Lesioning the thalamus for dyskinesia.

Recent advances on understanding the pallidothalamic relation lead us to perform Vim-Vo thalamotomy (combined thalamic lesion in ventralis intermedius nucleus and ventralis oralis nucleus) for cases with dyskinesia. In our recent series of thalamotomies, there are 12 cases of dyskinesia caused by various etiologies. Therefore the clinical manifestation of the involuntary movement was different in each case, including, more or less, some elements of irregular involuntary hyperkinetic movement. Stereotactic operation was performed using Leksell's apparatus aided by Surgiplan and MRI. The Vim nucleus was identified by physiological study using microelectrodes. High background activity and kinesthetic neurons are reliable indicators of Vim nucleus (but only for the lateral part). Then, selective coagulation was made by dual coagulation needles. Since the Vo nucleus is located just rostral to the Vim nucleus, the coagulation needle was turned toward the anterior part to partly cover the Vo nucleus. Thus, selective Vim-Vo thalamotomy was shown to be quite successful for the treatment of dyskinesia.

[Prospect of neurosurgical approach to Parkinson's disease in the 21st century].

After a brief review of the past and present status of stereotactic surgery, prospect of neurosurgical approach to Parkinson's disease in the 21st century was considered. The stereotactic surgery has progressed markedly in its technical and theoretical aspects due to the rapid development of the basic neuroscience and computerized imaging technique. Although there are some points to be clarified and estimated in the future, these new tendencies will stand to the next century, and further progress will be achieved if it contains some truth in the light of the modern neuroscience. Also it should be clinically effective, safety and smart. The idea of stereotaxy since the beginning, namely the maximum effect with minimal damage of the human brain always holds true.

The idea of stereotaxy toward minimally invasive neurosurgery.

The idea of stereotaxy in modern neurosurgery is reviewed. Stereotactic surgery has been one of the particular neurosurgical techniques mainly used for functional disorders. Nowadays, it is widely used in the field of general neurosurgery owing to the rapid development of computer-assisted 3D brain images. Functional neurosurgery itself is also changing in the sense that many alternative surgical procedures are now available due to the progress in neuroscience. The original premise of stereotaxy is exactly the same as that of minimally invasive neurosurgery today.

Evaluation of gamma thalamotomy for parkinsonian and other tremors: survival of neurons adjacent to the thalamic lesion after gamma thalamotomy.

OBJECT: The effects of gamma thalamotomy for parkinsonian and other kinds of tremor were evaluated. METHODS: Thirty-six thalamotomies were performed in 31 patients by using a 4-mm collimator. The maximum dose was 150 Gy in the initial six cases, which was reduced to 130 Gy thereafter. The longest follow-up period was 6 years. The target was determined on T2-weighted and proton magnetic resonance (MR) images. The point chosen was in the lateral-most part of the thalamic ventralis intermedius nucleus. This is in keeping with open thalamotomy as practiced at the authors' institution. In 15 cases, gamma thalamotomy was the first surgical procedure. In other cases, previous therapeutic or vascular lesions were visible to facilitate targeting. Two types of tissue reaction were onserved on MR imaging: a simple oval shape and a complex irregular shape. Neither of these changes affected the clinical course. In the majority of cases, the tremor subsided after a latent interval of approximately 1 year after irradiation. The earliest response was demonstrated at 3 months. In five cases the tremor remained. In four of these cases, a second radiation session was administered. One of these four patients as well as another patient with an unsatisfactory result underwent open thalamotomy with microrecording. In both cases, depth recording adjacent to the necrotic area revealed normal neuronal activity, including the rhythmic discharge of tremor. Minor coagulation was performed and resulted in immediate and complete arrest of the remaining tremor. CONCLUSIONS: Gamma thalamotomy for Parkinson's disease seems to be an alternative useful method in selected cases.

Use of selective thalamotomy for various kinds of movement disorder, based on basic studies.

Methods of selective thalamotomy with microrecording for several kinds of movement disorder are described. Precise thalamotomy (Vim, VO or Vim+VO) depends on the understanding of the functional organization of the human thalamus on the one hand, and the patient's specific feature of movement disorders on the other. To realize selective thalamotomy, microrecording and a computerized planning system are essential. Thus, a properly selected thalamotomy for movement disorders is quite useful.

