Transcallosal-Transchoroidal Approach for a Symptomatic Third Ventricular Cavernous Malformation in a Pediatric Patient: Surgical Video.

Cavernous malformations of the third ventricle are rare, deep-seated lesions that pose a formidable surgical challenge due to the rich, surrounding anatomy. Despite the potential morbidity of surgical treatment, the possibility of catastrophic, spontaneous hemorrhage in this location is even more feared and aggressive treatment is warranted, especially if the patient had suffered previous hemorrhages and is currently symptomatic. We demonstrate this approach (Video 1) on a 16-year-old boy who presented with right-sided hemiparesis (power grade 4), intense headaches, difficulties with learning and concentration, and memory loss, mainly affecting short-term memory. The patient had a previous unsuccessful excision at another center 3 months after initial hemorrhage. The absence of hydrocephalus and medial thalamic location favored a modified transcallosal transchoroidal (or subchoroidal) approach. Due to the anatomy of the lesion, no other microsurgical approaches were considered. The surgery at our center (second attempt) was performed 5 months after initial hemorrhage. The head was placed in neutral position, with a slight elevation of the vertex and the midline in a vertical position. A callosotomy had already been performed during the patient's first excision attempt at another center. Although dissection through the tela choroidea is commonly performed medially to the choroidal fissure when one wants to enter the third ventricle, we chose to carefully dissect through this structure laterally, because this thalamic lesion extended almost into the ependymal surface of the third ventricle. This way, the choroidal plexus became a protective cushion for the fornix. On entering the third ventricle, a mulberry-like lesion was readily identified and the cavernoma was located. The central contents of the cavernoma were dissected initially, causing relative deflation of the lesion and more maneuverability to dissect it away from the surrounding structures. Neuromonitoring was used to avoid brainstem injury. Postoperative magnetic resonance imaging showed complete resection with no signs of hemorrhage or ischemia. The patient was discharged on postoperative day 5 with no new neurologic deficits. The patient was also able to return to school after 1 month and showed complete recovery. Unfortunately, neuropsychologic evaluation was unavailable to understand his improvement better. Microsurgical dissection images in this video are a courtesy of the Rhoton Collection, American Association of Neurological Surgeons (AANS)/Neurosurgical Research and Education Foundation (NREF).

Surgical Approaches to the Temporal Horn: An Anatomic Analysis of White Matter Tract Interruption.

BACKGROUND: Surgical access to the temporal horn is necessary to treat tumors and vascular lesions, but is used mainly in patients with mediobasal temporal epilepsy. The surgical approaches to this cavity fall into 3 primary categories: lateral, inferior, and transsylvian. The current neurosurgical literature has underestimated the interruption of involved fiber bundles and the correlated clinical manifestations. OBJECTIVE: To delineate the interruption of fiber bundles during the different approaches to the temporal horn. METHODS: We simulated the lateral (trans-middle temporal gyrus), inferior (transparahippocampal gyrus), and transsylvian approaches in 20 previously frozen, formalin-fixed human brains (40 hemispheres). Fiber dissection was then done along the lateral and inferior aspects under the operating microscope. Each stage of dissection and its respective fiber tract interruption were defined. RESULTS: The lateral (trans-middle temporal gyrus) approach interrupted "U" fibers, the superior longitudinal fasciculus (inferior arm), occipitofrontal fasciculus (ventral segment), uncinate fasciculus (dorsolateral segment), anterior commissure (posterior segment), temporopontine, inferior thalamic peduncle (posterior fibers), posterior thalamic peduncle (anterior portion), and tapetum fibers. The inferior (transparahippocampal gyrus) approach interrupted "U" fibers, the cingulum (inferior arm), and fimbria, and transected the hippocampal formation. The transsylvian approach interrupted "U" fibers (anterobasal region of the extreme capsule), the uncinate fasciculus (ventromedial segment), and anterior commissure (anterior segment), and transected the anterosuperior aspect of the amygdala. CONCLUSION: White matter dissection improves our knowledge of the complex anatomy surrounding the temporal horn. Identifying the fiber bundles at risk during each surgical approach adds important information for choosing the appropriate surgical strategy.

