1
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Sala F. Intraoperative neurophysiology in pediatric neurosurgery: a historical perspective. Childs Nerv Syst 2023; 39:2929-2941. [PMID: 37776333 PMCID: PMC10613152 DOI: 10.1007/s00381-023-06155-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 10/02/2023]
Abstract
INTRODUCTION Intraoperative neurophysiology (ION) has been established over the past three decades as a valuable discipline to improve the safety of neurosurgical procedures with the main goal of reducing neurological morbidity. Neurosurgeons have substantially contributed to the development of this field not only by implementing the use and refinement of ION in the operating room but also by introducing novel techniques for both mapping and monitoring of neural pathways. METHODS This review provides a personal perspective on the evolution of ION in a variety of pediatric neurosurgical procedures: from brain tumor to brainstem surgery, from spinal cord tumor to tethered cord surgery. RESULTS AND DISCUSSION The contribution of pediatric neurosurgeons is highlighted showing how our discipline has played a crucial role in promoting ION at the turn of the century. Finally, a view on novel ION techniques and their potential implications for pediatric neurosurgery will provide insights into the future of ION, further supporting the view of a functional, rather than merely anatomical, approach to pediatric neurosurgery.
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Affiliation(s)
- Francesco Sala
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy.
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2
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Kurogi A, Murakami N, Suzuki SO, Shimogawa T, Mukae N, Yoshimoto K, Morioka T. Retained medullary cord and caudal lipoma with histopathological presence of terminal myelocystocele in the epidural stalk. Surg Neurol Int 2023; 14:279. [PMID: 37680925 PMCID: PMC10481812 DOI: 10.25259/sni_479_2023] [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: 06/05/2023] [Accepted: 07/14/2023] [Indexed: 09/09/2023] Open
Abstract
Background The retained medullary cord (RMC), caudal lipoma, and terminal myelocystocele (TMCC) are thought to originate from the failed regression spectrum during the secondary neurulation, and the central histopathological feature is the predominant presence of a central canal-like ependyma-lined lumen (CC-LELL) with surrounding neuroglial tissues (NGT), as a remnant of the medullary cord. However, reports on cases in which RMC, caudal lipoma, and TMCC coexist are very rare. Case Description We present two patients with cystic RMC with caudal lipoma and caudal lipoma with an RMC component, respectively, based on their clinical, neuroradiological, intraoperative, and histopathological findings. Although no typical morphological features of TMCC were noted on neuroimaging, histopathological examination revealed that a CC-LELL with NGT was present in the extraspinal stalk, extending from the skin lesion to the intraspinal tethering tract. Conclusion This histopathological finding indicates the presence of TMCC that could not be completely regressed and further supports the idea that these pathologies can be considered consequences of a continuum of regression failure during secondary neurulation.
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Affiliation(s)
- Ai Kurogi
- Department of Neurosurgery, Fukuoka Children’s Hospital, Fukuoka, Japan
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children’s Hospital, Fukuoka, Japan
| | | | | | - Nobutaka Mukae
- Department of Neurosurgery, Iizuka Hospital, Iizuka, Japan
| | - Koji Yoshimoto
- Department of Neurosurgery, Kyushu University, Fukuoka, Japan
| | - Takato Morioka
- Department of Neurosurgery, Hachisuga Hospital, Munakata, Japan
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3
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Kim KH, Lee JY, Wang KC. Secondary Neurulation Defects: Retained Medullary Cord. Adv Tech Stand Neurosurg 2023; 47:215-223. [PMID: 37640876 DOI: 10.1007/978-3-031-34981-2_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Retained medullary cord (RMC) is a defect resulting from impaired secondary neurulation. Intraoperatively, RMC is recognizable as an elongated cord-like structure caudal to the conus, that contains histologically confirmed neuroglial components and a lumen with an ependymal lining. It characteristically does not possess neurological function. This chapter aims to summarize (1) the mechanisms that lead to the occurrence of RMC; (2) the various forms of RMC, such as cystic RMC and 'possible RMC', and (3) the treatment strategies, especially untethering through limited exposure.
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Affiliation(s)
- Kyung Hyun Kim
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ji Yeoun Lee
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyu-Chang Wang
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Republic of Korea.
