Radiological evaluation of the cervical spinal units after anterior cervical interbody fusion

Abstract

Anterior cervical interbody fusion (ACIF) by means of dynamic plates is widely accepted for stabilization of the cervical functional spinal units (FSU). However the complete system of X-ray assessment of implants’ position in stabilized FSU is absent. Objective: substantiation, improvement and clinical testing of complex method of the X-ray assessment of spatial position of elements in system «cervical FSU – fixing constructions» after ACIF. Methods: we held X-ray survey of 42 patients with cervical spine injuries and diseases after bisegmental ACIF with using of the vertical cylindrical mesh implants as an interbody support filled with autografts, and cervical plates. In 34 (80,9 %) cases we used rigid plates (1st group), and in 8 (19 %) — hybrid translational-rotational dynamic ones (2nd group). The observation period in the 1st group was 12 months and in the 2nd one was 6 months. When studying the results of outcomes in patients of the group 1 X-ray criteria requiring systematization were defined. We have also proposed some novel criteria. Results: novel and improved known criteria of X-ray diagnostics of structural and functional state of elements of biomechanical system «vertebrae – interbody supports – plates – screws» were proposed. Some peculiarities and refined patterns of the state of stabilized FSU in postoperative period were identified. Conclusions: enhanced complex method of X-ray examination of the cervical spine enables to evaluate correctness of implants’ position, to analyze features of changing in their position during formation of interbody fusion, and to explore possible options of displacement between screws, plate, interbody support and vertebral bodies.