Motor cortical stimulation for the treatment of trigeminal neuropathic pain secondary to an arteriovenous malformation. A case report.

INTRODUCTION: Trigeminal neuropathic pain (TNP) is a syndrome of severe, disabling, constant facial pain arising from the trigeminal nerve or ganglion. Arteriovenous malformations (AVM) are a rare cause of TNP. The limited choices of intervention of TNP include peripheral nerve stimulation, trigeminal nucleotomy and motor cortex stimulation. CASE REPORT: We present a 56-year-old man who suffered from trigeminal neuropathic pain secondary to nerve compression due to a giant posterior fossa AVM. The pain was refractory to drug treatment. From all the therapeutic options available we declined the microvascular decompression of the trigeminal nerve due to the presence of the giant AVM, or stereotactic radiosurgery because of the AVM´s diffuse nidus. After a multidisciplinary discussion we proposed a minimally invasive, safe and reversible treatment: Motor Cortical Stimulation (MCS). We placed a 16-pole epidural electrode on the right precentral gyrus. The patient had satisfactory pain control with some supplemental medication. No complications or side effects such as seizures, sensory disturbances or infections were presented. DISCUSSION: The limited choices of intervention of TNP include peripheral nerve stimulation, trigeminal nucleotomy and MCS. Henssen et al performed a systematic review where they investigated the effectiveness of MCS and discovered that this is significantly different among different chronic neuropathic orofacial pain disorders. A visual analogue scale (VAS) measured median pain relief of 66.5% was found. CONCLUSION: MCS should be one more tool to consider in highly selected cases, when other treatments are unfeasible.

Introducción: El dolor neuropático trigeminal (DNT) es un síndrome de dolor facial intenso, incapacitante y constante que surge del nervio o ganglio del trigémino. Las malformaciones arteriovenosas (MAV) son una causa rara de DNT. Las opciones terapéuticas de DNT incluyen la estimulación de los nervios periféricos, la nucleotomía del trigémino y la estimulación cortical motora. Caso clínico: Presentamos el caso de un varón de 56 años con dolor neuropático trigeminal secundario a compresión nerviosa por una MAV gigante de fosa posterior. El dolor era refractario al tratamiento farmacológico. De todas las opciones terapéuticas disponibles, desestimamos la descompresión microvascular del nervio trigémino por la presencia de la MAV gigante, o la radiocirugía estereotáctica, por ser difuso el nido de la MAV. Tras una discusión multidisciplinar propusimos un tratamiento mínimamente invasivo, seguro y reversible: Estimulación cortical motora (ECM). Colocamos un electrodo epidural en el giro precentral derecho. El paciente tuvo un control satisfactorio del dolor con medicación suplementaria. No presentó complicaciones ni efectos secundarios como convulsiones, alteraciones sensoriales o infecciones. Discusión: Las opciones limitadas de intervención de DNT incluyen estimulación nerviosa periférica, nucleotomía trigeminal y ECM. Henssen et al realizaron una revisión sistemática donde investigaron la efectividad de MCS y descubrieron que esto es significativamente diferente entre los diferentes trastornos de dolor orofacial neuropático crónico. Se encontró un promedio de alivio del dolor medida por una escala analógica visual del 66,5%. Conclusión: La ECM debería ser una herramienta más a considerar en casos estrictamente seleccionados donde otros tratamientos no son viables.

Colgajo axial de fascia temporoparietal (TPFF) para cobertura de dispositivo de estimulación cerebral profunda. Reporte de caso / Axial temporoparietal fascia flap (TPFF) for deep brain stimulation device coverage. Case report

Presentamos el caso de una paciente con enfermedad de Parkinson y extrusión del fijador craneal del electrodo de estimulación cerebral profunda. Luego del explante de todo el sistema, se realizó un colgajo axial de fascia temporoparietal (TPFF) para cobertura del trépano residual y en el segundo tiempo se utilizó el colgajo para cubrir el nuevo implante. La paciente no presentó complicaciones durante el seguimiento de 2 años

We present the case of a patient with Parkinson's disease and extrusion of the cranial fixation of the deep brain stimulation electrode. After explantation of the entire system, an axial flap of temporoparietal fascia (TPFF) was performed to cover the residual Burr hole, and in the second procedure, the flap was used to cover the new implant. The patient did not experience any complications during the 2-year follow-up period.