- Neuro-oncology Clinic, National Cancer Center, Goyang, Republic of Korea.
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4
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Pasquali C, Basaldella F, Sala F. Updates on Intraoperative Neurophysiology During Surgery for Spinal Dysraphism. Adv Tech Stand Neurosurg 2023; 47:235-272. [PMID: 37640878 DOI: 10.1007/978-3-031-34981-2_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Spinal dysraphism is a group of disorders resulting from an embryologic failure of spinal cord development which can lead to a radicular-medullary mechanical stretch that generates vascular compromise and hypoxic-ischemic damage to the nervous structures of the conus-cauda region.Thus, the clinical relevance of the different types of spinal dysraphism is related to the possible neurologic deficits resulting from spinal cord tethering. The clinical presentation is heterogenous: from asymptomatic to very compromised patients. The indications and the time of a detethering surgery are still subject of debate, although there is an agreement on the high standards of treatment that have to be offered by the surgery. Intraoperative neurophysiology (ION) contributes to the safety of tethered cord surgery in reducing the risks of iatrogenic neurological damages.
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Affiliation(s)
- Claudia Pasquali
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy
| | - Federica Basaldella
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy
| | - Francesco Sala
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy.
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5
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Embryopathological relationship between retained medullary cord and caudal spinal lipoma. INTERDISCIPLINARY NEUROSURGERY 2022. [DOI: 10.1016/j.inat.2022.101534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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6
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TAŞKIRAN E, KEMERDERE R, KÜÇÜKYÜRÜK B, TAHMAZOĞLU B, KAFADAR AM. Mapping and Monitoring During Surgery for Congenital Spinal Malformation. BEZMIALEM SCIENCE 2022. [DOI: 10.14235/bas.galenos.2020.4452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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7
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Matsubara Y, Murakami N, Kurogi A, Lee S, Mukae N, Shimogawa T, Shono T, Suzuki SO, Yoshimoto K, Morioka T. Intramedullary abscess at thoracolumbar region transmitted from infected dermal sinus and dermoid through retained medullary cord. Surg Neurol Int 2022; 13:54. [PMID: 35242420 PMCID: PMC8888283 DOI: 10.25259/sni_1197_2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/28/2022] [Indexed: 11/23/2022] Open
Abstract
Background: A retained medullary cord (RMC) is a relatively newly defined entity of closed spinal dysraphism that is thought to originate from regression failure of the medullary cord during secondary neurulation. A congenital dermal sinus (CDS) may provide a pathway for intraspinal infections such as repeated meningitis. Intramedullary abscesses are the rarest but most serious complication of a CDS. Case Description: We treated a female infant with an intramedullary abscess in the thoracolumbar region, which was caused by infection of the CDS. Surgery revealed that the cord-like structure (C-LS) started from the cord with the intramedullary abscess, extended to the dural cul-de-sac, and further continued to the CDS tract and skin dimple. The boundary between the functional cord and the non-functional CL-S was electrophysiologically identified, and the entire length of the C-LS (the RMC) with an infected dermoid cyst was resected. As a result, the abscess cavity was opened and thorough irrigation and drainage of the pus could be performed. Histopathological examination of the C-LS revealed an infected dermoid cyst and abscess cavity with keratin debris in the fibrocollagenous tissue. The abscess cavity had a central canal-like ependymal lined lumen (CCLELL), with surrounding glial fibrillary acidic protein (GFAP)-immunopositive neuroglial tissues. Conclusion: We demonstrated that the transmission of an infection through the RMC was involved in the development of the intramedullary abscess. A good postoperative outcome was obtained because a terminal ventriculostomy for pus drainage could be achieved by excising the nonfunctional RMC.
