The changing landscape of electrical stimulation language mapping with subdural electrodes and stereoelectroencephalography for pediatric epilepsy: A literature review and commentary.

Electrical stimulation mapping (ESM) is used to locate the brain areas supporting language directly within the human cortex to minimize the risk of functional decline following epilepsy surgery. ESM is completed by utilizing subdural grid or depth electrodes (stereo-electroencephalography [sEEG]) in combination with behavioral evaluation of language. Despite technological advances, there is no standardized method of assessing language during pediatric ESM. To identify current clinical practices for pediatric ESM of language, we surveyed neuropsychologists in the Pediatric Epilepsy Research Consortium. Results indicated that sEEG is used for functional mapping at >80% of participating epilepsy surgery centers (n = 13/16) in the United States. However, >65% of sites did not report a standardized protocol to map language. Survey results indicated a clear need for practice recommendations regarding ESM of language. We then utilized PubMed/Medline and PsychInfo to identify 42 articles that reported on ESM of language, of which 18 met inclusion criteria, which included use of ESM/signal recording to localize language regions in children (<21 years) and a detailed account of the procedure and language measures used, and region-specific language localization outcomes. Articles were grouped based on the language domain assessed, language measures used, and the brain regions involved. Our review revealed the need for evidence-based clinical guidelines for pediatric language paradigms during ESM and a standardized language mapping protocol as well as standardized reporting of brain regions in research. Relevant limitations and future directions are discussed with a focus on considerations for pediatric language mapping.

Depth versus surface: A critical review of subdural and depth electrodes in intracranial electroencephalographic studies.

Intracranial electroencephalographic (IEEG) recording, using subdural electrodes (SDEs) and stereoelectroencephalography (SEEG), plays a pivotal role in localizing the epileptogenic zone (EZ). SDEs, employed for superficial cortical seizure foci localization, provide information on two-dimensional seizure onset and propagation. In contrast, SEEG, with its three-dimensional sampling, allows exploration of deep brain structures, sulcal folds, and bihemispheric networks. SEEG offers the advantages of fewer complications, better tolerability, and coverage of sulci. Although both modalities allow electrical stimulation, SDE mapping can tessellate cortical gyri, providing the opportunity for a tailored resection. With SEEG, both superficial gyri and deep sulci can be stimulated, and there is a lower risk of afterdischarges and stimulation-induced seizures. Most systematic reviews and meta-analyses have addressed the comparative effectiveness of SDEs and SEEG in localizing the EZ and achieving seizure freedom, although discrepancies persist in the literature. The combination of SDEs and SEEG could potentially overcome the limitations inherent to each technique individually, better delineating seizure foci. This review describes the strengths and limitations of SDE and SEEG recordings, highlighting their unique indications in seizure localization, as evidenced by recent publications. Addressing controversies in the perceived usefulness of the two techniques offers insights that can aid in selecting the most suitable IEEG in clinical practice.

Comparative effectiveness of stereotactic, subdural, or hybrid intracranial EEG monitoring in epilepsy surgery.

OBJECTIVE: Surgical intervention can be curative or palliative for drug-resistant focal epilepsy. However, if the seizure onset zone (SOZ) cannot be adequately localized via noninvasive tests, intracranial EEG (iEEG) recordings are often carried out to develop surgical plans in appropriate candidates. Stereotactic EEG (SEEG), subdural EEG (SDE), and SDE with depth electrodes (hybrid) are major tools used for investigation, but there is no class 1 or 2 evidence comparing the effectiveness of these modalities. METHODS: The authors identified an institutional cohort of patients who underwent iEEG monitoring between 2001 and 2022. Demographic data, preoperative clinical features, iEEG intervention, and follow-up data were identified. Primary study endpoints included the following: 1) likelihood of SOZ localization; 2) likelihood of surgical treatment after iEEG; 3) seizure outcomes; and 4) complications. RESULTS: A total of 329 patients were identified (176 in the SEEG, 60 in the SDE, and 93 in the hybrid cohort) who were followed for a median of 5.4 (IQR 6.8) years. Baseline characteristics, including demographics, mean age at epilepsy diagnosis, mean age at iEEG investigation, number of preoperative antiseizure medications, and preoperative seizure frequency, were not statistically different across the 3 cohorts. Patients in the SEEG cohort were more likely to have their SOZ localized than were the patients in the SDE group (OR 2.3) and were less likely to undergo subsequent resection (OR 0.3) or to have complications (OR 0.4), although there was no statistical difference with respect to likelihood of undergoing any subsequent neurosurgical treatment, or with respect to favorable seizure outcomes. Patients in the hybrid cohort were more likely to have SOZ localized than were patients in the SDE group (OR 3.1), but were more likely to undergo resection (OR 4.9) or any neurosurgical treatment (OR 2.5) compared to patients in the SEEG group. Patients in the hybrid cohort had better seizure outcomes compared to the SDE (OR 2.3) but not to the SEEG group. CONCLUSIONS: Patients in the SEEG group were more likely to have their SOZ localized and patients in the SDE group were more likely to undergo resection, but they did not differ with respect to seizure outcomes.

