Confinia neurol. 37: 378-383 (1975)
Personal Recollections o f the Development o f Human Stereotactic Neurosurgery S. O brador National Department of Neurosurgery of the Spanish Social Security, Faculty of Medicine, Autonomous University, Madrid
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
During my years of training in basic Neurophysiology, an invaluable and virtually essential introduction to the study of clinical and especially surgical Neurology, I was privileged to observe the renewed interest in the subcortical areas of the brain and to learn something of the experimental methods in vogue at that time. These studies were carried out from 1933 to 1936 in the Cajal Institute of Madrid, the laboratory of Sir C harles S herrington in Oxford, where L id d el was using stereotactic methods in monkeys, and in Dr. F ulton ’s laboratory in New Heaven. At that time D usser d e B arenne and Me C ulloch were also working on the interand subcortical connections. Later, during my visits to the laboratories of Prof. H ess in Zurich and Dr. B ailey in Chicago I was able to study the experimental techniques of implanted electrodes and the production of localized deep cerebral le sions. In the laboratory of Pharmacology of the University of Edinburgh, while doing my neurosurgical training with N orman D ott , I participated in an experimental study with W illiam C. W ilson and others on the modifications of the acetylcholine content of the cerebrospinal fluid under different conditions, especially following the stimulation of the hypothala mus with Hess implanted electrodes [A dam et al., 1938]. In the following years, and by now I was already practicing clinical neurosurgery in Madrid, one outstanding memory is the Fourth Interna tional Neurological Congress which was held in Paris in 1949, 10 years after the Congress in Copenhagen which took place as the war clouds were gathering. There I had the opportunity and privilege of hearing Prof.
O brador
379
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
E. A. Spiegel and Dr. H. W ycis presenting the first results of their ster eotactic methods started 2 years before. Intractable pain, mental disor ders, abnormal involuntary movements, subcortical epileptic foci as well as the localization and destruction of deep seated brain tumors were some of the first applications of human stereotactic neurosurgery. I was very impressed by the wide scope of this new method and, in the discussion, I remember asking Prof. Spieg el some details about the evolution of men tal disorders after dorsomedial thalamotomies in comparison with the ef fects of frontal leukotomies then widely used in some places. In 1950, just a year later, I visited L eksell ’s Clinic in Lund and saw for the first time the application of his stereotactic technique, beautiful in its simplicity, and a technique that was with further improvements to be come widely used as the years went by. The first experience in our Clinic with electrostimulation and electro coagulation of the thalamus concerned a patient with a very complex syn drome of localized myoclonic epilepsy in whom a previous cortical exci sion had failed. We used the human stereotactic atlas developed in Gran ada and later in Zaragoza by Prof. J. E scolar for this purpose [O brador et al, 1951]. In 1953 during a journey down the East coast of the United States and Canada, I visited several neurosurgical centers. In Philadelphia at the Temple University Hospital, Spieg el and W ycis already had a series of about 150 cases treated by stereotactic lesions. Pain, mental disorders and Parkinson’s disease formed the main clinical groups. For the relief of par kinsonian symptoms, their target was at that time the ansa lenticularis. The same year, Spiegel and W ycis presented a paper to the Fifth Inter national Neurological Congress held in Lisbon on stereoencephalotomy in extrapyramidal disorders, and I believe they also attended a meeting held in Madrid to honour C ajal immediately afterwards. It must have been about this time that I rving C ooper in New York embarked on his exten sive approach to the surgical treatment of the parkinsonian syndrome, first with the occlusion of the anterior choroidal artery and later by pro ducing chemical lesions (subsequently more accurately localized by means of the so-called ‘balloon technique’) in the globus pallidus and later in the ventrolateral nucleus of the thalamus. The pioneering work of Spiegel and W ycis in Philadelphia in 1947 had opened up a whole new field in neurosurgery and soon developments were taking place in many countries, notably T alairach and G u io t in