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Affiliation(s)
- Yoshie Matsubara
- Department of Pediatric Neurology, Fukuoka Children’s Hospital, Fukuoka,
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children’s Hospital, Fukuoka,
| | - Ai Kurogi
- Department of Neurosurgery, Fukuoka Children’s Hospital, Fukuoka,
| | - Sooyoung Lee
- Department of Pediatrics, National Hospital Organization, Fukuoka-Higashi Medical Center, Koga, Fukuoka,
| | - Nobutaka Mukae
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka,
| | - Takafumi Shimogawa
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka,
| | - Tadahisa Shono
- Department of Neurosurgery, Harasanshin Hospital, Fukuoka,
| | | | - Koji Yoshimoto
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka,
| | - Takato Morioka
- Department of Neurosurgery, Harasanshin Hospital, Fukuoka,
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Kurogi A, Murakami N, Mukae N, Shimogawa T, Shono T, Suzuki SO, Morioka T. Retained Medullary Cord Associated with Terminal Myelocystocele and Intramedullary Arachnoid Cyst. Pediatr Neurosurg 2022; 57:184-190. [PMID: 35259748 DOI: 10.1159/000523976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 03/04/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The retained medullary cord (RMC) is a newly defined entity of closed spinal dysraphism that is thought to originate from regression failure of the medullary cord during the last phase of secondary neurulation. The terminal myelocystocele (TMC) is an unusual type of closed spinal dysraphism, characterized by localized cystic dilatation of the terminal part of the central canal that then herniates through a posterior spinal bifida. The co-occurrence of RMC and TMC is extremely rare. CASE PRESENTATION We treated a baby girl with a huge sacrococcygeal meningocele-like sac with two components. Untethering surgery and repair surgery for the sac revealed that RMC, associated with intramedullary arachnoid cyst (IMAC), was terminated at the bottom of the rostral cyst, forming the septum of the two cystic components, and the caudal cyst was TMC derived from the central canal-like ependymal lining lumen (CC-LELL) of the RMC at the septum. IMAC within the RMC communicated with TMC, and both contained xanthochromic fluid with the same properties. CONCLUSION We speculated that the mass effect of the coexistent IMAC impeded the flow of cerebrospinal fluid in the CC-LELL within the RMC and eventually formed a huge TMC. In surgical strategies for such complex pathologies, it is important to identify the electrophysiological border between the functional cord and nonfunctional RMC and the severe RMC to untether the cord, as with a typical or simple RMC.
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Affiliation(s)
- Ai Kurogi
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Nobutaka Mukae
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | | | - Tadahisa Shono
- Department of Neurosurgery, Harasanshin Hospital, Fukuoka, Japan
| | | | - Takato Morioka
- Department of Neurosurgery, Harasanshin Hospital, Fukuoka, Japan
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Yang J, Lee JY, Kim KH, Yang HJ, Wang KC. Disorders of Secondary Neurulation: Suggestion of a New Classification According to Pathoembryogenesis. Adv Tech Stand Neurosurg 2022; 45:285-315. [PMID: 35976454 DOI: 10.1007/978-3-030-99166-1_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recently, advanced knowledge on secondary neurulation and its application to the clinical experience have led to the deeper insight into the pathoembryogenesis of secondary neurulation with new classifications of the caudal spinal dysraphic entities. Here, we summarize the dynamic changes in the concepts of disordered secondary neurulation over the last two decades. In addition, we suggest our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase may cause various corresponding lesions, such as (1) failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), (2) dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), (3) abnormal continuity of medullary cord to the surrounding layers, namely, failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neurocutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), and neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and (4) regression failure spectrum of the medullary cord (thickened filum and filar cyst, retained medullary cord and low-lying conus, terminal myelocele, and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association of the caudal cell mass with the activity of caudal mesenchymal tissue involves a wider range of surrounding structures in secondary neurulation than in primary neurulation. Although the majority of the data are from animals and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.
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Affiliation(s)
- Jeyul Yang
- Neuro-Oncology Clinic, Center for Rare Cancers, National Cancer Center, Goyang, Kyounggi-do, South Korea
| | - Ji Yeoun Lee
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, South Korea
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyung Hyun Kim
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, South Korea
| | - Hee Jin Yang
- Department of Neurosurgery, SMG-SNU Boramae Medical Center, Seoul, South Korea
| | - Kyu-Chang Wang
- Neuro-Oncology Clinic, Center for Rare Cancers, National Cancer Center, Goyang, Kyounggi-do, South Korea.