Granuloma formation as a late complication of burr-hole surgery for chronic subdural hematoma.

BACKGROUND: Surgical treatment remains the mainstream therapeutic regimen for chronic subdural hematoma (CSDH), and burr-hole craniostomy with subdural drainage is the preferable approach. Herein, we reported a case of intracranial granuloma formation as a late complication of burr-hole surgery for CSDH. CASE PRESENTATION: A 31-year-old man presented with a 1-month history of headache. Head computed tomography (CT) showed a subdural hematoma in the left frontal-temporal-parietal region with significant midline shifting. A burr-hole evacuation of the hematoma with closed-system drainage was performed. CT obtained immediately after the surgery demonstrated that the hematoma was mostly evacuated. Nine months later, he presented to us again due to intermittent headache in the left temporoparietal region. Brain magnetic resonance imaging revealed a space-occupying mass at the site of the original hematoma. A bone-flap craniotomy was performed for resecting the mass. Histopathological examination revealed a granuloma. The microbial cultivation of the resected specimen was negative. The postoperative course was uneventful, and the headache was relieved. CONCLUSION: Granuloma formation is an extremely rare late complication of burr-hole surgery for CSDH. Physicians involved in the perioperative management of CSDH should be aware of this condition, and bone-flap craniotomy may be warranted.

Inyección subdural: complicación en la técnica peridural lumbar: revisión bibliográfica / Subdural injection: complication in lumbar epidural block: review of the literature

Se realiza una revisión bibliográfica sobre inyección subdural en la técnica peridural lumbar. se analizan los aspectos anatómicos, se describen las diferentes formas de presentación y su imagen radiológica, se discuten los criterios diagnósticos, los posibles efectos de la inyección en dicho espacio y la conducta a tomar, una vez detectada la complicación.

A bibliographic review about lumbar epidural subdural injection is done. the anatomic aspects, the different forms of presentation, and the radiological image are described. the diagnostic criteria, the effects of injection in this space and the management of the complication are discussed.

Inyección subdural: informe de dos casos / Subdural injection: report of two cases / Injeção subdural: reporte de dois casos

Se presentan dos casos de inyección subdural accidental durante procedimientos epidurales para control del dolor. El primero fue un hombre con dolor lumbar crónico quien sufrió dicha complicación durante la inyección epidural de esteroides por vía interlaminar; el segundo, una mujer con síndrome de hipotensión endocraneana que requirió la aplicación de un parche hemático epidural para controlar múltiples fístulas de LCR, que debió ser abortada en dos ocasiones debido al patrón subdural que se evidenció luego de la administración del medio de contraste. El bloqueo subdural accidental es una complicación rara de la inyección epidural con fines analgésicos o anestésicos. Es de suma importancia la identificación temprana del patrón de distribución subdural y epidural del medio de contraste con el fin de disminuir el riesgo y aumentar la seguridad de los procedimientos en el espacio epidural.

Two cases are reported of accidental subdural injection during epidural procedures for pain control. The first one was a man with chronic lumbar pain who suffered such complication during an epidural injection of steroids using the interlaminar approach. The second one was a woman with intracranial hypotension syndrome who required the application of an epidural blood patch in order to control multiple CSF fistulae. The procedure had to be aborted twice due to the subdural pattern observed after injection of the contrast medium. Accidental subdural block is a rare complication of epidural injection for analgesic or anesthetic procedures.

Se apresentam dois casos ocorridos durante a execução de procedimentos da prática diária do especialista de dor. O primeiro, um doente com diagnóstico de dor lombar crónico quem apresenta uma injeção subdural acidental durante uma injeção epidural de esteroides por via interlaminar; o segundo uma doentecom síndrome de hipotensão endocraniana quem precisou da colocação de um curativo hemático epidural o qual teve que ser abortado em 2 ocasiões devido ao padrão subdural que se evidenciou logo da administração de meio de contraste. O bloqueio subdural acidental é uma rara complicação da injeção epidural com fins analgésicos ou anestésicos. Por tanto, resulta de suma importância a precoce identificação do padrão de distribuição do meio de contraste subdural e epidural com o fim de diminuir o risco e aumentar a segurança dos procedimentos no espaço epidural.