Pituitary adenomas treated by microsurgery with or without Gamma Knife surgery: experience in 122 cases.

The clinical outcome of 122 patients with pituitary adenomas treated by microsurgery and/or Gamma Knife radiosurgery (GKRS) was analyzed to evaluate patient selection criteria and the role of GKRS. Sixty-six resections were performed in 59 patients. All tumors were macroadenomas, except for 5 ACTH-producing adenomas. Twenty-four of the 31 hypersecreting adenomas showed normal serum hormone values after treatment. Postoperative complications were rhinorrhea, cranial nerve palsies, and a small thalamic infarct. GKRS was performed on 18 of the operated patients because of residual tumors, mostly in the cavernous sinus. Thirty-five of the 63 patients treated by GKRS were followed for more than 2 years. All adenomas except 2 were stable or had decreased in size. Eleven of 17 functioning adenomas showed normal serum hormone values after treatment. It is concluded that tumors that compress the optic pathway should be removed and that residual tumors in the cavernous sinus are good indications for radiosurgery.

The role of intravascular embolization prior to radiosurgery of cerebral arteriovenous malformations. from the standpoint of hemorrhage and early obliteration after gamma knife radiosurgery.

The role of intravascular embolization prior to radiosurgery of cerebral arteriovenous malformations was evaluated based on the basis of the results of gamma knife radiosurgery in relation to hemorrhage and early obliteration after treatment. Nine of 213 patients experienced hemorrhage 4 to 42 months after radiosurgery. All AVMs in these patients had dilated feeding arteries, and the flow of the AVM was rapid and/or high. An intranidal aneurysm was seen in one patient. Drainage of all AVMs consisted of a single and/or deep draining veins, and venous obstruction was found in six. Sixty-three of 87 patients followed for more than four years after radiosurgery were examined angiographically, and total obliteration of AVM was observed in 52 of them (82.5%). Early obliteration was found in 19 of the 34 patients examined within 12 months. The obliteration rate was significantly higher in slow- and low-flow AVMs (73.9%) than in rapid- and/or high-flow AVMs (18.2%). It is concluded that the role of intravascular embolization prior to radiosurgery is not only decreasing the size of the AVM but decreasing the risk of hemorrhage and shortening the latency period by decreasing their flow rate and flow volume.

Stereotactic treatment of central pain.

In the present study, the effect of stereotactic treatment on central pain is briefly reviewed. Studies have shown that the spinothalamic tract projects to the shell zone of the principal sensory nucleus (Vc) and its rostral part (Vim), where it forms clusters. Recent anatomophysiological studies have revealed specific nociceptive neurons in the thalamic submedius and VMpo nucleus, from which fibers project to the insular and cingulate cortex. In the abnormal state of central pain, these structures may be subjected to excess excitation. Thalamic recording during the course of stereotactic thalamotomy strongly supports this hypothesis. Thus, Vim-Vcpc thalamotomy ameliorates the so-called deep pain after stroke.

Effect of electrical stimulation of the thalamic Vim nucleus on hand tremor during stereotactic thalamotomy.

OBJECTIVE: The aim of this study was to analyze the correlation between neuronal responses in the thalamic ventralis intermedius (Vim) nucleus to peripheral, natural stimulation and the modulation of tremor by electrical stimulation during stereotactic thalamotomy. DESIGN AND METHODS: The authors studied 36 patients with hand tremor using a microelectrode. The responses of tremor to electrical stimulation were analysed electromyographically. Sixty stimulation sites were divided into three groups. RESULTS: Group A (20 sites) where responses to stretching of the contralateral forearm muscles were recorded. Group B (26 sites) where responses to stretching of the other muscles of the upper extremity were recorded. Electrical stimulation at sites in groups A and B temporarily suppressed the contralateral tremor, but the minimum current intensity to suppress tremor at sites in group A was less than that in group B. Electrical stimulation in group C (14 sites), where kinesthetic responses of contralateral lower extremity were recorded, resulted in increased amplitude of hand tremor. Selective coagulation including the area of tremor suppression resulted in abolition of the tremor in all patients. CONCLUSIONS: These results suggest that the most effective site for thalamotomy may also be suitable for chronic stimulation in the Vim nucleus.