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10
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Galloway G, Sala F. Mapping and monitoring of tethered cord and cauda equina surgeries. HANDBOOK OF CLINICAL NEUROLOGY 2022; 186:257-270. [PMID: 35772890 DOI: 10.1016/b978-0-12-819826-1.00018-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Surgery involving the cauda equina and tethered cord can be associated with significant functional disability including pain, motor and sensory deficits, as well as bladder, bowel, and sexual dysfunction. Neurophysiologic intraoperative monitoring and mapping during these surgeries using a variety of techniques and applications contributes to lessen the risk of permanent injury. This chapter reviews the anatomy of the pelvic floor, describes the techniques involved in monitoring and mapping this area, and describes the limitations of neurophysiology applications. Additionally, this chapter details mapping and monitoring techniques as they apply to tethered cord surgical release in both children and adults with review of outcome studies, and describes complications which can arise from tethered cord repair and injury to the cauda equina despite appropriate neurophysiologic intraoperative involvement.
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Affiliation(s)
- Gloria Galloway
- Department of Neurology, Wexner Medical Center, Ohio State University Medical Center, Columbus, OH, United States.
| | - Francesco Sala
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy
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11
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Morioka T, Murakami N, Suzuki SO, Mukae N, Shimogawa T, Kurogi A, Shono T, Mizoguchi M. Surgical histopathology of a filar anomaly as an additional tethering element associated with closed spinal dysraphism of primary neurulation failure. Surg Neurol Int 2021; 12:373. [PMID: 34513140 PMCID: PMC8422463 DOI: 10.25259/sni_340_2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/09/2021] [Indexed: 11/12/2022] Open
Abstract
Background: Closed spinal dysraphism of primary neurulation failure could be associated with filar anomalies, such as filar lipoma or thickened and tight filum terminale (TFT), resulting from impaired secondary neurulation. Retained medullary cord (RMC) is a remnant of the cavitary medullary cord originating from the secondary neurulation failure. Some filar lipomas are known to contain a central canal-like ependyma-lined lumen with surrounding neuroglial tissues (E-LC w/NGT), that is, a characteristic histopathology of RMC. To clarify the embryological background of these filar anomalies, we evaluated the histopathological findings. Methods: Among 41 patients with lesions of primary neurulation failure who underwent initial untethering surgery, the filum including cord-like structure (C-LS) was additionally resected in 10 patients (five dorsal and transitional lipomas; five limited dorsal myeloschisis). We retrospectively analyzed the clinical, neuroradiological, intraoperative, and histopathological findings. Results: Among 10 patients, two patients were diagnosed with RMC based on morphological features and intraoperative neurophysiological monitoring. The diagnosis of filar lipoma was made in six patients, since various amounts of fibroadipose tissue were histopathologically noted in the filum. Two patients were diagnosed with TFT, since the filum was composed solely of fibrocollagenous tissue. E-LC w/NGT was noted not only in both C-LSs of RMCs but also in two out of six fila both with filar lipomas and fila with TFTs. Conclusion: These findings provide further evidence for the idea that entities, such as filar lipoma, TFT, and RMC, can be considered consequences of a continuum of regression failure occurring during late secondary neurulation.
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Affiliation(s)
- Takato Morioka
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan.,Department of Neurosurgery, Harasanshin Hospital, Karatsu, Saga
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan
| | | | - Nobutaka Mukae
- Department of Neurosurgery, Graduate School of Medical Sciences, Fukuoka, Japan
| | | | - Ai Kurogi
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Tadahisa Shono
- Department of Neurosurgery, Harasanshin Hospital, Karatsu, Saga
| | - Masahiro Mizoguchi
- Department of Neurosurgery, Graduate School of Medical Sciences, Fukuoka, Japan
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12
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Yang J, Lee JY, Kim KH, Wang KC. Disorders of Secondary Neurulation : Mainly Focused on Pathoembryogenesis. J Korean Neurosurg Soc 2021; 64:386-405. [PMID: 33906343 PMCID: PMC8128515 DOI: 10.3340/jkns.2021.0023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/16/2021] [Indexed: 12/22/2022] Open
Abstract
Recent advancements in basic research on the process of secondary neurulation and increased clinical experience with caudal spinal anomalies with associated abnormalities in the surrounding and distal structures shed light on further understanding of the pathoembryogenesis of the lesions and led to the new classification of these dysraphic entities. We summarized the changing concepts of lesions developed from the disordered secondary neurulation shown during the last decade. In addition, we suggested our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase of development may cause corresponding lesions, such as failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neuro-cutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and regression failure spectrum of the medullary cord (thickened filum and filar cyst, low-lying conus, retained medullary cord, terminal myelocele and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association with the activity of caudal mesenchymal tissue in secondary neurulation involves a wider range of surrounding structures than in primary neurulation. Although the majority of the data are from animals, not from humans and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.
