Study Of The Effects Of Cervical Flexion-Distraction Injuries On The Flow Rate Of The Vertebral Artery

[Objective] To investigate and estimate the degrees of vertebral arterial flow rate and mechanism of injury in staged static flexion-distraction dislocation deformities of the lower cervical spine.[Methods] 14 fresh cervical spine specimens had undergone vertebral artery perfusion test and angiography to determine the static influence of the four stages of flexion-distraction dislocation injuries on flow rate of vertebral artery.[Results] Vertebral arterial flow decreases with the stages of flexion-distraction dislocation injuries advancing. No significant alteration in vertebral arterial flow was noted in the subluxations of the flexion-distraction Stage I injuries. Flexion-distraction Stage II to IV injuries demonstrated considerable decrease of vertebral artery flow in proportion to the degrees of dislocation. The irreversible changes was noted in the unilateral flow while collateral flow was not found significantly alteration in Stage II, and Stage III and IV could result in irreversible changes of bilateral flows. Longitudinal stretch deformities of the vertebral artery were limited primarily to the vertebral dislocation segment, no deformities was observed in the superior and inferior segments of the dislocation.[Conclusion] Subluxations of the lower cervical spine may cause no notable alteration of the vascular supply in Stage I injuries. The articular process and displacing foramen transversarium of the lesion segment of flexion-distraction Stage II to IV lower cervical injuries may produce conspicuous compression and undue traction on the vertebral artery, and could lead to irreversible the vascular lesion.