Saccular intracranial neonatal aneurysm.

INTRODUCTION: Neonatal cerebral aneurysms are very rare condition and distinct from those of the adults. CASE REPORT: We reported a 14-day-old male neonate who presented subarachnoid hemorrhage due to a ruptured anterior cerebral artery saccular aneurysm. In addition, we present a review of the relevant literature. CONCLUSION: Intracranial hemorrhage due to cerebral aneurysm rupture in a newborn is an uncommon diagnosis, but it must be unequivocally excluded.

Experiencia de la neuromodulación en un hospital de alta complejidad / High Complexity Hospital ́s experience in neuromodulation

La neuromodulación es una práctica médica implementada desde hace más de cuatro décadas. En lo que respecta a la Neurocirugía, cumple un papel en el tratamiento de diversas patologías (Parkinson, distonías, epilepsia, etc.) y con un gran potencial para aplicarlas en otras (trastorno obsesivo compulsivo [TOC], dolor pélvico). Es por ello que, en los últimos años, se cuadruplicaron las inversiones de empresas biotecnológicas en este campo por la demanda y aplicación de la terapia. La neuromodulación abarca también otras especialidades, como por ejemplo Otorrinolaringología (ORL) en implantes cocleares, Cardiología con diversos modelos de marcapasos cardíacos, Endocrinología con bombas de infusión de medicamentos, Uroginecología en incontinencia, etcétera. Nuestra institución aplica en su práctica clínica todas estas técnicas, y cumple una función jerárquica como centro de referencia en educación y políticas sanitarias. Por estos aspectos, sumados a su infraestructura, personal profesional y enfoque sanitario, puede ser considerada como un Centro de Neuromodulación referente en la región. (AU)

Neuromodulation is a medical practice established for more than forty years. In the neurosurgical field it plays a role in the treatment of different diseases (Parkinson, Dystonia, Epilepsy, etc) and has a great potential to apply in other pathologies (Obsessive Compulsive Disorder, Pelvic pain). In the last years the biotechnological industry has quadrupled the investment in this field because of the demand and therapy application. Neuromodulation encompasses other specialities, for example otorhinolaryngology in cochlear implants, in cardiology with different models of pacemakers, endocrinology with implanted infusion pumps, urological gynecology in incontinence treatments, etc. Our institution applies all these techniques in its clinical practice, having a hierarchical role as a reference center in education and health policies. Due to these aspects, added to its infrastructure, professional staff and health approach, it can be considered as a reference Neuromodulation Center in the region. (AU)

Resección transoral de la apófisis estiloides por síndrome de Eagle: caso clínico / Transoral resection of the stiloyd process for Eagle síndrome: case report

El síndrome de Eagle está caracterizado por una elongación o una curvatura medial excesiva de la apófisis estiloides o por una calcificación del ligamento estilohioideo que puede provocar dolor cervicofacial o síntomas neurológicos por la compresión de los vasos o nervios del cuello. El tratamiento más eficaz es el quirúrgico y consiste en la resección de la apófisis estiloides; puede ser realizado por vía externa o mediante un abordaje transoral. Se describe el caso clínico de un paciente con síndrome de Eagle que fue tratado con éxito mediante un abordaje transoral, sin amigdalectomía y con asistencia de endoscopios. (AU)

Eagle syndrome is characterized by an elongation or excessive medial curvature of the styloid process or calcification of the stylohyoid ligament that can cause cervicofacial pain or neurological symptoms due to compression of the vessels or nerves of the neck. The most effective treatment is surgical and consists of resection of the styloid process, it can be performed by externally or through a transoral approach.The clinical case of a patient with Eagle syndrome who was successfully treated by a transoral approach, without tonsillectomy and with the assistance of endoscopes, is described. (AU)

Neurocirugía en época de COVID-19. Protocolo de actuación / Neurosurgery in the time of COVID-19. Action protocol

