Tethered spinal cord
Related Terms
?-fetoprotein, alpha-fetoprotein, amniocentesis, Chiari II malformation, folic acid, hydrocephalus, maternal serum alpha fetoprotein (MSAFP), meninges, meningocele, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase gene (MTRR or MTR gene), myelomeningocele, neural tube defect, spina bifida manifesta, spina bifida occulta.
Background
Spina bifida is a birth defect that occurs when the tissue surrounding the spinal cord does not close properly. It is one of several disorders known as neural tube defects. Neural tube defects occur in about one out of every 1,000 births and spina bifida affects seven out of every 10,000 births. Spina bifida is the most common neural tube defect.
Spina bifida (Latin for "cleft spine") happens during the first month of pregnancy when the child has an incomplete and improper closure of the spine. Some infants are born with an opening in the back, exposing the spinal nerves. This may cause serious damage to the nerves and the spinal cord. Other complications are hydrocephalus (buildup of fluid in the brain), urinary and bladder problems, and learning disabilities.
There are three types of spina bifida. The mildest form, spina bifida occulta, is usually caused by a malformed vertebra (spinal bones) that is covered with skin. Most children with spina bifida occulta will have no symptoms and live completely normal lives. Meningocele and myelomeningocele are the other types, collectively known as spina bifida manifesta. Meningocele is when the spinal cord develops normally, but the membranes that cover the brain and spinal cord (called the meninges) stick out from the opening in the spine. Myelomeningocele is the most severe type of spina bifida in which the meninges and the spinal cord do not develop properly and can stick out of the open lesion.
With surgical treatment, most children will survive into adulthood. About 80% will have normal intelligence and almost 75% will be able to participate in sports and recreational activities. However, some will have complete paralysis of the legs. These children will depend on a wheelchair to move around but may still be able to live long and healthy lives.
Signs and symptoms
General: Symptoms of spina bifida vary and depend on the type of spina bifida a person has.
Patients with spina bifida occulta usually have very few signs and symptoms. The skin directly over the spinal defect may be thicker, dimpled, hairy, or may have a birthmark.
The symptoms in spina bifida meningocele vary, ranging from few to no symptoms (like spina bifida occulta) to severe (such as paralysis and urinary problems). Spina bifida meningocele is usually associated with a fluid-filled sac protruding from the opening in the back.
Spina bifida myelomeningocele has the most apparent signs and symptoms, and these can also vary from person to person. One can usually see the meninges, spinal nerves, and sometimes the spinal cord pushing through an opening in the back.
Paralysis: Depending on where the spinal cord is exposed (where the sac protrudes), a person with spina bifida can have partial to complete paralysis. Paralysis tends to be more severe the higher the opening in the back.
Hydrocephalus: Hydrocephalus occurs when there is a buildup of the cerebrospinal fluid, a fluid that cushions the brain and spinal cord. This affects about 70-90% of patients with spina bifida myelomeningocele. The defect in the spinal cord can block the flow of spinal fluid, which may not be able to drain properly. This results in an enlarged head and, if untreated, may lead to mental problems. A child with hydrocephalus should see a brain surgeon every 1-2 years. Hydrocephalus is treated by surgically placing a shunt, or hollow tube, into the brain so that extra fluid may drain into the abdomen.
Diagnosis
General: Most cases of spina bifida are diagnosed before the child is born. However, if it is a mild form of the disease, it may not be noticed until after birth or later in life. Sometimes, it is not diagnosed at all if no symptoms are present. There are three main ways to test for spina bifida while a woman is pregnant. Tests are typically done in the second trimester because spina bifida cannot be detected until that time.
MSAFP: During the second trimester of pregnancy, a maternal serum alpha-fetoprotein (MSAFP) screening should be performed. It is offered between weeks 15 and 20 of pregnancy and is usually part of a set of tests that look for a number of genetic defects. The doctor takes a sample of the mother's blood and looks for a protein called alpha fetoprotein (AFP), which is made by the fetus and placenta. The mother's blood will have a small amount of AFP, but abnormally high levels could indicate a neural tube defect. The test is not specific for spina bifida and is not always accurate. Spina bifida may be present with normal levels of AFP, and high levels of AFP may not always indicate a neural tube defect. High levels may warrant further testing with ultrasound or amniocentesis. Multiple fetuses and gestational age are two additional reasons the AFP may be high.
Ultrasound: In an ultrasound, high frequency waves are used to examine the fetus. Sound waves from a wand-like device will penetrate the mother's stomach and reflect off tissues to form a picture of the fetus. This will help identify if there is more than one fetus and will determine gestational age. An advanced ultrasound is able to detect certain signs of spina bifida, including an open spine or indications of defects in the fetus' brain.
Amniocentesis: The amniotic sac is where the fetus grows. During amniocentesis, the clinician removes samples of amniotic fluid with a needle. This test looks for chromosomal defects, genetic defects, and neural tube defects. Amniocentesis can also be used to detect AFP in the amniotic sac. Like the mother's blood, a small amount of AFP in the amniotic fluid is normal, but if there is a neural tube defect, AFP levels may be elevated. Amniocentesis may present a risk, however, and about one in 200 to one in 500 women may miscarry after the test.
Complications
Chiari II malformation: Chiari II malformation is common in children with myelomeningocele but rare in all other children. This is a condition in which the brain stem and cerebellum (back part of the brain) are located lower in the neck. This causes the spinal cord to be compressed and can lead to hydrocephalus (an increase of cerebrospinal fluid in the ventricles of the brain, which causes an increase in the size of the head and pressure changes in the brain). Other symptoms include: difficulties with feeding, swallowing, and breathing; choking; and stiffness in the neck, back, or arms.