380
O brador
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
Paris; R iech ert , M und in g er and U mbach in Germany; L eksell in Swe den, and N arabayashi in Tokyo. In our Clinic, with the collaboration of D ierssen , we started to per form pallidal lesions in parkinsonian patients in 1955 and developed a simplified technique to approach and damage the region of the globus pallidus [O brador and D ierssen , 1956; O brador , 1957]. In the early days of our foray into the field of stereotactic surgery, several methods were tried and during this time a total of 134 subcortical lesions were per formed; the results and complications of the first hundred cases were re ported [O brador and D ierssen , 1959]. At the beginning of 1959, G on zalo B ravo , trained by C o oper , undertook the stereotactic neurosurgery in our Clinic and worked with us for 12 months when he left to continue his activity in different centers in Madrid. In 1961 I created a special neurophysiological and stereotactic depart ment in our Clinic. D ierssen , who had completed his training with C oop er in New York and in other places, was in charge, and Sevillano , C ar rascosa , P astor , S anchez M oreno , J os , O doriz and others participated in this clinical and neurophysiological work. Several papers on the work of this unit were published [D ierssen and M arg , 1965; M arg and D i erssen , 1965; D ierssen , 1966]. The First International Symposium of Stereoencephalotomy, organ ized by H enry W ycis , took place in Philadelphia in 1961 under the Pres idency of E rnest Spieg el . I presented some findings of our group in Madrid [O brador , 1962], The Second International Symposium of Ster eoencephalotomy was held in Copenhagen and Vienna in 1965 in asso ciation with the International Congresses of Neurosurgery and Neurology held in those cities [O brador and D ierssen , 1965a, b]. D ierssen and myself, as Secretary and President of the Third Europe an Congress of Neurosurgery which took place in 1967 in Madrid, had the pleasure to organize together with H enry W ycis the Third Interna tional Symposium of Stereoencephalotomy held at the same time [D i erssen and O brador , 1967; O brador and D ierssen , 1967]. Unfortun ately, Prof. Spieg el was unable to attend these meetings, but 2 years later during the occasion of the combined meeting of the Ninth International Congress of Neurology and the Fourth of Neurosurgery in New York, the International Society of Stereoencephalotomy held a memorable dinner, at which I had the honor to be present, to pay homage to the great scien tific achievements of E rnest Spie g e l .
Development of Human Stereotactic Neurosurgery
381
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
I last saw H enry W ycis in the Summer of 1970 in Copenhagen during the Second International Conference of Psychosurgery. His health was al ready failing, but he presented a paper on his reminiscences of the first Conference held 22 years before in Lisbon under the Presidency of E gas M oniz , an historic occasion. We have continued our special interest in functional and stereotactic neurosurgery. D jerssen left in 1970 to set up a new neurosurgical unit in Santander and his place has been taken by J. G. M artin -R odriguez , trained by G illingham in Edinburgh and H ankinson in Newcastle. Dur ing the last 3 years we have worked in close collaboration with the De partment of Physiology directed by Prof. J. M. R. D elgado of the Facul ty of Medicine of our Autonomous University; apart from the intensive neurophysiological study of some patients and the recording of thalamic neurones, carried out by G arcia -A ustt and B uño with M artin -R odri g uez , we have a