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Jiang Q, Tao B, Gao G, Sun M, Wang H, Li J, Wang Z, Shang A. Filum Terminale: A Comprehensive Review with Anatomical, Pathological, and Surgical Considerations. World Neurosurg 2022; 164:167-176. [PMID: 35500871 DOI: 10.1016/j.wneu.2022.04.098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 11/28/2022]
Abstract
The conus medullaris is the distal tapering end of the spinal cord, and the filum terminale (FT) is regarded as a bundle of non-functional fibrous tissue; therefore, some scholars call it the spinal ligament, while others describe the human FT as "remnants of the spinal cord." It was later found that in the human spinal cord, the FT is composed of an intradural segment and an epidural segment, and the end of the FT is connected to the coccyx periosteum. Because some nerve tissue is also found in the FT, as research progresses, FT may have the potential for transplantation. A lack of exhaustive overviews on the FT in the present literature prompted us to conduct this review. Considering that a current comprehensive review seemed to be the need of the hour, herein, we attempted to summarize previous research and theories on the FT, elucidate its anatomy, and understand its pathological involvement in various diseases.
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Affiliation(s)
- Qingyu Jiang
- Chinese PLA Medical School, Beijing 100853, China
| | - Benzhang Tao
- Department of Neurosurgery, Chinese PLA General Hospital, Beijing 100853, China; Tianjin Medical University
| | - Gan Gao
- Chinese PLA Medical School, Beijing 100853, China
| | - Mengchun Sun
- Chinese PLA Medical School, Beijing 100853, China; Medical School, Nankai University, Nankai District, Tianjin, China
| | - Hui Wang
- Department of Neurosurgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Junyang Li
- Chinese PLA Medical School, Beijing 100853, China; Medical School, Nankai University, Nankai District, Tianjin, China
| | | | - Aijia Shang
- Department of Neurosurgery, Chinese PLA General Hospital, Beijing 100853, China.
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Dauleac C, Manet R, Meyronet D, Jacquesson T, Berhouma M, Robinson P, Berthiller J, Jouanneau E, Barrey CY, Mertens P. Prognostic factors for progression-free survival of the filum terminale ependymomas in adults. Neurochirurgie 2022; 68:273-279. [PMID: 34998798 DOI: 10.1016/j.neuchi.2021.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To define the prognostic factors for progression and to determine the impact of the histological grading (according to the World Health Organization) on the progression-free survival (PFS) of filum terminale ependymomas. METHODS A retrospective chart review of 38 patients with ependymoma of the filum terminale was performed, focusing on demographic data, preoperative symptoms, tumor size, quality of resection, presence of a tumor capsule, and histological grade. RESULTS Gross total resection (GTR) was achieved in 30 patients (78.9%). Histopathological analysis found 21 (55.3%) myxopapillary grade I ependymoma (MPE), 16 (42.1%) ependymoma grade II (EGII), and 1 (2.6%) ependymoma grade III. There was no significant difference between the mean ± SD volume of MPE (5840.5 ± 5244.2 mm3) and the one of EGII (7220.3 ± 6305.9 mm3, p=0.5). The mean ± SD follow-up was 54.1 ± 38.4 months. At last follow-up, 30 (78.9%) patients were free of progression. In multivariate analysis, subtotal resection (p=0.015) and infiltrative tumor (p=0.03) were significantly associated with progression. The PFS was significantly higher in patients with encapsulated tumor than in patients with infiltrative tumor (log-rank p=0.01) and in patients who had a GTR in comparison with those who had an incomplete resection (log-rank p=0.05). There was no difference in PFS between patient with MPE and EGII (p=0.1). CONCLUSION The progression of ependymoma of the filum terminale highly depends on the quality of resection, and whether the tumor is encapsulated. Except for anaplastic grade, histopathological type does not influence progression.
