Journal of spinal disorders
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The authors report three cases in which paraparesis related to a pseudarthrosis occurred several years after a posterior spinal fusion, but with a different mechanism (stretching of the spinal cord for progression of the deformity in kyphosis in two cases, and spinal cord compression for bone overgrowth within the canal in the site of pseudarthrosis in the third patient). Treatment was different. Partial correction of the deformity and stabilization of the spine by combined fusion (anterior and posterior) was sufficient in the first two cases for a complete neurological recovery. Posterior spinal cord decompression and stabilization of the spine by combined fusion was necessary for complete recovery in the third.
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Comparative Study
Effect of spinal cord ischemia on compound muscle action potentials and spinal evoked potentials following spinal cord stimulation in the dog.
We recorded the compound muscle action potentials (CMAP) from the soleus muscle and spinal evoked potentials (SpEP) from the caudal spinal cord after stimulation of the rostral spinal cord via epidural electrodes in 18 dogs. We examined the changes of CMAP and SpEP after the cord was made ischemic by clamping the aorta at different levels. Clamping the abdominal aorta below the artery of Adamkiewicz (five dogs) did not change either CMAP or SpEP significantly. ⋯ Then CMAP disappeared, but SpEP remained unchanged. These findings suggest that CMAP and SpEP are mediated through different pathways and that CMAP reflect anterior cord function. The described electrophysiologic technique would be useful to monitor spinal cord motor function during surgery of the spine, spinal cord, or thoracoabdominal aorta.