Simulation with 3D Neuronavigation for Learning Cortical Bone Trajectory Screw Placement.

BACKGROUND AND OBJECTIVE: Learning a new technique in neurosurgery is a big challenge especially for trainees. In recent years, simulations and simulators got into the focus as a teaching tool. Our objective is to propose a simulator for placement of cortical bone trajectory (CBT) screws to improve results and reduce complications. METHODS: We have created a platform consisting of a sawbone navigated with a 3D fluoroscope to familiarize our trainees and consultants with CBT technique and later implement it in our department. Objective Structured Assessment of Technical Skills (OSATS) and Physician Performance Diagnostic Inventory Scale (PPDI) were obtained before and after the use of the simulator by the five participants in the study. Patients who were operated on after the implementation of the technique were retrospectively reviewed. RESULTS: During the simulation, there were 4 cases of pedicle breach out of 24 screws inserted (16.6%). After having completed simulation, participants demonstrated an improvement in OSATS and PPDI (p = 0.039 and 0.042, respectively). Analyzing the answers to the different items of the tests, participants mainly improved in the knowledge (p = 0.038), the performance (p = 0.041), and understanding of the procedure (p = 0.034). In our retrospective series, eight patients with L4-L5 instability were operated on using CBT, improving their Oswestry Disability Index (ODI) score (preoperative ODI 58.5 [SD 16.7] vs. postoperative ODI 31 [SD 13.4]; p = 0.028). One intraoperative complication due to a dural tear was observed. In the follow-up, we found a case of pseudoarthrosis and a facet joint violation, but no other complications related to misplacement, pedicle fracture, or hardware failure. CONCLUSION: The simulation we have created is useful for the implementation of CBT. In our study, consultants and trainees have valued very positively the learning obtained using the system. Moreover, simulation facilitated the learning of the technique and the understanding of surgical anatomy. We hope that simulation helps reducing complications in the future.

[Is it possible to extract intracranial pressure information based on the EEG activity?] / Es posible obtener informacion de la presion intracraneal a partir de la actividad electroencefalografica?

INTRODUCTION: The capability of the electroencephalography (EEG) of recording the bioelectrical activity of the brain has made of it a fundamental tool for the evaluation of the patient's neurological condition. In recent years, moreover, it has also begun to be used in obtaining information for other kind of variables, as the ones related with the cerebral hemodynamics. AIM: To study the potential relationship between the EEG activity and the intracranial pressure (ICP) in patients suffering from traumatic brain injury and subarachnoid hemorrhage, during their stay at the intensive care unit. PATIENTS AND METHODS: Twenty-one adult patients (10 women) were included in the present observational prospective cohort study. They suffered from either traumatic brain injury or subarachnoid hemorrhage, requiring continuous EEG and ICP monitoring. In every patient, Granger causality between spectral functions of the EEG and the ICP was evaluated. Temporal windows of 10 minute were used to evaluate whether a causal relationship between those variables exist or not. In all of the cases, several days of continuous recording and assessment were performed. RESULTS: In most patients and during most of the time, Granger causality turns out to be significant in the direction from the EEG to the ICP, meaning that the EEG dynamics actually leads the ICP dynamics. CONCLUSIONS: The present work provides useful information and shed light in discovering a hidden relationship between the ICP and EEG dynamics. The potential use of this relationship could lead to develop a medical device to measure ICP in a non-invasive fashion.

TITLE: Es posible obtener informacion de la presion intracraneal a partir de la actividad electroencefalografica?Introduccion. El electroencefalograma (EEG) permite obtener informacion directa de la actividad bioelectrica del cerebro y es una herramienta fundamental para la evaluacion de la condicion neurologica del paciente. En los ultimos años ha comenzado a emplearse tambien para obtener indirectamente informacion sobre la hemodinamica cerebral y las variables que intervienen en la autorregulacion del flujo sanguineo cerebral. Objetivo. Estudiar la posible relacion entre la actividad electroencefalografica y la presion intracraneal (PIC) en pacientes con traumatismo craneoencefalico y hemorragia subaracnoidea ingresados en cuidados intensivos. Pacientes y metodos. Se incluyo a 21 pacientes (10 mujeres) mayores de 18 años con traumatismo craneoencefalico o hemorragia subaracnoidea que requerian monitorizacion de la PIC y a los que se les registro el EEG de forma continua. Se determino la causalidad de Granger entre la PIC con respecto a las variables espectrales del EEG para ventanas temporales de 10 minutos durante la estancia en cuidados intensivos. Resultados. La causalidad de Granger mostro una alta correlacion entre la PIC con las bandas del EEG. En la mayoria de los pacientes existe una causalidad de Granger significativa en la direccion del EEG hacia la PIC en gran parte del tiempo de monitorizacion, de forma que las variables del EEG precedian a la PIC. Conclusiones. El presente trabajo expone la relacion temporal subyacente entre la dinamica de la PIC y la actividad bioelectrica cerebral registrada mediante EEG en pacientes con traumatismo craneoencefalico y hemorragia subaracnoidea. El potencial uso de esta relacion podria permitir estimar la PIC de manera no invasiva.