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Affiliation(s)
- Corentin Dauleac
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France; Université de Lyon I, Université de Lyon, Lyon, France.
| | - Romain Manet
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France
| | - David Meyronet
- Université de Lyon I, Université de Lyon, Lyon, France; Service d'Anatomo-pathologie, Hospices Civils de Lyon, Lyon, France
| | - Timothée Jacquesson
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France; Université de Lyon I, Université de Lyon, Lyon, France
| | - Moncef Berhouma
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France; Université de Lyon I, Université de Lyon, Lyon, France
| | - Philip Robinson
- Unité d'Appui Méthodologique, Département de la Recherche Clinique et Innovation, Hospices Civils de Lyon, Lyon, France
| | - Julien Berthiller
- Unité d'Appui Méthodologique, EPICIME, Cellule Innovation DRCI, Hospices Civils de Lyon, Lyon, France
| | - Emmanuel Jouanneau
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France; Université de Lyon I, Université de Lyon, Lyon, France
| | - Cédric Y Barrey
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France; Université de Lyon I, Université de Lyon, Lyon, France
| | - Patrick Mertens
- Service de Neurochirurgie, Hospices Civils de Lyon, Hôpital neurologique Pierre Wertheimer, Lyon, France; Université de Lyon I, Université de Lyon, Lyon, France
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McElroy A, Klinge PM, Sledge D, Donahue JE, Glabman RA, Rashmir A. Evaluation of the Filum Terminale in Hereditary Equine Regional Dermal Asthenia. Vet Pathol 2021; 58:1100-1106. [PMID: 34056982 DOI: 10.1177/03009858211018660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The objectives of this study were to describe the anatomy, histology, and ultrastructure of the equine filum terminale (FT) and to describe the FT in hereditary equine regional dermal asthenia (HERDA), a model of human Ehlers-Danlos syndromes (EDS). Those humans suffer from tethered cord syndrome (TCS) caused by an abnormally structured FT wherein its attachment at the base of the vertebral column leads to long-term stretch-induced injury to the spinal cord. The pathophysiology of TCS in EDS is poorly understood, and there is a need for an animal model of the condition. Histopathologic and ultrastructural examinations were performed on FT from HERDA (n = 4) and control horses (n = 5) and were compared to FT from human TCS patients with and without EDS. Adipose, fibrous tissue, and neuronal elements were assessed. CD3 and CD20 immunohistochemistry was performed to clarify cell types (HERDA n = 2; control n = 5). Collagen fibrils were assessed in cross-section for fibril diameter and shape, and in longitudinal section for fibril disorganization, swelling, and fragmentation. The equine and human FT were similar, with both containing fibrous tissue, ependyma, neuropil, and nerve twigs. Hypervascularity was observed in both HERDA horses and human EDS-TCS patients and was not observed in equine or human controls. Moderate to severe abnormalities in collagen fibril orientation and architecture were observed in all HERDA horses and were similar to those observed in human EDS-TCS patients.