El manejo de pacientes debido a la aparición del nuevo coronavirus 2019 (COVID-19) representa un desafío para los equipos médicos y quirúrgicos, ya que modificó el funcionamiento de los sistemas de salud en casi todo el mundo. Para contribuir a la re organización del sistema de salud, el Servicio de Neurocirugía del Hospital Italiano de Buenos Aires trabajó en adoptar distintas medidas en concordancia con las tomadas a nivel institucional y nacional; por lo que se analizó la bibliografia publicada, asi como las normas dictadas por el comité de crisis de nuestra institucion. A su vez realizamos una breve encuesta dirigida a neurocirujanos de america latina para conocer como se manejaban actualmente en relación a niveles de protección y realización de cirugias. La actual pandemia de COVID-19 es el mayor desafío que enfrentan los sistemas nacionales de salud en los últimos tiempos. Los neurocirujanos podemos contribuir a la reducción del riesgo de infección nosocomial de los trabajadores de la salud al adaptar distintos protocolos en pacientes con COVID-19.

Patient's management due to the appearance of new coronavirus 2019 (COVID-19) represents a challenge for medical and surgical departments, since it modified the running of health systems in almost all the world. In order to help in this new situation, the Neurosurgical Department of our institution has adopted different measures in accordance with those taken at institutional and national level. In order to do this, we made a literature review and we added to this, the norms dictated by the crisis committee of our hospital. We also carried out a brief survey among neurosurgeons from Latin America to find out how they managed protection levels in relation to surgery. COVID-19 pandemic is certainly one of the greatest challenge national health systems face in a century. Adapting different protocols in neurosurgical patients with COVID-19 can contribute in reducing the risk of nosocomial infection of health workers.

Time to Face Language: Embodied Mechanisms Underpin the Inception of Face-Related Meanings in the Human Brain.

In construing meaning, the brain recruits multimodal (conceptual) systems and embodied (modality-specific) mechanisms. Yet, no consensus exists on how crucial the latter are for the inception of semantic distinctions. To address this issue, we combined electroencephalographic (EEG) and intracranial EEG (iEEG) to examine when nouns denoting facial body parts (FBPs) and nonFBPs are discriminated in face-processing and multimodal networks. First, FBP words increased N170 amplitude (a hallmark of early facial processing). Second, they triggered fast (~100 ms) activity boosts within the face-processing network, alongside later (~275 ms) effects in multimodal circuits. Third, iEEG recordings from face-processing hubs allowed decoding ~80% of items before 200 ms, while classification based on multimodal-network activity only surpassed ~70% after 250 ms. Finally, EEG and iEEG connectivity between both networks proved greater in early (0-200 ms) than later (200-400 ms) windows. Collectively, our findings indicate that, at least for some lexico-semantic categories, meaning is construed through fast reenactments of modality-specific experience.

Dissociable Neural Information Dynamics of Perceptual Integration and Differentiation during Bistable Perception.

At any given moment, we experience a perceptual scene as a single whole and yet we may distinguish a variety of objects within it. This phenomenon instantiates two properties of conscious perception: integration and differentiation. Integration is the property of experiencing a collection of objects as a unitary percept and differentiation is the property of experiencing these objects as distinct from each other. Here, we evaluated the neural information dynamics underlying integration and differentiation of perceptual contents during bistable perception. Participants listened to a sequence of tones (auditory bistable stimuli) experienced either as a single stream (perceptual integration) or as two parallel streams (perceptual differentiation) of sounds. We computed neurophysiological indices of information integration and information differentiation with electroencephalographic and intracranial recordings. When perceptual alternations were endogenously driven, the integrated percept was associated with an increase in neural information integration and a decrease in neural differentiation across frontoparietal regions, whereas the opposite pattern was observed for the differentiated percept. However, when perception was exogenously driven by a change in the sound stream (no bistability), neural oscillatory power distinguished between percepts but information measures did not. We demonstrate that perceptual integration and differentiation can be mapped to theoretically motivated neural information signatures, suggesting a direct relationship between phenomenology and neurophysiology.

