Comorbid impulsivity after one year of epilepsy surgery.

BACKGROUND: Psychiatric comorbidities in patients with drug-resistant epilepsy (DRE) are frequently observed before and after epilepsy surgery. Impulsivity, defined as behaviors that are poorly conceived, are also frequent among patients with epilepsy. The aim of this study was to determine the presence of comorbid impulsivity in patients with DRE after one year of epilepsy surgery. METHODS: Patients who underwent epilepsy surgery for DRE and completed the postsurgical assessment protocol one year after surgery were included. All patients underwent a presurgical protocol comprising of neurological, psychiatric, neuropsychological, video-EEG and MRI assessments. The psychiatric evaluation was performed before and one year after surgery using SCID-I, SCID-II, GAF scale of DSM IV, and Beck Depression Inventory II. One year after surgery, Barratt Impulsiveness Scale 11, and Engel classification of seizures, were administered. RESULTS: A total of 38 patients were included in this study, 21 women (55.3%) and 17 men (44.7%), mean age 36 years (SD = 9.4). Higher impulsivity was associated with a worse epilepsy seizure outcome (p < 0.05), one year after surgery. According to the multiple linear regression analysis, a worse epilepsy seizure outcome was associated with higher levels of nonplanning impulsivity (p < 0.05) (p < 0.05, ß -0.5, r2 0.25). The GAF score was negatively associated with motor score (p < 0.05, ß -0.584, r2 0.42) and with the total BIS-11 score (p < 0.05, ß -0.557, r2 0.39). CONCLUSIONS: Impulsivity has been associated with a worse post-surgical seizure outcome. Larger studies about impulsivity might confirm these preliminary findings.

Diagnostic Performance of MRI Volumetry in Epilepsy Patients With Hippocampal Sclerosis Supported Through a Random Forest Automatic Classification Algorithm.

Introduction: Several methods offer free volumetry services for MR data that adequately quantify volume differences in the hippocampus and its subregions. These methods are frequently used to assist in clinical diagnosis of suspected hippocampal sclerosis in temporal lobe epilepsy. A strong association between severity of histopathological anomalies and hippocampal volumes was reported using MR volumetry with a higher diagnostic yield than visual examination alone. Interpretation of volumetry results is challenging due to inherent methodological differences and to the reported variability of hippocampal volume. Furthermore, normal morphometric differences are recognized in diverse populations that may need consideration. To address this concern, we highlighted procedural discrepancies including atlas definition and computation of total intracranial volume that may impact volumetry results. We aimed to quantify diagnostic performance and to propose reference values for hippocampal volume from two well-established techniques: FreeSurfer v.06 and volBrain-HIPS. Methods: Volumetry measures were calculated using clinical T1 MRI from a local population of 61 healthy controls and 57 epilepsy patients with confirmed unilateral hippocampal sclerosis. We further validated the results by a state-of-the-art machine learning classification algorithm (Random Forest) computing accuracy and feature relevance to distinguish between patients and controls. This validation process was performed using the FreeSurfer dataset alone, considering morphometric values not only from the hippocampus but also from additional non-hippocampal brain regions that could be potentially relevant for group classification. Mean reference values and 95% confidence intervals were calculated for left and right hippocampi along with hippocampal asymmetry degree to test diagnostic accuracy. Results: Both methods showed excellent classification performance (AUC:> 0.914) with noticeable differences in absolute (cm3) and normalized volumes. Hippocampal asymmetry was the most accurate discriminator from all estimates (AUC:1~0.97). Similar results were achieved in the validation test with an automatic classifier (AUC:>0.960), disclosing hippocampal structures as the most relevant features for group differentiation among other brain regions. Conclusion: We calculated reference volumetry values from two commonly used methods to accurately identify patients with temporal epilepsy and hippocampal sclerosis. Validation with an automatic classifier confirmed the principal role of the hippocampus and its subregions for diagnosis.

Navegando por la fisura silviana: anatomía microquirúrgica, neuroimágenes y técnica quirúrgica / Navigating the sylvian fissure: microsurgical anatomy, neuroimaging, and surgical technique