Traumatic atlantoaxial rotatory fixation in an adult patient.

INTRODUCTION: Atlantoaxial rotational fixation (AARF) is a rare entity in adults, with only a few cases reported in the English literature and often associated with a traumatic mechanism. It is an underdiagnosed condition that must be taken into account in the initial assessment of all craniocervical trauma. Both diagnostic and therapeutic delay may be a potential cause of severe neurological damage or even death of the patient. The therapeutic management is controversial given the difficulty of achieving optimum stability and permanent reduction. METHODS AND RESULTS: A 28-year-old woman was involved in a traffic accident a week before coming to the emergency with rotation and irreducible cervical flexion from trauma and severe neck pain. CT and MRI column were performed and showed a cervical spinal AARF with transverse and alar ligaments intact and preserved atlantoaxial distance (Fielding I). The patient was treated by progressive cervical traction with 5 kg and manual reduction was completed in 24 h. Subsequently, an external immobilization was performed by cervical rigid collar for 16 weeks. The clinical course was good, with the patient regaining full mobility with cervical neck pain improvement. CONCLUSIONS: The purpose of this paper is to show a case of a young woman with a posttraumatic AARF successfully treated conservatively. This case delineates the difficulties in diagnosing this pathology, as well as the challenges encountered in its management.

[Bilateral two-stage implantation for deep brain stimulation in the treatment of bilateral idiopathic Parkinson's disease: clinical outcomes]. / Implantacion bilateral en dos tiempos para estimulacion cerebral profunda en el tratamiento de la enfermedad de Parkinson idiopatica bilateral: resultados clinicos.

AIMS: Simultaneous bilateral implantation of electrodes in the subthalamic nucleus for idiopathic Parkinson's disease (IPD) is associated with long surgery time, language disorders and post-operative confusion. Moreover, there is evidence of ipsilateral improvement after stimulation of the subthalamic nucleus. In order to optimise perioperative management a prospective study is conducted with deep brain stimulation (DBS) in the subthalamic nucleus in two consecutive unilateral procedures. PATIENTS AND METHODS: We conducted a prospective study of 41 patients with bilateral IPD, with DBS implantation in two unilateral surgical phases. Its clinical outcomes are analysed according to the Unified Parkinson's Disease Rating Scale (UPDRS), the Hoehn and Yahr, and the Schwab and England scales, together with their complications. RESULTS: The mean age was 61 ± 7 years old, 23 males. Five patients (12%) did not undergo surgery of the contralateral subthalamic nucleus due to good control. The mean on the motor UPDRS and the Hoehn and Yahr in preoperative pharmacological off was 44 ± 14 and 3, respectively, and 19 ± 8 and 1.8 at six months' follow-up. The mean improvement on the Schwab and England scale in the pre-operative period and at six months was 39%. Two patients suffered post-operative confusion, and one of them had transient dysarthria. CONCLUSIONS: Bilateral DBS in two unilateral stages was an effective option with few complications in our series of patients with IPD. 10% of the patients did not require contralateral electrodes. It would be necessary to conduct a randomised study in patients who underwent bilateral surgery in one and two stages in order to confirm these results.

TITLE: Implantacion bilateral en dos tiempos para estimulacion cerebral profunda en el tratamiento de la enfermedad de Parkinson idiopatica bilateral: resultados clinicos.Objetivo. La implantacion bilateral simultanea de electrodos en el nucleo subtalamico para la enfermedad de Parkinson idiopatica (EPI) se asocia a una duracion elevada de la intervencion, alteraciones del lenguaje y confusion posquirurgica; ademas, existe evidencia de mejoria ipsilateral tras la estimulacion del nucleo subtalamico. Para optimizar el manejo perioperatorio se realiza un estudio prospectivo con estimulacion cerebral profunda (ECP) en el nucleo subtalamico en dos procedimientos unilaterales consecutivos. Pacientes y metodos. Estudio prospectivo de 41 pacientes con EPI bilateral, con implantacion de ECP en dos fases quirurgicas unilaterales. Se analizan sus resultados clinicos segun las escalas Unified Parkinson's Disease Rating Scale (UPDRS), Hoehn y Yahr, y Schwab y England, asi como sus complicaciones. Resultados. La edad media fue de 61 ± 7 años, 23 hombres. Cinco pacientes (12%) no fueron intervenidos del nucleo subtalamico contralateral por buen control. La media en la UPDRS motora y la Hoehn y Yahr en off farmacologico preoperatorio fue de 44 ± 14 y 3, respectivamente, y de 19 ± 8 y 1,8 a los seis meses de seguimiento. La mejoria media en la escala de Schwab y England en el preoperatorio y a los seis meses fue del 39%. Dos pacientes tuvieron confusion postoperatoria, y uno, disartria transitoria. Conclusiones. La ECP bilateral en dos etapas unilaterales fue una opcion eficaz y con escasas complicaciones en nuestra serie de pacientes con EPI. El 10% de los pacientes no preciso electrodos contralaterales. Seria necesario un estudio aleatorizado en pacientes sometidos a cirugia bilateral en uno y dos tiempos para confirmar estos resultados.

