The Role of Neurophysiology in Managing Patients with Chiari Malformations

Chiari type 1 malformation; Electromyography; SyringomyeliaMalformación de Chiari tipo 1; Electromiografía; SiringomieliaMalformació de Chiari tipus 1; Electromiografia; SiringomieliaChiari malformation type 1 (CM1) includes various congenital anomalies that share ectopia of the cerebellar tonsils lower than the foramen magnum, in some cases associated with syringomyelia or hydrocephalus. CM1 can cause dysfunction of the brainstem, spinal cord, and cranial nerves. This functional alteration of the nervous system can be detected by various modalities of neurophysiological tests, such as brainstem auditory evoked potentials, somatosensory evoked potentials, motor evoked potentials, electromyography and nerve conduction studies of the cranial nerves and spinal roots, as well as brainstem reflexes. The main goal of this study is to review the findings of multimodal neurophysiological examinations in published studies of patients with CM1 and their indication in the diagnosis, treatment, and follow-up of these patients, as well as their utility in intraoperative monitoring.This study was partially supported by grants FIS PI22/01082, which was co-financed by the European Regional Development Fund (ERDF), awarded to M.A. Poca and Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR), Spain, grant 2021SGR/00810. The following nongovernmental associations have generously donated funding to support this research: (1) Asociación Nacional de Amigos de Arnold-Chiari (ANAC, http://www.arnoldchiari.es (accessed on 5 October 2023)), (2) Asociación Chiari y Siringomielia del Principado de Asturias (Ch.y.S.P.A., https://chyspa.org (accessed on 5 October 2023)), (3) Federación Española de Malformación de Chiari y Patologías Asociadas (FEMACPA), and (4) Mariana Dañobeitia https://vhir.vallhebron.com/es/sociedad/noticias/la-hija-de-una-paciente-con-malformacion-de-chiari-dona-21840-euros-para-impulsar-la-investigacion (accessed on 5 October 2023))

Consensus-based recommendations for diagnosis and surgical management of cranioplasty and post-traumatic hydrocephalus from a European panel

Cranioplasty; Post-traumatic hydrocephalus; Surgical strategyCraneoplastia; Hidrocefalia postraumática; Estrategia quirúrgicaCranioplàstia; Hidrocefàlia posttraumàtica; Estratègia quirúrgicaIntroduction Planning cranioplasty (CPL) in patients with suspected or proven post-traumatic hydrocephalus (PTH) poses a significant management challenge due to a lack of clear guidance. Research question This project aims to create a European document to improve adherence and adapt to local protocols based on available resources and national health systems. Methods After a thorough non-systematic review, a steering committee (SC) formed a European expert panel (EP) for a two-round questionnaire using the Delphi method. The questionnaire employed a 9-point Likert scale to assess the appropriateness of statements inherent to two sections: "Diagnostic criteria for PTH" and "Surgical strategies for PTH and cranial reconstruction." Results The panel reached a consensus on 29 statements. In the "Diagnostic criteria for PTH" section, five statements were deemed "appropriate" (consensus 74.2−90.3 %), two were labeled "inappropriate," and seven were marked as "uncertain." In the "Surgical strategies for PTH and cranial reconstruction" section, four statements were considered "appropriate" (consensus 74.2−90.4 %), six were "inappropriate," and five were "uncertain." Discussion and conclusion Planning a cranioplasty alongside hydrocephalus remains a significant challenge in neurosurgery. Our consensus conference suggests that, in patients with cranial decompression and suspected hydrocephalus, the most suitable diagnostic approach involves a combination of evolving clinical conditions and neuroradiological imaging. The recommended management sequence prioritizes cranial reconstruction, with the option of a ventriculoperitoneal shunt when needed, preferably with a programmable valve. We strongly recommend to adopt local protocols based on expert consensus, such as this, to guide patient care.This project was conducted with the non-conditioning assistance of Integra LifeSciences

A Critical Update of the Classification of Chiari and Chiari-like Malformations

Malformació d'Arnold-Chiari; Classificació; Malalties raresMalformación de Arnold-Chiari; Clasificación; Enfermedades rarasArnold-Chiari malformation; Classification; Rare diseasesChiari malformations are a group of craniovertebral junction anomalies characterized by the herniation of cerebellar tonsils below the foramen magnum, often accompanied by brainstem descent. The existing classification systems for Chiari malformations have expanded from the original four categories to nine, leading to debates about the need for a more descriptive and etiopathogenic terminology. This review aims to examine the various classification approaches employed and proposes a simplified scheme to differentiate between different types of tonsillar herniations. Furthermore, it explores the most appropriate terminology for acquired herniation of cerebellar tonsils and other secondary Chiari-like malformations. Recent advances in magnetic resonance imaging (MRI) have revealed a higher prevalence and incidence of Chiari malformation Type 1 (CM1) and identified similar cerebellar herniations in individuals unrelated to the classic phenotypes described by Chiari. As we reassess the existing classifications, it becomes crucial to establish a terminology that accurately reflects the diverse presentations and underlying causes of these conditions. This paper contributes to the ongoing discussion by offering insights into the evolving understanding of Chiari malformations and proposing a simplified classification and terminology system to enhance diagnosis and management.This research was partially supported by grant FIS PI22/01082, which was co-financed by the European Regional Development Fund (ERDF), awarded to M.A. Poca and by grant 2021SGR/00810 from the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR), Departament de Recerca i Universitats de la Generalitat de Catalunya, Spain. ASM is the recipient of a predoctoral fellowship from grant 2021SGR/00810 from the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR). The following nongovernmental associations have generously donated funding to support this research: 1. Asociación Nacional de Amigos de Arnold-Chiari (ANAC, http://www.arnoldchiari.es (accessed on 7 June 2023)); 2. Asociación Chiari y Siringomielia del Principado de Asturias (CHySPA, https://chyspa.org (accessed on 7 June 2023)); 3. Federación Española de Malformación de Chiari y Patologías Asociadas (FEMACPA); and 4. Mariana Dañobeitia (https://references.neurotrauma.com/chiari (accessed on 7 June 2023))