Microsurgical treatment for arteriovenous malformation of the corpus callosum and choroidal fissure.

The management of arteriovenous malformations (AVMs) of the corpus callosum and choroidal fissure is challenging because they commonly receive arterial feeders from the anterior and posterior circulation, and drain to deep veins. In this video the authors present the case of a 20-year-old man who presented with acute onset of headache, loss of consciousness, and nuchal rigidity. Computed tomography, MRI, and cerebral angiography performed in tandem revealed a ruptured, large, Grade IV AVM of the corpus callosum and choroidal fissure with two groups of arterial feeders: one from the pericallosal artery and the other from the medial and lateral posterior choroidal arteries. The treatment strategy included two stages. The first stage involved preoperative embolization of the arterial feeders from the posterior circulation, which promoted reduction of the nidus flow of the AVM. The second involved a microsurgical resection, using the interhemispheric approach, with the patient in the prone position, which allowed accessing the anterior circulation feeders and the complete resection of the AVM, without associated morbidity. The video can be found here: https://youtu.be/5wcYKhcJtls .

Extreme aplasia cutis congenita involving the skull.

Aplasia cutis congenita (ACC) is a rare congenital malformation of primarily the skin; it is most commonly seen on the scalp but can occur anywhere on the body. The exact etiology is still unclear but there are many suggested causes. Classification systems have been proposed to help categorize patients and assist with treatment. Treatment options are controversial and range from conservative to surgical interventions. We report an extreme case of ACC that included a significant part of the skull. We discuss this case and review salient literature. Although such cases of ACC with bony involvement are rare, this aspect of the pathology should be kept in mind when treating or imaging such patients.

Callosotomía: técnicas, resultados y complicaciones: revisión de la literatura / Callosotomy: techniques, results and complications: literature review

Background: Patients with intractable seizures who are not candidates for focal resective surgery are indicated for a palliative surgical procedure, the callosotomy. This procedure is based on the hypothesis that the corpus callosum is an important pathway for interhemispheric spread of epileptic activity and, for drug resistant epilepsy. It presents relatively low permanent morbidity and an efficacy in the control of seizures. Based on literature, the corpus callosotomy improves the quality of life of patients that has the indication to perform this procedure because it allows reducing the frequency of seizures, whether tonic or atonic, tonic-clonic, absence or frontal lobe complex partial seizures. Aim: The aim of this literature review is discuss the technical details, modalities, risks, complications, results as well de prognosis of callosotomy based on critical literature review and the authors experience. Casuistry and Methods: It was performed bibliographical consultation, using the databases MEDLINE, LILACS, SciELO, utilizing language as selection criteria, choosing preferably recent articles in Portuguese, Spanish or English, with publication year higher than 2000. Conclusion: According to author’s experience and references, callosotomy is a safe procedure when indicated to selected cases and the success rate is proportional to the extent of callosal resection. A greater resection can reduce the seizure frequency, however the morbidity may also be larger. There is no important study comparing VNS versus Callosotomy versus VNS plus callososotomy, what would be for future necessary for an important source of data about this topic.

