The Surgical Treatment of Extrapyramidal Diseases* by Paul C

J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.14.2.108 on 1 May 1951. Downloaded from J. Neurol. Neurosurg. Psychiat., 1951, 14, 108. THE SURGICAL TREATMENT OF EXTRAPYRAMIDAL DISEASES* BY PAUL C. BUCY From the Department ofNeurology and Neurological Surgery, the College ofMedicine, University of Illinois, Chicago Strictly speaking there is no satisfactory surgical VWe have not time now to give attention to the treatment of any of the disorders which arise from entire question of the organization of the central involvement of the extrapyramidal systems. Dis- nervous mechanism for the control of human eases which involve the extrapyramidal components muscular activity. That is a full subject in itself. of the central nervous system are numerous and However, we must tarry briefly to discuss just what give rise to many different clinical manifestations. is meant by the term " extra-pyramidal systems ". Only a very small minority of the victims of these A few years ago " extrapyramidal system " and diseases present problems which can in any measure "basal ganglia " were almost if not quite synony- be solved by surgical therapy. And even in such mous. As recently as 1928 in the index of the late cases measures are, at least at this moment, Kinnier Wilson's book, Modern Problems in surgical Protected by copyright. never curative and seldom benefit more than one Neurology, we find "Extrapyramidal Syndromes. of the many symptoms which are present. Even See Corpus striatum". And Grinker in 1934, in those few cases surgical treatment usually consists in the first edition of his book, Neurology, p. 405, of substituting an undesirable neurological deficit says: for an even more disabling and disturbing manifesta- " Numerous large and small ganglia at the base of tion of the disease. There are now reasons to the brain, forming together a relatively large area of hope that this may not continue to be true in the tissue, comprise the extrapyramidal motor system." future. Other examples could be cited but this is sufficient With few exceptions the disorders arising from to indicate the inadequate conception of the extra- lesions of the extrapyramidal systems which are so pyramidal systems which was so recently held. commonly seen in man are peculiar to him. Rarely Furthermore, at that time it was commonly thought has it been possible to produce in experimental that there were few if any connexions between the animals disturbances sufficiently akin to those seen cerebral cortex and the basal ganglia and that the in man to permit us to make reliable investigations pyramidal and extrapyramidal systems formed of these problems in the experimental laboratories. autonomous units which functioned nearly inde- Similarly, nature has failed to provide uswith animals pendently of each other, yet collaborated in the http://jnnp.bmj.com/ afflicted with such diseases as those seen in man. The dual control of the muscular system by means. of problem is further complicated by the fact that the some obscure, almost ethereal coordinating mech- central nervous mechanism which controls muscular anism. The extrapyramidal system was thought activity in man is different in many respects from to be " not directly concerned in the production that present even in the subhuman primate, and of voluntary movement" (Walshe, 1941), while widely different from that found in lower forms. the pyramidal system and the cerebral cortex were It is thus obvious that if we are to study these diseases generally regarded as being in no way related to we must study them in man. This is not the only those states which were commonly classified as on September 28, 2021 by guest. circumstance in which we must agree with the "extrapyramidal disorders ". French philosopher, Pierre Charron, and with Although our knowledge of the extrapyramidal England's Alexander Pope that " the proper study systems, their structure, functions and disorders, of mankind is man ", but it is one of the most is still woefully incomplete, it has progressed outstanding. far beyond the state of ignorance and confusion * A paper delivered to the Society of British Neurological Surgeons, indicated above. It is now well established, as at the National Hospital, Queen Square, London, on July 23, 1949, and to the Montreal Neurological Society, Montreal Neurological one might have anticipated in view of the beautiful, on Institute, P.Q., Canada, March 29, 1950. smooth coordination which characterizes all normal N 108 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.14.2.108 on 1 May 1951. Downloaded from EXTRAP YRAMIDAL SURGERY 109 muscular activity, that the pyramidal and extrapyramidal systems is very largely dependent upon pyramidal systems, the motor cortex and the basal information which it has been possible to accumulate ganglia and other subcortical motor centres, are from the study of laboratory animals, particularly all closely integrated and coordinated into one the subhuman primates, such