In vitro neuronal and glial production and differentiation of human central neurocytoma cells.

Human central neurocytoma cells were cultured and characterized immunophenotypically and electrophysiologically to clarify their developmental potential. We conducted systematic in vitro studies utilizing fresh tissues from three patients. Initially small homogeneous cell clusters settled down onto the bottom of the culture flasks, and, after 2 weeks from plating, mature neuron-like cells developed from these clusters and expressed neurofilament proteins (NF: specific neuronal markers). On the other hand, approximately 80% of small round cell clusters and flat glial-like cells from which these clusters developed were positively stained for glial fibrillary acidic protein (GFAP: a specific glial marker). Furthermore these neuronal and glial cells showed distinct morphology, and dual-label, indirect immunohistochemistry for GFAP and NF-200 kD disclosed that the two antigens were not found co-localized in the same cells. In single-cell clonal analysis, neuronal, glial, and mixed neuronal and glial clones were generated. Electrophysiologically, the cells of neuronal morphology possessed sodium channels, and also L-type calcium channels in whole-cell voltage clamp. The sodium channels were of a characteristic neuronal phenotype which appears in neurons. These findings suggest that small round human central neurocytoma cells exhibit both neuronal and glial differentiations and have the properties reminiscent of precursor cells derived from subventricular matrix; thus, these cultured cells may be a potential source for investigations of human CNS neuronal and glial development and differentiation.

Treatment of unruptured arteriovenous malformations in the brain.

Clinical features and treatment results of 33 patients with unruptured arteriovenous malformations (AVMs) were evaluated. Nine AVMs were located in the frontal lobe, 8 in the motor cortex, 5 in the parietal lobe, 6 in the temporal lobe, 2 in the occipital lobe and 3 in other parts of the brain. Nine patients were treated with microsurgery and 24 with radiosurgery. Total extirpation of the AVM was performed in all 9 microsurgery patients. One patient with an AVM in the motor cortex experienced upper extremity weakness postoperatively. Eleven of 24 patients treated with radiosurgery had follow-up imaging studies. Obliteration was obtained in 8 patients and decreased size in 3. Complications included 1 patient with a hemiparesis and 1 with an AVM rupture prior to obliteration. The remaining 13 patients did not experience any complications over a mean period of 21.2 months. Microsurgery appears to be the best treatment for unruptured AVMs in non-eloquent areas. Radiosurgery is a safe, effective treatment for unruptured AVMs in eloquent areas, although a bleeding risk remains during the latency period prior to obliteration.

Single-unit activity in the primate nucleus tegmenti pedunculopontinus related to voluntary arm movement.

In the pedunculopontine tegmental nucleus (PPN), single-unit activity was recorded in two monkeys trained to manipulate an on-off lever with a hand. Among 280 neurons recorded, a change in the firing rate related to the lever-off movement was observed in 125 neurons for the contralateral limb movement (53%) and in 96 neurons for the ipsilateral limb movement (48%). The changes were an increase in the firing rate in 122 neurons and a decrease in 99 neurons. These changes in the firing rate related to the task often occurred for both the contralateral and ipsilateral limb movements. The change of activity preceded the movement onset for both contralateral and ipsilateral arm movements. These findings suggest that in primates the PPN contributes to coordination of upper limb movements on both sides.

Basal interhemispheric supra- and/or infrachiasmal approaches via superomedial orbitotomy for hypothalamic lesions: preservation of hypothalamo-pituitary functions in combination treatment with radiosurgery.

Although several approaches to the hypothalamus have been used, none is able to give full views of the hypothalamus. The risk of permanent morbidity for hypothalamo-pituitary functions is still high, especially in patients with craniopharyngioma. Basal interhemispheric supra-chiasmal or infra-chiasmal approaches via superomedial orbitotomy were developed for better visualization of the hypothalamus. Operative techniques and results, including combination treatment with radiosurgery, are reported. Twelve patients with tumors compressing the hypothalamus upward or extending into the III ventricle, or both, were operated on: 3 tumors were removed totally, 6 tumors subtotally and 3 tumors partially. Six patients received radiosurgery for residual tumor. Four patients with hypopituitarism preoperatively required oral corticosteroids and thyroid hormones postoperatively. The basal interhemispheric approach via superomedial orbitotomy is useful for better visualization of the hypothalamus and preservation of hypothalamo-pituitary functions.