Introducción: Los pacientes con convulsiones intratables que no son candidatos para la cirugía de resección focal están indicados para un procedimiento quirúrgico paliativo, la callosotomía. Este procedimiento se basa en la hipótesis de que el cuerpo calloso es una importante vía para la propagación interhemisférica de la actividad epiléptica y, para la epilepsia resistente a fármacos. Presenta relativamente baja morbilidad permanente y una eficacia en el control de las convulsiones. Sobre la base de la literatura, la callostomía mejora la calidad de vida de los pacientes que tiene la indicación para realizar este procedimiento, ya que permite reducir la frecuencia de las crisis, ya sean tónica o átona, tónico-clónicas, ausencia o lóbulo frontal crisis parciales complejas. Objetivo: El objetivo de esta revisión de la literatura es discutir los detalles técnicos, modalidades, riesgos, complicaciones, resultados y de pronóstico de callosotomía basado en la revisión crítica de la literatura y la experiencia de los autores. Casuística y Métodos: Se realizó la consulta bibliográfica, utilizando la base de datos MEDLINE, LILACS, SciELO, que utiliza el lenguaje como criterios de selección, la elección de los artículos recientes preferiblemente en portugués, español o Inglés, con el año de publicación superior a 2000. Conclusión: De acuerdo con la experiencia y las referencias del autor, callosotomía es un procedimiento seguro cuando indicado para casos seleccionados y la tasa de éxito es proporcional a la extensión de la resección del cuerpo calloso. A mayor resección puede reducir la frecuencia de las crisis, sin embargo, la morbilidad puede ser también mayor. No hay ningún estudio que compara la estimulación del nervio vago frente a frente callosotomía VNS más callososotomy, lo que sería la futura necesaria para una importante fuente de datos sobre este tema.

Dietary therapy is not the best option for refractory nonsurgical epilepsy.

The ketogenic diet (KD) is currently a well-established treatment for patients with medically refractory, nonsurgical epilepsy. However, despite its efficacy, the KD is highly restrictive and constitutes a treatment with serious potential adverse effects, and often with difficulties in its implementation and compliance. Patients on the KD require strict follow-up and constant supervision by a medical team highly experienced in its management in order to prevent complications. Other alternative treatments for patients with refractory epilepsy include vagus nerve stimulation (VNS), new-generation antiepileptic drugs (AEDs), corpus callosotomy (CC), and responsive focal cortical stimulation (RNS). In this review, we explain not only the difficulties of the KD as a therapeutic option for refractory epilepsy but also the benefits of other therapeutic strategies, which, in many cases, have proven to have better efficacy than the KD itself.

Resultados de callosotomía en adultos con diagnóstico de epilepsia refractaria y drop-attack / Callosotomy results in adults with diagnosis of refractory epilepsy and drop-attack

Introduction: For patients with refractory epilepsy patients, the sub-group characterized for seizures involving falls or drop-attack, the technique of callosotomy, as a palliative measure has been validated and used to control this type of seizures. Method: Group of 16 patients operated during period of four years, evaluated by protocol, which was performed as a palliative callosotomy crisis management technique was evaluated. Results: The observed group, 10 were males and 6 females, mean age 30 years, range between 19-46 years. Average evolution of epilepsy in 20.8 years, 14 cases crisis was starting before age 14. Major crises were TCG (generalized tonic clonic) and a tonic seizures were being 62.5 percent daily and 37.5 percent monthly, 100 percent had a history of TEC (brain trauma) and 56 percent history of status epilepticus. Was performed anterior callosotomy two thirds in 8 patients (mean follow-up 23.8 months), 6 patients complete callosotomy (average follow-up 15.5 months), and in 2 cases, two anterior thirds and then total callosotomy (1 case 22 months, and another 1 month follow-up). Seizures management fall > 50 percent in 75 percent of patients (3 cases without seizures of fall with anterior callosotomy two thirds), and for complete callosotomy, 100 percent control crisis in > 80 percent of patients (3 cases without seizures of fall was found in this group). Conclusion: The technique callosotomy as a palliative measure in the context of drop-attack or crises involving falls, in our experience with adult patients, has been a good tool in controlling this type of seizures.

