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CASE REPORT
Year : 2022  |  Volume : 70  |  Issue : 8  |  Page : 326-329

Distinct Spinal Dysraphisms Arising from Each Hemicord of Type I Split Cord Malformation - A Rare Coexistence


Department of Neurosurgery, DKS Post Graduate Institute and Research Centre, Raipur, Chhattisgarh, India

Date of Submission23-Jun-2020
Date of Decision17-Mar-2021
Date of Acceptance27-Sep-2021
Date of Web Publication11-Nov-2022

Correspondence Address:
Lavlesh Rathore
Department of Neurosurgery, DKS Post Graduate Institute and Research Centre, DKS Bhawan, Raipur, Chhattisgarh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.360939

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 » Abstract 


In this report, we describe a 6-month-old child having Type I split cord malformation (SCM), associated with meningomyelocele of one hemicord and lipomeningomyelocele of other hemicord at the same level along with Type II Chiari malformation. The classical embryological theories on split cord malformation and neurulation defect do not clearly explain such a complex entity at one level. The new research on the genetic association of posterior neuropore defect opens a new horizon of research on such genesis.


Keywords: Lipomeningomyelocele, meningomyelocele, SCM, split cord malformation
Key Message: Although the unified theory of Pang and McLone explains the majority of neural tube defects, complex developmental defects need a better explanation on an embryological basis.


How to cite this article:
Rathore L, Sahana D, Kumar S, Sahu R. Distinct Spinal Dysraphisms Arising from Each Hemicord of Type I Split Cord Malformation - A Rare Coexistence. Neurol India 2022;70, Suppl S2:326-9

How to cite this URL:
Rathore L, Sahana D, Kumar S, Sahu R. Distinct Spinal Dysraphisms Arising from Each Hemicord of Type I Split Cord Malformation - A Rare Coexistence. Neurol India [serial online] 2022 [cited 2022 Dec 3];70, Suppl S2:326-9. Available from: https://www.neurologyindia.com/text.asp?2022/70/8/326/360939




Spinal dysraphisms in a split cord malformation (SCM) had been abundantly described in the literature. Pang's unified theory explains SCM development, which starts in the gastrulation phase of embryo development.[1] McLone et al.[2] had explained the embryological basis of meningomyelocele and Chiari II malformation due to primary neurulation defect. The present case had Type I SCM, with meningomyelocele arising from one of the hemicord and lipomeningomyelocele from the other hemicord. It is challenging to explain the persistence of this defect from the gastrulation period to the secondary neurulation stage by embryology alone. The genome study suggests a role of the ciliogenic copy number variant associated with neural tube defect.[3],[21],[22] This report intends to look for the embryological basis of such a complex spinal dysraphism with the possible role of gene analysis.


 » Case Report Top


A 6-month-old female presented with a large swelling in the lower back since birth. The swelling was bilobed, one being a large midline, primary cystic with 13 cm × 8 cm size, the other placed laterally, soft to a firm consistency of size 5 cm × 4 cm [Figure 1]a and [Figure 1]b. She had paraparesis with absent deep tendon reflexes. The child was continent. The magnetic resonance imaging (MRI) showed the posterior spinal fusion defect at L5 and S1 levels. Thick bony septa were arising from the L5 hemivertebra, splitting the thecal sac into two [Figure 2]a. There was associated lipomeningomyelocele from the left hemicord [Figure 2]b and meningocele from the right hemicord [Figure 2]c. Additionally, in sagittal T2WI, Type II  Chiari malformation More Details was evident as peg-like cerebellar tonsillar descending up to C 5 [Figure 2]d.
Figure 1: (a) Showing large lumbosacral myelomeningocele. (b) Showing small lipo-myelomeningocele on the left lateral side (black arrow).

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Figure 2: (a) Axial T 2 MRI image showing thick bony septa (black arrow) dividing two hemicords. (b) Axial T 1 MRI image showing neural tissue (black arrow) entering in the fat tissue which is hyperintense on T 1 MRI image. (c) Axial T 2 MRI image showing meningomyelocele of the right hemicord, black arrow showing neural tissue entering in the meningomyelocele. (d) Sagittal MRI of the brain showing peg-like tonsillar herniation.

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In surgery, we excised the meningomyelocele first and de-tethered the right hemicord. After this, we meticulously excised the lipomatous tissue till the white neural placode was visible. The bony spur was drilled off till attachment to the vertebral body. The dura was opened in an inverted Y shape fashion, and a single dural tube was constructed. The surgery went uneventful, and she got discharged after suture removal on day 10. At a follow-up of 8 months, she has an improvement in the lower limb power