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Affiliation(s)
- Abigail McElroy
- 23325Rhode Island Hospital, Providence, RI, USA.,Brown University, Providence, RI, USA
| | - Petra M Klinge
- 23325Rhode Island Hospital, Providence, RI, USA.,Brown University, Providence, RI, USA
| | - Dodd Sledge
- 116098Michigan State University, East Lansing, MI, USA
| | - John E Donahue
- 23325Rhode Island Hospital, Providence, RI, USA.,Brown University, Providence, RI, USA
| | - Raisa A Glabman
- 116098Michigan State University, East Lansing, MI, USA.,Dr Glabman is now with the National Institutes of Health, Bethesda, MD, USA
| | - Ann Rashmir
- 116098Michigan State University, East Lansing, MI, USA.,Dr Rashmir is now with the Veterinary Surgical Services, Washington, DC, USA
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Kwon M, Je BK, Hong D, Choi BM. Ultrasonographic features of the normal filum terminale. Ultrasonography 2017; 37:129-133. [PMID: 28736427 PMCID: PMC5885475 DOI: 10.14366/usg.17032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 11/21/2022] Open
Abstract
Purpose The filum terminale (FT) is a fibrous band that connects the conus medullaris to the posterior body of the coccyx. Considering the advances of ultrasonography (US) technology and improvements in the resolution of US images, we aimed to re-establish the US features of the normal FT in infants younger than 6 months of age. Methods We retrospectively reviewed 30 spinal US scans, stored as video clips. The internal structure of the FT and the marginal echogenicity of the FT were assessed, and transverse and longitudinal US were compared. Results On US, a central echogenic line was defined in 18 (60%) normal FTs; however, there was no visible internal structure in 12 cases (40%). The marginal echogenicity of the FT was hyperechoic in eight cases (27%) in comparison with the cauda equina and was isoechoic in 22 cases (73%). In differentiating the normal FT from the surrounding nerve roots, transverse US was superior in 18 cases (60%), while longitudinal US was superior in two cases (7%). Conclusion On US, the central canal of the FT was defined in 60% of normal FTs. Hyperechoic marginal echogenicity and the use of transverse US were helpful in distinguishing the normal FT from the nerve roots of the cauda equina.
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Affiliation(s)
- Myoungae Kwon
- Department of Radiology, Ansan Hospital, Korea University College of Medicine, Ansan, Korea
| | - Bo-Kyung Je
- Department of Radiology, Ansan Hospital, Korea University College of Medicine, Ansan, Korea
| | - Doran Hong
- Department of Radiology, Ansan Hospital, Korea University College of Medicine, Ansan, Korea
| | - Byung Min Choi
- Department of Pediatrics, Ansan Hospital, Korea University College of Medicine, Ansan, Korea
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Chrenek R, Magnotti LM, Herrera GR, Jha RM, Cardozo DL. Characterization of the Filum terminale as a neural progenitor cell niche in both rats and humans. J Comp Neurol 2016; 525:661-675. [PMID: 27511739 PMCID: PMC5216448 DOI: 10.1002/cne.24094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 07/26/2016] [Accepted: 07/26/2016] [Indexed: 01/24/2023]
Abstract
Neural stem cells (NSCs) reside in a unique microenvironment within the central nervous system (CNS) called the NSC niche. Although they are relatively rare, niches have been previously characterized in both the brain and spinal cord of adult animals. Recently, another potential NSC niche has been identified in the filum terminale (FT), which is a thin band of tissue at the caudal end of the spinal cord. While previous studies have demonstrated that NSCs can be isolated from the FT, the in vivo architecture of this tissue and its relation to other NSC niches in the CNS has not yet been established. In this article we report a histological analysis of the FT NSC niche in postnatal rats and humans. Immunohistochemical characterization reveals that the FT is mitotically active and its cells express similar markers to those in other CNS niches. In addition, the organization of the FT most closely resembles that of the adult spinal cord niche. J. Comp. Neurol. 525:661–675, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ryan Chrenek
- Department of NeurobiologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of GeneticsHarvard Medical SchoolBostonMassachusettsUSA
| | - Laura M. Magnotti
