Pia Mater Research Articles

The effect of meninges on the electric fields in TES and TMS. Numerical modeling with adaptive mesh refinement

BackgroundWhen modeling transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS) in the brain, the meninges – dura, arachnoid, and pia mater – are often neglected due to high computational costs. ObjectiveWe investigate the impact of the meningeal layers on the cortical electric field in TES and TMS while considering the headreco segmentation as the base model. MethodWe use T1/T2 MRI data from 16 subjects and apply the boundary element fast multipole method with adaptive mesh refinement, which enables us to accurately solve this problem and establish method convergence at reasonable computational cost. We compare electric fields in the presence and absence of various meninges for two brain areas (M1HAND and DLPFC) and for several distinct TES and TMS setups. ResultsMaximum electric fields in the cortex for focal TES consistently increase by approximately 30% on average when the meninges are present in the CSF volume. Their effect on the maximum field can be emulated by reducing the CSF conductivity from 1.65 S/m to approximately 0.85 S/m. In stark contrast to that, the TMS electric fields in the cortex are only weakly affected by the meningeal layers and slightly (∼6%) decrease on average when the meninges are included. ConclusionOur results quantify the influence of the meninges on the cortical TES and TMS electric fields. Both focal TES and TMS results are very consistent. The focal TES results are also in a good agreement with a prior relevant study. The solver and the mesh generator for the meningeal layers (compatible with SimNIBS) are available online.

Autophagy-related long non-coding RNA prognostic model predicts prognosis and survival of melanoma patients.

BACKGROUNDMelanomas are malignant tumors that can occur in different body parts or tissues such as the skin, mucous membrane, uvea, and pia mater. Long non-coding RNAs (lncRNAs) are key factors in the occurrence and development of many malignant tumors, and are involved in the prognosis of some patients. AIMTo identify autophagy-related lncRNAs in melanoma that are crucial for the diagnosis, treatment, and prognosis of melanoma patients.METHODSWe retrieved transcriptome expression profiles and clinical information of 470 melanoma patients from The Cancer Genome Atlas (TCGA) database. Then, we identified autophagy-related genes in the Human Autophagy Database. Using R, coexpression analysis of lncRNAs and autophagy-related genes was conducted to obtain autophagy-related lncRNAs and their expression levels. We also performed univariate and multivariate Cox proportional risk analyses on the obtained datasets, to systematically evaluate the prognostic value of autophagy-related lncRNAs in melanoma. Fifteen autophagy-related lncRNAs were identified and an autophagy-related prognostic signature for melanoma was established. The Kaplan-Meier and univariate and multivariate Cox regression analyses were used to calculate risk scores. Based on the risk scores, melanoma patients were randomly divided into high- and low-risk groups. Receiver operating characteristic curve analysis, dependent on time, was performed to assess the accuracy of the prognostic model. At the same time, we also downloaded the melanoma data sets GSE65904, GSE19234, and GSE78220 from the GENE EXPRESSION OMNIBUS database for model verification. Finally, we performed Gene Set Enrichment Analysis functional annotation, which showed that the low and the high-risk groups had different enriched pathways.RESULTSThe co-expression network for autophagy-related genes was constructed using R, and 936 lncRNAs related to autophagy were identified. Then, 52 autophagy-related lncRNAs were significantly associated with TCGA melanoma patients’ survival by univariate Cox proportional risk analysis (P < 0.01). Further, the 52 autophagy-related lncRNAs mentioned above were analyzed by multivariate Cox analysis with R. Fifteen lncRNAs were selected: LINC01943, AC090948.3, USP30-AS1, AC068282.1, AC004687.1, AL133371.2, AC242842.1, PCED1B-AS1, HLA-DQB1-AS1, AC011374.2, LINC00324, AC018553.1, LINC00520, DBH-AS1, and ITGB2-AS1. The P values in all survival analyses using these 15 lncRNAs were < 0.05. These lncRNAs were used to build a risk model based on the risk score. Negative correlations were observed between risk scores and overall survival rate in melanoma patients over time. Additionally, the melanoma risk curve and scatter plot analyses showed that the death number increased along with the increase in the risk score. Overall, we identified and established a new prognostic risk model for melanoma using 15 autophagy-related lncRNAs. The risk model constructed with these lncRNAs can help and guide melanoma patient prognosis predictions and individualized treatments in the future.CONCLUSIONOverall, the risk model developed based on the 15 autophagy-related lncRNAs can have important prognostic value and may provide autophagy-related clinical targets for melanoma treatment.