common project with D elgado and his group, supported by the Spanish Social Security, to develop new therapeutic techniques. The study and treatment of intractable pain by intracerebral stimulation has been our main interest during these 3 years and the first human appli cation of a chronic transdermal brain stimulator as a ‘pleasure’ cerebral pacemaker has been reported [D elgado et al., 1973; O brador el al., 1974]. In other neurosurgical clinics in Spain there has been a continuing in terest in stereotactic methods. As already mentioned, B ravo , who now works in the Clinic Puerta de Hierro of the Spanish Social Security, has performed many operations, and D ierssen in Santander and C arrascosa in Málaga, also working in Clinics of the Social Security, were two of the pioneers in this field. In Barcelona, I samat, trained by C ooper in 1959-1961 and previously by B ucy , Snider and W oolsey , has directed a part of his stereotaxic research programme to the treatment of spasmod ic torticollis and dystonia. B arcia -S alorio in Valencia started stereotaxic surgery in 1959 after several visits to various European clinics; he has de veloped his own models of stereotaxic guides, as well as localizing sys tems for the study of the anatomical variations in relation to target points. Since 1965 there has been further expansion in the field of stereotactic surgery first in Seville, in the neurosurgical clinic of the Social Security directed by P edro A lbert , and later in Granada, by A rjona who was trained by H ankinson . His main interests have been pain and aggressive behavior in erethic children. B urzaco , trained by L eksell , started in
382
O brador
Madrid in 1962 and has made the first lesions of the fundus stria terminalis for the treatment of aggressive behavior following the neurophysiologi cal studies of F ernandez M olina . He is also interested in the study of epilepsy and at present works in the Fundación Jiménez Díaz. Apart from the clinics and centers already mentioned, my associates and I have visited various places throughout the world where different techniques and methods of stereotactic and functional neurosurgery have been developed by many neurosurgeons: Boston (Sw eet and M ark ), L os Angeles (R an d and the UCLA Brain Institute), San Francisco (A dam s ), London (W alsh and Symon ), Birmingham (B rodie H ughes ), M oscow (Burdenko Institutes of Neurosurgery and Neurology, K andel ), Lenin grad (B echtereva ’s Department of Applied Neurophysiology of the Insti tute of Experimental Medicine and Polenov Institute of Neurosurgery), Berlin (U mbach ), Helsinki (L aitinen ), Copenhagen (V aernet ), Zurich (S ieg fried ), Bratislava (N advornhc), Santiago de Chile (A senjo ), Mexi co (V elasco Suarez and E scobedo , Institute of Neurology), Tokyo (N arabayashi), etc. This vast expansion of stereotactic neurosurgery throughout the world over the last 25 years has resulted in a consolidation of the principles set up by E rnest Spieg el and H enry W y cis . In the course of these years I had the privilege of seeing them both in many Congresses, Symposia and Meetings where I learned a great deal and gained their friendship. I recall them as a scientific pair resembling, in some respects, the literary and uni versally known figures of Don Quixote and Sancho created by Miguel de Cervantes as symbols of the human race. One of them aloof with great wisdom and theoretical knowledge enabling him to visualize new tech niques for the study and treatment of disorders of the central nervous sys tem; the other more realistic and more practical in putting their projects into effect and full of humanity and friendship. Everyone engaged in the field of so-called functional neurosurgery owes a particular debt to them both in their unique combination.
References A dam , H. M.; Me Kail , R. A.; O brador, S., and W ilson , W. C.: Acetylcholine in
the cerebrospinal fluid. J. Physio!., Lond. 93: 45-46 (1938). D elgado , J. M. R.; O brador, S., and M artin -R odriguez , J. G.: Two-way radio
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
communication with the brain in psychosurgical approaches in psychiatry. Proc.
