6)mm,髋臼后壁宽度平均分别为(40.7±2.9)mm、(38.4±2.4) mm,以上项目男女之间比较差异均有统计学意义(P＜0.05);但采用1/10髋臼直径(d)作为度量单位标准化后,男、女髋臼后壁宽度平均分别为(7.10±0.52)个d/10单位、(7.16±0.47)个d/10单位,差异无统计学意义(P＞0.05).设计的新型髋臼解剖锁定钢板与云数据库所拟合的髋臼后表面曲面吻合好,钢板偏离骨表面的平均距离为(3.2±1.0)mm.而且随机抽取髋臼样本三维图像与设计的钢板图像完全吻合.预设的螺钉打入方向可完全避让髋臼. 结论 设计的髋臼新型解剖锁定钢板解剖形态匹配性好,锁定螺钉成角稳定性强,可完全避开髋臼方向,安全性高,为复杂髋臼骨折的治疗提供了新的选择.