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Concept: Filum terminale


The spinal canal is frequently a source of difficulties, traps and diagnostic errors. Pitfalls related to artifacts are resolved by using appropriate sequences. Good knowledge of the appearance of certain particular anatomical structures (the cauda equina roots, the radicular veins of the lumbar spine and conus medullaris, the dorsal root ganglion) and of frequent variants (fibrolipoma of the filum terminale, common root sheaths, root cysts) will avoid a good many errors. Dilatation of epidural veins in intracranial hypotension can simulate the contrast enhancement of a tumour. An increase in epidural fat can induce pathogenic stenosis of the dural sheath.

Concepts: Spinal cord, Dorsal root ganglion, Lumbar vertebrae, Vertebral column, Lumbar puncture, Cauda equina, Filum terminale, Conus medullaris


Myxopapillary ependymoma (MPE) is a rare variant of ependymoma which usually occurs in the conus medullaris or the filum terminale. It is usually a single encapsulated lesion.

Concepts: Spinal cord, Cauda equina, Ependymoma, Filum terminale, Conus medullaris


The purpose of this case report is to present a rare finding of an intradural extramedullary hemangioblastoma of the cauda equina, with literature review. Spinal hemangioblastomas account for 1-5% of all spinal cord tumors. While spinal hemangioblastomas are rare, it is exceedingly rare to have a case of intradural extramedullary hemangioblastoma of the spine, especially in isolation without von-Hippel-Lindau syndrome. Only 20 previous cases have been reported.

Concepts: Spinal cord, Vertebral column, Report, Case, Cauda equina, Cauda equina syndrome, The Spine, Filum terminale


Traumatic thoracolumbar burst fractures are one of the most common forms of spinal trauma with the majority occurring at the junctional area where mechanical load is maximal (AOSpine Thoracolumbar Spine Injury Classification System Subtype A3 or A4). Burst fractures entail the involvement of the middle column, and therefore, they are typically associated with bone fragment in the spinal canal, which may cause compression of the spinal cord, conus medullaris, cauda equina, or a combination of these. Fortunately, approximately half of the patients with thoracolumbar burst fractures are neurologically intact due to the wide canal diameter. Recent evidences have revealed that functional outcomes in the long term may be equivalent between operative and nonoperative management for neurologically intact thoracolumbar burst fractures. Nevertheless, consensus has not been met regarding the optimal treatment strategy for those with neurological deficits. The present review article summarizes the contemporary evidences to discuss the role of nonoperative management in the presence of neurological deficits and the optimal timing of decompression surgery for neurological recovery. In summary, although operative management is generally recommended for thoracolumbar fracture with significant neurological deficits, the evidence is weak, and nonoperative management can also be an option for those with solitary radicular symptoms. With regards to timing of operative management, high-quality studies comparing early and delayed intervention are lacking. Extrapolating from the evidence in cervical spine injury leads to an assumption that early intervention would also be beneficial for neurological recovery, but further studies are warranted to answer these questions.

Concepts: Bone, Spinal cord, Bone fracture, Surgery, Vertebral column, Cervical vertebrae, Cauda equina, Filum terminale


Myxopapillary ependymoma (MPE) is a rare variant of ependymoma that is most commonly located in the cauda equina and filum terminale. We present a case of 23-year-old man diagnosed with MPE in the fourth ventricle and sacral canal area with extensive disseminated lesions along the cerebrospinal ventricular system. Additionally, a molecular pathological diagnosis was performed. The patient underwent a craniotomy and a lumbar laminectomy. In the course of 18 months of follow-up, the patient have recovered very well.

Concepts: Central nervous system, Spinal cord, Medical terms, Cerebrospinal fluid, Hydrocephalus, Ventricular system, Cauda equina, Filum terminale



Arteriovenous fistula (AVF) of the cauda equina (CE) fed by the proximal radicular artery (PRA) is very rare, and the differentiation from that of the filum terminale (FT) is important to avoid treatment-related injury to the CE when endovascular treatment is selected. The authors describe a case of AVF of the CE fed by the PRA, demonstrate the anatomical features and discuss the treatment precautions.

