From Resection to Disconnection for Seizure Control in Pediatric Epilepsy Children

Epilepsy surgery revealed dramatically improved seizure outcomes over medical therapy in drug-resistant epilepsy patients. Children with epilepsy, however, have multiple epileptic focuses which require multilobar resection for better seizure outcome. Multilobar resection has not only the several severe surgical complications, such as hydrocephalus and shunt-related craniosynostosis, due to intracranial volume reduction. Isolation method (disconnection surgery) was progressively studied over epileptic focus removal (resective surgery) for seizure control. This concept was first introduced for functional hemispherotomy, and its primary principle is to preserve the vital vascularized brain that is functionally disconnected from the contralateral healthy brain. Currently in most epilepsy centers, the predominant disconnection surgical methods, including functional hemispherotomy, are continually being refined and are showing excellent results. They allow the functional isolation of the hemisphere or multi-lobe, affected by severe epilepsy. This review describes recent findings concerning the indication, surgical technique, seizure outcome and complications in several disconnection surgeries including the functional hemispherotomy for refractory pediatric epilepsy.

From Resection to Disconnection for Seizure Control in Pediatric Epilepsy Children

Epilepsy surgery revealed dramatically improved seizure outcomes over medical therapy in drug-resistant epilepsy patients. Children with epilepsy, however, have multiple epileptic focuses which require multilobar resection for better seizure outcome. Multilobar resection has not only the several severe surgical complications, such as hydrocephalus and shunt-related craniosynostosis, due to intracranial volume reduction. Isolation method (disconnection surgery) was progressively studied over epileptic focus removal (resective surgery) for seizure control. This concept was first introduced for functional hemispherotomy, and its primary principle is to preserve the vital vascularized brain that is functionally disconnected from the contralateral healthy brain. Currently in most epilepsy centers, the predominant disconnection surgical methods, including functional hemispherotomy, are continually being refined and are showing excellent results. They allow the functional isolation of the hemisphere or multi-lobe, affected by severe epilepsy. This review describes recent findings concerning the indication, surgical technique, seizure outcome and complications in several disconnection surgeries including the functional hemispherotomy for refractory pediatric epilepsy.

La Insulectomía podría ser un abordaje ideal para crisis insulares y peri-insulares? / Insulectomy for insular and peri-insular seizures could be an ideal and safe approach?

La insulectomía es una técnica microquirúrgica establecida para el tratamiento de la epilepsia refractaria al tratamiento farmacológico. El origen insular de la epilepsia es inusual, sin embargo, con la investigación a través de electrodos híbridos este tipo de epilepsia ha incrementado su diagnóstico. Los autores hacen hincapié en las funciones insulares, así como los puntos de referencia anatómicos para la cirugía. Se discuten las principales complicaciones y las bases fisiológicas para las indicaciones de cirugía.

Insulectomy is an established microsurgical technique for treatment of insular epilepsy refractory to clinical management. The insular origin of epilepsy is unusual, however with depth investigation through hybrids electrodes such kind of epilepsy is increasing its diagnosis. The authors emphasizes the insular functions as well as the anatomical landmarks for surgery. The main complications are discussed and physiological basis for indications.

Possible roles of COX-1 in learning and memory impairment induced by traumatic brain injury in mice

People who suffer from traumatic brain injury (TBI) often experience cognitive deficits in spatial reference and working memory. The possible roles of cyclooxygenase-1 (COX-1) in learning and memory impairment in mice with TBI are far from well known. Adult mice subjected to TBI were treated with the COX-1 selective inhibitor SC560. Performance in the open field and on the beam walk was then used to assess motor and behavioral function 1, 3, 7, 14, and 21 days following injury. Acquisition of spatial learning and memory retention was assessed using the Morris water maze on day 15 post-TBI. The expressions of COX-1, prostaglandin E2 (PGE2), interleukin (IL)-6, brain-derived neurotrophic factor (BDNF), platelet-derived growth factor BB (PDGF-BB), synapsin-I, and synaptophysin were detected in TBI mice. Administration of SC560 improved performance of beam walk tasks as well as spatial learning and memory after TBI. SC560 also reduced expressions of inflammatory markers IL-6 and PGE2, and reversed the expressions of COX-1, BDNF, PDGF-BB, synapsin-I, and synaptophysin in TBI mice. The present findings demonstrated that COX-1 might play an important role in cognitive deficits after TBI and that selective COX-1 inhibition should be further investigated as a potential therapeutic approach for TBI.

Functional hemispherectomy variant a report of twenty one cases / Functional hemispherectomy variant a report of twenty one cases

Objective and importance: Although Rasmussen´s hemispherectomy is a proven effective technique, the reduction in surgical time and in blood volume los during its performance is crucial. This is achieved by means of the tecnichal variant intended to disconnect instead of to remove the temporal lobe. Clinical representation: We present 21 children operated between 1997 and 2004 in whom a functional hemisfactory (FH) variant was performed. The clinical manifestations included the following crises: hemianopsia, versive crises, abscences, CPC and tonic crises, with secondary generalization in some of the children. Intervention: The proposed variant is a sort of combination of Rasmussen´s hemispherectomy and Delalande´s hemispherectomy, involving disconnection and isolation of the temporal lobe. This is achieved at cortical level by prolonging the incision of the mesial aspect of the occipital lobe by intraventricular route is extended towards the fornix to reach the free border of the cerebellar tentorium. The juncture of both incisions disconnects the neocortex from the temporal lobe, as well as the parahippocampal gyrus and the hippocampus itself. Since aprevious complete callosotomy, a temporal stem section and amigdala suction had been performed, the temporal lobe remains in situ, but nonfunctional. Conclusion: It is the autor conviction that Rasmussen´s hemipherectomy is a valid procedure given its proven efficacy. We believe that the proposed technical variant is particularly useful for neurosurgeons that are in training in the field of epilepsy surgery, as a priori stage to the use of more restricted disconnecting techniques