as the monkey, the mechanism which is concerned with the control baboon, and the chimpanzee. How completely of muscular activity. The overall control of this this information is applicable to the human nervous neural mechanism is exercised through the pre- system is uncertain and must be inferred from central motor cortex. The extrapyramidal system inadequate observations. Even in the experimental is not an independent neural mechanism; neither animals, however, our knowledge of these functions is it a single unitary system. The extrapyramidal is distinctly imperfect, particularly as concerns the systems consist of a group of complex neural correlation of structure and function. Although organizations, all of which stem directly from the we know of a rather wide variety of extrapyramidal precentral motor cortex.* Areas 24, 8, 2, and 19 mechanisms there are still many situations in which also project to the caudate nucleus and probably we do not know which function a given system is must be considered as part of the extrapyramidal responsible for, or when the function is known, systems having a functional activity akin to that we are often unfamiliar with the structural means of the connexions known to exist between area by which it operates. 4s and the caudate nucleus. In all probability The various known functions ofthe extrapyramidal all of the anatomical extrapyramidal connexions systems can be classified as follows: (1) the pro- between the precentral motor cortex and the sub- duction of integrated primary movements of the cortical centres are not known; certainly many skeletal musculature; (2) the integration of details regarding them are still a mystery, and with- associated and ancillary movements; (3) the out a doubt the functional activity of many of these control and inhibition of postural reflexes; (4) connexions is still to be learned. At the present the suppression of electrical activity in other areas Protected by copyright. time it is known that there are descending connexions of the cortex; (5) the imperfect and partial control from area 4s of the precentral motor cortex (and of visceral and vegetative functions and their also from areas 24, 8, 2, and 19) to the caudate integration with the activity of the skeletal nucleus; from areas 4 and 6 to the putamen; musculature. from area 6 to the external segment of the globus The movements produced by the extrapyramidal pallidus; from the precentral motor cortex (areas 4, systems are crude and coarse. They lack the fine, 4s, and 6) to the zona incerta, the red nucleus, the discrete, precise nature characteristic of move- substantia nigra, and the reticular formation of the ments produced by the pyramidal system. They mesencephalon and pons. There is also a large are nonetheless voluntary and purposeful. The -group of descending fibres which pass from areas 4 movements produced by the extrapyramidal and 6 to the pontine nuclei. Here the impulses systems tend to involve the proximal joints such as are relayed via the middle cerebellar peduncle to the the shoulder and elbow, hip and knee, in contrast cortex of the neocerebellum, primarily in the to the movements produced by the pyramidal tract cerebellar hemispheres. There is also a very heavy which are most extensive in the digits. There is efferent projection from the precentral motor no evidence available at this time as to which of cortex to the lateral nuclear mass of the thalamus, the various extrapyramidal systems is concerned http://jnnp.bmj.com/ but it might be reasonably argued whether these in this production of voluntary movements. cortico-thalamic connexions are directly con- Fibres from the precentral motor cortex to the cerned in the control of muscular activity and should basal ganglia, to the brain stem, and to the pontine therefore be classified as extrapyramidal. I would nuclei where impulses are relayed on to the cere- define the extrapyramidal systems as those complex bellum appear to be concerned in the innervation of groups of descending fibre systems which are associated and ancillary movements which, although directly concerned with the control of muscular not directly concerned in the principal or primary activity, which arise in the cerebral cortex and movement, are nevertheless of great importance on September 28, 2021 by guest. descend through various subcortical centres through in the smooth, well coordinated performance of a variable number of synapses but have no fibres the act. The role which each one of these extra- which pass directly from the cerebral cortex to the pyramidal systems plays in the integration and spinal cord. production of these associated movements is not The study of the functional activity of the extra- clearly understood. One of the most important functions of the extra- * For the details and bibliography of the anatomical and physio- logical facts stated here see " The Precentral Motor Cortex " edited pyramidal systems is the control of the postural by Bucy (1949).

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