Objetivo: Describir la anatomía quirúrgica de la fisura silviana (FS) a través de disecciones cadavéricas y neuroimágenes; desarrollar su aplicación microquirúrgica. Materiales y métodos: Se estudiaron 10 hemisferios cadavéricos humanos fijados y un cráneo humano en seco, a través de la disección de fibras blancas y de la anatomía arterial y neural, utilizando un microscopio quirúrgico. Las arterias cerebrales fueron inyectadas con silicona coloreada. La anatomía quirúrgica fue correlacionada con la anatomía neuroimagenológica. Finalmente, se recolectó la experiencia microquirúrgica adquirida y, a su vez, la anatomía del Complejo Silviano, fue revisada. Resultados: La FS se extiende desde la cara basal a la lateral del cerebro. Cada superficie tiene una parte superficial (tronco silviano y sus ramos), intermedia (compartimientos anterior y opercular lateral) y profunda (compartimiento esfenoidal, hendidura insular anterior y lateral y la región retroinsular). En 7 de los 10 hemisferios, el surco central no se intersectó con la FS en la superficie lateral del cerebro. En el 80% de los hemisferios, la principal bifurcación de la arteria cerebral media se localizó en o proximal al limen insular. Debajo de la pars triangularis se localiza el punto más ancho de la superficie lateral de la FS. Los autores comienzan la disección de la misma en o proximalmente a este punto. Conclusiones: El conocimiento anatómico profundo y su aplicación a las neuroimágenes, son herramientas esenciales para el planeamiento prequirúrgico y son requisitos mandatorios para operar con seguridad a través y alrededor de la FS

Objective: The aim of this study is to describe the microsurgical anatomy of the sylvian fissure, through cadaveric dissections and neuroimaging and to elucidate its clinical application for microsurgery. Methods: One human skull and ten cadaveric human hemispheres were studied through white matter fiber dissections and arterial and neural anatomy of the sylvian fissure and insular dissections under the microscope. The cerebral arteries were perfused with colored latex. The surgical anatomy was correlated with neuroimaging anatomy. Finally, the microsurgical experienced gained applying this anatomical knowledge was gathered, and the literature about the anatomy of the sylvian complex was revised, as well. Results: The Sylvian fissure extends from the basal to the lateral surface of the brain. Each surface has a superficial (sylvian stem and its rami), intermediate (anterior and lateral opercular compartments) and deep parts (sphenoidal compartment, anterior and lateral insular clefts and retroinsular region). In 7 out of 10 hemispheres, the central sulcus did not intersect with the sylvian fissure on the lateral surface of the brain. In 80% of the hemispheres, the middle cerebral artery main bifurcation was localized at or proximal to the limen insulae. Beneath the pars triangularis, the widest point of the lateral surface of the sylvian fissure is located. The authors start dissecting the sylvian fissure at this point. Conclusion: The thorough anatomical knowledge with its clinical application in modern neuroimaging are essential tools for preoperative planning and are mandatory requisites to safely operate through and around the sylvian fissure anatomical complex.

Single Neuron Coding of Identity in the Human Hippocampal Formation.

Experimental findings show the ubiquitous presence of graded responses and tuning curves in the neocortex, particularly in visual areas [1-15]. Among these, inferotemporal-cortex (IT) neurons respond to complex visual stimuli, but differences in the neurons' responses can be used to distinguish the stimuli eliciting the responses [8, 9, 16-18]. The IT projects directly to the medial temporal lobe (MTL) [19], where neurons respond selectively to different pictures of specific persons and even to their written and spoken names [20-22]. However, it is not clear whether this is done through a graded coding, as in the neocortex, or a truly invariant code, in which the response-eliciting stimuli cannot be distinguished from each other. To address this issue, we recorded single neurons during the repeated presentation of different stimuli (pictures and written and spoken names) corresponding to the same persons. Using statistical tests and a decoding approach, we found that only in a minority of cases can the different pictures of a given person be distinguished from the neurons' responses and that in a larger proportion of cases, the responses to the pictures were different to the ones to the written and spoken names. We argue that MTL neurons tend to lack a representation of sensory features (particularly within a sensory modality), which can be advantageous for the memory function attributed to this area [23-25], and that a full representation of memories is given by a combination of mostly invariant coding in the MTL with a representation of sensory features in the neocortex.

Case Report of Worth Syndrome and Chiari I Malformation: Unusual Association and Surgical Treatment.

BACKGROUND: Worth syndrome or autosomal dominant endosteal hyperostosis (ADEH) is an extremely rare genetic disease involving increased bone density. To the author's knowledge, this is the second case report of a family with neurologic involvement associated with this condition along with its surgical treatment. The most effective treatment for clinically significant neurologic symptoms in this scenario is currently unknown, and there is sparse experience on surgical treatment for this condition reported in the literature. Therefore we aim to make a contribution to the identification of a standard and consistently successful surgical management. CASE DESCRIPTION: Two patients, mother (Patient 1) and daughter (Patient 2), were diagnosed with Worth syndrome. Both presented with the typical facial characteristics described for ADEH. Interestingly, Patient 1 presented the novel mutation in the LRP5 gene that is associated with different conditions involving increased bone density. Although neurologic symptoms are infrequent in ADEH, both referred chronic headache, nausea, and vomiting. Neuroimaging showed an increased cranial bone density and Chiari I malformation. The patients underwent a midline suboccipital craniectomy with excision of the posterior arch of C1 and duroplasty. However, due to a symptomatic recurrence 5 years after surgery, Patient 1 was reoperated on. We extended the craniectomy and also carried out a C2 laminectomy. CONCLUSION: After surgical interventions, patients' neurologic symptoms were successfully resolved. This report shows that posterior fossa decompression including duroplasty may be a valid treatment option in case of neurologic involvement.