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Affiliation(s)
- Jeyul Yang
- Neuro-oncology Clinic, Center for Rare Cancers, National Cancer Center, Goyang, Korea
| | - Ji Yeoun Lee
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Korea.,Department of Anatomy, Seoul National University College of Medicine, Seoul, Korea
| | - Kyung Hyun Kim
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Korea
| | - Kyu-Chang Wang
- Neuro-oncology Clinic, Center for Rare Cancers, National Cancer Center, Goyang, Korea
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13
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Morioka T, Murakami N, Suzuki SO, Nakamura R, Mizoguchi M. Subpial Lumbar Lipoma Associated with Retained Medullary Cord. NMC Case Rep J 2021; 8:51-55. [PMID: 34012749 PMCID: PMC8116927 DOI: 10.2176/nmccrj.cr.2020-0073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/08/2020] [Indexed: 11/20/2022] Open
Abstract
Subpial lipomas, which are also known as nondysraphic intramedullary spinal cord lipomas, are not associated with spinal dysraphism resulting from the failed primary neurulation. Retained medullary cord (RMC) is a newly defined entity of closed spinal dysraphism that originates from the late arrest of secondary neurulation. We treated a 6-year-old boy presented with myoclonus of the lower limbs, who had subpial lipoma at the lumbar cord, just rostral to the low-lying conus, which was tethered by a cord-like structure (C-LS) continuous from the conus and extending to the dural cul-de-sac. Following cord untethering from C-LS and minimal debulking of the lipoma, the myoclonus was improved. Histological examination of C-LS revealed a large central canal-like structure in the neuroglial core and the diagnosis of RMC was made. Subpial lipomas can be incidentally coexistent with spinal dysraphism resulting from the failed secondary neurulation, such as RMC.
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Affiliation(s)
- Takato Morioka
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Fukuoka, Japan
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Fukuoka, Japan
| | - Satoshi O Suzuki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Ryoko Nakamura
- Department of Pediatrics, Japan Community Health Care Organization (JCHO), Kyushu Hospital, Kitakyushu, Fukuoka, Japan
| | - Masahiro Mizoguchi
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
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14
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Kurogi A, Murakami N, Morioka T, Mukae N, Shimogawa T, Kudo K, Suzuki SO, Mizoguchi M. Two cases of retained medullary cord running parallel to a terminal lipoma. Surg Neurol Int 2021; 12:112. [PMID: 33880217 PMCID: PMC8053431 DOI: 10.25259/sni_626_2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 02/08/2021] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Retained medullary cord (RMC) is a newly defined entity believed to originate from the late arrest of secondary neurulation. Some RMCs contain varying amounts of lipomatous tissues, which need to be differentiated from spinal lipomas, such as filar and caudal lipomas (terminal lipomas). CASE DESCRIPTION We surgically treated two patients with a nonfunctional cord-like structure (C-LS) that was continuous from the cord and extended to the dural cul-de-sac, and ran parallel to the terminal lipoma. In both cases, untethering surgery was performed by resecting the C-LS with lipoma as a column, under intraoperative neurophysiological monitoring. Histopathological examination confirmed that the central canal-like ependyma-lined lumen with surrounding neuroglial and fibrocollagenous tissues, which is the central histopathological feature of an RMC, was located on the unilateral side of the resected column, while the fibroadipose tissues of the lipoma were located on the contralateral side. CONCLUSION Our findings support the idea proposed by Pang et al. that entities such as RMC and terminal lipomas are members of a continuum of regression failure occurring during late secondary neurulation, and the coexistence of RMC and terminal lipoma is not a surprising finding. Therefore, it may be difficult in clinical practice to make a distinct diagnosis between these two entities.