- Department of NeurobiologyHarvard Medical SchoolBostonMassachusettsUSA
| | | | - Ruchira M. Jha
- Department of NeurobiologyHarvard Medical SchoolBostonMassachusettsUSA
| | - David L. Cardozo
- Department of NeurobiologyHarvard Medical SchoolBostonMassachusettsUSA
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Uehara M, Hosaka YZ, Doi H, Sakai H. The shortened spinal cord in tetraodontiform fishes. J Morphol 2014; 276:290-300. [PMID: 25388857 DOI: 10.1002/jmor.20338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 09/27/2014] [Accepted: 10/17/2014] [Indexed: 11/09/2022]
Abstract
In teleosts, the spinal cord generally extends along the entire vertebral canal. The Tetraodontiformes, in which the spinal cord is greatly reduced in length with a distinct long filum terminale and cauda equina, have been regarded as an aberration. The aims of this study are: 1) to elucidate whether the spinal cord in all tetraodontiform fishes shorten with the filum terminale, and 2) to describe the gross anatomical and histological differences in the spinal cord among all families of the Tetraodontiformes. Representative species from all families of the Tetraodontiformes, and for comparison the carp as a common teleost, were investigated. In the Triacanthodidae, Triacanthidae, and Triodontidae, which are the more ancestral taxa of the Tetraodontiformes, the spinal cord extends through the entire vertebral canal. In the Triacanthidae and Triodontidae, the caudal half or more spinal segments of the spinal cord, however, lack gray matter and consist largely of nerve fibers. In the other tetraodontiform families, the spinal cord is shortened forming a filum terminale with the cauda equina, which is prolonged as far as the last vertebra. The shortened spinal cord is divided into three groups. In the Ostraciidae and Molidae, the spinal cord tapers abruptly at the cranium or first vertebra forming a cord-like filum terminale. In the Monacanthidae, Tetraodontidae, and Diodontidae, it abruptly flattens at the rostral vertebrae forming a flat filum terminale. The spinal cord is relatively longer in the Monacanthidae than that in the other two families. It is suggested by histological features of the flat filum terminale that shortening of the spinal cord in this group progresses in order of the Monacanthidae, Tetraodontidae, and Diodontidae. In the Balistidae and Aracanidae, the cord is relatively long and then gradually decreased in dorso-ventral thickness.
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Affiliation(s)
- Masato Uehara
- Department of Veterinary Anatomy, Faculty of Agriculture, Tottori University, Tottori, 680-8553, Japan
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Kural C, Guresci S, Simsek GG, Arslan E, Tehli O, Solmaz I, Izci Y. Histological structure of filum terminale in human fetuses. J Neurosurg Pediatr 2014; 13:362-7. [PMID: 24506339 DOI: 10.3171/2014.1.peds13520] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The structure of the filum terminale (FT) is important in the development of tethered cord syndrome (TCS) in children. Although many studies have been performed on the histological structure of the FT in adults, there has been no detailed investigation for those of fetuses. The aim of this study was to examine the histological structure of the FT in normal human fetuses and to compare the results with those of previous studies. METHODS The histological examination of the FT was performed in 15 normal human fetuses; 11 of them were female and 4 were male. The gestational age of the fetuses ranged between 14 weeks and 35 weeks, and they weighed between 180 g and 1750 g. The FT of each fetus was cut and examined for adipose tissue, fibrous tissue, peripheral nerve, ganglion, ependymal cells, gliosis, elastic fibers, and collagen types (Types I and III). RESULTS Adipose tissue was observed in 2 specimens (13%), whereas fibrous tissue was found in 8 specimens. Peripheral nerve was detected in 11 (73%), ganglion in 6, ependymal cells in 5, and glial tissue in 7 FT samples. Type III collagen was present in 12 specimens (80%) with different concentrations, whereas Type I collagen and elastic fibers were not detected. CONCLUSIONS The normal structure of the FT in fetuses is different from its structure in adults. The FT has no elasticity during intrauterine life because of the lack of elastic fibers. More detailed studies are needed to understand the histological basis of TCS in children.