[Medullar thoracic compression by tophaceous gout: presentation of a case and review of the literature]. / Compresion medular dorsal por tofos gotosos: presentacion de un caso y revision de la bibliografia.

INTRODUCTION: Spine involvement in gout is an extremely uncommon complication. Dorsalgia and quadriplegia are some manifestations that may occur, although these symptoms are seen more frequently in other more prevalent pathologies, such as spinal tumors. CASE REPORT: We present an unusual case of thoracic spinal cord compression at T10-T11 level caused by the extradural deposit of tophaceous material in a 52-year-old woman with uncontrolled chronic tophaceous gout. In addition to intensive medical treatment, the patient required surgery (hemilaminectomy and spinal decompression) and subsequent rehabilitation. Overall and neurological evolution were satisfactory.

TITLE: Compresion medular dorsal por tofos gotosos: presentacion de un caso y revision de la bibliografia.Introduccion. La afectacion de la columna vertebral en la gota es una complicacion extremadamente infrecuente. La dorsalgia y la cuadriplejia son algunas manifestaciones que se pueden presentar, aunque estos sintomas se ven con mas frecuencia en otras patologias mas prevalentes, como los tumores medulares. Caso clinico. Se presenta un caso inusual de compresion medular dorsal en D10-D11 causado por el deposito extradural de material tofaceo en una paciente de 52 años con gota tofacea cronica incontrolada. Ademas de un tratamiento medico intensivo, la paciente requirio cirugia (hemilaminectomia y descompresion medular) y rehabilitacion posterior. La evolucion general y neurologica fue satisfactoria.

[New thalamic potential associated with somatosensory evoked potentials]. / Nuevo potencial talamico asociado con potenciales evocados somatosensoriales.

INTRODUCTION: The response of the thalamus during the study with somatosensory evoked potentials (SSEP) is not sufficiently understood. CASE REPORT: A 17-year-old man undergoing surgery for deep brain stimulation in the centromedian nucleus for drug-resistant epilepsy under complete sedation. During the intervention, the responses to SSEPs of the thalamic nuclei were recorded by means of four microelectrodes. These responses can be decomposed into three types: local field potentials (LFP), low amplitude fast oscillations (LFO), and high amplitude slow oscillations (HSO). LFO are widespread in much of the registered regions. However, HSOs are located at a single point in the registry and are closely associated with LFPs. CONCLUSIONS: Although the presence of LFO has been considered as an indicator of the presence of the sensory thalamus, its wide extension by different thalamic nuclei suggests that it is an unspecific response to SSEPs. However, the restricted spatial location of HSO and their association with LFP suggest that these newly described potentials are the markers for the presence of the sensory thalamus. Their identification may prove very useful in thalamic deep brain stimulation either in awake patients or especially in those requiring sedation.

TITLE: Nuevo potencial talamico asociado con potenciales evocados somatosensoriales.Introduccion. La respuesta del talamo durante el estudio con potenciales evocados somatosensoriales (PESS) no esta suficientemente comprendida. Caso clinico. Varon de 30 años intervenido con sedacion completa mediante estimulacion cerebral profunda en el nucleo centromediano por epilepsia farmacorresistente. Durante la intervencion se registraron las respuestas de los nucleos talamicos mediante cuatro microelectrodos a los PESS. Estas respuestas se pueden descomponer en tres tipos: potenciales de campo local (PCL), oscilaciones rapidas de baja amplitud (ORB) y oscilaciones lentas de gran amplitud (OLG). Las ORB estan muy extendidas por gran parte de las regiones registradas (> 5 mm) y en los cuatro electrodos simultaneamente. Sin embargo, las OLG estan localizadas en un unico punto del registro y estan intimamente asociadas con los PCL. Ademas, el analisis de wavelets muestra un componente espectral y un tiempo de aparicion diferentes. Conclusiones. Aunque se ha considerado la presencia de ORB como indicador de la presencia del talamo sensorial, su amplia extension por diferentes nucleos talamicos sugiere que se trata de una respuesta poco especifica a los PESS. Sin embargo, la localizacion espacial restringida de los OLG y su asociacion con PCL sugiere que estos potenciales de nueva descripcion son los marcadores de la presencia del talamo sensorial. Su identificacion puede resultar muy util en estimulacion cerebral profunda talamica en pacientes despiertos y, especialmente, en los que precisen sedacion.

[When does post-ictal period start in temporal lobe epilepsy? A quantitative EEG perspective]. / Donde comienza el periodo postictal en la epilepsia del lobulo temporal? Hacia una definicion cuantitativa.

