Spina Bifida
Spina Bifida (Myelomeningocele) is the most common major birth defect among live- born infants. Spina bifida is the result of failure of the neural tube to close in the developing fetus. The condition is associated with varying degrees of neurologic impairment.
As in other injuries or diseases of the spinal cord, the anatomic level of the lesion generally correlates with the neurologic motor and sensory deficit. Impairment ranges from complete paralysis to minimal or no motor deficit.
The incidence of spina bifida is 0.15% among Caucasians and 0.04% among the Black population. The condition affects girls more frequently than boys. Maternal dietary folate deficiency is the chief cause of spinal bifida. Chromosomal abnormalities, single-gene abnormalities, and unknown causes are responsible for other cases of the disorder.
The mortality rate for infants who are not treated surgically in the perinatal period is more than 90%.
In the United States, medical or surgical interventions are not withheld. Typically, initial treatment includes sac closure and the placement of a ventriculoperitoneal shunt.
Paralytic scoliosis develops in 40-60% of children with spina bifida and is highly correlated with the level of motor deficit.
Paralytic scoliosis results in forced immobility. Because such patients cannot use exercise to maintain aerobic capacity, bellows function, and lung volume, they are at risk for developing restrictive lung disease.
Restrictive lung disease is characterized by static or diminished lung volumes and vital capacities. In diseases where respiratory muscles are weak and the spine and thorax deformed, the ability to take a big breath, to generate expiratory force, and to cough effectively are typically affected.
Immobile patients with restrictive lung disease suffer from an impaired ability to clear the airway of mucus, particulate matter, and bacteria. Such patients are a high risk for repeated, increasingly severe bouts of pneumonia, followed by progressive lung deterioration and, ultimately, respiratory failure.
Mobility-impaired spina bifida patients require regular Airway Clearance Therapy to prevent serious or fatal pulmonary complications.
Sources
Sewark, JF. Spina Bifida. Ped Clin N Am 1996 : 43 (5): 1151-1158. Centers for Disease Control: Recommendations for the Use of Folic Acid to Reduce the Number of Cases of Spina Bifida and Other Neural Tube Defects. MMWR 1992; 40:RR-14.
Hardy KA. A Review of Airway Clearance: New Techniques, Indications, and Recommendations. Respir Care. 1994; 39 (5): 440-455.
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