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Affiliation(s)
- Cahit Kural
- Department of Neurosurgery, Gulhane Military Medical Academy; and
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Gaddam SSK, Santhi V, Babu S, Chacko G, Baddukonda RA, Rajshekhar V. Gross and microscopic study of the filum terminale: does the filum contain functional neural elements? J Neurosurg Pediatr 2012; 9:86-92. [PMID: 22208327 DOI: 10.3171/2011.10.peds11102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The filum terminale (FT) is considered a fibrous structure that extends from conus medullaris of the spinal cord to coccyx. Based on previous studies and from their own experience with intraoperative electrophysiological monitoring of the sacral nervous system, the authors postulate that the FT contains functional neural elements in some individuals. METHODS The FT was dissected from 13 fresh stillborn cadavers (7 male, 6 female; mean gestational age 36 weeks and 1 day). The gross anatomical features were recorded, and connections between the FT and the nerve roots of the cauda equina were noted. These connections, when present, were sectioned for histological studies. The fila (both interna and externa) were also sectioned for histological and immunohistochemical studies. In addition, FT specimens were obtained from 5 patients undergoing sectioning of the FT in an untethering surgical procedure. RESULTS There were 5 gross connections between the FT and nerve roots demonstrating nerve fibers that were positive for S100. The FT showed islands of cells that were positive for GFAP in 10 cases, synaptophysin in 3 cases, S100 in 11 cases, and nestin in 2 cases. The nerve fibers in the FT were myelinated in 2 cases. The conus ended at the L-1 or L-2 vertebral level in all 13 specimens. The dural sac terminated at the S-2 vertebral level in most of the specimens. The 5 FT specimens that were obtained from patients revealed nerve bundles that were positive for S100 in 4 cases and cells that were positive for GFAP in 3 cases. CONCLUSIONS There are gross anatomical connections between the FT and nerve roots that contain nerve fibers. Apart from fibrous stroma, the FT may contain nerve bundles and cells that stain positive for GFAP, synaptophysin, S100, and nestin. These microscopic findings and previous intraoperative electrophysiological studies suggest a probable functional role for the FT in some individuals. At birth, the conus ends at a higher vertebral level (lower L-1 or upper L-2) than L-3.
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Varghese M, Olstorn H, Berg-Johnsen J, Moe MC, Murrell W, Langmoen IA. Isolation of human multipotent neural progenitors from adult filum terminale. Stem Cells Dev 2009; 18:603-13. [PMID: 18652547 DOI: 10.1089/scd.2008.0144] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Stem cells have been isolated from several CNS regions, including the spinal cord. However, the terminal end of the spinal cord, filum terminale, has been referred to as a fibrovascular tag without neurogenic potential and of no clinical significance. Recently, we were fortunate to acquire some samples of this tissue. We show for the first time that progenitor cells exhibiting the hallmarks of stem cells can be isolated from adult human filum terminale (FTNPs). More specifically, FTNPs self-renew and proliferate to form neurospheres, and exhibit tripotent differentiation into neurons, astrocytes, and oligodendrocytes. Equally important, FTNPs develop the electrophysiological profile of neurons and glia. Whole-cell patch-clamp recordings show beta-III-tubulin(+) neurons exhibiting overshooting action potentials, displaying both the fast inactivating TTX-sensitive sodium current as well as 4-AP and TEA sensitive potassium currents. To assess potency in vivo, FTNPs were transplanted into the posterior periventricular region of control or ischemic rat brains. Despite a vigorous immune response against the xenograft, FTNPs survived and were found not only in the graft area but had also migrated to the lesioned CA1 region. Notwithstanding the immune response, FTNPs differentiated into astrocytes, but no neuronal differentiation was observed in the transplant milieu tested. However, neuronal differentiation in vivo cannot be ruled out and assessment of the conditions necessary to promote neurogenesis in vivo requires more research. Significantly, no tumor formation or aberrant cell morphology was seen in or adjacent to the graft area. Thus, filum terminale provides a novel source of adult human neural progenitor cells that develop into functional neurons with possible clinical applications.
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Affiliation(s)
- Mercy Varghese
- Vilhelm Magnus Laboratory for Neurosurgical Research, Institute for Surgical Research, University of Oslo, Oslo, Norway.