Introducción: Dentro del grupo de pacientes refractarios en epilepsia, el sub-grupo caracterizado por crisis que involucran caídas o drop-attack, la técnica de callosotomía, como medida paliativa, ha sido validada y utilizada para el control de este tipo de crisis. Método: Se evaluó grupo de 16 pacientes adultos operados durante período de 4 años, evaluados por protocolo, donde se realizó callosotomía como técnica paliativa de control de crisis. Resultados: Del grupo observado, 10 fueron varones, 6 mujeres, promedio de edad 30 años, rango entre 19 a 46 años. Promedio de evolución de epilepsia de 20,8 años. En 14 casos el inicio de crisis fue antes de los 14 años. Principales crisis fueron TCG (tónico clónico generalizada) y atónicas, siendo en el 62,5 por ceinto diarias y en el 37,5 por ciento mensuales, el 100 por ceinto tenía antecedente de TEC (trauma encéfalo craneano) y en el 56 por ciento antecedente de status epiléptico. Se realizó callosotomía dos tercios anterior en 8 pacientes (seguimiento 23,8 meses promedio), 6 pacientes callosotomía total (seguimiento 15,5 meses promedio), y en 2 casos, dos tercios anterior y luego callosotomía total (1 caso 22 meses, y otro, 1 mes de seguimiento). Se encontró control de crisis de caídas > 50 por ciento en el 75 por ciento (3 casos sin crisis) de casos con callosotomía dos tercios anterior, para callosotomía completa, 100 por ciento control de crisis en > 80 por ciento (3 casos sin crisis) de este grupo. Conclusión: La técnica de callosotomía como medida paliativa en el contexto de drop-attack o crisis que involucren caídas, en nuestra experiencia en pacientes adultos, ha sido una herramienta útil en el control de este tipo de crisis.

Acute effect of callosotomy on cortical temporal coupling in humans: intraoperative electrocorticographic recording.

OBJECTIVE: To investigate the acute role of the corpus callosum in inter- and intrahemispheric temporal coupling. METHODS: Intraoperative electrocorticography (ECoG) makes it possible to investigate the acute role of the corpus callosum in cortical temporal coupling, or synchrony, without additional surgical intervention, thus avoiding the confounding effects of scalp recordings and the long-term reorganization of functional connectivity. ECoGs were recorded in three patients during callosotomies. Bilateral electrode grids were placed over the frontal cortex. ECoGs were recorded immediately before and after performing the anterior two-thirds callosal transection, were digitalized at a sampling rate of 512Hz, inspected for artifacts, and later analyzed offline. Cross-correlation between inter- and intrahemispheric electrode pairs were obtained for 1Hz bins and special broad bands obtained by principal component analysis for each patient pre- and post-callosotomy. RESULTS: A statistically significant change was observed in intrahemispheric temporal coupling between electrode pairs that exceeded the confidence limit of correlation. CONCLUSIONS: Present results show that interrupting the influence of the corpus callosum has an acute effect on intrahemispheric activity by decreasing temporal coupling between cortical areas. SIGNIFICANCE: Intrahemispheric temporal coupling does not depend exclusively on ipsilateral cortico-cortical pathways or on subcortical influences, but also on callosal pathways.

Corpus callosotomy in a patient with startle epilepsy.

Startle epilepsy is a syndrome of reflex epilepsy in which the seizures are precipitated by a sudden and surprising, usually auditory, stimulus. We describe herein a girl who had been suffering with startle-induced seizures since 2 years of age. She had focal, tonic and tonic-clonic seizures, refractory to antiepileptic treatment. Daily tonic seizures led to very frequent falls and morbidity. Neurologically, she had no deficit. Interictal EEG showed slow waves and epileptiform discharges in central and fronto-central regions. Video-polygraphic recordings of seizures, triggered by stimuli, showed generalised symmetric tonic posturing with ictal EEG, characterised by an abrupt and diffuse electrodecremental pattern of fast activity, followed by alpha-theta rhythm superimposed by epileptic discharges predominantly over the vertex and anterior regions. Magnetic resonance imaging showed no abnormalities. Corpus callosotomy was performed when the patient was 17. Since surgery, the patient (one year follow-up) has remained seizure-free. Corpus callosotomy may be considered in patients with startle epilepsy and tonic seizures, in the absence of focal lesions amenable to surgery. [Published with video sequences].

Long-term outcome after callosotomy or vagus nerve stimulation in consecutive prospective cohorts of children with Lennox-Gastaut or Lennox-like syndrome and non-specific MRI findings.

