Experimental study on acute aggravating factors of cervical spondylotic myelopathy.

Systemic arterial hypotension, systemic arterial hypertension, cervical hyperflexion, cervical hyperextension, and cervical instability were induced in experimental animal with cervical spondylotic myelopathy, and their effects on spinal cord pathology were investigated. An experimental animal model of cervical spondylotic myelopathy was produced by combining anterior cervical cord compression with occlusion of the cervical vertebral arteries in dogs. Spinal cord pathology at the site of compression was characteristically different and depended on the type of load; that is, peripheral necrosis of the central gray matter in systemic hypotension, capillary congestion and subarachnoid hemorrhage in systemic hypertension, and linear necrosis of the transversely elongated central gray matter combined with occluded anterior spinal artery in cervical hyperflexion, and the pathologic severity was proportional to the number of loadings. This study suggests that cervical spondylotic myelopathy might progress stepwise rather than linearly when these aggravating factors are loaded.