 » Discussion Top


The meningomyelocele cases coexisting with SCM are abundantly reported in the literature, with the incidence ranging from 5 to 36%.[4],[5],[6],[7] In a series of 106 cases of spinal dysraphism, Kumar et al.[6] described 16 cases of meningomyelocele that were coexisting with SCM. In 12/16 of their cases, SCM was present at 1–2 levels above, while in the rest four, SCM was at the same level. Although there are reports of myelomeningocele,[8],[9],[10] myeloschisis,[11] lipomeningomyelocele,[12] arising in only one hemicord of SCM, our case is peculiar as it had spinal dysraphism arising from both hemicords that too of different nature. The duplication of the spine at the dorso-lumbar region according to the Pang classification is an extreme form of Type 1 SCM described in the literature. In this case, lipomeningomyelocele was present, tethering one thecal sac containing neural element and no neural content was present in the other thecal sac.[13] In one case of Type I SCM, triplomyelia was reported coexisting with lipomyelomeningocele of one cord.[14] Two different lesions (lipoma and dermoid) in one hemicord had been seen in Type I SCM.[15]

The spinal dysraphism arising from each hemicord in Type I SCM is an extremely rare entity. To the best of our knowledge, only four such cases are reported in the literature [Table 1]. Dhandapani et al.[16] described a contiguous spinal dysraphism associated with SCM, in which meningomyelocele was tethering the right hemicord, and lipomeningomyelocele was tethering the distal “Y” portion of the hemicord. Solanki et al.[17] described an unusual quadruple dysraphism anomaly in a single child with concurrent segmental meningocele associated with Type I SCM with lipomyelomeningocele tethering each hemicord and a terminal myelocystocele.[26] Similarly, the lipomyelomeningocele of each hemicord was reported by Meena et al.[18] and Jamaluddin et al.[19] in Type I and Type II SCM, respectively. In our case, two different entities were found to be arising from two distinct hemicords.
Table 1: Review of the literature on split cord malformation having dual spinal dysraphism arising from each hemicord

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The unified theory of Pang et al.[1] suggests that all SCMs have an origin at the time of gastrulation and postulated that an accessory neurenteric canal (a fusion between the endoderm and ectoderm providing a patent channel between the yolk sac and amnion in the two-layered gastrula) bisects the neural plate and notochord. Each half of the neural plate is then induced to form a hemicord. Subsequently, this accessory neurenteric canal becomes lined with infiltrating mesodermal cells forming the endo-mesenchymal tract. It is speculated that Type I SCM results from the conversion of pluripotent mesenchymal cells in osteocartilaginous structure, dividing into two hemicords. This unified theory does not explain discrete or contiguous development of primary and secondary neurulation defect abnormalities.[23],[24],[25]

McLone et al.[2] had explained the development of lipomeningomyelocele. The process occurs due to defect in the later stage of primary neurulation. In expectant circumstances, the cutaneous ectoderm separates from the neuroectoderm after the complete neural tube's closure—a process known as disjunction; the early disjunction provides space for mesenchymal invasion. The subsequent pluripotent mesenchymal cell converts into fat, giving rise to lipomeningomyelocele.

In our case, the developmental error was present at a single level from gastrulation to secondary neurulation; thus, it is not clear from the currently postulated theories whether it was because of an error in each phase independently or a single inciting factor that led to a cascade of developmental errors. The synchronous occurrence of such complex spinal dysraphisms indicates that the defect persists from the gastrulation phase to the secondary neurulation stage. There is debate about whether the gastrulation phase acts as a primary inciting event for other neural tube defects or spinal dysraphism results due to their independent developmental defect. Duckworth et al.[10] described myelomeningocele in single hemicord in 16 cases and postulated that the endomesenchymal tract might affect the subsequent development of primary neurulation, which may be the cause of association of the SCM with myelomeningocele.

Copp et al.[20] suggested the genetic causes for neural tube defect in the lumbosacral region. Their study mentioned that the different mutations appear to achieve this developmental end-point by different underlying mechanisms. Chen et al.[3] performed a genome-wide copy number variant study in Chinese people with neural tube defects. They concluded that particular ciliogenic copy number variants are associated with neural tube defects, and 'tight junction' and 'protein kinase A signaling' are two potential ciliogenic pathways involved in the pathogenesis.


 » Conclusions Top


Our case presents a rare entity of Type I SCM, with each hemicord having a different spinal dysraphism pattern at the same level. An only embryological hypothesis does not clearly explain the origin of such a malformation. The new studies on genetic level analysis for neural tube defects are pretty exciting. In the near future, the possible role of specific gene regions may clearly explain such rare malformation's etiology.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 » References Top

1.
Pang D, Dias MS, Ahab-Barmada M. Split cord malformation: Part I: A unified theory of embryogenesis for double spinal cord malformations. Neurosurgery 1992;31:451-80.  Back to cited text no. 1
    
2.
McLone DG, Knepper PA. The cause of Chiari II malformation: A unified theory. Pediatr Neurosci 1989;15:1-12.  Back to cited text no. 2
    
3.
Chen X, Shen Y, Gao Y, Zhao H, Sheng X, Zou J, et al. Detection of copy number variants reveals association of cilia genes with neural tube defects. PLoS One 2013;8:1-13.  Back to cited text no. 3
    