How the heterogeneity of the severely injured brain affects hybrid 2 diffuse optical signals: case examples and guidelines

Significance: A shortcoming for the routine clinical use of diffuse optics (DO) in the injured head has been that the results from commercial near-infrared spectroscopy-based devices are not reproducible, often give phys iologically invalid values and differ between systems. Besides the limitations due to the physics of continuous23 wave light sources, one culprit is the head heterogeneity and the underlying morphological and functional abnor malities of the probed tissue. Aim: To investigate the effect that different tissue alterations in the damaged head has on DO signals and provide guidelines to avoid data misinterpretation. Approach: DO measurements and computed tomography scans were acquired on brain-injured patients. The relationship between the signals and the underlying tissue types was classified on a case-by-case basis. Results: Examples and suggestions to establish quality control routines were provided. The findings suggested guidelines for carrying out DO measurements and speculations towards improved devices. Conclusions: This study advocates for the standardization of the DO measurements to secure a role for DO in neurocritical care. We suggest that blind measurements are unacceptably problematic due to confounding effects and care using a priori and a posteriori quality control routines that go beyond an assessment of the signal-to-noise ratio that is typically utilized.Preprin

Intraoperative Neurophysiological Monitoring in Syringomyelia Surgery: A Multimodal Approach

Intraoperative neurophysiological monitoring; Spinal cord; SyringomyeliaMonitorización neurofisiológica intraoperatoria; Médula espinal; SiringomieliaMonitorització neurofisiològica intraoperatoria; Medul·la espinal; SiringomieliaSyringomyelia can be associated with multiple etiologies. The treatment of the underlying causes is first-line therapy; however, a direct approach to the syrinx is accepted as rescue treatment. Any direct intervention on the syrinx requires a myelotomy, posing a significant risk of iatrogenic spinal cord (SC) injury. Intraoperative neurophysiological monitoring (IONM) is crucial to detect and prevent surgically induced damage in neural SC pathways. We retrospectively reviewed the perioperative and intraoperative neurophysiological data and perioperative neurological examinations in ten cases of syringomyelia surgery. All the monitored modalities remained stable throughout the surgery in six cases, correlating with no new postoperative neurological deficits. In two patients, significant transitory attenuation, or loss of motor evoked potentials (MEPs), were observed and recovered after a corrective surgical maneuver, with no new postoperative deficits. In two cases, a significant MEP decrement was noted, which lasted until the end of the surgery and was associated with postoperative weakness. A transitory train of neurotonic electromyography (EMG) discharges was reported in one case. The surgical plan was adjusted, and the patient showed no postoperative deficits. The dorsal nerve roots were stimulated and identified in the seven cases where the myelotomy was performed via the dorsal root entry zone. Dorsal column mapping guided the myelotomy entry zone in four of the cases. In conclusion, multimodal IONM is feasible and reliable and may help prevent iatrogenic SC injury during syringomyelia surgery.This research was partially supported by grant FIS PI22/01082, which was co-financed by the European Regional Development Fund (ERDF), awarded to M.A. Poca and by grant 2021SGR/00810 from the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR), Departament de Recerca i Universitats de la Generalitat de Catalunya, Spain. ASM is the recipient of a predoctoral fellowship from grant 2021SGR/00810 from the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR). The following nongovernmental associations have generously donated funding to support this research: 1. Asociación Nacional de Amigos de Arnold-Chiari (ANAC, http://www.arnoldchiari.es (accessed on 7 June 2023)); 2. Asociación Chiari y Siringomielia del Principado de Asturias (CHySPA, https://chyspa.org (accessed on 7 June 2023)); 3. Federación Española de Malformación de Chiari y Patologías Asociadas (FEMACPA); and 4. Mariana Dañobeitia (https://references. neurotrauma.com/chiari (accessed on 7 June 2023))

Reduced hippocampal subfield volumes and memory performance in preterm children with and without germinal matrix intraventricular hemorrhage.