Neuroplasticidad y adaptación funcional del sistema nervioso: aproximación a la anatomía funcional del tronco cerebral / Neuroplasticity and funcional supply of nervous system: aproximation to brain stem funcional anatomy

Se revisa las últimas investigaciones sobre plasticidad neuronal, en relación con el crecimiento dendrítico y la regeneración de los cilindroejes en la suplencia funcional de la corteza cerebral y el sistema estriado en la reorganización de las funciones superiores. Se recuerda la importancia de las funciones del tronco cerebral en el hombre y se propone una nueva sistematización: el Arqui-tronco, en relación a sus funciones vegetativas, el Paleo-tronco, en relación con el hombre y su medio ambiente y el Neo-tronco, cuyas funciones aún desconocemos. En fin, se presenta la observación de una paciente decorticada mediante la evaluación clínica y la resonancia magnética que, sin embargo, mantiene sus funciones de percepción y elaboración de juicios y criterios; la expresión de estos la ejecuta mediante gritos.

Ether and immobilization stress effects on pituitary adrenal function in hemidecorticate rats

Hemidecortication (HD) (left cerebral hemisphere) performed in rats with the aim of analyzing the modulating effect of the cerebral cortex on the hypothalamic-pituitary-adrenal axis. Corticosterone release induced either by or immobilization stress was evaluated in control (C) and HD rats. The percentage increase in corticosterone was greater in HD than in C rats after 15 min of ether stress (HD = 142%, C = 50%) and after 60 min of immobilization stress (HD = 197%, C = 126%). An in vitro test showed that the release of ACTH induced by corticotropin releasing hormone (CRH) from hemipituitary fragments from HD rats was not different from that in control rats. These results suggest an inhibitory effect of the cerebral cortex on the hypothalamus which may modulate the secretion of corticoptropin releasing peptides

Swimming escape learning in rats with telencephalic lesions

Experiments were conducted to determine whether rats having unilateral or bilateral ablation of either the neocortex or telencephalon can learn to escape from a tank of water by climbing a platform. Hemi - or bilaterally decorticated rats were able to learn the swimming escape task, the same being observed for hemidetelencephalated rats. Fully detelencephalated rats, however, did not exhibit this capability. These results show that integrity of one the cerebral hemispheres is necessary in order to allow swimming escape learning

Increased susceptibility of detelencephalated rats to audiogenic seizures induced by microinjection of bicuculline into the inferior colliculus

The participation of telencephalic forebrain structures in the induction of audiogenic seizure (AGS) susceptibility and in the behavioral expression of AGS was investigated in rats. Rats that were initially susceptible (N = 12) or non-susceptible (N = 28) to audiogenic seizure were surgically detelencephalated. A unilateral microinjection of a low dose (30 pmol) of the GABA antagonist bicuculline methiodide (BM) was applied to the inferior colliculus (IC) before the animals were exposed to a 120-dB acoustic stimulus. All susceptible rats still exhibited all components of audiogenic seizure after removal of the telencephalon. After BM microinjection, a higher incidence (66% vs 41%) and shorter latencies (6-20 s vs 9-55) s) of occurrence of tonic seizures were observed in the detelencephalated non-susceptible rats when compared to non-operated non-susceptible rats(N = 12). These results suggest that the induction of the behavioral expression of audiogenic seizures issubserved by brain stem neuronal networks but does not require the telencephalon and that telencephalic structures may exert control over audiogenic seizures by inhibiting IC cells through GABAergic neurons

Hemisferectomia: modificaçäo técnica / Hemisferectomy: a techinical modification

Os autores relatam uma modificaçäo técnica nas hemisferectomias totais, com intuito de prevenir os sangramentos tardios e distorçöes cerebrais

Thyroid function in hemidecorticate rats

1. Throid function was evaluated in hemidecorticate (HD) and control (C) rats by determining serum T3 and T4 levels and the development of incisors and mandibles and through analysis of various histological features of the thyroid such as follicle size, colloid droplet content and [3H] - glycine uptake by follicular cells. 2. HD animals presented normal levels of circulating T3 but significantly lower T4 levels. 3. There was slight atrophy of the gland in HD animals and fewer colloid droplets were present in the cytoplasm of the follicular cells in this group, indicating a reduction in the breakdown of thyroglobulin. [3H] - glycine uptake by HD indicated that rate of thyroglobulin biosynthesis was not altered in the experimental animals. 4. the growth of mandibles (weight) and incisors (weight and lenght) was reduced in HD compared to the control animals. 5. These results suggest that hemidecortication causes mild hypothyroidism (trophoprivic type) probably by affecting hypothalamic function