PURPOSE: There is currently no resective (potentially curative) surgical option that is useful in patients with Lennox-Gastaut syndrome. Palliative procedures such as callosotomy (Cx), vagus nerve stimulation (VNS) or deep brain stimulation have been offered. We compared the outcomes after Cx or VNS in two consecutive prospective cohorts of patients with generalised epilepsy. METHODS: Twenty-four patients underwent callosotomy from 2006 to 2007 (Group 1); 20 additional patients were submitted to VNS from 2008 to 2009 (Group 2). They had generalised epilepsy of the Lennox-Gastaut or Lennox-like type. They were submitted to a neurological interview and examination, interictal and ictal video-EEG, high resolution 1.5T MRI, and cognitive and quality of life evaluations. The two-year post-operative follow-up results were evaluated for each patient. RESULTS: The final mean stimuli intensity was 3.0 mA in the Group 2 patients. Seizure-free patients accounted for 10% in Group 1 and none in Group 2. Ten and sixteen percent of the Group 1 and 2 patients, respectively, were non-responders. Improvements in attention and quality of life were noted in 85% of both Group 1 and 2 patients. Rupture of the secondary bilateral synchrony was noted in 85% of Group 1 patients; there was no EEG modification after VNS in Group 2. Both procedures were effective regarding the control of atypical absences and generalised tonic-clonic seizures. Both procedures were not effective in controlling tonic seizures. Callosotomy was very effective in reducing the frequency of atonic seizures, but VNS was ineffective. In contrast, callosotomy was not effective in reducing myoclonic seizures, whereas VNS was. DISCUSSION: Callosotomy might be preferred as the primary treatment in children with Lennox-Gastaut syndrome, and no specific findings on MRI if atonic seizures prevail in the patient's clinical picture; when myoclonic seizures prevail, the same might hold true in favour of VNS. When atypical absence or generalised tonic-clonic seizures are the main concern, although both procedures carry similar effectiveness, VNS might be considered a good option as an initial approach, taking into account the adverse event profile. Patients should be advised that both procedures are not very effective in the treatment of tonic seizures.

Diffusion tensor imaging in radiosurgical callosotomy.

Callosotomy by radioneurosurgery induces slow and progressive axonal degeneration of white matter fibers, a key consequence of neuronal or axonal injury (radionecrosis). However, the acute effects are not apparent when using conventional MRI techniques. Diffusion tensor imaging (DTI) during the first week following radioneurosurgical callosotomy allowed evaluation of these microstructural changes. The present report details that the use of sequential DTI to evaluate axonal degeneration following radioneurosurgical callosotomy in a patient normalized with the data of six healthy subjects. We describe a 25-year old woman with symptomatic generalized epilepsy who underwent a radioneurosurgical callosotomy using LINAC (Novalis® BrainLAB). DTI was acquired at the baseline, 3 and 9 months and showed a progressive decrease of the fractional anisotropy values in the irradiated areas compared to the controls that could be interpreted as a progressive disconnection of callosal fibers related to the outcome.

Parkinsonism induced by VNS in a child with double-cortex syndrome.

We describe a child with epilepsy associated with double-cortex syndrome in whom vagus nerve stimulation (VNS) generated parkinsonian symptoms. A 13-year-old girl presented with refractory secondary generalized epilepsy from the age of 6 years and mental retardation. Her electroencephalography (EEG) showed diffuse polyspike and wave discharges. Magnetic resonance imaging (MRI) showed double-cortex syndrome. She was submitted to extended callosal section at the age of 10 years, which yielded 50% seizure frequency reduction. She was submitted to VNS by the age of 12 years. As stimulation intensity was increased, there was appearance of extrapyramidal symptoms: She developed bilateral tremor and rigidity, and gait and postural disturbance. All symptoms disappeared 7-10 days after VNS was turned off. Several attempts to reactivate VNS led to the same results. During the periods when VNS was on she presented with marked seizure frequency reduction. This is the first report of a clinically evident direct effect of VNS on the basal ganglia.