Optic nerve-associated connective tissue structures revisited: A histological study using human fetuses and adult cadavers.

Unlike the usual peripheral nerve, the optic nerve accompanies a thick "dural sheath," a thin "sheath of pia mater" (SPM), and multiple "septa," which divides the nerve fibers into fascicles. We collected specimens from 25 adult cadavers and 15 fetuses and revisited the histological architecture of the optic and oculomotor nerves. In the optic chiasma, the meningeal layer of the dura joins the pia to form a thick SPM, and the periosteum of the sphenoid is continuous with the dural sheath at the orbital exit of the bony optic canal. The septa appeared as a cluster of irregularly arrayed fibrous plates in the intracranial course near the chiasma. Thus, the septa were not derived from either the SPM or the dural sheath. In the orbit, the central artery of the retina accompanies collagenous fibers from the dural sheath and the SPM to provide the vascular sheath in the optic nerve. These connective tissue configurations were the same between adult and fetal specimens. At the optic disk, the dural sheath and SPM merged with the sclera, whereas the septa appeared to end at the lamina cribrosa. However, in fetuses without lamina cribrosa, the septa extend into the nerve fiber layer of the retina. The SPM and septa showed strong elastin immunoreactivity, in contrast to the absence of reactivity in the sheaths of the oculomotor nerve. Each S100 protein-positive Schwann sheath of the oculomotor nerve was surrounded by collagenous endoneurium. Glial fibrillary acidic protein-positive astrocytes showed a linear arrangement along the septa.

Potential Therapeutic Benefits of Brahma Rasayana in the Management of Tuberculous Cerebrovascular Disease - A Case Report

Tuberculous meningitis (TBM) is an air-borne infectious disease caused by the bacteria Mycobacterium tuberculosis that affects the central nervous system (CNS). Among all the incident cases of TB, CNS TB represents approximately 1% with TBM as the most grievous among all. The basic pathology in TBM is the inflammation of the arachnoid membrane, the pia mater and the cerebrospinal fluid (CSF). It typically presents as mild fever, headache, anorexia and general debility that progress over one to two weeks to cause severe headache, fever, vomiting, confusion, meningismus and cranial nerve deficits. The most common complications of TBM include hydrocephalus, optico-chiasmatic arachnoiditis, seizures and stroke. Out of these, tuberculous cerebrovascular disease is a common neurological sequelae. This case study elaborates the treatment line and observations made in a 29 year old male patient who presented with hemiparesis and significant sensory deficit following an event of tuberculous meningitis. MRI brain was suggestive of basilar meningitis, optico-chiasmatic arachnoiditis, infarcts and tuberculoma with chest X-ray revealing increased bronchovascular markings in bilateral lung fields. Initially on admission, Deepana-pachana was done followed by snehapana with Shadpala ghrta and Virechana as Sodhana karma. Abhyanga, Ushma Sweda, Churna pinda sweda and Jambeera pinda sweda were successively done allied with physiotherapy. Yogavasti with Vedanasthapana gana as Kashaya and Kalka was done intervened by Anuvasana vasti. Succeedingly, Murdhni taila prayoga and Marsha nasya were also incorporated with periodical neurological, hematological and biochemical assessment. On discharge, Brahmi kalyanaka ghrta and Brahma Rasayana were advised inclusive of physiotherapy.

