SHORT REPORT
Double myelomeningocele: case report
ABDERRAZZAK BERTAL, SAID HILMANI, ABDENABI ELKAMAR &
ABDESSAMAD ELAZHARI
Department of neurosurgery, UCH Casablanca, Morocco
Abstract
Double myelomeningocele is very rare, with only a few cases are published in the world’s literature. The mechanism of this form of neural tube defects constitutes a challenging problem. The authors present an unusual case of a 3 month-old child, with two myelomeningoceles, one at the cervical level and the other at the lumbar level, without hydrocephalus or Chiari malformation.
Key words: Myelomeningocele, double neural tube defect, spina bifida, ventricular shunt.
Introduction
Myelomeningocele (MMC) is a complex congenital spinal anomaly caused by a defective closure of the neural tube. The simultaneous presence of double spinal neural tube defects has been rarely reported. The exact pathogenesis of double or multiple MMC remains complex. We report the case of a 3 month-old girl who had two MMCs, one at the cervical level and the other at the lumbar level.
Case report
This 3 month-old child was born by an uneventful vaginal delivery full term to non-consanguineous parents. She presented at our department of neurosurgery with a double midline transilluminant swellings on the back present since birth, one in the neck and the second in the lumbar region were found (Fig. 1). There was no active cerebrospinal fluid leakage. Neurological examination was un- remarkable, with no other congenital anomaly.
Cerebral CT scan was normal without hydro- cephalus or Chiari malformation. CT scan of the cervical sac shows the presence of neural elements.
Both lesions were surgically treated in the prone position, without ventriculoperitoneal shunt inser- tion. No post-operative complications were re- ported and the patient did not develop hydrocephalus or any neurological deficit. Her progress at school after 4-year follow-up is normal.
Discussion
MMC is the most common form of neural tube defect (NTD), it is the result of a teratogenic process that causes failed closure and abnormal differentia- tion of the embryonic neural tube during the first 4 weeks of gestation. The incidence of MMC varies from 0.4 to 1.9 per 1000 live births, according to the country, culture and socio-economic status. In most of the cases, there is no obvious identifiable cause and several factors are incriminated, genetic and non-genetic component.
1Number of environmental agent have been suggested as causative factors, the most recent being maternal vitamin and folate deficiency.
Double or multiple MMC is a very rare event occurring in less than 1% of the cases. As far as we know, there are only a few cases reported in the literature. Ahmad et al.
1reported the largest series of seven cases of multiple NTDs. Among these, five had double NTDs while two had a triple NTD. Despite years of intensive epidemiological and experimental research, the exact pathogenesis of NTDs remains largely unknown. Morphologically, closure of the neural tube involves apposition of the dorsal edges of the neural folds along the median plane, epithelial breakdown at contact sites accompanied by apoptosis and merger of the neuroepithelium. Two main theories have been postulated: the continuous, bidirectional, ‘Zipper-like’ process emerged as the pattern of neural tube closure: In this model, the neural tube has been described to start from a single
Correspondence: A. Bertal, 66 rue Elfourat, Maarif, CP 20330, Morocco. Tel:þ212666248201. Fax:þ212522204743. E-mail: abbertal@yahoo.fr
Received for publication 19 April 2010. Accepted 10 February 2011.
British Journal of Neurosurgery, June 2011; 25(3): 335–336
ISSN 0268-8697 print/ISSN 1360-046X onlineª2011 The Neurosurgical Foundation DOI: 10.3109/02688697.2011.562989
initiation, the first site of contact between the dorsal edges of the neural folds occurs in the cervical region and the fusion progresses cranially and caudally until the entire tube is formed. However, this more widely held orderly closure theory fails to explain multiple NTDs.
2The second is the multisite closure theory, proposed by Van allen et al.,
3according to which there could be five sites of initiation of closures:
closure1 occurs in the midcervical region and progresses bidirectionally in the rostral and caudal direction. Closure 2 begins in the head at the junction between the prosencephalon and mesence- phalon, forming two neuropores and proceeds bidirectionally. Closure 3 is unidirectional and appears from the stomodeum and goes caudally to meet the descending rostral segment of closure 2.
Closure 4 starts between closure 1 and closure 2 over the rhombencephalon and completes the closure of the cranial portion of the neural tube from which the brain develops. Closure 5 starts at the caudal end of the neural groove and proceeds cranially to meet
closure 1 thus completing closure of the spinal portion of the neural tube. The closure proceeds in an orderly fashion. Initially, it begins at site 4 followed by sites 2 and 3 then sites 1 and 5. The closure failures of sites 2, 4 and 1 are the most frequent and have similar prevalence figures among liveborn infants, site 3 being less frequent.
3The NTD affects or implies two contiguous closure sites, in about 50% of the cases.
1Using this multisite model, clinically observed NTD can all be attributed to defects at specific closure sites. Nakatsu et al.
2supported this hypothesis after studying human embryos.
Approximately 50–60% of patients with MMC develop hydrocephalus after closure of the MMC lesion. However, in our department, in the absence of hydrocephalus, we do not routinely use VP shunts, and prefer expectant management with close post- operative surveillance, if hydrocephalus develops then a shunt is placed.
Usually closure of the MMC is performed im- mediately after birth if external cerebrospinal fluid (CSF) leakage is present and typically within the first 24–48 h in the absence of CSF leakage. But surgery can be delayed for several days without additional morbidity or mortality as in our case.
Declaration of interest: The authors report no conflicts of interest. The authors alone are respon- sible for the content and writing of the paper.
References
1. Ahmad FU, Dwarakanath S, Sharma BS, Mahapatra AK.
Multiple neural tube defects: a clinical series of seven cases and their embryological basis.Pediatr Neurosurg2008;44(4):280–7.
2. Nakatsu T, Uwabe C, Shiota K. Neural tube closure in human initiates at multiple sites: evidence from human embryos and implications for the pathogenesis of neural tube defects.Anat Embryol (Berl)2000;201(6):455–66.
3. Van Allen MI, Kalousek DK, Chernoff GF,et al. Evidence for multi-site closure of the neural tube in humans. Am J Med Genet1993;47(5):723–43.
FIG. 1. Pre-operative photograph of the patient. Double myelomenigocele, one at the cervical level and the second at the lumbar level.