Raquianestesia: prós e contras / Spinal anesthesia: pros and cons

O desenvolvimento da raquianestesia vem acontecendo há pouco mais de 100 anos. Da técnica inicial, muito se mudou, com instrumentais diferenciados, fármacos com melhor perfil, refinamento da técnica, assim como indicações e contraindicações mais precisas. Hoje, grande parte das cirurgias infraumbilicais é passível de serem realizadas sob raquianestesia, provendo estabilidade clínica e excelente analgesia pós-operatória. Para alguns segmentos populacionais, como idosos e gestantes, essa técnica ganhou ainda mais importância. Contudo, apesar de ser amplamente difundida, o bloqueio subaracnóideo tem limitações de uso, trazendo consigo, como qualquer outra técnica, vantagens e desvantagens. Este trabalho de revisão visa a relatar as principais vantagens e desvantagens do bloqueio subaracnóideo, elencando seu papel em grupos especiais e abordando as mais recentes descobertas sobre essa técnica.

The development of spinal anesthesia has been underway for just over 100 years. Much has changed from the initial technique, with different instruments, drugs with better profile, technical refinement and more precise indications and contraindications. Today, much of the infra-umbilical surgeries are likely to be performed under spinal anesthesia, providing clinical stability and excellent postoperative analgesia. For some population groups such as the elderly and pregnant women, this technique gained even more importance. However, despite being widespread, the spinal block has limitations of use, bringing with it like any other technique, advantages and disadvantages. This review paper aims at reporting the main advantages and disadvantages of spinal block, listing its role in special groups and addressing the latest discoveries about this technique.

El saco dural humano. Morfología de la dura-aracnoides espinal. Origen del espacio subdural espinal / The human dural sac. Morphology of the spinal dura-arachnoid membrane. Origin of the spinal subdural space

Esta revisión resume los hallazgos encontrados en el saco dural de cadáveres de recién fallecidos estudiados con diferentes técnicas histológicas. El saco dural espinal está formado por tres estructuras concéntricas: la duramadre, que ocupa el 85-90 por ciento de su espesor, del lado externo; el compartimiento subdural, integrado por células neuroteliales, y la lámina aracnoidea, que ocupa el 5 al 8 por ciento interno. La duramadre, que consta de aproximadamente 80 láminas durales concéntricas, es una estructura permeable y fibrosa, por lo cual posee resistencia mecánica. El compartimiento subdural es una estructura concéntrica, celular, de resistencia mecánica muy baja, donde se pueden producir fisuras concéntricas por rotura de las células neuroteliales dando origen a un espacio subdural adquirido. La lámina aracnoidea es una estructura celular con mayor resistencia mecánica que el compartimiento subdural. Sus células están firmemente unidas por uniones especializadas de membrana y forman una barrera semipermeable que regula el pasaje de sustancias a través del espesor del saco dural.

Cavum carotideo: controversia anatomía microquirúrquica / Carotid cave: controversy microsurgical anatomy

Debido a que la anatomía de esta región es compleja y variable, no ha sido comprendida adecuadamente. El cavum carotídeo se encuentra localizado en el segmento clinoideo, que es una zona de transición entre el espacio cavernoso y el subdural. La comprensión del segmento clinoideo es importante para el adecuado diagnóstico y manejo de aneurismas localizadas en esta compleja región. El abordaje quirúrgico depende de la localización exacta de la lesión. Este artículo revisa aspectos relevantes de la anatomía microquirúrgica del segmento clinoideo, cavum carotídeo y espacio clinoideo. Palabras claves: cavum carotídeo, segmento clinoideo, espacio clinoideo, anatomía microquirúrgica.

Seizure's outcome after cortical resections including the face and tongue rolandic areas in patients with refractory epilepsy and normal MRI submitted to subdural grids' implantation

PURPOSE: To study the seizure's outcome in patients with refractory epilepsy and normal MRI submitted to resections including the rolandic cortex. METHODS: Four adult patients were studied. All patients had motor or somatosensory simple partial seizures and normal MRI and were submitted to subdural grids' implantation with extensive coverage of the cortical convexity (1 in the non-dominant and 3 in the dominant hemisphere). RESULTS: ECoG was able to define focal areas of seizures' onset in every patient. All patients were submitted to resection of the face and tongue motor and sensitive cortex; two patients had resections including the perirolandic cortex and 2 had additional cortical removals. Three patients are seizures' free and one had a greater then 90 percent reduction in seizure frequency. CONCLUSION: Resections including the face and tongue rolandic cortex can be safely performed even within the dominant hemisphere

Secondary bilateral synchrony due to front-mesial lesions: an invasive recording study