4.
Pang D. Split cord malformation: Part II: Clinical syndrome. Neurosurgery 1992;31:481-500.  Back to cited text no. 4
    
5.
Jindal A, Mahapatra AK, Kamal R. Spinal dysraphism. Indian J Pediatr 1999;66:697-705.  Back to cited text no. 5
    
6.
Kumar R, Bansal KK, Chhabra DK. Occurrence of split cord malformation in meningomyelocele: Complex spina bifida. Pediatr Neurosurg 2002;36:119-27.  Back to cited text no. 6
    
7.
Ansari S, Nejat F, Yazdani S, Dadmehr M. Split cord malformation associated with myelomeningocele. J Neurosurg 2007;107 (4 Suppl):281-5.  Back to cited text no. 7
    
8.
Singh N, Singh DK, Kumar R. Diastematomyelia with hemimyelomeningocele: An exceptional and complex spinal dysraphism. J Pediatr Neurosci 2015;10:237-9.  Back to cited text no. 8
[PUBMED]  [Full text]  
9.
Okechi H, Albright AL, Nzioka A. Tethered cord syndrome secondary to the unusual constellation of a split cord malformation, lumbar myelomeningocele, and coexisting neurenteric cyst. Case Rep Neurol Med 2012;2012:1-4.  Back to cited text no. 9
    
10.
Duckworth T, Sharrard WJ, Lister J, Seymour N. Hemimyelocele. Dev Med Child Neurol 1965;69-75.  Back to cited text no. 10
    
11.
Yamanaka T, Hashimoto N, Sasajima H, Mineura K. A case of diastematomyelia associated with myeloschisis in a hemicord. Pediatr Neurosurg 2001;35:253-6.  Back to cited text no. 11
    
12.
Murakami N, Morioka T, Ichiyama M, Nakamura R, Kawamura N. Lateral lipomyelomeningocele of the hemicord with split cord malformation type I revealed by 3D heavily T2-weighted MR imaging. Childs Nerv Syst 2017;33:993-7.  Back to cited text no. 12
    
13.
Yigit H, Ozdemir HM, Yurduseven E. Duplication of spine with hemi-lipomyelomeningocele. Eur Spine J 2013;22(Suppl 3):S487-90.  Back to cited text no. 13
    
14.
Gandhoke CS, Gupta SK, Sharma AK, Ayalasomayajula S, Sinha M, Pati SK, et al. Triplomyelia in a case of diastematomyelia: A new entity. Surg Neurol Int 2020;11:1-2.  Back to cited text no. 14
    
15.
Am U, Beniwal M, Dwarakanath S, Santosh V, Sampath S. Split cord malformation type 1 with two hemicord lesions. Childs Nerv Syst 2018;34:2313-6.  Back to cited text no. 15
    
16.
Dhandapani S, Srinivasan A. Contiguous triple spinal dysraphism associated with Chiari malformation Type II and hydrocephalus: An embryological conundrum between the unified theory of Pang and the unified theory of McLone. J Neurosurg Pediatr 2016;17:103-6.  Back to cited text no. 16
    
17.
Solanki GA, Evans J, Copp A, Thompson DN. Multiple coexistent dysraphic pathologies. Childs Nerv Syst 2003;19:376-9.  Back to cited text no. 17
    
18.
Meena RK, Doddamani RS, Sharma R. Contiguous diastematomyelia with lipomyelomeningocele in each hemicord—An exceptional case of spinal dysraphism. World Neurosurg 2019;123:103-7.  Back to cited text no. 18
    
19.
Jamaluddin MA, Nair P, Divakar G, Gohil JA, Abraham M. Split cord malformation type 2 with double dorsal lipoma: A sequela or a chance. J Pediatr Neurosci 2020;15:135-9.  Back to cited text no. 19
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20.
Copp AJ. Genetic models of mammalian neural tube defects. Ciba Found Symp 1994;181:118-34; discussion 134-43.  Back to cited text no. 20
    
21.
Blount JP, Maleknia P, Hopson BD, Rocque BG, Oakes WJ. Hydrocephalus in Spina Bifida. Neurol India 2021;69(Supplement):S367-S371.  Back to cited text no. 21
    
22.
Tandon PN. Meningo-Encephalocoele. Neurol India 2020;68:5-8.  Back to cited text no. 22
[PUBMED]  [Full text]  
23.
Meena RK, Doddamani RS, Gurjar HK, Kumar A, Chandra PS. Type 1.5 Split Cord Malformations: An Uncommon Entity. World Neurosurg. 2020 Jan;133:142-149.  Back to cited text no. 23
    
24.
Doddamani R, Meena R. Type 1.5 Split Cord Malformations : Bridging the Gap. J Korean Neurosurg Soc. 2022 Sep;65:758-759.  Back to cited text no. 24
    
25.
Meena RK, Doddamani RS. In Reply to the Letter to the Editor Regarding “Type 1.5 Split Cord Malformations: An Uncommon Entity”. World Neurosurg. 2020 Jul;139:642-644.  Back to cited text no. 25
    
26.
Sreenivasan R, Sharma R, Borkar SA, Arumulla S, Garg K, Chandra SP, Kale SS, Mahapatra AK. Cervical Split Cord Malformations: A Systematic Review. Neurol India 2020;68:994-1002.  Back to cited text no. 26
[PUBMED]  [Full text]  


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