INTRODUCTION: In partial seizures, from a clinical point of view or even from electroencephalography characterization of post-ictal period can be difficult. The spectral and complex network analysis could lead to a more accurate definition of its limits, as well as to a great understanding of the seizures. PATIENTS AND METHODS: Digital EEG recordings from scalp and foramen oval electrodes were used, 32 seizures, from 15 patients with drug-resistant mesial temporal lobe epilepsy (Engel I). We analyzed numerically: the spectral entropy, the different frequency bands and several variables used to characterize the cortical network, density of links, modularity, cluster coefficient and average path length. Variations of for post-ictal versus pre-ictal periods were quantified. RESULTS: The cortical network density of links increased during the post-ictal period of complex seizures matching with an spectral entropy decrease, mainly due to an increase in Delta band activity. This variables reached extreme values around one minute after seizure end, defined by classical electroencephalography. CONCLUSIONS: Our results can be explained by the appearance of an 'ending' mechanism that starts in the ictal period, classically defined, and reach their maximum effect during the post-ictal period. These results could be useful to define the post-ictal period start, as the moment with maximum synchrony, which has a highest density of links and a lowest spectral entropy.

TITLE: Donde comienza el periodo postictal en la epilepsia del lobulo temporal? Hacia una definicion cuantitativa.Introduccion. En las crisis parciales, el periodo postictal presenta grandes dificultades de caracterizacion, tanto desde el punto de vista clinico como en electroencefalografia. Un analisis espectral y de redes complejas permitiria una definicion mas precisa de sus limites y una comprension mas completa de las crisis. Pacientes y metodos. Se analizaron registros digitales de electroencefalografia de electrodos de scalp y foramen oval, 32 crisis, de 15 pacientes con epilepsia farmacorresistente del lobulo temporal (Engel I). Numericamente se estudio la entropia espectral, las distintas bandas de frecuencia y medidas de caracterizacion de la red cortical, la densidad de enlaces, la modularidad, el coeficiente de agrupamiento y la longitud de camino medio, y se cuantifico la variacion del periodo postictal respecto al preictal. Resultados. Durante el periodo postictal de las crisis complejas existe un marcado aumento de la densidad de enlaces en la red cortical coincidente con un descenso en la entropia espectral, principalmente debido al aumento de la actividad en la banda delta. Los valores extremos de estas medidas se alcanzan aproximadamente un minuto despues del fin de las crisis, definidas electroencefalograficamente usando metodos tradicionales. Conclusiones. Nuestros resultados pueden explicarse por la aparicion de un mecanismo de 'finalizacion' de las crisis que comienza dentro del periodo ictal definido clasicamente y que alcanzan su efecto maximo durante el periodo postictal. Estos resultados podrian emplearse para definir el inicio del periodo postictal como aquel donde la sincronizacion es maxima, esto es, donde la densidad de enlaces resulta mayor y la entropia espectral es minima.

[Bromocriptine: could it be the cure for post-surgical akinetic mutism?] / Bromocriptina: podria ser la cura para el mutismo acinetico posquirurgico?

INTRODUCTION: Akinetic mutism is considered as an alteration of the motivational state of the person, which the patient is unable to initiate verbal or motor responses voluntary, even with preserved sensorimotor and surveillance functions. CASE REPORT: A 43 year-old male involved in a cerebellum arteriovenous fistula complicated with hydrocephalus, who responded dramatically to treatment with bromocriptine. CONCLUSION: Typically, akinetic mutism is described as a transient surgeries posterior fossa. However, it can also occur after multiple valvular failure in patients with hydrocephalus.

TITLE: Bromocriptina: podria ser la cura para el mutismo acinetico posquirurgico?Introduccion. El mutismo acinetico se considera una alteracion del estado motivacional de la persona, por el cual el paciente es incapaz de iniciar respuestas verbales o motoras de caracter voluntario, aun teniendo preservadas las funciones sensomotoras y de vigilancia. Caso clinico. Varon de 43 años, intervenido de una fistula arteriovenosa del cerebelo complicada con hidrocefalia, que respondio espectacularmente al tratamiento con bromocriptina. Conclusion. Tipicamente se ha descrito el mutismo acinetico como una complicacion transitoria de las cirugias de la fosa posterior. Sin embargo, tambien puede aparecer tras multiples fallos valvulares en pacientes con hidrocefalia.

Effectiveness of vagal nerve stimulation in medication-resistant epilepsy. Comparison between patients with and without medication changes.

BACKGROUND: Vagal nerve stimulation (VNS) response is not immediate. A progressive decline in seizure frequency is usually found during a period of 12-18 months after implantation. During this time, the patient's medication is usually modified, which can create doubts about whether their clinical improvement is due to medication changes or to VNS itself. Our goal is to compare two groups of patients treated with VNS, with and without changes in their medication. METHODS: We prospectively analyze 85 patients who were treated with VNS in our hospital between 2005 and 2014. In 43 patients, changes in the antiepileptic drugs (EAD) were not allowed during the postoperative follow-up and they were compared with 42 patients who were left at the option of neurologist make changes in medication. We analyzed the clinical situation at 18 months and compared the two groups. RESULTS: Overall, 54.1% of patients had a reduction in seizures of 50% or higher (responders). In the group with no changes in medication, responders reached 63%, while in the group in which changes in medication were allowed, 45.2% were responders. Between responders and non-responders, there were no statistical differences in type of epilepsy, frequency, previous surgery, or intensity of stimulation. CONCLUSIONS: We did not find a statistical difference in seizure frequency reduction between patients with or without changes in medication during their follow-up, so changes in medication did not improve the outcome. Furthermore, the absence of changes in AED can help to optimize the parameters of the stimulator in order to improve its effectiveness.