Development of Human Stereotactic Neurosurgery
383
3rd Int. Congr. on Psychosurgery, Cambridge 1972 (Medical and Technical Pub lishing, Lancaster 1973). D ierssen , G.: Treatment of dystonic and athetoid symptoms by lesions in the senso ry portion of the internal capsule. Confinia neurol. 26: 404-406 (1966). D ierssen , G. and M arg, E.: The value of impedance measurements to aid in the lo calisation in stereotactic surgery. Confinia neurol. 26: 407-410 (1965). D ierssen , G. and O brador, S.: The problem of bliateral lesions in stereotaxic sur gery. Confinia neurol. 29: 181-185 (1967). M arg, E. and D ierssen , G.: Reported visual percepts from stimulation of the hu man brain with microelectrodes during therapeutic surgery. Confinia neurol. 26: 57-75 (1965). Obrador, S.: A simplified neurosurgical technique for approaching and damaging the region of the globus pallidus in Parkinson’s disease. J. Neurol. Neurosurg. Psychiat. 20: 47-49 (1957). O brador, S.: Some physiological aspects related to subcortical therapeutical lesions. Confinia neurol. 22: 283-290 (1962). O brador, S. y D ierssen , G.: Cirugía de la región palidal en el sindrome de Parkin son. Técnica personal y resultados inmediatos en los seis primeros casos opera dos. Revta clin. esp. 61: 229-237 (1956). O brador, S. and D ierssen , G.: Results and complications following one hundred subcortical lesions performed in Parkinson’s disease and other hyperkinesias. Acta neurochir. 7: 206-215 (1959). O brador, S. and D ierssen , G.: Observations on the treatment of intentional and postural tremor by subcortical stereotaxic lesions. Confinia neurol. 26: 250-253 (1965a). O brador, S. and D ierssen , G.: Sensory response to subcortical stimulation and management of pain disorders by stereotaxic methods. Confinia neurol. 27: 45-51 (1965b). O brador, S. and D ierssen , G.: Mental changes induced by subcortical stimulation and therapeutic lesions. Confinia neurol. 29: 168 (1967). O brador, S.; L arramendi, M. H. y U rquiza , P.: Ensayos de coagulación del tálamo y de la corteza sensorial en un sindrome de epilepsia mioclónica localizada. Revta clin. esp. 41: 8-14 (1951). O brador, S.; D elgado, J. M. R., and M artin -R odriguez , J. G.: The future of functional neurosurgery; in Recent progress in neurological surgery. Proc. 5th Int. Congr. Neurological Surgery, Tokyo 1973, pp. 265-269 (Excerpta Medica, Amsterdam 1974).
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
Dr. S. O brador, Eduardo, 23, Madrid, 10 (Spain)
Personal Recollections o f the Development o f Human Stereotactic Neurosurgery S. O brador National Department of Neurosurgery of the Spanish Social Security, Faculty of Medicine, Autonomous University, Madrid
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
During my years of training in basic Neurophysiology, an invaluable and virtually essential introduction to the study of clinical and especially surgical Neurology, I was privileged to observe the renewed interest in the subcortical areas of the brain and to learn something of the experimental methods in vogue at that time. These studies were carried out from 1933 to 1936 in the Cajal Institute of Madrid, the laboratory of Sir C harles S herrington in Oxford, where L id d el was using stereotactic methods in monkeys, and in Dr. F ulton ’s laboratory in New Heaven. At that time D usser d e B arenne and Me C ulloch were also working on the interand subcortical connections. Later, during my visits to the laboratories of Prof. H ess in Zurich and Dr. B ailey in Chicago I was able to study the experimental techniques of implanted electrodes and the production of localized deep cerebral le sions. In the laboratory of Pharmacology of the University of Edinburgh, while doing my neurosurgical training with N orman D ott , I participated in an experimental study with W illiam C. W ilson and others on the modifications of the acetylcholine content of the cerebrospinal fluid under different conditions, especially following the stimulation of the hypothala mus with Hess implanted electrodes [A dam et al., 1938]. In the following years, and by now I was already practicing clinical neurosurgery in Madrid, one outstanding memory is the Fourth Interna tional Neurological Congress which was held in Paris in 1949, 10 years after the Congress in Copenhagen which took place as the war clouds were gathering. There I had the opportunity and privilege of hearing Prof.