Study on the function of the basal ganglia and frontal cortex using depth microrecording and PET scan in relation to the outcome of pallidotomy for the treatment of rigid-akinesia-type Parkinson's disease.

Stereotactic posteroventral pallidotomy was carried out in 13 cases with rigid-akinesia-type Parkinson's disease with the aid of depth microrecording. The outcome of the pallidotomy was classified into four groups: excellent (6 cases), good (3 cases), moderate (3 cases) and fair (1 case). Electrophysiological study during the operation showed continuous high-frequency and high-amplitude spike discharges in the globus pallidus (GPi) in the excellent-response group. Before the operation, a PET study had revealed low regional cerebral glucose metabolism in the prefrontal area in all the patients. Unilateral sequential opposite finger movement induced less increase of regional cerebral blood flow both in the supplementary and primary motor area in the less effective-response groups. The indications of pallidotomy for the treatment of rigid-akinesia-type Parkinson's disease are discussed.

Gamma knife for glioma: selection factors and survival.

PURPOSE: To determine factors associated with survival differences in patients treated with radiosurgery for glioma. METHODS AND MATERIALS: We analyzed 189 patients treated with Gamma Knife radiosurgery for primary or recurrent glioma World Health Organization (WHO) Grades 1-4. CONCLUSION: The median minimum tumor dose was 16 Gy (8-30 Gy) and the median tumor volume was 5.9 cc (1.3-52 cc). Brachytherapy selection criteria were satisfied in 65% of patients. Median follow-up of all surviving patients was 65 weeks after radiosurgery. For primary glioblastoma patients, median survival from the date of pathologic diagnosis was 86 weeks if brachytherapy criteria were satisfied and 40 weeks if they were not (p = 0.01), indicating that selection factors strongly influence survival. Multivariate analysis showed that increased survival was associated with five variables: lower pathologic grade, younger age, increased Karnofsky performance status (KPS), smaller tumor volume, and unifocal tumor. Survival was not found to be significantly related to radiosurgical technical parameters (dose, number of isocenters, prescription isodose percent, inhomogeneity) or extent of preradiosurgery surgery. We developed a hazard ratio model that is independent of the technical details of radiosurgery and applied it to reported radiosurgery and brachytherapy series, demonstrating a significant correlation between survival and hazard ratio. CONCLUSIONS: Survival after radiosurgery for glioma is strongly related to five selection variables. Much of the variation in survival reported in previous series can be attributed to differences in distributions of these variables. These variables should be considered in selecting patients for radiosurgery and in the design of future studies.

[Automatic anatomic-physiologic correspondence of deep structures of the central nervous system in stereotaxic functional neurosurgery]. / Automatización de la correlación anatomofisiológica de las estructuras profundas del sistema nervioso central en la neurocirugía funcional estereotáxica.

This work describes in detail the graphic facilities of a neurosurgical deep recording system for the anatomic-physiologic analysis of central nervous system deep structures in stereotaxic function neurosurgery guided by deep semi-microrecordings of the brain, as developed by the International Center of Neurologic Restoration in Cuba. This system for digitization of electrical activity in the brain uses an IBM-compatible 80386/80486 microprocessor in place of analog equipment for the visualization and recording of signals, thereby providing easier manipulation of recorded data and greater flexibility of analysis. The system automatically integrates each pulse recorded and quantifies its average amplitude. For each brain region explored, the behavior of the integrated activity recorded can be displayed on the corresponding sagittal view from the cerebral atlas of Schaltenbrand-Wahren, and then automatically scaled to the anatomic dimensions of each patient. The picture, with its different options, Facilitates analysis of anatomic correspondence of deep electrophysiologic signals so the various structures, nuclei and specific neuronal groups can be precisely located in the patient's brain. To date the system has been used successfully in over 110 neurosurgical procedures ventral intermedios (vim)-thalamotomy, pallidotomy, subthalotomy and neurotransplantation, providing more certain location of lesions or grafting sites for managing symptoms in Parkinson's disease and other movement disorders.