A CASE SERIES ON MENINGIOMA BASED ON WHO GRADING SYSTEM

Background:The dura mater, arachnoid mater and pia mater are layers of meninges surrounding brain and spinal cord. Meningiomas are tumors arising from them.These are heterogeneous group of tumors and are have 14 distinct histologic types and 03 grades of malignancy.We have studied the variants of meningiomas, as early detection helps in the treatment and improves quality of life. Objectives: -Study the histological types as per WHO grading system 2016 for meningiomas. -Differentiate the benign and malignant meningiomas on histopathology. Methods: The study is carried out in the department of pathology, D.Y. Patil medical college and hospital kolhapur from June 2020 to June 2021. Total 19 intracranial tumors were received. Sections were stained with H&amp;E and IHC was done wherever necessary. Results:We had total 19 patients with tumors in different locations of brain. Mainly parasagital followed by intradural . Age range was 32 to 70 years with female predominance. Common histological subtypes were meningothelial (5 cases) and fibrous (5 cases), followed by transitional and angiomatous (2 cases each) and psamomatous (1 case) - WHO grade I tumors. Clear cell and atypical - grade II. Papillary, anaplastic variant - grade III. Conclusion: Meningiomas are slow growing tumors arising from the meningothelial cells. Commonly they are benign WHO grade I with female predominance. Early detection helps in the treatment and improves quality of life.

The neuroglia of the rat optic nerve. Part I. Golgi-Hortega and Golgi-EM studies

In the present study, one describes the morphology of the macroglia (astrocytes and oligodendrocytes) of the optic nerve of the albino rat, having been stained according to the modification of del Rio-Hortega of Golgi-Kopsch’s method. This cytology has been studied in the intra-orbital optic nerve, in the intracranial portion of the same, in the optic chiasm and in a first segment of the optic tract. Astrocytes show small differences between those located in the marginal zone of the nerve and those located in the center, being all of them classified as belonging to the fibrous type of astrocytes. With their extensions, these cells establish contact with the external limiting membrane, blood vessels and myelinic nerve fibers. On the level of the limiting membrane, their terminal feet form a kind of cellular barrier similar to that of the cerebral cortex in contact with the pia mater. With the nervous fibers, they establish close relationships at Ranvier’s nodes level, being arranged around them forming small rings. The oligodendrocytes show their main branches impregnated up to where they reach the myelin sheath, but the protoplasmic compartment of this one is not impregnated, giving a different image to the one seen after microinjections with markers. Morphometric studies using fractal dimension and related parameters are presented next in part II of this work.

Leptomeningeal anastomoses: Mechanisms of pial collateral remodeling in ischemic stroke

Arterial collateralization, as determined by leptomeningeal anastomoses or pial collateral vessels, is a well-established vital player in cerebral blood flow restoration and neurological recovery from ischemic stroke. A secondary network of cerebral collateral circulation apart from the Circle of Willis, exist as remnants of arteriole development that connect the distal arteries in the pia mater. Recent interest lies in understanding the cellular and molecular adaptations that control the growth and remodeling, or arteriogenesis, of these pre-existing collateral vessels. New findings from both animal models and human studies of ischemic stroke suggest a multi-factorial and complex, temporospatial interplay of endothelium, immune and vessel-associated cell interactions may work in concert to facilitate or thwart arteriogenesis. These valuable reports may provide critical insight into potential predictors of the pial collateral response in patients with large vessel occlusion and may aid in therapeutics to enhance collateral function and improve recovery from stroke.

Effect of Anatomical Sites on the Mechanical Properties of Spinal Dura Subjected to Biaxial Stretching

