Effects of Dorsal Rhizotomy Upon Subthalamic Dyskinesia in the Monkey

ONE UNRESOLVED question concerning various forms of dyskinesia is the role that sensory input plays in the underlying basic neural mechanism. Relatively little data are available concerning the effects of dorsal rhizotomies upon human dyskinesia mainly because this procedure would have to be extensive and would result in widespread sensory loss. In the human, dorsal rhizotomy has been performed primarily for relief of pain, visceral crises, and spasticity or rigidity.10,13,15,16,18,33There are, however, a few instances in which dorsal rhizotomies have been performed upon patients with dyskinesia. According to Frazier,¹⁵surgical section of successive cervical dorsal roots in a patient with infantile diplegia caused spasticity to be diminished and all athetoid movements to disappear. A similar result was reported by Clark and Taylor¹⁰but all spasticity was abolished in this case. Foerster,¹³whose extensive experience with dorsal rhizotomy is well known, summarized his views on resection