基于3D打印齿状突空心钉置入的数字化导航(英文)

Odontoid cannulated screw fixation using digital navigation based on three-dimensional printing technique

背景:齿状突骨折因部位特殊,毗邻重要解剖结构,置钉难度大,稍有偏移亦可能导致内固定强度下降甚至失效。提高置钉的安全性和准确性,确定方便推广实施的个体化手术显得尤为重要。目的:探讨Mimics软件数字化设计结合3D打印模块进行齿状突空心钉置入导航的方法,探讨其可行性及准确性。方法:将16具人尸体颈椎标本进行连续薄层CT扫描,采集Dicom格式图像。Mimics软件予以三维重建,设计C2椎体齿状突空心钉置钉钉道及支撑柱、分割可剥离骨面,设计带钉道的导航模块并3D打印。导航模块在尸体标本上进行置钉导航,观察卡位、置钉情况,以X射线、CT扫描评价置钉效果。结果与结论:共制作16个导航模块,植入22枚螺钉,观察钉道及置钉后椎体周围骨质,未见爆裂。术后行X射线、CT扫描重建,发现所有螺钉的进钉点,进钉方向、长度均与Mimics软件中模拟的预定理想进钉点、方向和长度一致,导航模块和相对应的椎体前方骨性结构贴合紧密,嵌合度良好,在应用时卡位及稳定性良好。结果证实,在导航模块的辅助下,前路齿状突空心钉置钉精准。基于3D打印的数字化技术有望良好实现骨科内固定物置入导航并普及应用。

BACKGROUND：Odontoid fracture is very common in cervical spine injuries, the special position of odontoid process, which is adjacent to important anatomic structure, makes screw placement difficult, and a slight discrepancy in position and orientation of the inserted screw leads to a decrease in intensity of internal fixation, even invalid internal fixation. Therefore, it is very necessary to develop an individualized treatment protocol by which screws can be precisely and safely placed and which is worthy of clinical popularization. OBJECTIVE：To study the navigation of Mimics software and three dimensional （3D）-printed module in anterior odontoid cannulated screw fixation and to investigate its feasibility and accuracy. METHODS：Sixteen human cadaveric cervical spines were scanned by a continuous thin-slice CT scanner. Original DICOM CT images were three-dimensional y reconstructed using Mimics software. The screw channel and support column were designed for C2 vertebra odontoid cannulated screw fixation for odontoid fracture. Segmentation of bone surface was performed. Navigation modules with screw channel were built using 3D printing technique. Navigation modules were used to aid screw placement. Screw fitting and placement were evaluated using X-ray and CT scan. RESULTS AND CONCLUSION：Total y 16 navigation modules were built and 22 screws were implanted. During and after screw placement, the cortical bone along screw channel and surrounding the vertebral body was not cracked. Postoperative X-ray and CT scans showed that some factors regarding screw placement such as entry point, orientation and depth of placement were consistent with those ideal factors simulated by Mimics software. The navigation modules were closely attached to the corresponding bony structure in front of the vertebral body, with a satisfactory gomphosis. Screw fitting and stability were good during application. These results verify that with the aid of navigation module, anterior odontoid cannulated screw fixation is reliable for treatment of odontoid fracture, which provides insights into the popularization of 3D printing-based digital navigation technique in orthopedic implantation.