What Is the Connection Between Folic Acid and Spina Bifida?

Spinal bifida is also called spinal insufficiency, a common congenital malformation. It is caused by incomplete closure of the spinal canal during embryonic development. It can range from smaller deformities such as absent spinous processes or laminar insufficiency to severe deformities. The cause of spina bifida deformities is unknown. Some scholars believe that it is related to the chemical or physical damage of embryos in early pregnancy. Maternal health (maternal intake of folic acid) is important to prevent fetal malformations.

Du Jianxin	(Chief physician)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University
Gaopeng	(Attending physician)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University

Spinal bifida is also called spinal insufficiency, a common congenital malformation. It is caused by incomplete closure of the spinal canal during embryonic development. It can range from smaller deformities such as absent spinous processes or laminar insufficiency to severe deformities. The cause of spina bifida deformities is unknown. Some scholars believe that it is related to the chemical or physical damage of embryos in early pregnancy. Maternal health (maternal intake of folic acid) is important to prevent fetal malformations.

Western Medicine Name

Spina bifida

English name

spinal bifida

Other name

Spinal canal insufficiency

Affiliated Department

Surgery-Neurosurgery

Disease site

spine

Contagious

Non-contagious

Spina bifida disease classification

Spina bifida is generally divided into two types: spinal bifida apertum and spinal bifida occultum.

Invisible spina bifida is more common than dominant spina bifida and has few clinical symptoms. It is generally divided into unilateral type, floating spine type, kiss spinal type, complete spina bifida type and mixed type.

Invisible spina bifida has only a defect of the spinal canal and no bulging of the spinal canal content, no special treatment is required.

The dominant spina bifida can be divided into meningocele, myelomeningocele, and mylocele according to the contents of the bulge. ^[1]

Causes of spina bifida

At the third week of the embryonic period, the neural crests on both sides fuse to the dorsal midline to form a neural tube, which starts from the middle (equivalent to the thoracic segment), then develops to the upper and lower ends, and closes at the fourth week. After the neural tube is formed, it gradually separates from the epidermis and moves deep. Gradually, cerebral vesicles form at the head of the tube, and the remaining parts develop into spinal cords.

In the third month of the embryo, spinal components are formed from the mesodermal leaves on both sides, and the spinal canal is formed by surrounding the neural tube in a ring shape. At this time, if the neural tube is not closed, the pedicle cannot be closed and remains open, and spinal meningocele can develop. The occurrence of spina bifida is related to many factors, and various abnormal factors affecting fertilization and pregnancy may contribute to the formation of this deformity. ^[2]

Spina bifida pathogenesis

Spinal meningocele is formed by abnormal formation of the primary neuroembryo or secondary normal spinal cord division. When the neural tube is not closed, the surface ectoderm does not separate from the underlying neuroectoderm, so the stroma cannot move between the neural tube and the surface ectoderm, resulting in the inability to form normal vertebral body, cartilage, muscle and spinal ligament structures Make them lack these structures. A red, multivascular, flat, unreflexed nerve plate can be seen in the middle of the back. If you examine it carefully, the nerve groove can be seen in the middle of the nerve plate and it becomes the central tube upward. Because the disease raises alpha-fetoprotein, prenatal diagnosis is easy.

Spinal meningocele is associated with some risk factors. In the United States, 1 in 400 children suffer from spinal meningocele. Current data suggest that the incidence of spinal meningocele is 3.2 / 10,000 in newborns, slightly lower in African-American populations, and slightly higher in some specific populations. In recent years, the incidence has declined, which is related to improving pregnant women's nutrition, prenatal screening and elective termination of pregnancy. The incidence of spina bifida is higher in poor and poorly nutritioned people. In children with spinal meningocele, the incidence of spinal canal insufficiency in the second child is as high as 10-15%. Many studies suggest that the disease is also related to seasons, socioeconomic status, maternal age, birth status, and various teratogenic drugs, and most importantly to pregnant women's inadequate folic acid intake. At present, it is recommended that all women who are preparing to give birth should properly supplement folic acid, as neural tube defects often occur in the third to third week of pregnancy.

Spinal cord bulge, also known as spina bifida or spina bifida, is caused by severe deformities during the formation of neuroembryos that do not form nerve folds and unfusion. It occurs before the 28th day of pregnancy. If the malformation occurs after the neuroblast is completely formed, a relatively complete spinal cord may be formed in the malformed cystic structure. This cystic neurodeformation can be partially or completely covered by the meninges. In most cases, the cysts rupture and form cerebrospinal fluid Leakage, this incompletely developed spinal cord can be seen in spinal meningocele.