[The role of diffusion tensor imaging in the pre-surgical study of temporal lobe epilepsy]. / Papel de la imagen por tensor de difusion en el estudio prequirurgico de la epilepsia del lobulo temporal.

INTRODUCTION: Diffusion tensor imaging (DTI) is a non-invasive technique that can be used to assess the integrity of the white matter in the brain. AIMS: To investigate the usefulness of DTI in patients with temporal lobe epilepsy (TLE) and to observe its relationship with lateralisation of the epileptogenic focus in these patients. PATIENTS AND METHODS: We analysed 11 patients diagnosed with TLE in accordance with the pre-surgical protocol of our epilepsy unit, and who were seizure-free two years after performing a temporal lobectomy plus amygdalohippocampectomy (Spencer technique). As part of their pre-operative study, a 1.5 T magnetic resonance brain scan with diffusion tensor imaging was performed. A voxel-based analysis was then employed to study the differences in connectivity between the hemisphere that underwent surgery and the contralateral hemisphere. RESULTS: Compared with the contralateral hemisphere, a statistically significant reduction in fractional anisotropy (p < 0.05) was observed in the corpus callosum, the cingulate, the superior longitudinal fasciculus, the anterior thalamic radiations, the internal capsule, the ventral lateral and pulvinar nuclei of the thalamus, the inferior frontooccipital fasciculus, the uncinate fasciculus, the inferior longitudinal fasciculus and the parahippocampal gyrus, all ipsilateral to the epileptogenic focus. CONCLUSIONS: The characterisation of the abnormalities in the connectivity of the cerebral white matter, by means of DTI in patients with TLE, can be a valuable aid for the lateralisation of the epileptogenic focus in the pre-surgical evaluation of these patients. Further studies with a higher number of patients would be needed to confirm these results.

TITLE: Papel de la imagen por tensor de difusion en el estudio prequirurgico de la epilepsia del lobulo temporal.Introduccion. La imagen por tensor de difusion (DTI) es una tecnica no invasiva que puede ser utilizada para evaluar la integridad de la sustancia blanca cerebral. Objetivo. Investigar la utilidad de la DTI en pacientes con epilepsia del lobulo temporal (ELT) y ver su relacion con la lateralizacion del foco epileptogeno en estos pacientes. Pacientes y metodos. Se analizan 11 pacientes diagnosticados de ELT segun el protocolo de evaluacion prequirurgica de nuestra unidad de epilepsia, y libres de crisis a los dos años de la realizacion de una lobectomia temporal mas amigdalohipocampectomia (tecnica de Spencer). Como parte de su estudio preoperatorio, se realiza una resonancia magnetica cerebral de 1,5 T con secuencia de tensor de difusion y se estudian, mediante un analisis basado en voxel, las diferencias en la conectividad entre el hemisferio intervenido y el contralateral. Resultados. Comparado con el hemisferio contralateral, se observo una reduccion de la anisotropia fraccional estadisticamente significativa (p < 0,05) en el cuerpo calloso, el cingulo, el fasciculo longitudinal superior, las radiaciones talamicas anteriores, la capsula interna, los nucleos ventral lateral y pulvinar del talamo, el fasciculo frontooccipital inferior, el fasciculo uncinado, el fasciculo longitudinal inferior y el giro parahipocampal ipsilaterales al foco epileptogeno. Conclusiones. La caracterizacion de las anormalidades en la conectividad de la sustancia blanca cerebral, a traves de la DTI en pacientes con ELT, puede tener un valor importante para la lateralizacion del foco epileptogeno en la evaluacion prequirurgica. Serian necesarios estudios con un numero mas elevado de pacientes para confirmar estos resultados.

[Haemorrhagic pineal cysts: two clinical cases successfully treated by means of microsurgery]. / Quistes pineales hemorragicos: dos casos clinicos tratados con exito mediante microcirugia.

INTRODUCTION: Pineal cysts are a relatively frequent incidental finding in imaging tests; yet, pineal apoplexy is considered to be rare and is associated to severe symptoms. CASE REPORTS: We report the cases of a 25-year-old male and a female aged 15 years who visited the emergency department with signs and symptoms of intracranial hypertension. The existence of a pineal haemorrhage was confirmed by imaging tests. They were successfully treated by means of microsurgery. CONCLUSION: In our experience, and backed by the literature, we believe that the best treatment for this infrequent pathology is the microsurgical approach. Nevertheless, we do not rule out the possibility that, sometime in the future, endoscopic techniques may play an important role in the treatment of pineal apoplexy.

