Spasticity: Physiologic and Neurosurgical Considerations with Preliminary Report of Two Cases

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Spasticity is a condition of the musculature identified by partial or complete paralysis and increased resistance to movement associated with hyperactivity of the reflexes of the tendon and periosteum. The control of discharges going out over "the final common pathway" to produce normal muscle tone is a fine adjustment of many descending impulses arriving at the anterior horn cell, a summation of those from the cortex, basal ganglia, reticular substance, tegmentum, and cerebellum. In the surgical treatment of spasticity four distinct methods have been utilized: excision of the cerebral cortex, resections at lenticular level, cordotomy, and resection of the spinal nerve roots. This paper will discuss these procedures and present the results in two cases treated by cordotomy.

Knowledge of the pathologic process that brings about spasticity is far from complete. It has been shown that changes in muscle tonus can be produced by lesions in cortical areas 4, 6, and 4s, as well as in certain portions of the basal ganglia, reticular substance, tegmentum, cerebellum, and spinal cord.

Physiologically there is a wide diversity of opinion as to the mechanism producing spasticity. In the opinion of the authors it appears advisable to consider that increase in tonus is not always due to a release phenomenon but often to a predominance of one group of descending pyramidal and extrapyramidal impulses over another, or as Magoun has phrased it, "spasticity results from combined disturbances of extrapyramidal innervation." Hence, when attempting surgically to alter the tonus of muscle groups, we must consider. . .



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