Consistent Gradient of Performance and Decoding of Stimulus Type and Valence From Local and Network Activity.

The individual differences approach focuses on the variation of behavioral and neural signatures across subjects. In this context, we searched for intracranial neural markers of performance in three individuals with distinct behavioral patterns (efficient, borderline, and inefficient) in a dual-valence task assessing facial and lexical emotion recognition. First, we performed a preliminary study to replicate well-established evoked responses in relevant brain regions. Then, we examined time series data and network connectivity, combined with multivariate pattern analyses and machine learning, to explore electrophysiological differences in resting-state versus task-related activity across subjects. Next, using the same methodological approach, we assessed the neural decoding of performance for different dimensions of the task. The classification of time series data mirrored the behavioral gradient across subjects for stimulus type but not for valence. However, network-based measures reflected the subjects' hierarchical profiles for both stimulus types and valence. Therefore, this measure serves as a sensitive marker for capturing distributed processes such as emotional valence discrimination, which relies on an extended set of regions. Network measures combined with classification methods may offer useful insights to study single subjects and understand inter-individual performance variability. Promisingly, this approach could eventually be extrapolated to other neuroscientific techniques.

Identification of a somatic mutation in the RHEB gene through high depth and ultra-high depth next generation sequencing in a patient with Hemimegalencephaly and drug resistant Epilepsy.

Malformations of cortical development are a frequent cause of drug-resistant Epilepsy and developmental delay. Hemimegalencephaly is a Malformation of cortical development characterized by enlargement of all or a part of one cerebral hemisphere. Germline and somatic mutation in genes belonging to the Mammalian Target of Rapamycin (mTOR) pathway has been identified in patients suffering from epilepsy secondary to Hemimegalencephaly and focal cortical dysplasia. We present here a patient suffering from severe neonatal Epilepsy since 3 h of life secondary to Hemimegalencephaly, requiring an anatomic hemispherectomy surgical procedure for seizure control, where by means of next-generation sequencing at an ultra-high depth coverage, we were able to identify a novel somatic mutation in the RHEB gene (NM_005614: c.119A > T: p. Glu40Val). The histopathological diagnosis was Cortical Dysplasia type IIB determined by the presence of dysmorphic neurons of variable size with nuclear alteration and balloon cells in the context of Hemimegalencephaly, which are similar to that have been demonstrated in hyperactivating RHEB models. This is the first report of a somatic mutation in RHEB gene in a patient suffering from Epilepsy secondary to Hemimegalencephaly. It highlights different current topics in the fields of genetics of Malformations of cortical development: a-somatic mosaicism is not uncommon in these neurodevelopmental disorders; b-the molecular diagnostic approach should involve the use of state-of-the-art methods and the sampling of different tissues; c-new findings might facilitate therapeutics discoveries while providing an improved understanding of normal brain development.

Application of Fibrin Rich in Leukocytes and Platelets in the Reconstruction of Endoscopic Approaches to the Skull Base.

BACKGROUND: The objective of this work is to report the feasibility and results of an institutional protocol for the application of an innovative biologically active hemoderivative autologous material, denominated leukocyte- and platelet-rich fibrin (L-PRF), in the reconstruction of endoscopic approaches to the sellar region. METHODS: L-PRF membranes were produced from centrifuged autologous venous blood. They were used for the reconstruction of transsphenoidal endoscopic approaches to the sellar region in 12 patients. The trophism of the mucosa was monitored during the first 30 days by means of fiberoptic endoscopic controls on the second and seventh postoperative days. Follow-up was performed to rule out complications up to 30 postoperatively days. RESULTS: The product obtained bore the characteristics of the original descriptions of L-PRF. Standardized preparation of L-PRF membranes promoted early regeneration of the sphenoid sinus mucosa to close endoscopic approaches to the sellar region. No complications within the first 30 postsurgical days were reported. CONCLUSIONS: L-PRF membranes offer characteristics that are superior to other techniques and products, mainly because of their role as biological promoters of tissue regeneration, their low economic cost, and immediate availability. However, it would be necessary to confirm these results in studies involving more patients.