TITLE: Quistes pineales hemorragicos: dos casos clinicos tratados con exito mediante microcirugia.Introduccion. Los quistes pineales son un hallazgo incidental relativamente frecuente en las pruebas de imagen; sin embargo, la apoplejia pineal se considera rara y se asocia a sintomas graves. Casos clinicos. Varon de 25 a˜os y mujer de 15 a˜os, que acudieron a urgencias con clinica de hipertension intracraneal; mediante pruebas de imagen se confirmo la existencia de una hemorragia pineal. Se les trato con exito mediante microcirugia. Conclusion. En nuestra experiencia, y avalado por la bibliografia, creemos que el mejor tratamiento de esta infrecuente patologia es el abordaje microquirurgico. Sin embargo, no se excluye la posibilidad de que, en un futuro, las tecnicas endoscopicas puedan tener un lugar importante en el tratamiento de la apoplejia pineal.

Classification of structural lesions in magnetic resonance imaging. Surgical implications in drug-resistant epilepsy patients.

INTRODUCTION: The presence of a structural lesion in the preoperative magnetic resonance imaging (MRI) of drug-resistant epilepsy patients has been usually associated with a favourable surgical outcome. We present our experience in our Epilepsy Surgery Unit. PATIENTS AND METHODS: Clinical records from 265 patients, operated on from 1990-2010 in our institution, were reviewed. Patients were classified, according to MRI findings, into three groups: surgical lesion (SL), tumors or vascular malformations requiring surgery 'per se'; orientative lesion (OL), dysplasia, atrophy or mesial temporal sclerosis; and (NL) group, with normal MRI. Seizure outcomes were analysed in relation to this classification. RESULTS: Period 1990-2000, 151 patients: 87% of SL, 65% of OL and 57% of NL patients were in Engel class I or II at the two-year follow-up. Among temporal lobe epilepsy cases (TLE), 87% of SL, 67% of OL and 56% of NL patients achieved seizure control. Differences were statistically significative. Period 2001-2010, 114 patients: 100% of SL, 90% of OL, and 81% of NL patients were in Engel's class I or II. Both TLE and extratemporal (ETLE) SL patients obtained a 100% seizure control. Among the OL patients, 95% with TLE and 43% of ETLE achieved seizure control. In the NL group, the percentages were 88% in TLE, and 50% in ETLE. CONCLUSIONS: In our series, SL was a predictor of a favorable outcome. In TLE patients, good results were achieved despite normal MRI. Patients with ETLE and NL did not have a worse outcome than those with OL. A classification in SL, OL and NL seems more helpful for predicting the surgical outcome than the traditional classification lesion versus non-lesion MRI. Radiological findings must be carefully evaluated in the context of a complete epilepsy surgery evaluation.

TITLE: Clasificacion de las lesiones estructurales en resonancia magnetica. Implicaciones quirurgicas en pacientes con epilepsia farmacorresistente.Introduccion. En la seleccion quirurgica del paciente con epilepsia farmacorresistente, el papel de la resonancia magnetica (RM) no se ha cuantificado hasta el momento. Presentamos la experiencia en nuestra Unidad de Cirugia de la Epilepsia. Pacientes y metodos. Se estudiaron retrospectivamente los pacientes intervenidos por epilepsia farmacorresistente. Distinguimos dos periodos: 1990-2000 (RM de 0,5 T) y 2001-2008 (RM de 1,5 T). La RM preoperatoria se clasifico en tres grupos: RM con lesion quirurgica (LQ), RM orientativa (LO) y RM normal (NL). Tambien se efectuo una clasificacion anatomopatologica similar. Se correlacionaron las distintas clasificaciones y los resultados quirurgicos. Resultados. Periodo 1990-2000: 151 pacientes. El 70% quedo en las clases de Engel I o II. Segun la RM, los resultados fueron: LQ, 87%; LO, 65%; y NL, 57%. Las diferencias fueron estadisticamente significativas. Periodo 2001-2008: 114 pacientes. El 89% quedo en las clases de Engel I o II. Segun la RM: LQ, 100%; LO, 90%; y NL, 81%. Las diferencias fueron estadisticamente significativas. Los pacientes con epilepsia del lobulo temporal y extratemporal con LQ tuvieron un 100% de control; con LO, el 95% con epilepsia del lobulo temporal y el 43% con estado epileptico; en aquellos pacientes sin lesion (NL), el 88% con epilepsia del lobulo temporal se controlo frente al 50% con estado epileptico. Conclusiones. La RM es una herramienta eficaz en la seleccion de candidatos quirurgicos en la epilepsia. La LQ asocia muy buen pronostico. En la epilepsia del lobulo temporal se pueden obtener muy buenos resultados (80-90% de control) a pesar de una RM normal. En el estado epileptico, las LO pueden tener peor resultado que la NL en la RM.

Dumbbell-Shaped Epidural Capillary Hemangioma Presenting as a Lung Mass: Case Report and Review of the Literature.

