导向器辅助下个体化后路颈椎椎弓根螺钉固定的疗效评价

Clinical evaluation of guiding apparatus assisted individual posterior cervical pedicle screw fixation

目的探讨自制导向器辅助下个体化后路颈椎椎弓根螺钉固定的临床效果。方法选择2008年1月-2010年12月收治的24例患者，均行颈椎后路单开门扩大成形椎管减压＋椎弓根钉棒固定矫形术。术前行置钉颈椎椎弓根CT平扫及经椎弓根轴线矢状面二维成像，测量置钉颈椎经椎弓根轴线进钉通道的横向倾角（transverse nail angle，TNA）和纵向倾角（sagittal nail angle，SNA），确定进钉点及进钉方向。根据cT测量结果按个体化原则，在自制导向器辅助下置入颈椎椎弓根螺钉，减压后固定钉棒矫形。术后1周行置钉颈椎椎弓根cT平扫及经椎弓根轴线矢状面二维成像，测量置入螺钉的横向倾角（transverse screw angle，TSA）及纵向倾角（sagittal screw angle，SSA），比较分析置入椎弓根螺钉的准确程度；术后定期摄颈椎正、侧位x线片，观察内固定钉棒的牢固程度。结果从C3～C7共置入椎弓根螺钉223枚，术后CT复查220枚置钉准确，3枚略有偏斜，置钉准确率98．7％；术后测量置入螺钉倾斜角度与术前测量椎弓根置钉轴线倾斜角度比较，差异无统计学意义（P〉0．05）。所有患者均获随访，随访时间6—34个月，平均18．5个月。未发现与螺钉置入穿破椎弓根皮质相关的神经血管损伤问题，未出现内固定物松动、脱出或断裂。结论导向器辅助下CT测量个体化置钉后路颈椎椎弓根置钉准确率高，简单易行，安全可靠。

Objective To evaluate the clinical effects of guiding apparatus assisted individual posterior cervical pedicle screw fixation technique. Methods The study enrolled 24 patients treated with posterior cervical decompressive single open-door laminoplasty and transpedicular screw-rod fixation from January 2008 to December 2010. The point of screw penetration and screw path direction were con- firmed by measuring the transverse nail angle （TNA） and sagittal nail angle （SNA） of nail channel on the pre-operative CT plain scan of cervical pedicle and sagittal two-dimensional imaging of transpedicular axis. According to the results of CT measurement, individual cervical pedicle screw was implanted with the assistance of self-made guiding apparatus and then fixed after decompression. Transverse screw angle （TSA） and sagittal screw angle （SSA） were determined on the CT scan of cervical pedicle and sagittal two-dimensional imaging of transpedicular axis one week postoperatively in order to analyze the accuracy of placement of pedicle screws. Periodical anteroposterior and lateral X-ray radiographs of cervical vertebra were taken postoperatively to detect the stabilization of internal fixation. Results A total of 223 pedicle screws were inserted successfully into the C3 - C7, of which 220 crews were inserted accurately but three had slight inclination according to the postoperative CT, with placement accuracy of 98.7%. The compar- ison between inclination angle of inserted screws and that of preoperative transpedicular axis showed insig- nificant statistical difference （ P 〉 0.05 ）. All the patients were followed up for 6-34 months （ mean, 18.5 months）, which showed no neurovascular complications related to screws perforation out of pedicle cortex or no screw loosening, prolapse or breakage. Conclusion Posterior cervical pedicle screw insertionperformed according to the individual CT measurement is easy and safe and has a high accuracy rate under the assistance of self-made guiding apparatus.