Introduction:
Herniation of only meninges (covering over the spinal cord) or meninges along with neural elements (spinal cord elements) is called meningocele or meningomyelocele (MMC) respectively. This occurs due to failure of closure of the neural tube during the third week of foetal life. There is defect in the spine through which the meningomyelocele is open to the surface of the skin. The children born with this defect are prone to have bacterial meningitis due to the leak of cerebrospinal fluid (CSF) though the spinal defect. Therefore the child should be operated within 48 hours of delivery to prevent meningitis.The neurological deficit caused by MMC is irreversible and very rarely improves following repair. The further deterioration, however, can be prevented with the surgical repair of MMC.
Clinical presentation:
1. Prenatal diagnosis of MMC by ultrasound during pregnancy is one of the commonest mode of presentation. In such cases maternal serum alpha-fetoprotein is raised.
2. After birth, mid-line spinal swelling which is covered with the meninges. It can be cystic or some neural plaque can be seen into the swelling after trans-illumination test.
3. There may be weakness in the lower limbs i.e. legs or paralysis of lower limbs.
4. Bladder and bowel involvement may be seen in some cases with incontinence of passage of meconium & full bladder.
5. If MMC is associated with hydrocephalus then there is enlarged head with increased head circumference.
Diagnosis:
1. Prenatal - Fetal USG shows the spinal swelling and there is increased maternal serum alpha-fetoprotein.
2. Postnatal- X-ray spine- defect in spinal arch with soft tissue swelling
3. MRI spine- swelling content may be only CSF or neural strands or sometimes whole spinal cord.
4. USG/ CT scan Head- to rule out associated hydrocephalus.
Treatment:
Surgical repair of MMC is done within 48 hours of birth to prevent infection. MMC repair includes dissection & restoration of neural plaque in to spinal cord. Closure of dura followed by skin mobilization & skin closure.If there is associated hydrocephalus then ventriculoperitoneal shunting is also required.