STUDY DESIGN: A case report and literature review. OBJECTIVE: We present the fourth case of a spinal epidural capillary hemangioma with a dumbbell-shaped appearance in the magnetic resonance image reported in the literature and the second presented as a lung mass. SUMMARY OF BACKGROUND DATA: Hemangiomas are congenital vascular malformations that pathologists frequently consider to be hamartomatous malformations. Hemangiomas of the spine are usually lesions of the vertebral bodies, but they can sit in other locations such as the intramedullary or epidural space. Purely epidural hemangiomas are rare and most of them are of cavernous type. METHODS: We present a 67-year-old female with a thoracic dumbbell-shaped capillary hemangioma with both foraminal and intrathoracic extensions, whose presentation was pleural effusion associated with mediastinal mass suggestive of pulmonary neoplasia. Surgical treatment consisted of total removal en bloc of the lesion. RESULTS: Microscopic evaluation showed a fibrofatty tissue with a proliferation of vascular structures that were generally of a small size, with areas of myxoid appearance. To date, there have been 8 epidural capillary hemangiomas of the thoracic and lumbar spine reported in the literature, and only 3 of them were dumbbell-shaped with extraforaminal extension. CONCLUSION: It is important to consider the diagnosis of hemangiomas in the differential diagnosis of epidural lesions with dumbbell-shaped appearance in the magnetic resonance image, especially at the thoracic level. It is a benign and potentially curable disease and the most appropriate surgical treatment is en bloc resection of the entire lesion. They are usually presented as a progressive myelopathy, so early treatment may prevent permanent neurological deficits. LEVEL OF EVIDENCE: 5.

Electrocorticographic evidence and surgical implications of different physiopathologic subtypes of temporal epilepsy.

OBJECTIVE: Mesial temporal lobe epilepsy (MTLE) might have a focal or a network physiopathology. Therefore, the objective of this study was to demonstrate that changes in the spiking activity during electrocorticography (ECoG) could reflect changes in the epileptic network, and the resection of the epileptogenic zone could eliminate the mesial spikes. METHODS: Twenty-five MTLE patients were intraoperatively evaluated by ECoG and the mesial strip was maintained until the lateral cortectomy (LC) was completed. Total spiking activity (TSA, mean spikes/min for all the mesial channels) was computed off-line before and after LC. Either a tailored anterior medial temporal resection or LC was carried out based on the TSA changes. RESULTS: The outcome at 19.1±1.4 months was Engel's class I, 84%; II, 8%; or III, 8%. During the LC, the TSA recorded from the mesial strip did not change in 14 patients, increased in three patients, and decreased in eight patients. In 20% of patients, the mesial activity completely disappeared, and the mesial structures were spared. All of these patients were Engel's class IA. CONCLUSIONS: Our results strongly suggest the existence of physiopathologic differences in MTLE. The identification of these subtypes is fundamental for an individualized surgical approach. SIGNIFICANCE: ECoG would be needed to offer a better surgical approach.

Long-term results of vagal nerve stimulation for adults with medication-resistant epilepsy who have been on unchanged antiepileptic medication.

PURPOSE: Several studies suggest that vagal nerve stimulation (VNS) is an effective treatment for medication-resistant epileptic patients, although patients' medication was usually modified during the assessment period. The purpose of this prospective study was to evaluate the long-term effects of VNS, at 18 months of follow-up, on epileptic patients who have been on unchanged antiepileptic medication. METHODS: Forty-three patients underwent a complete epilepsy preoperative evaluation protocol, and were selected for VNS implantation. After surgery, patients were evaluated on a monthly basis, increasing stimulation 0.25mA at each visit, up to 2.5mA. Medication was unchanged for at least 18 months since the stimulation was started. The outcome was analysed in relation to patients' clinical features, stimulation parameters, epilepsy type, magnetic resonance imaging (MRI) results, and history of prior brain surgery. RESULTS: Of the 43 operated patients, 63% had a similar or greater than 50% reduction in their seizure frequency. Differences in the responder rate according to stimulation intensity, age at onset of epilepsy, duration of epilepsy before surgery, previous epilepsy surgery and seizure type, did not reach statistical significance. Most side effects were well tolerated. CONCLUSIONS: 62.8% of our series of 43 medication-resistant epileptic patients experienced a significant long-term seizure reduction after VNS, even in a situation of on unchanged medical therapy. Patient characteristics predictive of VNS responsiveness remain subject to investigation. Controlled studies with larger sample sizes, on VNS for patients with medication-resistant epilepsy on unchanged medication, are necessary to confirm VNS efficacy for drug-resistant epilepsy, and to identify predictive factors.

[Contamination of paroxysmal activity in quantitative EEG methods in epileptic patients]. / Contaminacion de la actividad paroxistica en los metodos cuantitativos de electroencefalografia en pacientes epilepticos.