O brador
379
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
E. A. Spiegel and Dr. H. W ycis presenting the first results of their ster eotactic methods started 2 years before. Intractable pain, mental disor ders, abnormal involuntary movements, subcortical epileptic foci as well as the localization and destruction of deep seated brain tumors were some of the first applications of human stereotactic neurosurgery. I was very impressed by the wide scope of this new method and, in the discussion, I remember asking Prof. Spieg el some details about the evolution of men tal disorders after dorsomedial thalamotomies in comparison with the ef fects of frontal leukotomies then widely used in some places. In 1950, just a year later, I visited L eksell ’s Clinic in Lund and saw for the first time the application of his stereotactic technique, beautiful in its simplicity, and a technique that was with further improvements to be come widely used as the years went by. The first experience in our Clinic with electrostimulation and electro coagulation of the thalamus concerned a patient with a very complex syn drome of localized myoclonic epilepsy in whom a previous cortical exci sion had failed. We used the human stereotactic atlas developed in Gran ada and later in Zaragoza by Prof. J. E scolar for this purpose [O brador et al, 1951]. In 1953 during a journey down the East coast of the United States and Canada, I visited several neurosurgical centers. In Philadelphia at the Temple University Hospital, Spieg el and W ycis already had a series of about 150 cases treated by stereotactic lesions. Pain, mental disorders and Parkinson’s disease formed the main clinical groups. For the relief of par kinsonian symptoms, their target was at that time the ansa lenticularis. The same year, Spiegel and W ycis presented a paper to the Fifth Inter national Neurological Congress held in Lisbon on stereoencephalotomy in extrapyramidal disorders, and I believe they also attended a meeting held in Madrid to honour C ajal immediately afterwards. It must have been about this time that I rving C ooper in New York embarked on his exten sive approach to the surgical treatment of the parkinsonian syndrome, first with the occlusion of the anterior choroidal artery and later by pro ducing chemical lesions (subsequently more accurately localized by means of the so-called ‘balloon technique’) in the globus pallidus and later in the ventrolateral nucleus of the thalamus. The pioneering work of Spiegel and W ycis in Philadelphia in 1947 had opened up a whole new field in neurosurgery and soon developments were taking place in many countries, notably T alairach and G u io t in
380
O brador
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
Paris; R iech ert , M und in g er and U mbach in Germany; L eksell in Swe den, and N arabayashi in Tokyo. In our Clinic, with the collaboration of D ierssen , we started to per form pallidal lesions in parkinsonian patients in 1955 and developed a simplified technique to approach and damage the region of the globus pallidus [O brador and D ierssen , 1956; O brador , 1957]. In the early days of our foray into the field of stereotactic surgery, several methods were tried and during this time a total of 134 subcortical lesions were per formed; the results and complications of the first hundred cases were re ported [O brador and D ierssen , 1959]. At the beginning of 1959, G on zalo B ravo , trained by C o oper , undertook the stereotactic neurosurgery in our Clinic and worked with us for 12 months when he left to continue his activity in different centers in Madrid. In 1961 I created a special neurophysiological and stereotactic depart ment in our Clinic. D ierssen , who had completed his training with C oop er in New York and in other places, was in charge, and Sevillano , C ar rascosa , P astor , S anchez M oreno , J os , O doriz and others participated in this clinical and neurophysiological work. Several papers on the work of this unit were published [D ierssen and M arg , 1965; M arg and D i erssen , 1965; D ierssen , 1966]. The First International Symposium of Stereoencephalotomy, organ ized by H enry W ycis , took place in Philadelphia in 1961 under the Pres idency of E rnest Spieg el . I presented some findings of our group in Madrid [O brador , 1962], The Second International Symposium of Ster eoencephalotomy was held in Copenhagen and Vienna in 1965 in asso ciation with the International Congresses of Neurosurgery and Neurology held in those cities [O brador and D ierssen , 1965a, b]. D ierssen and myself, as Secretary and President of the Third Europe an Congress of Neurosurgery which took place in 1967 in Madrid, had the pleasure to organize together with H enry W ycis the Third Interna tional Symposium of Stereoencephalotomy held at the same time [D i erssen and O brador , 1967; O brador and D ierssen , 1967]. Unfortun ately, Prof. Spieg el was unable to attend these meetings, but 2 years later during the occasion of the combined meeting of the Ninth International Congress of Neurology and the Fourth of Neurosurgery in New York, the International Society of Stereoencephalotomy held a memorable dinner, at which I had the honor to be present, to pay homage to the great scien tific achievements of E rnest Spie g e l .