Far-Lateral Approach Without Drilling the Occipital Condyle for Vertebral Artery-Posterior Inferior Cerebellar Artery Aneurysms.

BACKGROUND: The far-lateral transcondylar surgical approach is often used to clip vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms. The role of condyle resection during this approach is controversial. OBJECTIVE: To evaluate patient outcomes in patients with VA-PICA aneurysms in whom drilling the occipital condyle was not necessary. METHODS: Between May 2005 and December 2012, a total of 56 consecutive patients with incidental or ruptured VA-PICA aneurysms underwent surgery with a far-lateral approach without condylar resection. Clinical presentation, surgical reports, presurgery and postsurgery radiological examinations, and clinical follow-up reports were assessed. Anatomic aneurysm location was analyzed through angiography or computed tomography angiography. We compared postsurgical Glasgow Outcome Scale scores, modified Rankin Scale scores, and morbidity in 2 groups: those with aneurysms in the anterior medullary segment and those with aneurysms in the lateral medullary segment. RESULTS: The predominant presentation was subarachnoid hemorrhage in 34 patients (60.7%). Most aneurysms (n = 27 [48.2%]) were located in the lateral medullary segment of the PICA, followed by the anterior medullary segment (n = 25 [44.6%]). Total aneurysm occlusion was achieved in 100% of patients, and bypass techniques were necessary in 3 patients (5.4%). Fifty-two patients (92.8%) had Glasgow Outcome Scale scores of 4 or 5 postsurgery. CONCLUSIONS: A far-lateral approach that leaves the occipital condyle intact is adequate for treating most patients with VA-PICA aneurysms.

Quantitative Anatomical Study of Tailored Far-Lateral Approach for the VA-PICA Regions.

Objective The extent of the far-lateral approach (FLA) has not yet been quantified for the region of the vertebral and posterior inferior cerebellar arteries (VA-PICA). We quantitatively analyzed six main sequential steps of the FLA. Methods A modified small FLA (msFLA) and a classic large FLA (clFLA) were performed sequentially on both sides of five cadaveric heads. A frameless navigational system was used to quantify the angle of attack for the origin (T1) and lateral medullary segment (T2) of the PICA and the surgical area of exposure above and below the vagus nerve (cranial nerve [CN] X). Results The total area of exposure above CN X increased significantly (p < 0.05) from the msFLA to the clFLA. However, the surgical exposure area below CN X did not change (p > 0.05). C1 hemilaminectomy increased (p < 0.05) the vertical angle of attack, and drilling the posteromedial third of the occipital condyle increased (p < 0.05) the horizontal angle of attack to the origin of the PICA. Conclusions For the VA-PICA region, the msFLA offered a similar practical surgical working area and similar angles of attack when compared with the clFLA. The FLA should be tailored based on the location, size, and pathology of lesions and on the exposure required for effective surgical treatment.

Correlación entre el defecto del campo visual y tractografía postoperatoria en casos de cirugía de epilepsia por esclerosis temporomesial. Estudio anátomo-imagenológico del fascículo de Meyer / Correlation between visual field defect and postoperative tractography in cases of epilepsy surgery due to temporomandibular sclerosis. Anatomic-imaging study of Meyer's fascicle

Objetivo: describir la anatomía del fascículo de Meyer (FM) y los resultados del campo visual computarizado (CVC) y tractografía, por tensor de difusión (TTD) en la identificación del compromiso de este fascículo en pacientes tratados quirúrgicamente por epilepsia refractaria. Introducción: Hasta un 80% de los pacientes con epilepsia temporo-mesial asociada a esclerosis hipocampal son refractarios a la medicación. Para estos pacientes la cirugía es un tratamiento bien establecido y efectivo. No obstante son frecuentes los defectos del campo visual por lesión del FM luego de este tipo de procedimientos. Materiales y métodos: Se realizó disección de fibras blancas de tres cerebros humanos, fijados en formaldehído, mediante la técnica de Klingler, con el fin de reconocer los fascículos que conforman la vía visual en la profundidad del lóbulo temporal. A su vez, se estudiaron 8 pacientes sometidos a lobectomía temporal anterior y amigdalohipocampectomía por esclerosis temporomesial, realizándose TTD y CVC, al menos 3 meses después de la cirugía. Los individuos se clasificaron en cuatro grupos según el defecto campimétrico y se realizaron distintas mediciones en tractografía y resonancia magnética. Finalmente se correlacionaron los resultados de las distintas variables y se realizó una extensa revisión bibliográfica...