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Abstract
Diffusion in the extracellular space (ECS) of the brain is constrained by the volume fraction and the tortuosity and a modified diffusion equation represents the transport behavior of many molecules in the brain. Deviations from the equation reveal loss of molecules across the blood-brain barrier, through cellular uptake, binding, or other mechanisms. Early diffusion measurements used radiolabeled sucrose and other tracers. Presently, the real-time iontophoresis (RTI) method is employed for small ions and the integrative optical imaging (IOI) method for fluorescent macromolecules, including dextrans or proteins. Theoretical models and simulations of the ECS have explored the influence of ECS geometry, effects of dead-space microdomains, extracellular matrix, and interaction of macromolecules with ECS channels. Extensive experimental studies with the RTI method employing the cation tetramethylammonium (TMA) in normal brain tissue show that the volume fraction of the ECS typically is approximately 20% and the tortuosity is approximately 1.6 (i.e., free diffusion coefficient of TMA is reduced by 2.6), although there are regional variations. These parameters change during development and aging. Diffusion properties have been characterized in several interventions, including brain stimulation, osmotic challenge, and knockout of extracellular matrix components. Measurements have also been made during ischemia, in models of Alzheimer's and Parkinson's diseases, and in human gliomas. Overall, these studies improve our conception of ECS structure and the roles of glia and extracellular matrix in modulating the ECS microenvironment. Knowledge of ECS diffusion properties is valuable in contexts ranging from understanding extrasynaptic volume transmission to the development of paradigms for drug delivery to the brain.
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Affiliation(s)
- Eva Syková
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Boros C, Lukácsi E, Horváth-Oszwald E, Réthelyi M. Neurochemical architecture of the filum terminale in the rat. Brain Res 2008; 1209:105-14. [DOI: 10.1016/j.brainres.2008.02.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 02/04/2008] [Accepted: 02/05/2008] [Indexed: 11/16/2022]
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Fontes RBV, Saad F, Soares MS, de Oliveira F, Pinto FCG, Liberti EA. Ultrastructural Study of the Filum Terminale and Its Elastic Fibers. Neurosurgery 2006; 58:978-84; discussion 978-84. [PMID: 16639335 DOI: 10.1227/01.neu.0000210224.54816.40] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE:
The filum terminale (FT) is a fibrovascular band involved in the pathophysiology of tethered cord syndrome (TCS). Its morphological and ultrastructural properties remain largely unknown even though they are thought to play a role in the generation of TCS in adult patients with normal level conus medullaris.
MATERIALS AND METHODS:
Twenty fresh adult human cadavers had their fila measured and removed. Transversal and longitudinal sections of the proximal, middle, and distal thirds of FT were submitted to light microscopy analysis with four different techniques. Five fila were selected for longitudinal and transversal scanning electron microscopy analysis.
RESULTS:
The bulk of the FT is composed of 5- to 20-μm thick longitudinal bundles of Type 1 collagen separated by 3- to 10-μm intervals, although capillaries and other elements may be present. A delicate (0.05–1.5 μm) meshwork of predominantly Type 3 collagen transversal fibers connects these bundles. Abundant longitudinally oriented elastic and elaunin fibers are found inside collagen bundles. A complex tridimensional structure is evidenced on electron microscopy.
CONCLUSION:
The longitudinal arrangement of collagen bundles and the impressive amount of elastic and elaunin fibers should elicit considerable elastic properties to the FT. An altered elasticity mechanism has been proposed for TCS; further studies are needed with TCS patients to define whether the collagen structure, Type 1/Type 3 proportion, or elastic fiber content are altered, which could lead to new histopathological definitions of TCS, helping neurosurgeons in the difficult management of TCS patients with normal level conus medullaris.
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Affiliation(s)
- Ricardo B V Fontes
- VQM Laboratory, Department of Anatomy, Instituto de Ciencias Biomedicas, and Liga de Neurocirurgia, Faculdade de Medicina, da Universidade de São Paulo, São Paulo, Brazil.