Outcome after extended callosal section in patients with primary idiopathic generalized epilepsy.

PURPOSE: We report the outcome of patients with refractory idiopathic generalized epilepsy (IGE) who were submitted to extended one-stage callosal section. METHODS: Eleven patients with IGE who were submitted to extended one-stage callosal section were studied. Preoperative workup included history and neurologic examination, interictal, and ictal electroencephalography (EEG) recording, high resolution 1.5T magnetic resonance imaging (MRI) and intelligence quotient (IQ) testing. All patients were submitted to extended one-stage microsurgical callosal section, leaving only the splenium intact. RESULTS: Preoperative ictal patterns included repetitive spike and wave or polyspike and wave discharges or fast epileptic recruiting rhythm. MRI showed no focal lesions. Preoperatively, mean general IQ was 85. Postoperatively, at least a 75% reduction in the frequency of generalized tonic-clonic seizures was noted in all patients. In three patients absences disappeared completely, and the others had at least 90% reduction in seizure frequency. Only one patient had myoclonic seizures preoperatively, and these seizures disappeared after callosal section. After surgery, mean general IQ was 89. A very clear increase in attention level was noted in all patients. Postoperative interictal EEG recordings showed rupture of bilateral synchrony in all patients. DISCUSSION: This article reports on a large and homogeneous series of patients with refractory IGE submitted for callosal section. There was a marked decrease in generalized seizure frequency and increase in the attention level in this patient population. Our results suggest that corticocortical interaction might have a role in IGE pathogenesis. Callosotomy is a safe, effective, and underused palliative procedure in these well-selected patients with refractory IGE.

[Deep-seated (corpus callosum, intraventricular, basal ganglia and insula) and brain stem cavernous angiomas. Experience in Brazil]. / Cavernomes profonds (corps calleux, intraventriculaires, ganglions de la base, insulaires) et du tronc cérébral. Expérience d'une série brésilienne.

With a review of the literature, we report our experience with surgical treatment of deep-seated cavernomas (intraventricular, of the corpus callosum, the capsula interna, the insula and the brain stem). Outcome was good in all nine patients after surgery for deep-seated brain cavernomas. There we also 13 cases of the brain stem cavernomas treated surgically. Of them, nine patients were stabilized or improved, one patient worsened, one patient died and two were lost to follow-up. Whatever the location, surgery should only concern symptomatic or hemorrhagic lesions close to the pia-matter or the ependyma as well as those covered by a thin layer of parenchyma. Neuronavigation and microsurgical procedures are essential in the treatment of deep-seated cavernomas.

Role of corpus callosum in interhemispheric coherent activity during sleep.

OBJECTIVE: To investigate to what extent the increase in interhemispheric coherent activity observed from wakefulness to sleep depends on the integrity of the corpus callosum (CC). METHODS: Interhemispheric coherent activity was analyzed in two epileptic patients selected for callosotomy because of multifocal refractory epilepsy, before and 4 months after callosotomy. One patient underwent complete callosotomy and another was subjected to callosotomy of the anterior 2/3, which offered the possibility of comparing the role of the CC in the coherent activity increase from wakefulness to sleep, between anterior regions with interrupted CC communication (in the two patients) and posterior regions with intact communication (in one of them). Results were compared with a group of normal subjects. RESULTS: Both patients showed increased coherent activity from wakefulness to sleep after surgery. CONCLUSIONS: Results demonstrate that interhemispheric coherent activity, despite an attenuation after surgery, is higher during SWS than during wakefulness after sectioning the CC; however, they have to be taken with caution because they come from two patients only. SIGNIFICANCE: Present results show that the increase in coherent activity during sleep does not depend exclusively on callosal integrity but also on state-dependent influences from sleep-promoting mechanisms, probably spread throughout the thalamo-cortical network.

Early callosal absence disrupts the establishment of normal neocortical structure in Swiss mice.

