无框架立体定向机器人引导颈椎弓根螺钉植入的实验研究

目的探讨基于虚拟现实可视化技术的无框架立体定向机器人（CRAS-2型）引导颈椎弓根螺钉植入的可行性。方法 3例成人颅-颈椎标本,以不同单一椎体作为独立目标分别进行1 mm的薄层扫描,不同的椎体图像序列分组在手术规划工作站进行三维重建。然后对标本的颅颈和上位颈椎切开暴露,以完全暴露同一椎体表面突出的、细小的、唯一的（CT上能清晰显示的）骨性标志为准;在目标椎体的薄层CT图像上,选择突出的、容易在标本上识别的唯一性骨性标志作为空间位置注册点,用5个自由度的CRAS-2型无框架立体定向机械臂进行靶点的注册。将目标椎弓根和侧块作为一个容积块对待,在每一个断层平面上对其进行轮廓的逐层标记。在计算机软件的辅助下进行椎弓根的三维容积重建,确定钉头预达点为靶点后,将可能的路径显示在重建的三维模型上,并在容积块内调整选择合适的路径。利用机械臂对骨性注册点在手术空间和图像空间的测量结果,计算机辅助直接将手术空间中实物结构坐标映射变换到图像空间中去;在手术空间中移动机械臂末端的手术导引探针;当手术导引针图像的轴向与预先设计的轨迹重合时锁定机械臂;在机械臂末端的操作把持平台上,严格按照导引方向细钻钻孔后,插入导向钢针,最后CT复查验证导向植入螺钉的准确性。结果无框架立体定向机器人辅助椎弓根螺钉植入25枚（部分标本因为下颈椎缺失,未行椎弓根钢钉植入）,钢钉完全与规划路径吻合,准确率达到100%。结论无框架立体定向机器人引导的颈椎弓根螺钉植入具有精确度高、操作简便、图像引导直观清晰、经济实用等特点,有十分广阔的应用前景。

Experimental study of the computer and robot assisted surgery in cervical pediculus arcus vertebrae screw implantation

Objective To explore the feasibility of computer and robot assisted surgery in guiding cervical pediculus arcus vertebrae screw implantation.Methods Three adult cadaver were used and 1 mm thick CT scan was performed to reconstruct three dimension images of individual vertebral bodies by the surgery planning work station.Then the cranio-vertebral junction structures and upper vertebral bodies were surgically exposed with the bony structures that could be revealed by the CT scan as the only register target being identified.The targets were registered by the CRAS-2 frameless stereotactic arms with 5 free direction ranges.The vertebral arch was 3D volume reconstructed by tracing the target vertebral arch and lateral mass as single volume block.After the reconstruction,the target was located as the arrival spot of the implanted screw point,and the alternative approaches were manifested in the reconstructed 3D model,and then adjustments were performed in the volume block.According to the registration and measurement by the mechanic arm,the real objects during the surgery were mapped to the reconstructed images.During the surgery,the mechanic arm was guided to the planned projection in the images and then the directing needle was introduced under the guidance.CT scan was performed the assure the accuracy the screw imolantation.