Objective: to describe the anatomy of the Meyer´s loop (ML) and the results of computerized visual field (CVF) and diffusion tensor tractography (DTT) to identify the damage of this fascicle in patients surgically treated for refractory epilepsy secondary to mesial-temporal sclerosis. Introduction: Up to 80% of patients with temporo-mesial epilepsy associated with hippocampal sclerosis are refractory to medication. For these patients, surgery is a well established and effective treatment. However visual field defects are frequent by optic radiation´s injury after these procedures. Materials and methods: We performed the dissection of white fibers on three human brains, previously fixed in formaldehyde, by Klingler´s technique, to recognize the fascicles that make up the visual pathway in the depth of the temporal lobe. Then, eight patients submitted to anterior temporal lobectomy and amygdalohippocampectomy were studied performing CVF and TTD at least 3 months after surgery. Individuals were classified into four groups according to visual field defects and other measurements in magnetic resonance imaging and tractography. Finally the results of the different variables were correlated and an extensive review of literature was performed...

Utilización de la vía transcoroidal para craneofaringioma recidivado / Utilization of the transchoroidal approach for the recidivant craniopharingioma

Objetivos. Describir la anatomía quirúrgica del abordaje transcoroidal al tercer ventrículo por vía transcallosa anterior. Describir y comparar los otros corredores posibles, y presentar dos casos de craneofaringioma recidivado tratados por esta vía de abordaje. Material y método: Se estudiaron las estructuras involucradas en tres especímenes cadavéricos fijados e inyectados para este menester. Se revisaron las Historias Clínicas, estudios, partes quirúrgicos y fotos intraoperatorias de dos casos de craneofaringioma recidivado tratados en nuestro Servicio. Ambos eran gigantes y comprometían el tercer ventrículo en su parte anterior. Para su análisis se tuvo en cuenta las clasificaciones de craneofaringiomas de Samii y de Yasargil. Resultados: La tela coroidea se adhiere al trígono por la tenia fórnices, y al tálamo por la tenia thalami. Consta de una membrana superior, que yace debajo del trígono, un espacio vascular, por donde circulan las venas cerebrales internas y las arterias coroideas posteromediales, y una membrana inferior, que forma el techo del tercer ventrículo y porta el plexo coroideo del mismo. El abordaje transcoroideo ingresa por la tenia fórnices, reclina el trígono y atraviesa la tela coroidea sin sacrificar estructuras vasculares. En ambos pacientes se pudo reducir la masa tumoral parcialmente, vaciando los quistes existentes y colocando un catéter con reservorio en el componente quístico. Ambos pacientes evolucionaron favorablemente. En un caso no se observó recidiva después de 11 meses. En el otro, se realizan punciones cada 4-5 meses para vaciamiento del quiste, por cefalea y disminución de la agudeza visual (follow up 20 meses). Conclusiones: La vía transcoroidal no es un abordaje de elección para el tratamiento de los craneofaringiomas...

Objective. To describe the surgical anatomy of transcallosal transchoroidal approach to the third ventricle. The other corridors are also analyzed and compared. To present two cases ofrelapsing craniopharyngiomas treated through this approach. Material and methods. Three fixed and injected brains were prepared to study the involved structures. The clinical reports of two patients with relapsing craniopharyngiomas treated in ourService were analyzed. Both were giant and involved the anterior third ventricle and were classified after the scales ofSamii and Yasargil. Results. The velum interpositum adheres to the fornix by thetenia fornices and to the thalamus by the tenia thalami. It consists of three layers. The superior lays under the fornix. Theintermediate is the vascular layer and contains the internal cerebral veins and the posteromedial choroidal arteries. Thethird forms the roof of the third ventricle and carries the chorioid plexus of the third ventricle. The transchoroidal approach goes through the tenia fornices, opens the tree layers of the tela chorioidea passing between the internal cerebral veins, without sacrificing vascular structures. In both patients it could be possible to reduce partially the tumor, empty the cysts, and leave an indwelling catheter with reservoir draining the cysts. In one patient there is no relapse in 11 months. By the other, sporadic punctures (every 5-6 months) of the reservoir areneeded to drain the cyst, when the patient becomes symptomatic, after 20 months of follow up. Conclusion. The transchoroidal corridor is not the preferred election approach for the surgical treatment of craniopharyngiomas. However, in recidivant cases, postoperative and scartissue in the tumoral loge may hinder the identification of vascular, nervous and functional structures; the selection a“virgin” approach that allows a correct identification of these structures is desirable...