In the present study, we tested the hypothesis that the ontogenetic development of the corpus callosum is relevant for the establishment of a normal neocortical structure. To that effect, neocortical morphology (thickness and neuronal density) was analyzed in adult Swiss mice rendered acallosal by midline transection at the first postnatal day (Acallosal group) and in non-manipulated mice. The neocortical thicknesses and neuronal densities of layers II+III through VI were measured in area 6 and at the 17/18a border, both of which present abundant callosal inputs, and in the relatively acallosal area 17. For the thickness measure, significant differences between Non-manipulated and Acallosal groups were only found in the areas that receive massive callosal connections. In area 6, Acallosal mice presented a reduced thickness of layer V, while at the 17/18a border, these mice presented a reduced thickness of layers II+III when compared to non-manipulated ones. No statistical difference between acallosal and non-manipulated mice was found regarding the neuronal density measure. The reduced cortical thickness associated with a comparatively normal neuronal density in neocortical regions which normally have abundant callosal connections suggest a reduction in the number of cortical neurons in acallosal mice. Altogether, the present data indicate that the input provided by callosal axons is necessary for the normal development of the neocortex.

Abordaje interhemisferico transcalloso. Resultados quirurgicos / Interhemispheric transcallosal approach. Surgical results

Objetivos: evaluar aplicaciones y resultados de uso de la via interhemisferica trancallosa. Analizar los detalles del manejo quirurgico obtenido en lesiones de los ventriculos laterales, III ventriculo y cara ventricular talamica. Metodo: Veintitres abordajes transcallosos fueron aplicados en dieciocho pacientes entre enero de 1995 y enero de 2003. Se revisaron las historias clinicas, partes quirurgicos e imagenes obtenidas en el pre y postoperatorio (18 TAC y 13 IRM al diagnostico); se evaluaron la extension de callosotomia y los hallazgos quirurgicos. Se compararon los resultados anatomopatologicos en casos de repeticion del procedimiento. Resultados: la edad promedio fue de : 6 años (3-17 años). Se realizaron 23 procedimientos. En cuatro pacientes se repitio el abordaje (un astrocitoma pilocitico en dos oportunidades, un cavernoma tambien en dos y una MAV en una). Nueve tumores solidos, un quiste coloideo y un craneofaringioma ubicados en el III ventriculo fueron explorados por via transforaminal. Tres tumores talamicos se resecaron desde la cara ventricular, uno con la variante transcoroidea. Dos tumores de la prolongacion frontal fueron resecados desde la callosotomia. En una MAV la callosotomia se utilizo para control y reseccion de grenajes profundos. Anatomia patologica: 7 astrocitomas pilociticos, 3 glioblastomas, 1 papiloma de plexo coroideo, 1 neurocitoma, 1 ependimoma, 1 germinal mixto, 1 cavernoma, 1 quiste coloideo, 1 craneofaringioma y 1 MAV. Se realizaron: 10 resecciones completas, 7 subtotales, 5 parciales. Dos pacientes presentaron deterioro neuropsicologico postquirurgico: uno portador de Astrocitoma talamico; el otro fue un niño con papiloma de plexos coroideos con hidrocefalia persistente. Conclusion: la minima incision neural de la callosotomia permite resecciones amplias sin agregar lesion, aun con la repeticion del procedimiento. La extension de la callosotomia resulto ser mayor en IRM que la estimacion del cirujano. No se necesitaron secciones de fornix ni coagulacion venosa ya que el agradamiento del Foramen de Monro es suficiente para la exploracion (AU)

Aspectos anatomicos del abordaje transcalloso - interfornicial / Anatomic aspects of trans-callosum inter-fornicial approach

El presente estudio esta dirigido a analizar las indicaciones y anatomia quirurgica del abordaje transcalloso - interfornicial al IIIer ventriculo. El adecuado conocimiento de la relacion anatomica existente entre el cuerpo callos , el septum lucidum y el fornix permite llevar a cabo estos procedimientos sin comprometer significativamente a esas estructuras, evitando secuelas neuropsicologicas irreversibles (AU)

Corpus callosotomy in Colombia and some reflections on care and research among the poor in developing countries.