Abstract The spinal cord is encased by spinal meninges called the pia, arachnoid, and dura maters. Among these membranes, the dura mater is the thick and outermost layer and is the toughest and strongest. Thus, mechanical failure of the dura mater can lead to spontaneous cerebrospinal fluid leaks or hypovolemia, resulting in a complication or exacerbation of unfavorable symptoms involved in a mild traumatic brain injury. To develop protective equipment that can help prevent such injuries, accurate characterization of the spinal dura mater is required, especially regarding the mechanical properties at different anatomical sites. In this study, we used an equiload biaxial tensile tester to investigate the mechanical properties of porcine meningeal dura mater along the whole length of the spine. The resultant strain of the dorsal side was greater than that of the ventral side (P &amp;lt; 0.01), while the circumferential direction was significantly stiffer than the longitudinal direction (P &amp;lt; 0.01) at lower strains regardless of the spinal level. We also found that the material stiffness progressively increased from the cervical level to the thoracolumbar level at lower strains, which implies that the dura mater inherently possesses structurally preferred features or functions because the neck requires sufficient flexibility for daily activities. Further, Young's modulus was significantly less on the dorsal side than on the ventral side at higher strains (P &amp;lt; 0.05), suggesting that the dorsal side is readily elongated by spinal flexion even within the range of physiological motion.

Abstract 166: Loss Of Endothelial Cell Specific EphA4 Improves Acute Leptomeningeal Collateral Growth Following Ischemic Stroke

Leptomeningeal anastomoses, or pial collateral vessels, are a major determinant of patient outcome following ischemic stroke. These vessels form in the pia mater of the brain during development and connect distal arterioles of cerebral arteries. Following vascular obstruction, pial collaterals expand through arteriogenesis, an adaptive process that allows for retrograde perfusion into the obstructed artery and its affected tissue. However, acute arteriogenesis following ischemic stroke has been poorly investigated, therefore our research aims to fill this knowledge gap. Our novel pre-clinical murine findings suggest EphA4, a receptor tyrosine kinase, plays a role in restricting arteriogenesis following permanent middle cerebral artery occlusion (pMCAO). To investigate the role of endothelial cell-specific EphA4 in acute arteriogenesis, we employed 3-month old conditional endothelial cell (EC)-specific EphA4 knockout ( EphA4 fl/fl /Cdh5::Cre ERT2 ; KO) and wild type ( EphA4 fl/fl ; WT) mice. Compared to WT controls, we find KO mice displayed a significant reduction in infarct volume (24.0±1.8mm 3 vs 14.3±2.5mm 3 ; n=9) which correlated with larger ipsilateral pial collateral vessels as early as 4.5-hours (27.31±0.6um vs 32.41±0.8um; n=15) and up to 24-hours post-pMCAO (31.14±0.8um vs 36.7±0.9um; n=15). Additionally, our previous work has indicated that EphA4 may exert its inhibitory function on arteriogenesis by hindering Tie2 signaling. To identify gene expression changes in the collateral vessels and connecting cerebral arteries, the pial surface was carefully isolated from four mice per sample and pooled. Analysis of mRNA expression in the pial surface 24-hours post-pMCAO revealed that WT mice had significantly higher fold change of angiopoietin-2 (1.4±0.2 vs 0.8± 0.09; n=5) and Tie1 (5.3±1.8 vs 0.9±0.2; n=5) compared to KO mice, indicating potential inhibition of Tie2 signaling. These findings demonstrate that EC-specific EphA4 negatively regulates collateral growth and inhibition of this receptor could serve as a novel therapeutic strategy for improving collateral response following ischemic stroke.

Comparison of numerical methods for cerebrospinal fluid representation and fluid-structure interaction during transverse impact of a finite element spinal cord model.

Spinal cord impacts can have devastating consequences. Computational models can investigate such impacts but require biofidelic numerical representations of the neural tissues and fluid-structure interaction with cerebrospinal fluid. Achieving this biofidelity is challenging, particularly for efficient implementation of the cerebrospinal fluid in full computational human body models. The goal of this study was to assess the biofidelity and computational efficiency of fluid-structure interaction methods representing the cerebrospinal fluid interacting with the spinal cord, dura, and pia mater using experimental pellet impact test data from bovine spinal cords. Building on an existing finite element model of the spinal cord and pia mater, an orthotropic hyperelastic constitutive model was proposed for the dura mater and fit to literature data. The dura mater and cerebrospinal fluid were integrated with the existing finite element model to assess four fluid-structure interaction methods under transverse impact: Lagrange, pressurized volume, smoothed particle hydrodynamics, and arbitrary Lagrangian-Eulerian. The Lagrange method resulted in an overly stiff mechanical response, whereas the pressurized volume method over-predicted compression of the neural tissues. Both the smoothed particle hydrodynamics and arbitrary Lagrangian-Eulerian methods were able to effectively model the impact response of the pellet on the dura mater, outflow of the cerebrospinal fluid, and compression of the spinal cord; however, the arbitrary Lagrangian-Eulerian compute time was approximately five times higher than smoothed particle hydrodynamics. Crucial to implementation in human body models, the smoothed particle hydrodynamics method provided a computationally efficient and representative approach to model spinal cord fluid-structure interaction during transverse impact.