Preterm newborns with germinal matrix-intraventricular hemorrhage (GM-IVH) are at a higher risk of evidencing neurodevelopmental alterations. Present study aimed to explore the long-term efects that GM-IVH have on hippocampal subfelds, and their correlates with memory. The sample consisted of 58 participants, including 36 preterm-born (16 with GM-IVH and 20 without neonatal brain injury), and 22 full-term children aged between 6 and 15 years old. All participants underwent a cognitive assessment and magnetic resonance imaging study. GM-IVH children evidenced lower scores in Full Intelligence Quotient and memory measures compared to their low-risk preterm and full-term peers. High-risk preterm children with GM-IVH evidenced signifcantly lower total hippocampal volumes bilaterally and hippocampal subfeld volumes compared to both low-risk preterm and full-term groups. Finally, signifcant positive correlations between memory and hippocampal subfeld volumes were only found in preterm participants together; memory and the right CA-feld correlation remained signifcant after Bonferroni correction was applied (p= .002). In conclusion, memory alterations and both global and regional volumetric reductions in the hippocampus were found to be specifcally related to a preterm sample with GM-IVH. Nevertheless, results also suggest that prematurity per se has a long-lasting impact on the association between the right CA-feld volume and memory during childhood

Consensus statement from the 2014 International Microdialysis Forum.

Microdialysis enables the chemistry of the extracellular interstitial space to be monitored. Use of this technique in patients with acute brain injury has increased our understanding of the pathophysiology of several acute neurological disorders. In 2004, a consensus document on the clinical application of cerebral microdialysis was published. Since then, there have been significant advances in the clinical use of microdialysis in neurocritical care. The objective of this review is to report on the International Microdialysis Forum held in Cambridge, UK, in April 2014 and to produce a revised and updated consensus statement about its clinical use including technique, data interpretation, relationship with outcome, role in guiding therapy in neurocritical care and research applications.We gratefully acknowledge financial support for participants as follows: P.J.H. - National Institute for Health Research (NIHR) Professorship and the NIHR Biomedical Research Centre, Cambridge; I.J. – Medical Research Council (G1002277 ID 98489); A. H. - Medical Research Council, Royal College of Surgeons of England; K.L.H.C. - NIHR Biomedical Research Centre, Cambridge (Neuroscience Theme; Brain Injury and Repair Theme); M.G.B. - Wellcome Trust Dept Health Healthcare Innovation Challenge Fund (HICF-0510-080); L. H. - The Swedish Research Council, VINNOVA and Uppsala Berzelii Technology Centre for Neurodiagnostics; S. M. - Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; D.K.M. - NIHR Senior Investigator Award to D.K.M., NIHR Cambridge Biomedical Research Centre (Neuroscience Theme), FP7 Program of the European Union; M. O. - Swiss National Science Foundation and the Novartis Foundation for Biomedical Research; J.S. - Fondo de Investigación Sanitaria (Instituto de Salud Carlos III) (PI11/00700) co-financed by the European Regional Development; M.S. – NIHR University College London Hospitals Biomedical Research Centre; N. S. - Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00134-015-3930-

Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research

No abstract available

Consensus statement from the 2014 International Microdialysis Forum

This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00134-015-3930-yMicrodialysis enables the chemistry of the extracellular interstitial space to be measured. Use of this technique in patients with acute brain injury has increased our understanding of the pathophysiology of several acute neurological disorders. In 2004 a consensus document on the clinical application of cerebral microdialysis was published. Since then there have been significant advances in the clinical use of microdialysis in neurocritical care. The objective of this review is to report on the International Microdialysis Forum held in Cambridge, UK, in April 2014 and to produce a revised and updated consensus statement about its clinical use including technique, data interpretation, relationship with outcome, role in guiding therapy in neurocritical care and research applications.We gratefully acknowledge financial support for participants as follows: P.J.H. - National Institute for Health Research (NIHR) Professorship and the NIHR Biomedical Research Centre, Cambridge; I.J. ? Medical Research Council (G1002277 ID 98489); A. H. - Medical Research Council, Royal College of Surgeons of England; K.L.H.C. - NIHR Biomedical Research Centre, Cambridge (Neuroscience Theme; Brain Injury and Repair Theme); M.G.B. - Wellcome Trust Dept Health Healthcare Innovation Challenge Fund (HICF-0510-080); L. H. - The Swedish Research Council, VINNOVA and Uppsala Berzelii Technology Centre for Neurodiagnostics; S. M. - Fondazione IRCCS C? Granda Ospedale Maggiore Policlinico; D.K.M. - NIHR Senior Investigator Award to D.K.M., NIHR Cambridge Biomedical Research Centre (Neuroscience Theme), FP7 Program of the European Union; M. O. - Swiss National Science Foundation and the Novartis Foundation for Biomedical Research; J.S. - Fondo de Investigaci?n Sanitaria (Instituto de Salud Carlos III) (PI11/00700) co-financed by the European Regional Development; M.S. ? NIHR University College London Hospitals Biomedical Research Centre; N. S. - Fondazione IRCCS C? Granda Ospedale Maggiore Policlinico