Intracranial high-γ connectivity distinguishes wakefulness from sleep.

Neural synchrony in the γ-band is considered a fundamental process in cortical computation and communication and it has also been proposed as a crucial correlate of consciousness. However, the latter claim remains inconclusive, mainly due to methodological limitations, such as the spectral constraints of scalp-level electroencephalographic recordings or volume-conduction confounds. Here, we circumvented these caveats by comparing γ-band connectivity between two global states of consciousness via intracranial electroencephalography (iEEG), which provides the most reliable measurements of high-frequency activity in the human brain. Non-REM Sleep recordings were compared to passive-wakefulness recordings of the same duration in three subjects with surgically implanted electrodes. Signals were analyzed through the weighted Phase Lag Index connectivity measure and relevant graph theory metrics. We found that connectivity in the high-γ range (90-120 Hz), as well as relevant graph theory properties, were higher during wakefulness than during sleep and discriminated between conditions better than any other canonical frequency band. Our results constitute the first report of iEEG differences between wakefulness and sleep in the high-γ range at both local and distant sites, highlighting the utility of this technique in the search for the neural correlates of global states of consciousness.

Attention, in and Out: Scalp-Level and Intracranial EEG Correlates of Interoception and Exteroception.

Interoception, the monitoring of visceral signals, is often presumed to engage attentional mechanisms specifically devoted to inner bodily sensing. In fact, most standardized interoceptive tasks require directing attention to internal signals. However, most studies in the field have failed to compare attentional modulations between internally- and externally-driven processes, thus probing blind to the specificity of the former. Here we address this issue through a multidimensional approach combining behavioral measures, analyses of event-related potentials and functional connectivity via high-density electroencephalography, and intracranial recordings. In Study 1, 50 healthy volunteers performed a heartbeat detection task as we recorded modulations of the heartbeat-evoked potential (HEP) in three conditions: exteroception, basal interoception (also termed interoceptive accuracy), and post-feedback interoception (sometimes called interoceptive learning). In Study 2, to evaluate whether key interoceptive areas (posterior insula, inferior frontal gyrus, amygdala, and somatosensory cortex) were differentially modulated by externally- and internally-driven processes, we analyzed human intracranial recordings with depth electrodes in these regions. This unique technique provides a very fine grained spatio-temporal resolution compared to other techniques, such as EEG or fMRI. We found that both interoceptive conditions in Study 1 yielded greater HEP amplitudes than the exteroceptive one. In addition, connectivity analysis showed that post-feedback interoception, relative to basal interoception, involved enhanced long-distance connections linking frontal and posterior regions. Moreover, results from Study 2 showed a differentiation between oscillations during basal interoception (broadband: 35-110 Hz) and exteroception (1-35 Hz) in the insula, the amygdala, the somatosensory cortex, and the inferior frontal gyrus. In sum, this work provides convergent evidence for the specificity and dynamics of attentional mechanisms involved in interoception.

Epilepsy surgery in children and adolescents: Report on 43 cases. / Cirugía de la epilepsia en niños y adolescentes: experiencia de 43 casos.

Epilepsy surgery in children with refractory epilepsy is one of the most effective methods to control seizures. The proper selection and assessment of surgery candidates is critical for surgical treatment to be adequately effective and safe. The purpose of this article is to describe our experience with 43 consecutive pediatric patients that underwent epilepsy surgery for refractory epilepsy between September 2005 and May 2014. Effectiveness, safety, and prognostic factors were analyzed. The median age was 12 years old at the time of surgery and 4.5 years old at epilepsy onset, with a latency period of up to 6 years until surgery. Since the surgery, the 43 patients have been in follow-up for a median of 5.4 years (±2.3 years). Resective surgery was performed in 32 patients and hemispherectomy, in 11 patients. To date, 62.8% of patients remain seizure-free. Abetterprognosis was observed in patients who underwent surgery with a duration of epilepsy of less than two years and in patients in whom a complete resection of the epileptogenic zone was achieved.