Frontal lobe epilepsies may present difficulties in focus localization in the pre-operative work-up for epilepsy surgery. This is specially treu in patients with normal MRIs. We report on a 16 years-old girl that started with seizures by the age of 8 years. They were brief nocturnal episodes with automatisms such as bicycling and boxing. Seizure frequency ranged from 4-10 per night. Scalp EEG showed few right frontal convexity spiking and intense secondary bilateral syncrhony (SBS). High resolution MRI directed to the frontal lobes was normal. Ictal SPECT suggested a right fronto-lateral focus. Ictal video-EEG showed no focal onset. She was submitted to invasive recordings after subdural plates implantation. Electrodes covered all the frontal convexity and mesial surface bilaterally. Ictal recordings disclosed stereotyped seizures starting from the right mesial frontal. Using a high-resolution tool to measure intra and interhemispheric latencies, the timing and direction of seizure spread from the right fronto-mesial region were studied. Motor strip mapping was performed by means of electrial simulation. She was submitted to a right frontal lobe resection, 1,5 cm ahead of the motor strip and has been seizure free since surgery (8 months). Pathological examination found a 4 mm area of cortical dysplasia. Invasive studies are needed to allow adequate localization in patients with non-localizatory non-invasive work-up and may lead to excellent results in relation to seizures after surgery.

Empiema espinhal subdural: relato de um acso / Spinal subdural empyema: a case report

A raridade do empiema subdural pode ser verificada pela escassez de casos descritos na literatura. Os autores apresentam mais um caso, mostrando as dificuldades diagnósticas principalmente quando näo há aparente porta de entrada. Enfatizam, nestas circunstâncias, a importância de certos sinais clínicos, o valor da punçäo lombar e da imagem por ressonância nuclear magnética na elucidaçäo diagnóstica. Este último exame näo foi mencionado anteriormente na literatura consultada sobre o assunto. O tratamento cirúrgico, associado à antibioticoterapia, mostrou-se bastante eficaz, principalmente se realizado precocemente

Contribuiçäo da monitorizaçäo da pressäo intracraniana na hidrocefalia a pressäo normal / Intracranial pressure monitoring in normal pressure hydrocephalus

Säo apresentados 10 doentes com hidrocefalia a pressäo normal. O diagnóstico foi firmado pelo quadro clínico e pelos seguintes exames complementares: líquido cefalorraquiano, cisterno-cintilografia e tomografia computadorizada do crânio. Os 10 doentes foram submetidos a monitorizaçäo da pressäo intracraniana por metodologia subdural com um total de 675 horas de registro, durante os 3 primeiros dias. Os traçados de monitorizaçäo foram estudados do ponto de vista quantitativo e qualitativo. Näo houve registro, em nenhum caso, de valor da pressäo intracraniana acima da normalidade. Em todos os casos foram registradas alteraçöes qualitativas do traçado, representadas por ondas patológicas. Ondas tipo B de Lundberg foram registradas em todos os casos. Ondas em platô (tipo A de Lundberg) apareceram em 6 casos. Ondas intermediárias (ou ondas A atípicas) foram observadas em 7 casos. O aparecimento de ondas patológicas ocorrem indiferentemente durante os períodos diurnos e noturnos. Dos 10 casos, estudados, 8 foram submetidos a derivaçäo do líquido cefalorraquiano, com boa evoluçäo clínica

Indicadores clínicos de colección subdural en meningitis bacteriana aguda / Clinical indicators of subdural colletion in acute bacterial meningitis

La aparición de colección subdural (CSD) sintomática complica un porcentaje considerable de las meningitis bacterianas agudas (MBA). Con el objeto de encontrar elementos clínicos que permitan sospechar precozmente la presencia de esta complicación, se revisaron 72 fichas de pacientes ingresados a la Unidad de Infecciosos del Hospital Roberto del Río, con diagnóstico de MBA. La presencia de CSD, demostrada por punción o tomografía axial cerebral, separó los pacientes en 2 grupos: G.1=24 (33%) con CSD y G2=48 (66%) sin CSD. Se analizó la asociación de fiebre, compromiso sensorial, síndrome de hipertensión endocraneana (SHE) y convulsiones con la presencia de colecciones subdurales. Se encontraron diferencias significativas en la distribución de las 3 primeras variables. En base a estos datos se calculó la sensibilidad y especificidad y valor predictivo positivo (VPP) de cada variable. La prolongación del SHE por más de 24 horas y su reaparición tuvieron alta especificidad y VPP para la presencia de CSD inflamatoria. La reaparición de la fiebre se presentó en el 100% de estos pacientes. Ningún signo clínico aislado es útil para el diagnóstico de colección subdural