Spinal fissure pathophysiology and clinical manifestations

Dominant spina bifida is more common, more than 90% of which occur in the lumbosacral region, depending on the degree of involvement of the spinal cord tissue, and the clinical symptoms can be very different. Can be summarized into two aspects:

Local manifestations of spina bifida

After birth, there is a sexual mass in the midline of the back, which increases with age. Smaller ones are round, larger ones may be irregular, and some have broad bases and some have narrow neck-like pedicles. The skin on the surface of the mass may be normal, or there may be sparse or dense long hair and its abnormal pigmentation, some with capillary hemangioma, or some shades of skin depression, crying or pressing the anterior condyle, the tension of the cyst May be increased; if the capsule wall is thinner and the capsule cavity is larger, the light transmission test may be positive.

Spina bifida spinal cord, nerve damage manifestations

Can show varying degrees of lower limb paralysis and bladder and anal sphincter dysfunction.

Spina bifida other complications

Cerebral malformations and mental retardation, children with spinal meningocele may have various brain malformations, including lobular hypoplasia, multiple cerebellar gyrus, cerebral fissures, hypoplasia of the corpus callosum, arachnoid cysts, forebrain cleavage deformities, and brain dysplasia Wait. Examination of the brain tissue revealed abnormal cell migration, and the brainstem was particularly pronounced.

Hydrocephalus, 80% -90% of children with spinal meningocele may develop hydrocephalus, and the incidence of spinal deformity in the lumbosacral region combined with hydrocephalus is low.

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

Delayed neurological complications, such as increased limb spasms, increased levels of segmental motor or sensory dysfunction, progressive neuromusculoskeletal deformities, or increased scoliosis.

Chiari II malformation: almost completely seen in patients with spinal meningocele, including cerebellar vermicular and tonsil hypoplasia, extension of the fourth ventricle, and descending cerebellar tonsils and lower brain stem into the spinal canal. In infants, symptoms include dysphagia, aspiration, apnea, weak crying, posterior cranial nerve palsy, and growth disorders.

1) Meningocele: more common in the lumbosacral region. The pathological changes are mainly caused by the meninges bulging outward through the defective lamina to form a cyst-like mass on the back. Its contents are mainly filled with cerebrospinal fluid, except for a few nerve root tissues. Therefore, the light transmission test is positive, and there is a sense of fluctuation in the pressure, and root symptoms occur when the pressure is heavy. When the abdominal pressure is increased or the child is crying, the cystic pressure increases. The skin surface is mostly normal in color; a few are thin, brittle, and adhere to the dura mater.

2) Spinal meningocele: more common than the former. Except for the meninges, the spinal cord also protrudes into the sac, which is seen above the thoracolumbar, and the scope of the bone defect behind the spinal canal is large. The base of the cyst is wider. The light transmission test is mostly negative, and spinal symptoms may occur with manual pressure (pressurization tests should be avoided). Accompanied by lower limb nerve disorders and sphincter dysfunction.

3) Spinal bulge: The spinal cord is exposed. One segment of the spinal cord is exposed to the outside in the form of a flat plate. The bulged spinal cord has no skin and the spinal canal and meninges are open. With a large amount of cerebrospinal fluid overflow, granulation surface can be formed on the surface. This is the most severe type, which is often accompanied by lower limbs or other types of the whole body, and has a high mortality rate.

Diagnosis and differential diagnosis of spina bifida

Spina bifida

Due to the deformity of the child's body surface, it was discovered early by family members or midwives.

According to the clinical manifestations, spinal X-ray film courseware spinous process, lamina defect, puncture the cystic cavity to draw cerebrospinal fluid, the diagnosis can be established. MRI examination showed spinal cord and nerves in the bulge, and deformities such as syringomyelia.

The skin changes of this disease need to be distinguished from congenital fur sinus, the wall of the sinus is composed of skin tissue, the length of the sinus is different, and the short is a blind tube. The elderly can reach the spinal canal, which can cause infection or tumor. .

Spina bifida Recessive spina bifida

More than 80% of the cases can be clinically without any complaints and no positive signs. Most of them are accidentally found during physical examination.

During the growth of some patients with recessive spina bifida, dysuria becomes more and more obvious until the school age, and urinary incontinence still exists. This is the spinal cord tethering syndrome caused by the formation of adhesions and tight spinal cords at the end of the fissure. MRI showed that the spinal cord cone moved downward, the terminal filament became thicker, and the transverse diameter was above 2mm.

Some types (such as floating spines) are susceptible to chronic low back pain such as lumbar muscle strain due to lumbosacral structural dysplasia. Compression may be painful or nerve radiation symptoms in the lower limbs, especially when the lumbar spine is excessively forward flexed or extended. The diagnosis is based on plain radiography or CT.

