[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 C3,4, C4,5, C5,6 and C6,7. 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.