Finite element modeling of the complex anisotropic mechanical behavior of the human sclera and pia mater

Background and objectiveAccurate finite element (FE) simulation of the optic nerve head (ONH) depends on accurate mechanical properties of the load-bearing tissues. The peripapillary sclera in the ONH exhibits a depth-dependent, anisotropic, heterogeneous collagen fiber distribution. This study proposes a novel cable-in-solid modeling approach that mimics heterogeneous anisotropic collagen fiber distribution, validates the approach against published experimental biaxial tensile tests of scleral patches, and demonstrates its effectiveness in a complex model of the posterior human eye and ONH. MethodsA computational pipeline was developed that defines control points in the sclera and pia mater, distributes the depth-dependent circumferential, radial, and isotropic cable elements in the sclera and pia in a pattern that mimics collagen fiber orientation, and couples the cable elements and solid matrix using a mesh-free penalty-based cable-in-solid algorithm. A parameter study was performed on a model of a human scleral patch subjected to biaxial deformation, and computational results were matched to published experimental data. The new approach was incorporated into a previously published eye-specific model to test the method; results were then interpreted in relation to the collagen fibers’ (cable elements) role in the resultant ONH deformations, stresses, and strains. ResultsResults show that the cable-in-solid approach can mimic the full range of scleral mechanical behavior measured experimentally. Disregarding the collagen fibers/cable elements in the posterior eye model resulted in ∼20–60% greater tensile and shear stresses and strains, and ∼30% larger posterior deformations in the lamina cribrosa and peripapillary sclera. ConclusionsThe cable-in-solid approach can easily be implemented into commercial FE packages to simulate the heterogeneous and anisotropic mechanical properties of collagenous biological tissues.

Measurement of Filum Terminale in the Foetuses of Third Trimester Gestational Age: An Observational Study

Introduction: The covering of spinal cord is same as that of brain. The pia mater, arachnoid and dura mater covers the spinal cord from inside out. The pia mater extends from cephalic end of spinal cord upto terminal portion i.e., conus medullaris. Beyond the conus, the pia mater extends in the form of filum terminale. The filum terminale extends beyond the conus medullaris and attaches upto dorsal aspects of coccyx to stabilise the spinal cord in its position. Aim: To study the length of filum terminale in the foetuses of third trimester gestational age. Materials and Methods: The present cross-sectional observational study was carried out in 30 foetuses collected from museum of Department of Anatomy and Department of Obstetrics and Gynaecology. The permission and approval from university ethical committee was taken before starting the study. The foetuses were divided into three groups taking into consideration their gestational age (four foetuses in 1st group 28- 31 weeks, 12 foetuses in 2nd group 32-35 weeks and 14 foetuses were in 3rd group 36-40 weeks gestational age). Also, the gender wise variation (11 male and 19 female foetuses) was also taken into account. All the data were recorded in Microsoft excel sheet and Statistical Package for the Social Sciences (SPSS) 23.0 software was used for statistical analysis. Numerical values were reported as the mean±standard deviation. Student’s t-test or one way ANOVA was used to analyse quantitative variables. Two tailed p-values were considered significant (p&lt;0.05). Results: In this study, the mean length of filum terminale was 4.35±1.04 cm with range minimum 2.31 cm to maximum 5.90 cm. The length of spinal cord and length of filum terminale measurements significantly increased with increasing gestational age (p&lt;0.001). The length of spinal cord, length of filum terminale measurement and ratio of length of filum terminale to length of spinal cord (FT/SC) were significantly higher in male foetuses (p&lt;0.05). Conclusion: The association between gestational age (weeks), length of filum terminale, and length of spinal cord among all foetuses, and male and female separately were statistically significant