The authors present the results of a series of corpus callosotomies (CCS) in 97 patients performed from 1989 to 1997 at the Hospital Neurologico of the Liga Colombiana Contra La Epilepsia, Cartagena, Colombia. This study demonstrates the feasibility of performing these procedures in the developing world and analyzes the outcome and cost of treatment. Patients with medically intractable secondarily generalized epilepsy, bilateral nonfocal epileptic electroencephalogram (EEG), and absence of progressive encephalopathy were accepted as candidates (patients aged 0-30 years; 62 children, 19 girls and 43 boys, with mean age at surgery of 7.9 years; 35 adults, 19 women and 16 men, with mean age at surgery of 25.8 years). Preoperatively, the mean seizure frequency was 12.1 per day, or 364 per month (range, 0.06-200 per day, 1.8-6000 per month). Before surgery, 40% of patients were classified with generalized tonic-clonic seizures of different etiologies, or cryptogenic seizures; 36% had mixed seizures; 19% had Lennox-Gastaut Syndrome; and 5% had West Syndrome. Usually, routine EEG, computed tomography, and clinical findings sufficed for the surgical decision. The standard microsurgical technique performed was an anterior two-thirds CCS by the same surgeon under general anesthesia. In five cases, an additional frontal lobe excision after electrocorticography and subdural electrode monitoring was carried out in the same session. The results were evaluated after a mean follow-up of 35 months (range, 12-28). Two thirds of patients became seizure-free or were left with none or some disabling seizures. AED medication was eased slightly after surgery. The complication rate was low. The patients underwent postoperative psychosocial studies and neuropsychological rehabilitation and showed tendencies toward improvement. The direct cost of CCS in U.S. dollars (US$) ranged between 3,137 and 3,995 depending on the preoperative studies. Thus, CCS is well suited for selected patients in developing countries. Thus far, implantation of a vagus nerve stimulator has exceeded our economic possibilities in treating similar patients. Some reflections on care and research among epilepsy patients in developing countries are discussed.

Comparison of the epilepsy surgery programs in Cartagena, Colombia, and Zürich, Switzerland.

The organization, financing, productivity, quality of work, and cost-effectiveness of the Epilepsy Center in Cartagena, Colombia, were studied and compared with the epilepsy surgery program at the University Hospital Zürich, Switzerland. During a 2-month visit, one of the authors (I.T.) evaluated the center in Cartagena as a welfare institution and evaluated its epilepsy surgery program. The postoperative results of the Cartagena program were compared with those reported at the Second International Palm Desert Conference 1992, which revealed a similar rate of postoperative seizure control in temporal lobe epilepsy, slightly inferior results with hemispherectomy, and slightly better results with anterior callosotomy. A comparison between the two epilepsy centers showed that pre and postoperative antiepileptic drug treatment is more restricted in Colombia because of high costs. Although important diagnostic tools such as electroencephalography, seizure monitoring, neuropsychology, computed tomography, and magnetic resonance imaging are available in both centers, the Zürich program also has access to positron emission tomography, single photon emission computed tomography, magnetic resonance spectroscopy, and intracarotid and selective amobarbital tests. The postoperative seizure outcome is similar in surgical temporal lobe epilepsy patients (temporal lobectomy series, Cartagena; selective amygdalohippocampectomy series, Zürich). The comparison of direct costs of epilepsy surgery in Cartagena and Zürich showed that for the average patient undergoing epilepsy surgery in Cartagena, the cost is 5.5% of that in Zürich. This study presents evidence that epilepsy surgery is an inexpensive and efficient treatment option for epilepsy patients in developing countries. Epilepsy surgery in developing countries may even be considered at an early stage in patients who cannot afford the costs of lifetime medical treatment but can afford the one-time cost of a surgical treatment.