Spina bifida emergency measures

Patients rarely need emergency surgery. Can be performed within 48-72 hours after birth. Repair surgery, delaying the wall of the neural tube will increase the damage to the exposed spinal nerve, thereby reducing motor function. The function of untreated patients will gradually deteriorate, and nearly 40% of patients will develop ventricular inflammation.

Spina bifida disease treatment

Spina bifida

Spontaneous spina bifida requires surgical treatment. The timing of surgery is 1-3 months after birth. Simple meningocele, or other types of mild neurological symptoms, should be operated as soon as possible. If the operation is postponed due to systemic conditions and other reasons, it should be protected locally, especially those with exposed spinal cord to prevent infection.

The principle of surgery is to divide and loosen the adhesions around the spine, to incorporate the spinal cord or nerve root of the posterior process into the spinal canal, remove the excess dural sac, closely suture the spinal opening, and flip the fascia on both sides of the hole to overlap and repair it. Laminar defect (bone graft, etc.). For patients with spinal cord tethering syndrome, spinal canal exploration can be performed to loosen adhesions and cut off the terminal filaments.

Spina bifida Recessive spina bifida

Recessive spina bifida need not be treated in general cases, but medical education should be carried out to eliminate the patient's nervousness and bad mental state. For those with mild symptoms, exercise of the lumbar muscles (or abdominal muscles) should be emphasized to enhance the internal balance of the waist.

Prognosis of spina bifida disease

Dominant spina bifida, such as nerve root and spinal cord compression in the meningocele, may have motor and sensory disorders, and the prognosis is poor. Invisible spina bifida, the prognosis is generally better.

Spina bifida disease prevention

The cause of spina bifida deformities is unknown. Some scholars believe that it is related to the chemical or physical damage of embryos in early pregnancy. Maternal health (maternal intake of folic acid) is important to prevent fetal malformations.

Spina bifida disease care

Asymptomatic spina bifida requires no treatment.

The natural development of dominant spina bifida is that most of the ruptures cause meningitis and lead to patient death. More than 90% died within one year of age. Therefore, removal of cysts and repair of holes are the main operations. Meningitis often occurs postoperatively, with high fever, shock, vomiting, and bulging forehead. Such as wound infection is also very serious. Therefore, nursing before and after surgery is very important.

Management of spina bifida respiratory tract

Observe whether the spontaneous breathing and the ventilator are synchronized. When the spontaneous breathing and the mechanical ventilation are not synchronized, and the human-machine confrontation is serious, you should find out whether the cause is blocked sputum, whether the ventilation is insufficient, and whether the mask is leaking. Sputum suction should be given in time when sputum is blocked, and a suitable suction tube should be selected when suctioning. The depth of insertion should be appropriate and the action should be gentle. The time for each suction should be less than 15 seconds to avoid damage to the respiratory mucosa.

Observation of spina bifida vital signs

Pay attention to the child's consciousness, heart rate, breathing, blood pressure, blood oxygen saturation, skin color and peripheral circulation. Strengthen inspections every 30 minutes to observe the above conditions in a timely and accurate manner. While autonomously observing, you should also pay attention to the response of the children accompanying the family members. Any minor changes should be vigilant and the cause should be promptly identified.

Observation and nursing of spina bifida cerebrospinal fluid

Closely observe the color, nature, and amount of the epidural drainage fluid. The epidural drainage tube is routinely removed 24 hours after surgery. The wound dressing should be closely observed after the drainage tube is removed, and the wound dressing should be kept dry. Blood should be notified to the doctor in a timely manner. When cerebrospinal fluid is present, it should be bandaged under pressure. In order to prevent wound infection, the dressing should be changed in time, and severe exudation should be performed to repair the dura mater.

Observation and nursing of spina bifida pulmonary infection

All the patients were treated with tracheal intubation under general anesthesia. Due to aggressive operation. Can reduce respiratory tract mucosal function, and easily damage the respiratory tract mucosa and increase the chance of infection. Due to the imperfect immune system development and low resistance of children, prone to lung infections after surgery, the temperature of children should be closely monitored to guide them to effectively cough and sputum, and give aerosol inhalation 2 times a day Enter antibiotics on time and volume.

Spina bifida strengthens skin care

Children's skin stratum corneum is thin, which can easily lead to bacterial infection of the skin. On the other hand, because the skin's barrier function is fragile, and the skin contains more water, the pH value is higher, which is conducive to the growth of pathogenic bacteria. Children's skin care, turn over every 1-2 hours, and should be gentle when turning over, to avoid dragging, etc. Pay attention to keeping the bed unit clean and tidy, no wrinkles, massage the protruding part of the bone after each turn, and when turning over Pay attention to the axis turning over to avoid excessive distortion of the body. ^[3]