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Affiliation(s)
- Ai Kurogi
- Department of Neurosurgery, Fukuoka Children’s Hospital, Saga, Japan
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children’s Hospital, Saga, Japan
| | - Takato Morioka
- Department of Neurosurgery, Harasanshin Hospital, Saga, Japan
| | - Nobutaka Mukae
- Department of Neurosurgery, Kyushu University, Saga, Japan
| | | | - Kyoko Kudo
- Department of Dermatology, Fukuoka Children’s Hospital, Saga, Japan
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15
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Rhodes RH. Congenital Spinal Lipomatous Malformations. Part 2. Differentiation from Selected Closed Spinal Malformations. Fetal Pediatr Pathol 2021; 40:32-68. [PMID: 31535937 DOI: 10.1080/15513815.2019.1651799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Congenital spinal lipomatous malformations (spinal lipomas, lipomyeloceles, and lipomyelomeningoceles) are closed neural tube defects over the lower back. Differentiation from some other closed neural tube defects in this region can be problematic for pathologists. MATERIALS AND METHODS This review is based on PubMed searches of the embryology, gross and histopathologic findings, and laboratory reporting requisites for retained medullary spinal cords, coccygeal medullary vestiges and cysts, myelocystoceles, true human vestigial tails, and pseudotails for comparison with congenital spinal lipomatous malformations. RESULTS Embryology, imaging, gross and histopathology of these closed neural tube lesions have different but overlapping features compared to congenital spinal lipomatous malformations, requiring context for diagnosis. CONCLUSION The lipomyelocele spectrum and to some degree all of the malformations discussed, even though they may not share gross appearance, anatomic site, surgical approach, or prognosis, require clinical and histopathologic correlation for final diagnosis.
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Affiliation(s)
- Roy H Rhodes
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
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16
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Mukae N, Morioka T, Suzuki SO, Murakami N, Shimogawa T, Kanata A, Tsukamoto H, Mizoguchi M. Two Cases of Large Filar Cyst Associated with Terminal Lipoma: Relationship with Retained Medullary Cord. World Neurosurg 2020; 142:294-298. [PMID: 32668332 DOI: 10.1016/j.wneu.2020.07.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 07/04/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND A small, incidental filar cyst associated with terminal lipoma is thought to be caused by failure of secondary neurulation; however, the precise embryologic background is not fully understood. Retained medullary cord (RMC) also originates from late arrest of secondary neurulation. The central feature of RMC histopathology is a central canal-like ependyma-lined lumen with surrounding neuroglial core. CASE DESCRIPTION We surgically treated 2 patients with a large cyst in the rostral part of the filum and lipoma in the caudal filum. At cord untethering surgery, the filum was severed at the caudal part of the cyst. Histopathologically, the filar cyst was the cystic dilatation of the central canal-like structure at the marginal part of the lipoma. The central canal-like structure was continuous caudally in the lipoma, and its size decreased toward the caudal side. CONCLUSIONS The present findings support the idea raised by Pang et al that entities such as filar cyst, terminal lipomas, and RMC can all be considered consequences of a continuum of regression failure occurring during late secondary neurulation.
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Affiliation(s)
- Nobutaka Mukae
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
| | - Takato Morioka
- Department of Neurosurgery, Harasanshin Hospital, Fukuoka, Japan
| | | | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Takafumi Shimogawa
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Akiko Kanata
- Department of Neurosurgery, Kitakyushu Municipal Medical Center, Kitakyushu, Japan
| | - Haruhisa Tsukamoto
- Department of Neurosurgery, Kitakyushu Municipal Medical Center, Kitakyushu, Japan
| | - Masahiro Mizoguchi
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Rhodes RH. Congenital Spinal Lipomatous Malformations. Part 1. Spinal Lipomas, Lipomyeloceles, and Lipomyelomeningoceles. Fetal Pediatr Pathol 2020; 39:194-245. [PMID: 31342816 DOI: 10.1080/15513815.2019.1641859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Background: Lumbosacral spinal lipomas and lipomyeloceles are usually identified in early childhood. Terminology, histopathology, and diagnosis for these malformations can be confusing. Materials and Methods: This is a PubMed review with comparison of embryology, gross, and histopathology, and reporting requisites for these and related closed spinal malformations. Results: The spinal lipoma group (congenital spinal lipomatous malformations) includes subcutaneous, transdural, intradural, and noncontiguous malformations stretching through the entire lower spinal region. This lipomyelocele trajectory overlaps the embryonic tail's caudal eminence. Histopathologically, the lipomyelocele spectrum is a heterogeneous, stereotypical set of findings encountered from dermis to spinal cord. Diagnosis requires detailed correlation of images, intraoperative inspection, and histopathology. Conclusions: Appropriate terminology and clinicopathologic correlation to arrive at a diagnosis is a critical activity shared by pathologist and clinician. Prognostic and management differences depend on specific diagnoses. Familial and genetic influences play little if any role in patient management in closed spinal malformations.