INTRODUCTION. The presence of an acute spike-wave pattern in the recordings of epileptic patients can contaminate the calculated synchronisation values between pairs of electrodes. MATERIALS AND METHODS. We present a simple procedure, involving a numeric simulation of a bivariate electroencephalogram recording with paroxysmal activity, to determine whether or not a method for quantifying synchronisation must be used on any of the recordings that are typically employed in the preoperative evaluation of patients with epilepsy. RESULTS. The information provided by this procedure makes it possible to distinguish between the authentic synchronisation of baseline activity and that produced by paroxysmal activity, such as acute spike-wave patterns. The procedure developed in this study makes it possible to quantify the degree of 'contamination' produced by the synchronisation of the paroxysmal activity on the synchronisation values of the baseline activity. CONCLUSIONS. The issue addressed in this work is of fundamental importance when automatic methods are utilised in the clinical applications of quantitative electroencephalography and can help to prevent diagnostic errors in which synchronisation is used as a marker of the pathology.

[Deep brain stimulation for refractory epilepsy: extrathalamic targets]. / Estimulacion cerebral profunda para la epilepsia resistente: dianas extratalamicas.

Epilepsy is a neurological disorder that affects 1-2% of the population. The majority of epileptic patients achieve a good seizure control with the current available treatments. However, there is a subgroup of patients that remain severely disable despite the variety of anti-epileptic drugs, the possibility of surgery for resection of the epileptogenic foci in selected patients, and vagal nerve stimulation; various lines of research are being carried out to look for new treatment alternatives. Deep brain stimulation (DBS) of the thalamus has emerged as a therapeutic alternative for patients who remain in-capacitated; the efficacy of this new therapy is subject of several studies, and its effectiveness and safety has not been established yet. There are other targets for deep brain stimulation that may be useful for drug-resistant epilepsy. Experiments with animal models and preliminary human studies have shown encouraging results with DBS on cerebellum, subthalamic nucleus, substantia nigra, hippocampus and cerebral cortex, among others. The purpose of this review is to revisit the studies that have been carried out on these brain nuclei, as targets for DBS for drug-resistant epilepsy. Studies have shown varying degrees of effectiveness, and there is a need for controlled trials to draw any definite conclusions.

[Frontal aneurysmal bone cyst. A case report and review of the literature]. / Quiste oseo aneurismatico frontal. Caso clinico y revision de la bibliografia.

INTRODUCTION: Cranial aneurysmal bone cyst (ABC) is a rare pathological finding that is usually diagnosed in young patients. It is defined as a benign lesion made up of intervillous spaces limited by connective bone tissue septa and osteoclast-type giant cells; these histological characteristics are common to extracranial ABC. Clinically, in most patients, they manifest as cranial tumours which may be painful and vary in size. About 100 cases of cranial ABC have been reported in the literature. We present a literature review of the cases of frontal ABC reported to date, including one that was recently treated in our own service. CASE REPORT: A 29-year-old female, with no history of traumatic brain injury, who was examined due to the presence of a fixed, painless frontal cranial lesion on the right-hand side. The results of a radiological study revealed the presence of a lytic cranial lesion with well-delimited edges and marginal sclerosis; peripheral and linear contrast enhancement was also observed in the magnetic resonance imaging of the brain. The patient was submitted to a surgical intervention and the entire lesion was removed. There were no incidents in the post-operative period and the definitive pathological diagnosis was cranial ABC. CONCLUSIONS: Cranial ABC is a pathological condition with well-defined histological and radiological characteristics, despite the fact that its aetiopathogenesis is still not fully understood. Complete excision of the tumour is considered to be the preferred treatment, which often leads to full recovery of the patient and also offers a good long-term prognosis.

New insights on culture and calcium signalling in neurons and astrocytes from epileptic patients.

Primary brain cell cultures are a useful tool for understanding the physiopathology of epilepsy and for searching new potential antiepileptic drugs. These cell types are usually prepared from murine species and few human models have been described. The main goal of this study is the establishment of experimental conditions to isolate and culture neurons and astrocytes from human brain and to test its functionality. The tissues came from antiepileptic drug-resistant epileptic patients undergoing surgery. Human neurons and astrocytes were isolated following an enzymatic and mechanical dissociation protocol. Cultures were viable for 3-6 weeks. Cytological characterization was performed by immunocytochemistry using specific antibodies against both neuron (anti-NeuN) and astrocyte (anti-GFAP) protein markers. In order to test their viability and functionality, cells were loaded with the fluorescent calcium probe fura-2 and variations in cytosolic calcium concentrations ([Ca2+]c) were measured by cell imaging. [Ca2+]c increases were evoked upon cell stimulation with high K+ (KCl 75 mM), glutamate (500 µM) or bicuculline (100 µM). Interestingly, spontaneous [Ca2+]c transients were also observed in some neuron-like cells. A novel unreported finding in this study has been the incorporation of human serum that was critical for cell functionality. The setting of these human cultures open the opportunity to new insights on culture and calcium signalling studies on the mechanism(s) of cell resistance to antiepileptic drugs, as well as to studies on plasticity, maturation and possible neurite emission for graft studies.