Automatización de la correlación anatomofisiológica de las estructuras profundas del sistema nervioso central en la neurocirugía funcional estereotóxica / Automatic anatomic-physiologic correspondence of deep structures of the central nervous system in stereotaxic functional neurosurgery

Este trabajo describe en detalle las facilidades gráficas que brinda el sistema de programas NDRS (Neurosurgical Deep Recording System) para el análisis anatomofisiológico de las estructuras profundas del sistema nervioso central en la neurocirugía funcional estereotóxica guiada por semimicrorregistros profundos del cerebro, desarrollado en el Centro Internacional de Restauración Neurológica de Cuba. Este sistema de registro y procesamiento digital de la actividad eléctrica cerebral, además de permitir la sustitución con un microordenador personal 80386/80486 IBM compatible, del equipamiento electrónico de procesamiento analógico, visualización, y grabación de las señales, brinda una mayor facilidad para la manipulación de la información registrada y una mayor flexibilidad para la implementación de diferentes tipos de análisis de las señales. El sistema, como una de sus posibilidades, realiza automáticamente un proceso de integración de cada señal registrada, como cuantificación de su amplitud general. El comportamiento de esta actividad integrada puede ser mostrado a lo largo de cada trayectoria explorada dentro del cerebro, sobre la correspondiente vista sagital del atlas cerebral de Schaltenbrand-Wahren, después de una escala automática del mismo según las dimensiones automáticas de cada paciente. Este gráfico, con sus diferentes opciones, facilita el análisis de la correlaci›n anatómica de los registros electrofisiológicos profundos realizados para localizar la ubicación exacta, dentro del cerebro de cada paciente, de sus diferentes estructuras, núcleos y grupos neuronales específicos. Hasta el presente, este sistema ha sido utilizado con éxito en más de 110 intervenciones neuroquirúrgicas de núcleo ventral intermedio-talamotomías, palidotomías, subtalamotomías y neurotrasplantes, contribuyendo a aumentar la seguridad en la correcta selección de los lugares de lesión o implante para el control de los diferentes síntomas de la enfermedad de Parkinson y otros movimientos anormale (AU)

Automatización de la correlación anatomofisiológica de las estructuras profundas del sistema nervioso central en la neurocirugía funcional estereotóxica / Automatic anatomic-physiologic correspondence of deep structures of the central nervous system in stereotaxic functional neurosurgery

Este trabajo describe en detalle las facilidades gráficas que brinda el sistema de programas NDRS (Neurosurgical Deep Recording System) para el análisis anatomofisiológico de las estructuras profundas del sistema nervioso central en la neurocirugía funcional estereotóxica guiada por semimicrorregistros profundos del cerebro, desarrollado en el Centro Internacional de Restauración Neurológica de Cuba. Este sistema de registro y procesamiento digital de la actividad eléctrica cerebral, además de permitir la sustitución con un microordenador personal 80386/80486 IBM compatible, del equipamiento electrónico de procesamiento analógico, visualización, y grabación de las señales, brinda una mayor facilidad para la manipulación de la información registrada y una mayor flexibilidad para la implementación de diferentes tipos de análisis de las señales. El sistema, como una de sus posibilidades, realiza automáticamente un proceso de integración de cada señal registrada, como cuantificación de su amplitud general. El comportamiento de esta actividad integrada puede ser mostrado a lo largo de cada trayectoria explorada dentro del cerebro, sobre la correspondiente vista sagital del atlas cerebral de Schaltenbrand-Wahren, después de una escala automática del mismo según las dimensiones automáticas de cada paciente. Este gráfico, con sus diferentes opciones, facilita el análisis de la correlaciøn anatómica de los registros electrofisiológicos profundos realizados para localizar la ubicación exacta, dentro del cerebro de cada paciente, de sus diferentes estructuras, núcleos y grupos neuronales específicos. Hasta el presente, este sistema ha sido utilizado con éxito en más de 110 intervenciones neuroquirúrgicas de núcleo ventral intermedio-talamotomías, palidotomías, subtalamotomías y neurotrasplantes, contribuyendo a aumentar la seguridad en la correcta selección de los lugares de lesión o implante para el control de los diferentes síntomas de la enfermedad de Parkinson y otros movimientos anormale