Mimics软件模拟置钉在腰椎关节突重度退变椎弓根螺钉内固定中的应用

Mimics simulation software for screw placement in pedicle screw fixation for treating severe lumbar facet joint degeneration

背景:目前腰椎椎弓根螺钉置入为脊柱外科非常成熟的一项技术,临床上有多种术中确定进钉点、进钉方向的方法。但腰椎关节突重度退变患者由于手术区域骨赘增生严重,顺利准确置钉有一定难度。目的:观察腰椎关节突关节重度退变患者修复术前应用Mimics软件模拟置钉对椎弓根螺钉置入内固定效果的影响。方法:将78例需要行腰椎椎弓根螺钉置入单节段内固定且治疗前CT、MR评估为腰椎关节突重度退变的患者纳入研究,随机分为两组,模拟置钉组39例,对照组39例,两组共置入312枚椎弓根螺钉。模拟置钉组术前对需要置钉的椎体使用Mimics软件行3D重建,并在拟置钉椎体模拟椎弓根螺钉,在3D影像上观察椎弓根螺钉进钉点与周围骨性标志的关系并测量进钉的角度和深度,术中参考观察和测量的结果进行椎弓根螺钉置入。对照组采用传统方式置入椎弓根螺钉。治疗后均行X射线、CT检查对椎弓根螺钉置入准确性进行评估。结果与结论:模拟置钉组置入椎弓根螺钉后均未发生相关并发症,置钉后复查156枚螺钉中153枚位于椎弓根内,置钉正确率显著高于对照组(98.1%,88.5%,χ2=11.49,P<0.05)。且模拟置钉组手术时间、出血量及患者放射线暴露时间少于对照组,差异均有显著性意义(P<0.05)。提示需要行腰椎椎弓根螺钉置入内固定的患者中,腰椎关节突关节退变占相当大的比例,而关节突的退变使进钉点解剖标志难以辨别,给螺钉置入带来很大的难度。Mimics软件模拟置钉可辅助腰椎关节突重度退变患者修复术中椎弓根螺钉的正确置入,降低相关并发症,减少手术时间及出血量,减少患者放射线暴露时间。

BACKGROUND： Lumbar pedicle screw placement technique is a very mature technology in spinal surgery. There are many methods for determining the screw entry points and direction in the clinic. However, for patients with severe lumbar facet degeneration, severe osteophytosis can be found in the surgical area. Smooth and accurate screw placement has some difficuJties. OBJECTIVE： To observe the effects of screw placement simulation using Mimics software on pedicle screw fixation before repair of severe lumbar facet joint degeneration. METHODS： A total of 78 cases of severe lumbar zygapophysial degeneration evaluated by CT and MR, who received single-segment lumbar pediele screw fixation, were enrolled in this study. They were randomly divided into two groups, including simulation screw group （n=39） and control group （n=39）. Totally 312 pedicle screws were implanted in the two groups. In the simulation screw group, Mimics software was used to perform 3D reconstruction before surgery and to simulate vertebral pedicle＇screw operation. In the 3D images, screw entry points and surrounding bony landmarks of pedicle screw were observed. The angle and depth of screw placement were measured. During the operation, pedicle screw placement was conducted in accordance with above results of observation and measurement. In the control group, pedicle screw was implanted according to the conventional method. After treatment, an X-ray CT examination was performed in the evaluation of the accuracy of pedicle screw placement. RESULTS AND CONCLUSION＂ No postoperative complication occurred in the simulation screw group. 153 of 156 screws were located in vertebral pedicie in the postoperative examination. The correct rate of screw placement was significantly higher in the simulation screw group than in the control group （98.1%, 88.5%, X2=11.49, P 〈 0.05）. The operation time, amount of bleeding and radiation exposure time were significantly shorter in the simulation screw group than in the control group （P 〈 0.05）. These findings indicate that the lumbar facet joint degeneration accounted for a large proportion in patients with lumbar pedicle screw fixation. Facet joint degeneration increases the difficulties on distinguishing anatomical landmarks of insertion point, which brings a great difficulty.for screw placement. The simulation of Mimics software in screw placement can improve accuracy in pedicle screw fixation in patients with severe lumbar facet joint degeneration, reduce complications, operation time, amount of bleeding, and radiation exposure time.