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Affiliation(s)
- Roy H Rhodes
- LSUHSC, Pathology, New Orleans, Louisiana, USA.,Rutgers Robert Wood Johnson Medical School, Pathology, New Brunswick, New Jersey, USA
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Kim KH, Lee JY, Wang KC. Secondary Neurulation Defects-1 : Retained Medullary Cord. J Korean Neurosurg Soc 2020; 63:314-320. [PMID: 32336057 PMCID: PMC7218196 DOI: 10.3340/jkns.2020.0052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 11/27/2022] Open
Abstract
Retained medullary cord (RMC) is a relatively recent term. Pang et al. newly defined the RMC as a late arrest of secondary neurulation leaving a non-functional vestigial portion at the tip of the conus medullaris. RMC, which belongs to the category of closed spinal dysraphism, is a cord-like structure that is elongated from the conus toward the cul-de-sac. Because intraoperative electrophysiological confirmation of a non-functional conus is essential for the diagnosis of RMC, only a tentative or an assumptive diagnosis is possible before surgery or in cases of limited surgical exposure. We suggest the term ‘possible RMC’ for these cases. An RMC may cause tethered cord syndrome and thus requires surgery. This article reviews the literature to elucidate the pathoembryogenesis, clinical significance and treatment of RMCs.
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Affiliation(s)
- Kyung Hyun Kim
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Korea
| | - Ji Yeoun Lee
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Korea.,Department of Anatomy, Seoul National University College of Medicine, Seoul, Korea
| | - Kyu-Chang Wang
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Korea
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Morioka T, Murakami N, Kanata A, Tsukamoto H, Suzuki SO. Retained medullary cord with sacral subcutaneous meningocele and congenital dermal sinus. Childs Nerv Syst 2020; 36:423-427. [PMID: 31297584 DOI: 10.1007/s00381-019-04301-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/07/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated cord-like structure extending continuously from the conus medullaris to the dural cul-de-sac that is caused by late arrest of secondary neurulation. Five patients with RMC extending to an associated sacral subcutaneous meningocele have been reported. CASE PRESENTATION We report an additional patient with RMC, in whom a congenital dermal sinus (CDS) was found in the caudal portion of the RMC. At the age of 3 days, the patient underwent surgery consisting of meningocele excision and cord untethering, and CDS was noted histologically in the proximal cut end of the RMC. During a second surgery at the age of 5 months, after determining the exact border of the nonfunctional RMC and the true conus by neurophysiological mapping, we removed the entire length of the remnant RMC, including newly developed epidermoid cysts in the CDS. CONCLUSION Although the exact pathoembryogenesis of concurrent RMC and CDS is unknown, an associated subcutaneous meningocele, caused by failure of primary neurulation, could be involved. Surgeons should be aware of the possibility of the coexistence of CDS when dealing with RMCs that extend out to the extradural space.