Development of Human Stereotactic Neurosurgery
381
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
I last saw H enry W ycis in the Summer of 1970 in Copenhagen during the Second International Conference of Psychosurgery. His health was al ready failing, but he presented a paper on his reminiscences of the first Conference held 22 years before in Lisbon under the Presidency of E gas M oniz , an historic occasion. We have continued our special interest in functional and stereotactic neurosurgery. D jerssen left in 1970 to set up a new neurosurgical unit in Santander and his place has been taken by J. G. M artin -R odriguez , trained by G illingham in Edinburgh and H ankinson in Newcastle. Dur ing the last 3 years we have worked in close collaboration with the De partment of Physiology directed by Prof. J. M. R. D elgado of the Facul ty of Medicine of our Autonomous University; apart from the intensive neurophysiological study of some patients and the recording of thalamic neurones, carried out by G arcia -A ustt and B uño with M artin -R odri g uez , we have a common project with D elgado and his group, supported by the Spanish Social Security, to develop new therapeutic techniques. The study and treatment of intractable pain by intracerebral stimulation has been our main interest during these 3 years and the first human appli cation of a chronic transdermal brain stimulator as a ‘pleasure’ cerebral pacemaker has been reported [D elgado et al., 1973; O brador el al., 1974]. In other neurosurgical clinics in Spain there has been a continuing in terest in stereotactic methods. As already mentioned, B ravo , who now works in the Clinic Puerta de Hierro of the Spanish Social Security, has performed many operations, and D ierssen in Santander and C arrascosa in Málaga, also working in Clinics of the Social Security, were two of the pioneers in this field. In Barcelona, I samat, trained by C ooper in 1959-1961 and previously by B ucy , Snider and W oolsey , has directed a part of his stereotaxic research programme to the treatment of spasmod ic torticollis and dystonia. B arcia -S alorio in Valencia started stereotaxic surgery in 1959 after several visits to various European clinics; he has de veloped his own models of stereotaxic guides, as well as localizing sys tems for the study of the anatomical variations in relation to target points. Since 1965 there has been further expansion in the field of stereotactic surgery first in Seville, in the neurosurgical clinic of the Social Security directed by P edro A lbert , and later in Granada, by A rjona who was trained by H ankinson . His main interests have been pain and aggressive behavior in erethic children. B urzaco , trained by L eksell , started in
382
O brador
Madrid in 1962 and has made the first lesions of the fundus stria terminalis for the treatment of aggressive behavior following the neurophysiologi cal studies of F ernandez M olina . He is also interested in the study of epilepsy and at present works in the Fundación Jiménez Díaz. Apart from the clinics and centers already mentioned, my associates and I have visited various places throughout the world where different techniques and methods of stereotactic and functional neurosurgery have been developed by many neurosurgeons: Boston (Sw eet and M ark ), L os Angeles (R an d and the UCLA Brain Institute), San Francisco (A dam s ), London (W alsh and Symon ), Birmingham (B rodie H ughes ), M oscow (Burdenko Institutes of Neurosurgery and Neurology, K andel ), Lenin grad (B echtereva ’s Department of Applied Neurophysiology of the Insti tute of Experimental Medicine and Polenov Institute of Neurosurgery), Berlin (U mbach ), Helsinki (L aitinen ), Copenhagen (V aernet ), Zurich (S ieg fried ), Bratislava (N advornhc), Santiago de Chile (A senjo ), Mexi co (V elasco Suarez and E scobedo , Institute of Neurology), Tokyo (N arabayashi), etc. This vast expansion of stereotactic neurosurgery throughout the world over the last 25 years has resulted in a consolidation of the principles set up by E rnest Spieg el and H enry W y cis . In the course of these years I had the privilege of seeing them both in many Congresses, Symposia and Meetings where I learned a great deal and gained their friendship. I recall them as a scientific pair resembling, in some respects, the literary and uni versally known figures of Don Quixote and Sancho created by Miguel de Cervantes as symbols of the human race. One of them aloof with great wisdom and theoretical knowledge enabling him to visualize new tech niques for the study and treatment of disorders of the central nervous sys tem; the other more realistic and more practical in putting their projects into effect and full of humanity and friendship. Everyone engaged in the field of so-called functional neurosurgery owes a particular debt to them both in their unique combination.
