骶骨骨折手术导航模板的设计与临床应用

目的 利用三维重建与逆向工程技术为骶骨骨折手术固定提供一种精确匹配的方法. 方法对2006年6月至2008年9月收治的6例骶骨骨折患者骨盆进行连续螺旋CT扫描,将原始.dicom格式数据导入Amira3.1(TGS)软件,三维重建骨折模型以.8tl格式保存,导入Image-ware10.0软件,模拟复位后设计拉力螺钉固定的最佳方向及长度,提取髂骨后部解剖学形态,建立与髂后上棘解剖学形态一致的模板,拟合模板和骶髂关节拉力螺钉孔道成定位模板,将定位模板通过激光快速成形技术生产出实物模板,手术时将建立的定位模板与髂骨后部结构相吻合,通过导航孔进行拉力螺钉的定位,置入拉力螺钉. 结果 6例患者拉力螺钉固定位置满意,重建的导航模板有较好的匹配性.本组6例患者手术时间为40～80min,术中出血量150～400mL术中X线暴露时间为2～6min.经6～24个月随访,根据Majeed评分标准评定疗效:优2例,良3例,可1例. 结论通过三维重建与逆向工程分析构建的定位导航模板为骶骨骨折拉力螺钉的定位、定向提供了一种新的方法.

Navigation template for sacral fracture fixation using three-dimensional reconstruction and reverse engineering technique

Objective To provide a new method for sacral fracture fixation by means of 3D recon-struction and reverse engineering technique. Methods Pelvis images of 3D CT scan were obtained from patients with sacral fracture. The digital data were transferred into a computer workstation. 3D models of pelvis were reconstructed using Amira 3.1 software and saved in STL format. The 3D fracture models were imported into Imageware 10.0 software. Different situations of reduction (total reduction, half reduction and no-reduction) were simulated using Imageware 10.0 software. The extract locations and the best directions of inserting iliosacral lag screws were defined using Reverse Engineering according to the 3 situations to before navigation templates were designed according to the posterior anatomic features of the ilium and the insertion channels. Exact navi-gational templates were manufactured by rapid prototyping. Drill guides were sterilized and used intraoperatively to assist surgical navigation and placement of iliosacral lag screws. Results Accurate screw placement was confirmed with postoperative X-ray and CT scanning. The navigation templates were found to be helpful and highly accurate. Conclusion The navigation template may be a useful method for mini-invasive fixation of sacroiliac joint fracture.