Effect of cerebrospinal fluid elements on stress distribution in stress analysis model of brain tissue constrained by skull in infancy

The purpose of this study was to clarify the effect of cerebrospinal fluid elements on the brain stress model, in order to develop a tool to support the treatment of craniosynostosis using the finite element method. The growth of the brain was expressed by the thermal expansion. A soft solid element, which imitates cerebrospinal fluid, was introduced into the model consisting of brain, pia mater, arachnoid mater, dura mater and skull. The thermal expansion coefficient of the brain was set as 0.04049, which corresponds to a volumetric expansion of the brain of 1% when the pia mater element contacts the cerebrospinal fluid elements. As a result, a maximum stress of 2.588×10-5 [MPa] was generated in the brain, and the stress on the brain element was reduced by introducing the cerebrospinal fluid elements. Here, the stress distribution of the cerebrospinal fluid elements was not uniform, due to the coarse meshing, resulting in the generation of the localized high stresses. Therefore, it would be necessary to improve the accuracy of the stress analysis model in the future.

Neurotoxicity of N-Nitrosodimethylamine (NDMA) in Swiss albino mice and neuroprotection by nanocurcumin

Nitrosamine is a highly toxic compound which is released in various industries like rubber, cosmetics, pesticides etc. NDMA is formed in the processed food where sodium nitrite is used as preservative. It can also be found in alcoholic beverages and vegetables. Human’s exposure to NDMA is unavoidable. Mutagenic and hepatotoxic effects of NDMA has been reported but neurotoxicity data is not well established. In this study-four groups of Swiss albino mice were taken; Group I received the vehicle i.e. distilled water, group II received NDMA at the dose of 0.58 mg/kg body weight (1/25th of LD50) and group III received NDMA (0.58 mg/kg b.w.) + Nanocurcumin (20 mg/kg body weight) and group IV received only Nanocurcumin (20 mg/kg body weight). Various parameters of neuromuscular strength and neurotransmitters like Serotonin, Dopamine and Acetylcholinesterase were significantly decreased by NDMA treatment. Nanocurcumin administration along with NDMA didn’t cause any toxicity. In NDMA treated group’s antioxidant enzymes viz. SOD, catalase and glutathione peroxidase were significantly reduced whereas nanocurcumin showed protective effects as the nanocurcumin administration with NDMA showed near normal levels of the antioxidant enzymes. Cerebral cortexshowed pia mater encephalic, intracellular and extracellular vacuoles, irregular, pyramidal cells and broadening vessel peripheral clearance was also seen in NDMA treatment group, which were normal in the control and nanocurcumin treated group. These findings proved that NDMA caused neurotoxicity at the tested dose level and nanocurcumin have neuroprotective potential against NDMA treatment.

Reinvestigating Tumor-Ventricle Relationship of Craniopharyngiomas With Predominantly Ventricular Involvement: An Endoscopic Endonasal Series Based on Histopathological Assessment.

