What is Spina Bifida?

Spina Bifida

Spinal bifida, also known as spinal canal insufficiency, is a common congenital malformation. It is caused by incomplete spinal canal closure during embryonic development. It can range from smaller deformities such as missing spinous processes or incomplete closure of the lamina to severe deformities. The cause of spina bifida deformity is unclear. Some scholars believe that it is related to the chemical or physical damage to embryos in early pregnancy. The health care of pregnant women (pregnant women consume enough folic acid) is very important to prevent fetal malformation.

Causes of Spina Bifida

At the third week of embryonic period, the nerve folds on both sides merged to the dorsal midline to form a neural tube, which started from the middle (equivalent to the thoracic segment), then developed to the upper and lower ends, and closed at the fourth week. After the neural tube is formed, it gradually separates from the epidermis and moves deeper. Brain vesicles gradually formed at the head of the tube, and the remaining parts developed into spinal cord.

In the third month of the embryo, the mesodermal leaves on both sides form the spinal component, and the spinal canal is formed in a ring shape surrounding the neural tube. At this time, if the neural tube is not closed, the pedicle cannot be closed and remains open, and can develop spinal meningeal bulge. The appearance of spina bifida is related to many factors, and all abnormal factors that affect fertilization and pregnancy may contribute to the formation of this deformity. 

Other Combordities

Brain malformation and mental retardation, children with spinal meningocele may present with various brain malformations, including hypoplasia of the lobe, polycerebral gyrus, cerebral fissure, corpus callosum hypoplasia, arachnoid cyst, anterior foramen fissure, and dysplasia of the brain Wait. Examination of brain tissue revealed abnormal cell migration, especially the brain stem.

Hydrocephalus , 80%-90% of children with spinal meningocele may have hydrocephalus, and the incidence of lumbosacral spinal cord deformity with hydrocephalus is low.

Sphincter function, 80%-90% of children with spinal meningocele may have neurogenic bladder dysfunction, such as urinary retention, infection , bladder diverticulum, ureteral reflux, and chronic renal failure .

Delayed neurological complications, such as increased limb spasm, increased levels of segmental motor or sensory dysfunction, progressive neuromuscular skeletal deformities, or increased scoliosis.

Chiari II malformations: Almost completely seen in patients with spinal meningeal bulge, including hypoplasia of the cerebellar vermis and tonsils, elongation of the fourth ventricle, and lowering of the tonsils and the lower part of the brainstem into the spinal canal. In infants, symptoms include dysphagia, inhalation, apnea, weak crying, posterior cranial nerve palsy, and growth disorders.

1) Meningeal bulging type: more common in the lumbosacral region. The main pathological changes are that the meninges bulge outward through the defective lamina to reach the habit, forming a mid-back cyst-like mass. Except for a few nerve root tissues, its contents are mainly filled with cerebrospinal fluid, so the light transmission test is positive, there is a sense of fluctuation in pressure, and root symptoms appear under heavy pressure. When the abdominal pressure increases or the child cries, the pressure of this cystic substance increases. The skin surface is mostly normal in color; a few become thin, brittle and hard, and adhere to the dura mater.

2) Spinal meningeal bulging type: more common than the former. In addition to the meninges, the swollen contents also protrude into the sac, seen above the thoracolumbar segment, and the range of bone defects behind the spinal canal is large. The base of the bulging sac is wider. The light transmission test is mostly negative, and spinal cord symptoms may occur when the hand is pressed (compressive examination should be avoided). Mostly accompanied by lower limb nerve disorders and sphincter dysfunction.

3) Bulging of the spinal cord: the spinal cord is exposed. A section of the spinal cord is exposed to the outside world in a flat style. There is no skin in the bulging of the spinal cord, and the spinal canal and spinal membrane are open. With a large amount of cerebrospinal fluid overflow, granulation surface can be formed on the surface. This is the most severe type, often accompanied by lower limbs or other types of the whole body, with a high mortality rate.