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Réthelyi M, Lukácsi E, Boros C. The caudal end of the rat spinal cord: transformation to and ultrastructure of the filum terminale. Brain Res 2004; 1028:133-9. [PMID: 15527738 DOI: 10.1016/j.brainres.2004.08.069] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2004] [Indexed: 11/13/2022]
Abstract
Contrary to the current belief, the spinal cord of the rat does not terminate with the conus terminalis (CT), but its basic components (central canal, gray matter, white matter) continue in the filum terminale (FT). Proceeding caudally in the conus terminalis, first the motoneuron cell column discontinues in the ventral horn. More caudally the dorsal horns separate from the intermediate zone, and discontinue. The ensuing filum terminale consists of the slit-like central canal lined by ciliated ependymal cells, the periventricular gray matter and the peripheral white matter. Uniform small size neurons and glial cells populate the gray matter. Ultrastructural analysis revealed various types of axodendritic and axosomatic synapses as well as fine unmyelinated axons. The white matter consists mainly of myelinated nerve fibers. The neuronal components of the filum terminale, if they occur also in the human spinal cord, should be involved in the diagnosis and treatment of various diseases, e.g. tethered spinal cord syndrome, vascular malformations and disraphysm.
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Affiliation(s)
- Miklós Réthelyi
- Department of Anatomy, Semmelweis University, Tuzoltó utca 58, H-1098 Budapest, Hungary.
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Chvátal A, Andĕrová M, Ziak D, Orkand RK, Syková E. Membrane currents and morphological properties of neurons and glial cells in the spinal cord and filum terminale of the frog. Neurosci Res 2001; 40:23-35. [PMID: 11311402 DOI: 10.1016/s0168-0102(01)00211-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Using the patch-clamp technique in the whole-cell configuration combined with intracellular dialysis of the fluorescent dye Lucifer yellow (LY), the membrane properties of cells in slices of the lumbar portion of the frog spinal cord (n=64) and the filum terminale (FT, n=48) have been characterized and correlated with their morphology. Four types of cells were found in lumbar spinal cord and FT with membrane and morphological properties similar to those of cells that were previously identified in the rat spinal cord (Chvátal, A., Pastor, A., Mauch, M., Syková, E., Kettenmann, H., 1995. Distinct populations of identified glial cells in the developing rat spinal cord: Ion channel properties and cell morphology. Eur. J. Neurosci. 7, 129-142). Neurons, in response to a series of symmetrical voltage steps, displayed large repetitive voltage-dependent Na(+) inward currents and K(+) delayed rectifying outward currents. Three distinct types of non-neuronal cells were found. First, cells that exhibited passive symmetrical non-decaying currents were identified as astrocytes. These cells immunostained for GFAP and typically had at least one thick process and a number of fine processes. Second, cells with the characteristic properties of rat spinal cord oligodendrocytes, with passive symmetrical decaying currents and large tail currents after the end of the voltage step. These cells exhibited either long parallel or short hairy processes. Third, cells that expressed small brief inward currents in response to depolarizing steps, delayed rectifier outward currents and small sustained inward currents identical to rat glial precursor cells. Morphologically, they were characterized by round cell bodies with a number of finely branched processes. LY dye-coupling in the frog spinal cord gray matter and FT was observed in neurons and in all glial populations. All four cell types were found in both the spinal cord gray matter and FT. The glia/neuron ratio in the spinal cord was 0.78, while in FT it was 2.0. Moreover, the overall cell density was less in the FT than in the spinal cord. The present study shows that the membrane and morphological properties of glial cells in the frog and rat spinal cords are similar. Such striking phylogenetic similarity suggests a significant contribution from distinct glial cell populations to various spinal cord functions, particularly ionic and volume homeostasis in both mammals and amphibians.
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Affiliation(s)
- A Chvátal
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic.
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Ruiz MS, Anadon R. Ultrastructural Study of the Filum Terminate and Caudal Ampulla of the Spinal Cord of Amphioxus (Branchiostoma lanceolatumPallas). ACTA ZOOL-STOCKHOLM 1991. [DOI: 10.1111/j.1463-6395.1991.tb00318.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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