ObjectiveCraniopharyngiomas (CPs) predominantly involving the third ventricle were commonly termed “intraventricular” lesions. The aim of this study was to clarify the anatomical relationship between the tumor and the third ventricle by both surgical and histological investigation.MethodsA retrospective review of primarily resected CPs by endoscopic endonasal surgery was performed. CPs with predominantly ventricular involvement were selected for study inclusion by preoperative imaging. The surgical procedure of each case was reviewed. The wholly removed tumor specimens were histologically analyzed, in all cases, to investigate the tumor–third ventricle relationship using hematoxylin and eosin, immunochemical, and immunofluorescence staining.ResultsTwenty-six primary CPs predominantly involving the third ventricle were selected from our series of 223 CPs treated by endoscopic endonasal surgery between January 2017 and March 2021. Gross-total resection was achieved in 24 (92.3%) of 26 patients, with achievement of near-total resection in the remaining patients. A circumferential layer of stretched third ventricle floor was identified surrounding the tumor capsule, which could be peeled off easily from the ventricle floor remnants at most areas of the plane of tumor attachment. Some portions of the tumor capsule tightly adhered to the third ventricle floor were removed together with the floor. A breach of various size was observed at the third ventricle floor after tumor removal in most cases, the floor remaining intact in only two cases (7.7%). Histological examination on marked portions of tumor capsule showed that the pia mater was frequently detected at most of the tumor–brain interface, except at the antero-frontal border of tumor contacting with the third ventricle floor. At this point, a layer of gliosis with various thickness was observed between the tumor and the neural tissue of the third ventricle floor.ConclusionCPs with predominantly ventricular involvement should be considered as lesions with an extraventricular, epi-pia topography rather than “intraventricular” or “subpial” topography. Accurate understanding of the relationship between the third ventricle and such tumors would predict the circumferential cleavage plane of dissection, and remind neurosurgeons of performing dissection along the safe surgical plane to achieve total tumoral resection with minimizing hypothalamic damage.

Experimental Bi-axial tensile tests of spinal meningeal tissues and constitutive models comparison

Introduction This study aims at identifying mechanical characteristics under bi-axial loading conditions of extracted swine pia mater (PM) and dura and arachnoid complex (DAC). Methods 59 porcine spinal samples have been tested on a bi-axial experimental device with a pre-load of 0.01 N and a displacement rate of 0.05 mm·s−1. Post-processing analysis included an elastic modulus, as well as constitutive model identification for Ogden model, reduced Gasser Ogden Holzapfel (GOH) model, anisotropic GOH model, transverse isotropic and anisotropic Gasser models as well as a Mooney-Rivlin model including fiber strengthening for PM. Additionally, micro-structure of the tissue was investigated using a bi-photon microscopy. Results Linear elastic moduli of 108 ± 40 MPa were found for DAC longitudinal direction, 53 ± 32 MPa for DAC circumferential direction, with a significant difference between directions (p < 0.001). PM presented significantly higher longitudinal than circumferential elastic moduli (26 ± 13 MPa vs 13 ± 9 MPa, p < 0.001). Transversely isotropic and anisotropic Gasser models were the most suited models for DAC (r2 = 0.99 and RMSE:0.4 and 0.3 MPa) and PM (r2 = 1 and RMSE:0.06 and 0.07 MPa) modelling. Conclusion This work provides reference values for further quasi-static bi-axial studies, and is the first for PM. Collagen structures observed by two photon microscopy confirmed the use of anisotropic Gasser model for PM and the existence of fenestration. The results from anisotropic Gasser model analysis depicted the best fit to experimental data as per this protocol. Further investigations are required to allow the use of meningeal tissue mechanical behaviour in finite element modelling with respect to physiological applications. Statement of significanceThis study is the first to present biaxial tensile test of pia mater as well as constitutive model comparisons for dura and arachnoid complex tissue based on such tests. Collagen structures observed by semi-quantitative analysis of two photon microscopy confirmed the use of anisotropic Gasser model for pia mater and existence of fenestration. While clear identification of fibre population was not possible in DAC, results from anisotropic Gasser model depicted better fitting on experimental data as per this protocol. Bi-axial mechanical testing allows quasi-static characterization under conditions closer to the physiological context and the results presented could be used for further simulations of physiology. Indeed, the inclusion of meningeal tissue in finite element models will allow more accurate and reliable numerical simulations.