References A dam , H. M.; Me Kail , R. A.; O brador, S., and W ilson , W. C.: Acetylcholine in
the cerebrospinal fluid. J. Physio!., Lond. 93: 45-46 (1938). D elgado , J. M. R.; O brador, S., and M artin -R odriguez , J. G.: Two-way radio
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
communication with the brain in psychosurgical approaches in psychiatry. Proc.
Development of Human Stereotactic Neurosurgery
383
3rd Int. Congr. on Psychosurgery, Cambridge 1972 (Medical and Technical Pub lishing, Lancaster 1973). D ierssen , G.: Treatment of dystonic and athetoid symptoms by lesions in the senso ry portion of the internal capsule. Confinia neurol. 26: 404-406 (1966). D ierssen , G. and M arg, E.: The value of impedance measurements to aid in the lo calisation in stereotactic surgery. Confinia neurol. 26: 407-410 (1965). D ierssen , G. and O brador, S.: The problem of bliateral lesions in stereotaxic sur gery. Confinia neurol. 29: 181-185 (1967). M arg, E. and D ierssen , G.: Reported visual percepts from stimulation of the hu man brain with microelectrodes during therapeutic surgery. Confinia neurol. 26: 57-75 (1965). Obrador, S.: A simplified neurosurgical technique for approaching and damaging the region of the globus pallidus in Parkinson’s disease. J. Neurol. Neurosurg. Psychiat. 20: 47-49 (1957). O brador, S.: Some physiological aspects related to subcortical therapeutical lesions. Confinia neurol. 22: 283-290 (1962). O brador, S. y D ierssen , G.: Cirugía de la región palidal en el sindrome de Parkin son. Técnica personal y resultados inmediatos en los seis primeros casos opera dos. Revta clin. esp. 61: 229-237 (1956). O brador, S. and D ierssen , G.: Results and complications following one hundred subcortical lesions performed in Parkinson’s disease and other hyperkinesias. Acta neurochir. 7: 206-215 (1959). O brador, S. and D ierssen , G.: Observations on the treatment of intentional and postural tremor by subcortical stereotaxic lesions. Confinia neurol. 26: 250-253 (1965a). O brador, S. and D ierssen , G.: Sensory response to subcortical stimulation and management of pain disorders by stereotaxic methods. Confinia neurol. 27: 45-51 (1965b). O brador, S. and D ierssen , G.: Mental changes induced by subcortical stimulation and therapeutic lesions. Confinia neurol. 29: 168 (1967). O brador, S.; L arramendi, M. H. y U rquiza , P.: Ensayos de coagulación del tálamo y de la corteza sensorial en un sindrome de epilepsia mioclónica localizada. Revta clin. esp. 41: 8-14 (1951). O brador, S.; D elgado, J. M. R., and M artin -R odriguez , J. G.: The future of functional neurosurgery; in Recent progress in neurological surgery. Proc. 5th Int. Congr. Neurological Surgery, Tokyo 1973, pp. 265-269 (Excerpta Medica, Amsterdam 1974).
Downloaded by: University Toronto Libr. 142.150.190.39 - 1/6/2020 8:23:31 PM
Dr. S. O brador, Eduardo, 23, Madrid, 10 (Spain)
