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| Spina Bifida Occulta |
1. Of the three embryonic layers (ectoderm, mesoderm, and endoderm), the neural structures develop from the ectoderm. (MCQ)
2. The neural tube forms from the neural placode at approximately 21 days of gestation (MCQ)
3. It is important to realize that neural tube defects have already formed by the time pregnancy is diagnosed; thus, prevention of these defects by the administration of folic acid has to commence prior to 21 days of gestation. (MCQ)
4. The disorders of spine, vertebral column and nerve roots are included in spinal dysraphisms. They can be classified as spina bifida aperta (open defects, usually apparent) and spina bifida occulta (closed defects, commonly missed by an untrained observer)
Myelomeningocele
5. Myelomeningocele is the most common type of spina bifida aperta (MCQ)
6. Thoracic defects have the highest incidence of weakness and sacral defects often have only bladder involvement. (MCQ)
7. Hydrocephalus is present in 80% of patients. (MCQ)
8. Thoracic defects have the highest incidence and low sacral defects the lowest incidence of hydrocephalus. (MCQ)
9. Spina bifida is associated with Chiari II malformation. It occurs in 90% to 95% of cases. (MCQ)
10. Associated brain anomalies include corpus callosal anomalies, fused tectal plates, and thalamic fusion.
11. Surgical closure of the myelomeningocele is undertaken within 24 to 48 hours of birth to avoid CNS infection (MCQ)
12. Of children with myelomeningocele, 60% to 70% will ultimately require a shunt insertion (MCQ)
13. Only 15% to 30% of children will require a Chiari decompression (MCQ)
14. Children with Myelomenigocele have a 20% to 65% incidence of latex allergies. Thus universal latex allergy precautions are adopted for this group of children (MCQ)
15. There is no specific treatment for occult spina bifida if the abnormality is limited to the bone. Usually these deformities are found at the last lumbar vertebrae (L5) or at the first sacral vertebrae (S1)
16. - The term spina bifida occulta includes following:
a. Simple Spina Bifida Occulta: Mildest form of spina bifida. Usually asymptomatic.
b. Dermal Sinus: Dermal sinus tract from the cutaneous to spinal subarachnoid space. It can cause ascending infection
c. Diastematomyelia: Spinal cord is split into two hemicords, often by a bony or fibrous band that tethers the cord. Needs to be repaired surgically
d. Lipomyelomeningocele: There is fatty tissue in the spinal cord and in the spinal canal tethering the cord. Associated neurologic deficits, although uncommon at birth, usually develop later because of the tethering
