下颈椎前路椎弓根螺钉固定系统的设计与运用

目的：研究下颈椎前路椎弓根螺钉钢板系统运用的可行性，为临床使用提供依据。方法：对16具颈椎标本随机分割获得C3．4，C4加C5．6，C6，7各8个运动单元（functionalspinalunit，FSu），共32个FSU。运用下颈椎前路椎弓根螺钉钢板系统模拟植入重建FSU稳定性。测量钢板螺钉与椎体之间的适应性，运用X线摄片及CT扫描及重建评估下颈椎前路椎弓根螺钉植入的准确性，对于穿破椎弓根的标本，解剖明确其累及周围组织的情况。结果：32个FSU共计植入下颈椎前路椎弓根螺钉64枚，所有螺钉均顺利植入，无术中植入困难者。螺钉植入后与钢板螺钉孔之间的匹配程度好，未见难以锁紧的情况。钢板与椎体之间适应性良好。X线片提示所有64枚下颈椎前路椎弓根螺钉植入位置满意，螺钉长短合适。CT横断位像提示共有6枚螺钉在下颈椎椎弓根穿出，2枚内侧皮质1度穿破，4枚1度外侧缘皮质穿破累及横突孔内侧缘，未见螺钉≥2度穿破椎弓根。2枚下颈椎前路椎弓根内侧皮质1度穿破的患者，解剖发现仅有椎管内椎弓根内侧的静脉丛累及，未见硬膜囊受压，未见神经根受累。4枚1度外侧缘穿破的患者有1枚横突孔内椎静脉的累及，未见椎动脉穿破累及的情况，但其中1枚螺钉紧换椎动脉而行。结论：下颈椎前路椎弓根螺钉钢板系统适应下颈椎前路椎弓根螺钉固定重建，有临床运用价值。

The design and application of anterior cervical pedicle screw-plate system in lower cervical spine

Objective: To explore the applied feasibility of the anterior cervical pedicle screw-plate system in lower cervical spine,in order to provide basic data for clinical application. Methods: Total thirty-two units (functional spinal unit,FSU)were got randomly from 16 cervical speciments,8 units in each group of C_3,4,C_4,5,C_5,6 and C_6,7. The anterior cervical pedicle screw-plate system was implanted to reconstruct the stability of FSU after discectomy and bone graft. The adaptability was measured between the screw-plate system and vertebral body. X-ray and CT were used to evaluate the accuracy of anterior cervical pedicle screws. The subject will be dissected to identify the situation of involvement if screw perforating the pedicle. Results: Sixty-four anterior pedicle screws were inserted smoothly in the 32 units. The screw and the plate were harmonious locked in the system. The position and length of all screws were satisfactory through X-ray views. However,6 screws perforated the transpedicular (degree 1) according to CT axial views,2 internally cortex and 4 laterally cortex. None perforation was degree 2 or more. None cervical sac compression and nerve root injury was observed in two internal perforation cadavers. One vertebral vein involvement was found in the four lateral perforation screws. The vertebral artery was not pinched though one screw near to the artery. Conclusion: The anterior cervical pedicle screw-plate system is adapted to reconstruct in lower cervical spine and it deserved to be used for clinical application.