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Affiliation(s)
- Takato Morioka
- Department of Neurosurgery, Fukuoka Children's Hospital, 5-1-1 Kashii-teriha, Higashi-ku, Fukuoka, 813-0017, Japan.
| | - Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children's Hospital, 5-1-1 Kashii-teriha, Higashi-ku, Fukuoka, 813-0017, Japan
| | - Akiko Kanata
- Department of Neurosurgery, Kitakyushu Municipal Medical Center, Kitakyushu, Japan
| | - Haruhisa Tsukamoto
- Department of Neurosurgery, Kitakyushu Municipal Medical Center, Kitakyushu, Japan
| | - Satoshi O Suzuki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Enlargement of sacral subcutaneous meningocele associated with retained medullary cord. Childs Nerv Syst 2018; 34:1785-1790. [PMID: 29704125 DOI: 10.1007/s00381-018-3812-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac. Four cases of RMC extending down to the base of an associated subcutaneous meningocele at the sacral level have been reported. CLINICAL PRESENTATION We report an additional case of RMC, in whom serial MRI examination revealed an enlargement of the meningocele associated with RMC over a 3-month period between 8 and 11 months of age, when he began to stand. At the age of 12 months, untethering of the cord was performed. Histologically, the presence of ependyma-lined central canals in the dense neuroglial cores was noted in all cord-like structures in the intradural and intrameningocele sacs and at the attachment to the meningocele. CONCLUSION It is conceivable that the hydrodynamic pressure with standing position and the check valve phenomenon were involved in meningocele enlargement. We should be mindful of these potential morphological changes.
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21
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Retained medullary cord extending to a sacral subcutaneous meningocele. Childs Nerv Syst 2018; 34:527-533. [PMID: 29101613 DOI: 10.1007/s00381-017-3644-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac. One case extending down to the base of a subcutaneous meningocele at the sacral level has been reported. CLINICAL PRESENTATION We report on three cases of closed spinal dysraphism, in which a spinal cord-like tethering structure extended out from the dural cul-de-sac and terminated at a skin-covered meningocele sac in the sacrococcygeal region, which was well delineated in curvilinear coronal reconstructed images of 3D-heavily T2-weighted images (3D-hT2WI). Intraoperative neurophysiology revealed the spinal cord-like tethering structure was nonfunctional, and histopathology showed that it consisted of central nervous system tissue, consistent with RMC. The tethering structure histologically contained a glioneuronal core with an ependymal-like lumen and smooth muscle, which may indicate developmental failure during secondary neurulation. CONCLUSIONS When the RMC extending to a meningocele is demonstrated with the detailed magnet resonance imaging including 3D-hT2WI, decision to cut the cord-like structure for untethering of the nervous tissue should be made under careful intraoperative neurophysiological monitoring.
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22
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Murakami N, Morioka T, Shimogawa T, Mukae N, Inoha S, Sasaguri T, Suzuki SO, Iihara K. Ependyma-Lined Canal with Surrounding Neuroglial Tissues in Lumbosacral Lipomatous Malformations: Relationship with Retained Medullary Cord. Pediatr Neurosurg 2018; 53:387-394. [PMID: 30391938 DOI: 10.1159/000494029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 09/23/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND An ependyma-lined canal with surrounding neuroglial tissues can be present in lumbosacral lipomatous malformations; however, the precise embryological significance is still unclear. METHOD Six out of 50 patients with lipomatous malformations had ependymal structures. We retrospectively analyzed the clinical, neuroradiological, and histological findings of these patients to demonstrate the relationship with the embryological background of the retained medullary cord (RMC), which normally regresses, but was retained here because of late arrest of secondary neurulation. RESULTS Five (13.9%) of 36 patients with filar and caudal types and 1 of 3 lipomyelomeningoceles had ependymal structures, while none with dorsal and transitional types had these tissues. Histologically, the ependymal structures surrounded by neuroglial tissue and containing various amounts of adipose tissue bear a striking resemblance to the ependymal structures in RMC. CONCLUSION The 13.9% incidence of association between the ependymal structures and filar and caudal types is thought to be because of second ary neurulation failure with the same embryological background as that of RMC. Dorsal and transitional types, resulting from primary neurulation failure, therefore, did not have ependymal structures.
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Affiliation(s)
- Nobuya Murakami
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan,
| | - Takato Morioka
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Takafumi Shimogawa
- Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan.,Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Nobutaka Mukae
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoshi Inoha
- Department of Neurosurgery, Japan Community Health Care Organization (JCHO), Kyushu Hospital, Kitakyushu, Japan
| | - Takakazu Sasaguri
- Department of Pathology, Japan Community Health Care Organization (JCHO), Kyushu Hospital, Kitakyushu, Japan
| | - Satoshi O Suzuki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koji Iihara
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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