Spine
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To clarify the pathophysiology of intermittent claudication in 37 patients with lumbar spinal stenosis, neural function was evaluated by examining somatosensory evoked potentials (stress-SEPs), and nerve action potentials (stress-NAPs) before and after walking stress. It was shown preoperatively that the stress-SEPs became abnormal immediately after walking in 31 of 37 patients. ⋯ The present method is noninvasive, simple in technique, painless, and safe, a procedure therefore that is useful as the initial step in the diagnosis and treatment of patients with lumbar canal stenosis. It also may help to differentiate neurogenic from vascular intermittent claudication.
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It has been suggested that the pattern of development and attrition of blood vessels and notochord remnants leaves congenitally weak points in the cartilage disc plates. There is strong presumptive evidence that nuclear prolapse can take place through these weak spots in the cartilage plates to form Schmorl's nodes. It has been postulated that the development of Schmorl's nodes may also lead to anomalies of the vasculature in the end-plates, which may lead to further end-plate lesions. ⋯ The specimens examined were from individuals ranging in age from 17 to 90 years. The specimens were sectioned at 150 microns, stained, and the percentage of the bone cartilage interface occupied by marrow spaces was measured using a microscope with an ocular micrometer. The specimens with Schmorl's nodes had a significantly greater proportion of disc marrow contacts than did the normal vertebrae.