Case Report on Subarachnoid Hemorrhage

Introduction: Subarachnoid haemorrhage (SAH) is caused by intracranial bleeding into the cerebrospinal fluid-filled space between the arachnoid and pia mater membranes on the surface of the brain.&#x0D; Patient History: The 65-year-old female patient was hospitalised to AVBR hospital in neurosurgery ward on December 25, 2020 with the chief complaints of headache, vomiting and episodes of seizures since three days. The patients had episodes of seizures on 21/12/2020 and 24/12/2020. The day later she was admitted to the Intensive Care Unit.she underwent all routine investigations like blood tests, and CT scan. After a thorough examination, the final diagnosis was subarachnoid haemorrhage.&#x0D; Past History: Patient did not have any history of communicable disease, asthma, tuberculosis, or any hereditary disease. Patient was COVID – negative and did not have any significant surgical history.&#x0D; Pharmacology: Patient was treated with proton pump inhibitor, antiemetic, antiepileptic, calcium channel blocker, stool softener analgesic and antipyretic.&#x0D; Management: Inj. Levipril 500 mg, Inj.pan40-40mg, cap.nimodipine 60mg every four hourly, Inj.emset 4 mg, Inj. Neomol 100 ml, Syp. glycerol 30 ml, Syp. Zincovit 2tsp and Tablet Dolo 650mg.&#x0D; Nursing Management: Patient’s vital sign (including blood pressure) and neurological status were monitored with bed rest, pain management and assessment of risk of bleeding.&#x0D; Conclusion: Patient was hospitalised with a threeday history of headache, vomiting, and episodes of seizures actively managed; condition satisfactory.

Subarachnoid Hemorrhage: A Case Report

We reported a case report of a 50-year-old woman with stroke hemorrhage due to subarachnoid hemorrhage with hypertensive urgency, left ventricular hypertrophy, and dyslipidemia. Subarachnoid hemorrhage indicates the presence of blood in the subarachnoid space between the pia mater and arachnoid mater which usually results from a ruptured cerebral aneurysm or arteriovenous malformation. The patient presents with decreased consciousness preceded by severe headache and projectile vomiting. In physical examination, we found hypertensive emergencies and positive meningeal signs, neck stiffness, and positive Brudzinski. CT scan shows bleeding in the pontocerebellar cistern and ventricular system. The patient was diagnosed with subarachnoid hemorrhage, intraventricular hemorrhage, and emergency hypertensive. The patient was hospitalized in the neurology ward of Ulin Hospital for 20 days with the management of antihypertensive, neuroprotectant, other symptomatic medications, and ventriculoperitoneal shunt surgery. The patient was then discharged home in a stable condition.

Apnea Spells in a Term Neonate.

Apnea Spells in a Term Neonate.

Application of 3D Printing Support Material for Neurosurgical Simulation.

Brain dissection, an intricate neurosurgical skill, is central to life-saving procedures such as intrinsic brain tumor excision and resective epilepsy surgery. The aims of this manuscript are to outline the selection process of a suitable material for the development of a dissectible brain simulator and to present the use of support material, SUP 706, manufactured by Stratasys Ltd. as a non-waste alternative for sustainably engineering solutions for surgical education. A feasibility study was conducted through qualitative function deployment (QFD) followed by a material selection process. End-user requirements and manufacturing product characteristics were incorporated into the workflow. Three materials, silicone, TissueMatrix™ and support material each formed the primary component of the first two prototypes. Expert feedback, manufacturing cost, safety profiling, functional fidelity and post-processing time data were collected and analyzed. The unique break-away feature of moist support material was found to be more suitable than using silicone or TissueMatrix™ for demonstrating brain dissection techniques. In addition, support material displayed higher functional fidelity by mimicking surgical tissues such as pia mater, gray and white matter, and blood vessels. The cost of the support material prototype was 39% less that of TissueMatrix™ and roughly the same as the silicone model. It took twice as long to post-process the support material prototype than it did the TissueMatrix™ design. Support material lost its ideal dissection properties and began to disintegrate after 30 - 45 minutes. In conclusion 3D printer support material is a low-cost material for a dissectible brain simulator.Clinical Relevance- The use of support material as the primary material in developing a dissectible brain simulator is a promising way of advancing neurosurgical education.