- Department of Radiodiagnosis, Chhatrapati Sahuji Maharaj Medical University (CSMMU), Lucknow, Uttar Pradesh, India
- Department of Neurosurgery, Dr. RML Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Department of Radiodiagnosis, Chhatrapati Sahuji Maharaj Medical University (CSMMU), Lucknow, Uttar Pradesh, India
DOI:10.4103/2152-7806.104741Copyright: © 2012 Singh N. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Singh N, Singh DK, Aga P, Singh R. Multiple neural tube defects in a child: A rare developmental anomaly. Surg Neurol Int 14-Dec-2012;3:147
How to cite this URL: Singh N, Singh DK, Aga P, Singh R. Multiple neural tube defects in a child: A rare developmental anomaly. Surg Neurol Int 14-Dec-2012;3:147. Available from: http://sni.wpengine.com/surgicalint_articles/multiple-neural-tube-defects-in-a-child-a-rare-developmental-anomaly/
Background:The presence of multiple neural tube defects (NTDs) is a rare entity. Published literature shows not more than 10 case reports. Such cases contradict the well-established “zipper model” of neural tube closure and support “multi-site closure model.”
Case Description:We are reporting a unique case of multiple NTDs in a 5-month-o ld female child. Occipital encephalocele, dorsal meningomyelocele, Split cord malformation (SCM), and tethered cord were present in this case.
Conclusion:This case report further substantiate the “multisite closure model,” however, more research work on human neuro-embryology is needed to overcome the controversies of neural tube closure.
Keywords: Meningocele, multiple neural tube defects, multisite closure, neural tube, Zipper model
Neural tube defects (NTDs) refer to the congenital deformities involving the coverings of nervous system. These can be classified on the basis of embryological considerations and the presence or absence of exposed neural tissue, as open or closed types. Open NTDs (ONTDs) occur due to failure of primary neurulation and the neural tissue is exposed with associated cerebrospinal fluid (CSF) leakage.[
A 5-month-old female patient, first child of healthy parents, presented with two cystic swellings since birth, one in the suboccipital area and the other in the mid-thoracic region [
The swellings were covered with skin and 10 × 9 × 7 cm and 7 × 6 × 4 cm in dimensions, respectively. The swellings were translucent and increased in tension when the child cried. The child was moving all four limbs normally and sphincter functions were unimpaired. Developmental assessment revealed normal milestones and growth parameters were within normal range.
Brain MRI revealed herniation of meninges, CSF, and brain parenchyma through a midline defect in occipital bone consistent with meningoencephalocele. Hydrocephalous and features of Chiari malformation were also present.
MRI thoracic spine demonstrated spina bifida from mid thoracic to upper lumbar spine with herniation of meninges, CSF, and neural elements at D7/8 levels diagnostic of meningomyelocele (MMC). The cord was low lying and tethered posteriorly with the intact posterior elements of D6. Syrinx was present in the cord proximal to the site of defect [
Axial T2- and T1-weighted MR images revealed a longitudinally split lower thoracic spinal cord with one dural tube and CSF intervening between the two hemicords [
Reports of multiple NTDs in the same patient are very rare in the published literature. Potter (1962) described two cases and Bertan (1968) described one case of dorsal and lumbar meningomyelocele.[
Over the past few years, in-depth descriptive research has been conducted on brain and spinal cord development in human embryos to know the embryological basis of such complex anomalies. Most important are the studies conducted by O’ Rahilly and Muller who concentrated their efforts on expanding several stages (8 through 23) related to CNS development.[
Two primary theories exist regarding the neural tube closure. The widely accepted theory is that neural tube closure is a continuous, bidirectional process which begins in the mid cervical region and progresses in a zipper-like fashion both rostrally and caudally, with the cranial and caudal neuropores being the last to close (at Days 24 and 26, respectively). Thus, the neural tube forms up to S-2, and the areas caudal to S-2 form through secondary neurulation. The embryogenesis of myelomeningocele has been attributed to the defects in primary neurulation. There are many fallacies of this rather simplistic “zipper model.” According to this theory, the most common site of MMC is at the most cranial or most caudal ends, but it fails to explain the occurrence of encephaloceles, cervical MMCs and multiple NTDs.
In 1993, Van Allen et al. proposed the second theory “multi-site closure model,” in which they hypothesized that there are five sites of initiation of neural tube closure and the NTDs occur at the “collision sites” of neural tube closure with opposing closure directions.[
Thus, the multisite closure theory is more inclusive than the zipper model but has the shortcomings that the double or multiple NTDs should have been more commonly seen but in reality only a few case reports are available. It may be explained by the hypothesis given by some and supported by Nakatsu et al., that such malformations, particularly the multiple NTDs, are usually incompatible with life. The other drawback has been the etiogenesis of cervical MMC.
Martínez-Frias et al. conducted an epidemiological study of 774 live-born infants with NTDs based on the multisite closure theory. They found that isolated closure failure is the most prevalent and the most commonly effected site is closure site 1 followed by sites 4 and 2, respectively. They also found that multiple closure defects are rare.
Split cord malformation, though a common association of meningomyelocele, has never been reported in the published literature with double meningocele.
Our case report further substantiate the “multisite closure model,” however, more research work on human neuro- embryology is needed to overcome the controversies of neural tube closure.
1. Ahmad FU, Dwarakanath S, Sharma BS, Mahapatra AK. Multiple neural tube defects: A clinical series of seven cases and their embryological basis. Pediatr Neurosurg. 2008. 44: 280-7
2. Bertan V, Wilson CB. Double myelomeningocele. A case report. Turk J Pediatr. 1968. 10: 88-90
3. Fahrenkrug A, Hojgaard K. Multiple paravertebral lumbar meningocele. Br J Radiol. 1963. 36: 574-7
4. Harris LW, Oakes WJ, Tindall GT, Cooper PR, Barrow DL.editors. Open neural tube defects. The practice of neurosurgery. Baltimore: Williams and Wilkins; 1996. p. 2779-89
5. Lemire RJ. Neural tube defects. JAMA. 1988. 259: 558-62
6. McComb JG, Chen TC, Tindall GT, Cooper PR, Barrow DL.editors. Closed spinal neural tube defects. The Practice of Neurosurgery. Baltimore: Williams and Wilkins; 1996. p. 2754-77
7. Muller F, O’ Rahilly R. The development of human brain, the closure of the caudal neuropore and the beginning of secondary neurulation at stage 12. Anat Embryol (Berl). 1987. 176: 413-30
8. Van Allen MI, Kalousek DK, Chernoff GF, Juriloff D, Harris M, Mcgillivray BC. Evidence for multi-site closure of the neural tube in humans. Am J Med Genet. 1993. 47: 723-43