X线透视与计算机导航系统引导颈椎椎弓根螺钉内固定技术的对比研究

目的对X线透视下和计算机导航系统引导下颈椎椎弓根螺钉内固定的精确性进行对比研究。方法X线透视引导下145枚和CT三维导航系统辅助下置入的159枚颈椎椎弓根螺钉,术后进行经椎弓根螺钉水平的CT平扫或术后c型臂透视3D重建,观察椎弓根螺钉置入的精确性。结果X线透视引导组螺钉置入满意率为91．7％,CT三维导航系统引导组螺钉置入满意率为97．5％,两组满意率有显著性差异（P〈0．05）。两组病例均未出现明显的神经血管损伤并发症。对其中20例病例进行了术中导航操作时间和导航精确性的监测,术中工具注册和参考点照合时间平均3．5min（2～8min）,位置误差率平均0．31mm（0．12～0．56mm）。每颗椎弓根螺钉定位针置入所需时间平均2min（1-3．5min）。术中只需进行两次C型臂透视印证螺钉定位针和螺钉置入的准确性。结论采用CT三维导航系统辅助,能显著提高椎弓根螺钉置入的精确性。

Accuracy of CT-based navigation of pedicle screws implantation in the cervical spine compared with X-ray fluoroscopy technique

OBJECTIVE: To evaluate the feasibility and accuracy of cervical spine pedicle screw fixation assisted by X-ray fluoroscopy and CT-based navigation system. METHODS: 145 cervical pedicle screws were placed assisted by X-ray fluoroscopy and 159 cervical pedicle screws were placed assisted by CT-based navigation system. Screw positions were evaluated by postoperative CT scans or C-arm X-ray 3 dimensional reconstruction. RESULTS: In the computer- assisted group, 155 (97.5%) screws were found completely within their pedicles compared with 133 (91.7%) correctly placed screws in the X-ray assisted group (P < 0.05). The process of navigation investigated in twenty patients showed that the mean time for registration and surface matching was 3.5 (range from 2 to 8 minutes) minutes and the mean time for screw-marker insertion was 2 (range from 1 to 3.5 minutes) minutes with the mean position deviation 0.31 mm (0.12-0.56 mm) per screw. Only twice C-arm fluoroscopy were performed to verify the accuracy of one screw position intraoperatively. No severe complications like neurovascular lesion occurred in both groups. CONCLUSION: CT-based navigation system can increase the accuracy of cervical pedicle screw implantation significantly.