SPINA BIFIDA

Spina bifida is part of a group of birth defects called neural tube defects. It is caused by a defect in the neural arch generally in the lumbosacral region.

spina bifida is a failure of the posterior laminae of the vertebrae to close; this leaves an opening through which the spinal meninges and spinal cord may protrude.

SPINA BIFIDA CLASSIFICATION 

Spina bifida can be classified into three:

1) Spina bifida occulta. A bony defect that occurs without soft tissue involvement. The defect is only in the vertebrae, the spinal cord and meninges are usually normal. A child with this may be symptomless.

2) Spina bifida with meningocele. When part of the spinal meninges protrudes through the bony defect and forms a cystic sac. Is filled with cerebrospinal fluid and covered with skin.

3) Spina bifida with myelomeningocele. In spina bifida with myelomeningocele, there is a protrusion of the spinal cord and the meninges, with nerve roots embedded in the wall of the cyst.

NB

Meningomyeloceles/ myelomeningocele, are usually covered by a thin membrane

Pathophysiology

Neural tube defects are the result of a teratogenic process that causes failed closure and abnormal differentiation of the embryonic neural tube. During prenatal development, neuroectoderm thickens into the neural plate which folds into a neural groove by the time somites appear.

The groove deepens to become the neural tube, and dorsal fusion begins centrally,

extending cephalad and caudally, with the cephalad pole fusing at the 25th day.

Causes

The ventricle becomes permeable at the 6th to 8th week of gestation but this does not

proceed normally in patients with spina bifida.

STATISTICS AND INCIDENCES

The occurrence of spina bifida in the United States and internationally are estimated in the following 

1-2 cases per 1000 population, with certain populations having a significantly greater

incidence based on genetic predilection.

Neural tube defects are the second most common type of birth defect after congenital

heart defects, and myelomeningocele is the most common form of neural tube defect.

In the United States, approximately 1, 500 infants are born with myelomeningocele each year.

The rate of myelomeningocele and other neural tube defects has declined since the late 20th century.

The average worldwide incidence of spina bifida is 1 case per 1000 births, but marked geographic variations occur.

The etiology in most cases of spina bifida is multifactorial, involving genetic, racial, and
environmental factors, in which nutrition, particularly folic acid intake, is key.

• Low folic acid intake. Research indicates folate can reduce the incidence of neural tube defects by about 70% and can also decrease the severity of these defects when they occur.

• Genetics, If a woman gives birth to a baby with spina bifida, she has a  higher-than normal risk of having another baby with spina bifida too (about 5% risk).

• Certain medications. Some medications, such as some for treating epilepsy or bipolar disorder have been associated with a higher risk of giving birth to babies with congenital defects, such as spina bifida.

• Diabetes. Women with diabetes are more likely to have a baby with spina bifida compared to other females.

• Obesity. Obese women, those whose BMI (body mass index) is 30 or more have a high-risk of having a baby with spina bifida. The higher the woman's BMI is over 30, the higher the risk.

Clinical Manifestations

Clinical manifestations may vary depending on the type of spina

bifida.

• Paralysis. If the opening occurs at the top of the spine, the patient's legs are more likely

to be completely paralyzed, and there will be other problems with movement elsewhere

in the body.

• Cognitive symptoms. Problems occurring in the neural tube have a negative effect on

brain development; the main part of the brain (cortex), especially the frontal part does not

develop properly, leading to some cognitive problems.

. Arnold-Chiari malformation. There may also be Type 2 Arnold-Chiari malformation, an abnormal brain development involving the cerebellum - this may affect the patient's

language processing and physical coordination skills.

Birthmarks. There may be a small birthmark, dimple or tuft of hair on the skin where the

spinal defect has occurred.

Assessment and Diagnostic Findings
Assessment and laboratory findings of a patient with Spina bifida may reveal the following:

EAP Ievels. Elevated maternal alpha fetoprotein levels in the maternal serum and the amniotic fluid indicates the probability of CNS abnormalities.

Ultrasonography. Ultrasonographic examination of the fetus may show an incomplete neural tube.

• Clinical examination. Diagnosis of spina bifida can also be made from clinical observation and

examination.

. Other imaging studies. Additional evaluation of the defect may include magnetic

resonance imaging (MRI), computed tomography (CT), and myelography.

SURGICAL MANAGEMENT

Many specialists are involved in the treatment of these newborns, especially in the case of

myelomeningocele.

• Laminectomy and closure of the open lesion and removal of the sac can be done soon

after birth to prevent further deterioration of neural function, minimize the danger of

rupture and infection.

• Surgery. Surgery is required to close the open defect but may not be performed

immediately, depending on the surgeon's decision.

• Prenatal surgery. In this procedure - which takes place before the 26th week of

pregnancy, surgeons expose a pregnant mother's uterus surgically, open the uterus and

repair the baby's spinal cord. Open fetal surgery involves making a small opening in the

uterus (Hysterotomy) in mid-pregnancy to access the fetus and close the spina bifida

defect.

Ongoing care. Babies with myelomeningocele may also start exercises that will prepare

their legs for walking with braces or crutches when they're older.

Cesarean birth. Cesarean birth may be part of the treatment for spina bifida; many babies

with myelomeningocele tend to be in a feet-first (breech) position.

Nursing Management

Highly skilled nursing care is necessary in all aspects of the newborn's care.

Nursing Assessment

A routine newborn examination is conducted with emphasis on neurologic impairment.

• Physical examination. When collecting date during the examination, observe the

movement and response to stimuli of the lower extremities; carefully measure the head

circumference and examine the fontanelles.