La cirugía de la epilepsia en niños con epilepsia refractaria es uno de los métodos más efectivos para obtener el control de crisis epilépticas. La apropiada selección y evaluación de los candidatos esfundamentalpara alcanzar una adecuada efectividad y seguridad del tratamiento quirúrgico. El objetivo es presentar nuestra experiencia con 43 pacientes pediátricos consecutivos sometidos a tratamiento quirúrgico de su epilepsia refractaria entre septiembre de 2005 y mayo de 2014. Se analizó la efectividad, la seguridad y los factores pronósticos. La mediana de edad de la cirugía fue de 12 años y la mediana de edad del inicio de la epilepsia fue 4,5 años, con una latencia hasta la cirugía de 6 años. Los 43 pacientes se encuentran en seguimiento con una mediana de 5,4 años (±2,3) desde la cirugía. Los procedimientos realizados fueron, en 32 pacientes, cirugías resectivas y, en 11, desconexiones hemisféricas. Un 62,8% de los pacientes permanecen libres de crisis. Los pacientes que se operaron con una duración de la epilepsia menor de 2 años y en los que se pudo realizar una resección completa del área epileptógena presentaron un mejor pronóstico.

Early detection of intentional harm in the human amygdala.

A decisive element of moral cognition is the detection of harm and its assessment as intentional or unintentional. Moral cognition engages brain networks supporting mentalizing, intentionality, empathic concern and evaluation. These networks rely on the amygdala as a critical hub, likely through frontotemporal connections indexing stimulus salience. We assessed inferences about perceived harm using a paradigm validated through functional magnetic resonance imaging, eye-tracking and electroencephalogram recordings. During the task, we measured local field potentials in three patients with depth electrodes (n = 115) placed in the amygdala and in several frontal, temporal, and parietal locations. Direct electrophysiological recordings demonstrate that intentional harm induces early activity in the amygdala (<200 ms), which--in turn--predicts intention attribution. The amygdala was the only site that systematically discriminated between critical conditions and predicted their classification of events as intentional. Moreover, connectivity analysis showed that intentional harm induced stronger frontotemporal information sharing at early stages. Results support the 'many roads' view of the amygdala and highlight its role in the rapid encoding of intention and salience--critical components of mentalizing and moral evaluation.

Surgical treatment of focal symptomatic refractory status epilepticus with and without invasive EEG.

PURPOSE: Neurosurgery appears to be a reasonable alternative in carefully selected patients with refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE). We discuss the optimal timing of the surgery and the use of previous stereoelectroencephalography (SEEG) invasive evaluation. METHODS: We identified 3 patients (two pediatric and one adult) who underwent epilepsy surgery because of RSE or SRSE from our epilepsy surgery database, one of them with previous SEEG. RESULTS: Status epilepticus resolved acutely in all of them with no mortality and no substantial morbidity. At follow-up (median: 2 years), 1 patient was seizure-free, and 2 had significant improvement. CONCLUSION: Surgery should be considered in all cases of RSE and SRSE early in the course of the evolution of the disease.

Auditory Feedback Differentially Modulates Behavioral and Neural Markers of Objective and Subjective Performance When Tapping to Your Heartbeat.

Interoception, the perception of our body internal signals, plays a key role in maintaining homeostasis and guiding our behavior. Sometimes, we become aware of our body signals and use them in planning and strategic thinking. Here, we show behavioral and neural dissociations between learning to follow one's own heartbeat and metacognitive awareness of one's performance, in a heartbeat-tapping task performed before and after auditory feedback. The electroencephalography amplitude of the heartbeat-evoked potential in interoceptive learners, that is, participants whose accuracy of tapping to their heartbeat improved after auditory feedback, was higher compared with non-learners. However, an increase in gamma phase synchrony (30-45 Hz) after the heartbeat auditory feedback was present only in those participants showing agreement between objective interoceptive performance and metacognitive awareness. Source localization in a group of participants and direct cortical recordings in a single patient identified a network hub for interoceptive learning in the insular cortex. In summary, interoceptive learning may be mediated by the right insular response to the heartbeat, whereas metacognitive awareness of learning may be mediated by widespread cortical synchronization patterns.