Concepts: Spinal cord, Arteriovenous fistula, Cauda equina, Filum terminale


OBJECTIVE Spinal lipomas are generally thought to occur as a result of failed primary neurulation. However, some clinical features cannot be explained by this theory. The authors propose a novel classification of spinal lipomas based on embryonic changes seen during primary and secondary neurulation. METHODS A total of 677 patients with occult spinal dysraphism underwent 699 surgeries between August 2002 and May 2015 at the National Center for Child Health and Development and Tokyo Metropolitan Children’s Medical Center. This group of patients had 378 spinal lipomas, including 119 conus spinal lipomas, 27 lipomyelomeningoceles, and 232 filum lipomas, which the authors classified into 4 types based on neural tube formation during embryonic development. Type 1 is defined as pure primary neurulation failure; Type 2 ranges from primary to secondary neurulation failure; Type 3 consists of secondary neurulation failure (early phase); and Type 4 is defined as secondary neurulation failure (late phase). The authors also review embryogenesis in secondary neurulation and analyze the clinical utility of the new classification. RESULTS There were 55 Type 1 spinal lipomas, 29 Type 2, 62 Type 3, and 232 Type 4. All filum lipomas fell into the Type 4 spinal lipoma category. Association with anorectal and/or sacral anomalies was seen in none of the Type 1 cases, 15 (52%) of Type 2, 35 (56%) of Type 3, and 31 (13%) of Type 4. Urogenital anomalies were observed in none of the Type 1 or Type 2 cases, 1 (2%) of Type 3, and 28 (12%) of Type 4. Anomaly syndromes were present in none of the Type 1 cases, 6 (21%) of Type 2, 3 (5%) of Type 3, and 16 (7%) of Type 4. Associated anomalies or anomaly syndromes were clearly observed only for Type 2-4 spinal lipomas encompassing failed secondary neurulation. Radical resection was feasible for Type 1 spinal lipomas. CONCLUSIONS Secondary neurulation of the spinal cord gives rise to the conus medullaris and filum terminale, which are often involved in spinal lipomas. Formation of spinal lipomas seems to be a continuous process overlapping primary and secondary neurulation in some cases. Association with other anomalies was higher in Type 2-4 spinal lipomas, which included failed secondary neurulation, than in Type 1 lipomas, with failed primary neurulation. On the other hand, radical resection was indicated for Type 1, but not for Type 2, spinal lipomas. The new classification of spinal lipomas based on embryonic stage has the potential for clinical use and agrees well with both clinical and surgical findings. The classification proposed here is still preliminary. Further studies and verification are necessary to establish its clinical utility.

Concepts: Central nervous system, Spinal cord, Paralysis, Neural tube, Cauda equina, Filum terminale, Conus medullaris, Neurulation


The filum terminale has oven been overlooked in the literature probably due to its small size and historical lack of research on its true morphology. However, this structure’s roll in the tethered cord syndrome has become more apparent. Therefore, the current comprehensive review seemed timely.

Concepts: Spinal cord, The Current, History of science, Cauda equina, Filum terminale, Conus medullaris, Tethered spinal cord syndrome, Filum terminale internum


Myxopapillary ependymoma (MPE) is a slow-growing tumor occurring most often in adults. It originates from the filum terminale in the area of the conus medullaris and cauda equina, and is considered a benign lesion. Despite this classification, however, recurrence after both partial and gross total resection is well known. In the pediatric population, primary MPE seeding is well documented and treated through gross total resection, followed by irradiation. In adults, however, primary MPE seeding is not recognized. Only one prior report describes primary drop metastases into multiple spinal locations in an adult before resection of an MPE, and there are only 3 reports of such an occurrence cranially. The reason for this difference between pediatric and adult MPE remains unclear. We present here the case of a 32-year-old man with primary seeding of an MPE into multiple lumbosacral areas. The patient underwent gross total resection of the lesions and had an uneventful postoperative course. Primary seeding could be a sign of aggressive behavior in this tumor. Complete craniospinal magnetic resonance imaging (MRI) studies should be done before and after surgery in patients who present with a multifocal primary MPE. Furthermore, patients with a history of primary tumor seeding of MPE should be thoroughly evaluated radiologically. Unlike in pediatric population, the need for postoperative irradiation in adults is unclear, and further studies, particularly genetic ones, are warranted.

Concepts: Spinal cord, Oncology, Brain tumor, Anatomical pathology, Magnetic resonance imaging, Cauda equina, Filum terminale, Conus medullaris