Journal of Korean Neurosurgical Society

The Korean Neurosurgical Society (대한신경외과학회)
권호 표지
DOI QR코드

DOI QR Code

Type 1.5 Split Cord Malformation : A New Theory of Pathogenesis

  • Sun, Mengchun (Department of Neurosurgery, the First Medical Center of Chinese PLA General Hospital) ;
  • Tao, Benzhang (Department of Neurosurgery, the First Medical Center of Chinese PLA General Hospital) ;
  • Luo, Tianbao (Department of Neurosurgery, Yuquan Hospital) ;
  • Gao, Gan (Department of Neurosurgery, the First Medical Center of Chinese PLA General Hospital) ;
  • Shang, Aijia (Department of Neurosurgery, the First Medical Center of Chinese PLA General Hospital)
  • Received : 2020.12.23
  • Accepted : 2021.04.28
  • Published : 2022.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

To report two cases of type 1.5 split cord malformation (SCM), a subtype of SCM with combined characteristics of types I and II and to review the relevant literature and propose a new possible pathogenetic theory for type 1.5 SCM. A 52-year-old woman had hemicords within a single dural sac with a dorsal bony septum at the L5 level. A 9-year-old boy had hemicords within a single dural sac with a ventral bony septum and fibrous extension at the L3 level. Both patients underwent microsurgical treatments for removing the bony septum, detethering the spinal cord, and sectioning the filum terminale. The surgical procedure revealed an extradural partial bony septum and hemicords within an intact single dural sac in each patient. Both patients were discharged from the hospital without de novo nerve dysfunction. Published cases have validated that types I and II SCM can overlap. We recommend recent type 1.5 SCM as a normative terminology for this overlapping SCM and report two rare cases of this SCM. We propose an associated pathogenesis consisting of uneven distribution and regression to explain type 1.5 SCM. Furthermore, we postulate that the amount of condensing meninx primitiva might determine whether the left bony septum has fibrous extensions to the opposite dura in type 1.5 SCM.

Keywords

References

  1. Akay KM, Izci Y, Baysefer A : Dorsal bony septum: a split cord malformation variant. Pediatr Neurosurg 36 : 225-228, 2002 https://doi.org/10.1159/000058424
  2. Akay KM, Izci Y, Baysefer A, Timurkaynak E : Composite type of split cord malformation: two different types at three different levels: case report. J Neurosurg 102(4 Suppl) : 436-438, 2005
  3. Basak M, Ozel A, Erturk M : An unusual case of diastematomyelia. Presence of one dural sheath associated with a bony spur. Acta Radiol 43 : 626, 2002 https://doi.org/10.1034/j.1600-0455.2002.430618.x
  4. Bruce A, M'Donald S, Pirie JHH : A second case of partial doubling of the spinal cord. Rev Neurol Psychiatr 4 : 6, 1906
  5. Chandra PS, Kamal R, Mahapatra AK : An unusual case of dorsally situated bony spur in a lumbar split cord malformation. Pediatr Neurosurg 31 : 49-52, 1999 https://doi.org/10.1159/000028831
  6. Colas JF, Schoenwolf GC : Towards a cellular and molecular understanding of neurulation. Dev Dyn 221 : 117-145, 2001 https://doi.org/10.1002/dvdy.1144
  7. Ersahin Y : An unusual split cord malformation. Pediatr Neurosurg 32 : 109, 2000 https://doi.org/10.1159/000028909
  8. Garg K, Mahapatra AK, Tandon V : A rare case of type 1 C split cord malformation with single dural sheath. Asian J Neurosurg 10 : 226-228, 2015 https://doi.org/10.4103/1793-5482.161196
  9. Herren RY, Edwards JE : Diplomyelia (duplication of the spinal cord). Arch Pathol 30 : 1203-1213, 1940
  10. Hertwig O : Urmund und spina bifida. Archiv f mikrosk Anatomie 39 : 353-502, 1892 https://doi.org/10.1007/BF02961535
  11. Izci Y, Kural C : Composite type of split cord malformation: rare and difficult to explain. Pediatr Neurosurg 47 : 461, 2011 https://doi.org/10.1159/000339209
  12. Lichtenstein BW : Spinal dysraphism: spina bifida and myelodysplasia. Arch Neur Psych 44 : 792-810, 1940 https://doi.org/10.1001/archneurpsyc.1940.02280100094007
  13. Marr GE, Uihlein A : Diplomyelia and compression of the spinal cord and not of the cauda equina, by a congenital anomaly of the third lumbar vertebra. Surg Clin North Am 24 : 963-977, 1944
  14. Maxwell HP, Bucy PC : Diastematomyelia; report of a clinical case. J Neuropathol Exp Neurol 5 : 165-167, 1946 https://doi.org/10.1097/00005072-194604000-00007
  15. Meena RK, Doddamani RS, Gurjar HK, Kumar A, Chandra PS : Type 1.5 split cord malformations: an uncommon entity. World Neurosurg 133 : 142-149, 2020 https://doi.org/10.1016/j.wneu.2019.09.076
  16. Pang D, Dias MS, Ahab-Barmada M : Split cord malformation: part I: a unified theory of embryogenesis for double spinal cord malformations. Neurosurgery 31 : 451-480, 1992 https://doi.org/10.1227/00006123-199209000-00010
  17. Pickles W : Duplication of the spinal cord; an account of a clinical example with a consideration of other reports. J Neurosurg 6 : 324-331, 1949 https://doi.org/10.3171/jns.1949.6.4.0324
  18. Salunke P, Kovai P, Malik V, Sharma M : Mixed split cord malformation: are we missing something? Clin Neurol Neurosurg 113 : 774-778, 2011 https://doi.org/10.1016/j.clineuro.2011.07.023
  19. Singh PK, Khandelwal A, Singh A, Ailawadhi P, Gupta D, Mahapatra AK : Long-segment type 1 split cord malformation with two-level split cord malformation and a single dural sac at the lower split. Pediatr Neurosurg 47 : 227-229, 2011 https://doi.org/10.1159/000334278
  20. Vaishya S, Kumarjain P : Split cord malformation: three unusual cases of composite split cord malformation. Childs Nerv Syst 17 : 528-530, 2001 https://doi.org/10.1007/s003810100482
  21. Van Aalst J, Beuls EA, Vles JS, Cornips EM, van Straaten HW : The intermediate type split cord malformation: hypothesis and case report. Childs Nerv Syst 21 : 1020-1024, 2005 https://doi.org/10.1007/s00381-005-1159-8
  22. Xu X, Li C, Takahashi K, Slavkin HC, Shum L, Deng CX : Murine fibroblast growth factor receptor 1alpha isoforms mediate node regression and are essential for posterior mesoderm development. Dev Biol 208 : 293-306, 1999 https://doi.org/10.1006/dbio.1999.9227