Latex allergy: Latex is a natural rubber found in surgical gloves. Since children with spina bifida are exposed to latex during surgeries and other medical procedures, it is common for them to develop allergies to it. Up to 73% of myelomeningocele patients have a latex allergy. Symptoms range from watery eyes and wheezing, to a rash and hives, to a life-threatening reaction called anaphylaxis. Doctors should be aware and avoid the use of latex gloves. Mothers should also be aware because baby bottle nipples, pacifiers, and balloons can all contain latex.
Learning disabilities: Most children with spina bifida, even 80% of those with myelomeningocele, have normal intelligence. However, some learning problems can occur. The most common learning disabilities include difficulty paying attention, problems with language and reading comprehension, and difficulty learning math.
Meningitis: Meningitis is a bacterial or viral infection that causes inflammation of the meninges, which form a protective layer around the spinal cord and brain. Because the spinal nerves and spinal cord may be exposed in babies with spina bifida, it is more likely for them to develop infections. Meningitis is a serious infection that can cause brain damage and may be life-threatening. Bacterial infections may be treated with antibiotics. Viral meningitis cannot be treated with antibiotics and is usually less severe than bacterial meningitis.
Tethered spinal cord: The spinal cord usually slides up and down as a person moves. In spina bifida, the spinal cord may be attached, or tethered, to surrounding tissues. Some children do not experience symptoms, while others can get leg weakness, back and leg pain, scoliosis (curvature of the spine), and changes in bladder function. Surgery can be used to detach the spinal cord from surrounding tissue. Even with no symptoms, surgery is strongly advised. Some risks of surgery include infection, anesthesia complications, functional loss, and pain.
Urinary tract disorders: Children that have myelomeningocele can have problems fully emptying their bladders. This may lead to urinary tract infections and even kidney disease. To prevent urinary tract infections, intermittent catheterization may be used. A catheter, which is a small, plastic tube, is placed into the child's bladder through the urethra. This is done several times a day, usually every three to four hours. This is usually helpful, but children with spina bifida should regularly visit a specialized doctor, called an urologist, to prevent infections and other urinary problems.
Others: Other complications seen in children with spina bifida include obesity, gastrointestinal disorders, and skin problems. As a person gets older, sexual issues and depression have also been reported.
Treatment
General: There is no cure for spina bifida. If there is any nerve or tissue damage, it cannot be corrected. Most of the symptoms and complications can only be improved with surgery. Surgery is used to close the open lesion caused by spina bifida, but there may be irreversible damage, including paralysis.
Surgery: Surgery is the main treatment for a person born with spina bifida, and the child is usually operated on within 24 hours of birth. This decreases the exposure of the spinal nerves and spinal cord, decreasing the risk of infection and preserving spinal function. Surgery is performed in children with meningocele, when paralysis is not usually present, and myelomeningocele. Spina bifida occulta usually requires no treatment, but some children with occulta may require surgery as they get older.
There is developing research on the use of in utero (within the uterus) surgery for a fetus that has myelomeningocele. This involves opening the mother's stomach and uterus and surgically sewing shut the opening over the fetus' spinal cord. This procedure is performed between weeks 19 and 25 of pregnancy. Doctors believe that this type of surgery decreases the exposure of the fetus' spinal cord to amniotic fluid, which may be toxic, and allows for better development of the brain, decreasing the number of cases of Chiari II malformation. There are serious risks involved to the fetus and the mother with in utero surgical procedures. For the unborn baby, the surgery may result in premature delivery, resulting in underdeveloped organs, bleeding in the brain (hemorrhage), and death. The risks to the mother include infection, loss of blood, and gestational diabetes.
Surgery may also be performed if a tethered spinal cord is present. This happens when the spinal cord is attached to surrounding tissues and causes loss of leg function and bowel and bladder dysfunction. Surgery may allow for normal functioning and may stop the progression of neurological deterioration.
Surgery is also used to treat hydrocephalus, which is the buildup of fluid in the brain. A shunt, which is a narrow catheter or tubing, is placed into the ventricles of the brain leading to another part of the body into which it can be drained. Three common spots include the abdomen, heart cavity, or jugular vein (large vein in the neck). Shunts can malfunction due to blockage, infections, or over-drainage of the brain. Symptoms of shunt malfunction include head enlargement, headache, nausea/vomiting, sleepiness, irritability, vision changes, and seizures. A newer surgery is endoscopic third ventriculostomy, in which a hole is made in the ventricle of the brain in order to create a new pathway for draining the cerebrospinal fluid. It is being studied for patients with shunt malfunction. This procedure is not recommended in children under six months of age and has been most successful in children over two years old.
Physical therapy: Even with surgery, spina bifida may cause irreversible damage to the nerves affecting the legs. Physical therapy can be initiated to help teach the parents and children certain exercises for the legs and feet. This will prepare the child to be able to walk with crutches, a walker, or braces when he/she is older and may help to attain maximal mobility. A wheelchair may be needed if there is extensive paralysis of the legs, however.
Not all physical therapy programs are suited for everyone, and patients should discuss their medical history with qualified healthcare professionals before beginning any treatments. Based on the available literature, physical therapy appears generally safe when practiced by a qualified physical therapist. However, physical therapy may aggravate some pre-existing conditions. Persistent pain and fractures of unknown origin have been reported. Physical therapy may increase the duration of pain or cause limitation of motion. Pain and anxiety may occur during the rehabilitation of patients with burns. Both morning stiffness and bone erosion have been reported in the physical therapy literature, although causality is unclear. Erectile dysfunction has also been reported. All therapies during pregnancy and breastfeeding should be discussed with a licensed obstetrician/gynecologist before initiation.
Bladder catheterization: Use of a catheter can be helpful for patients with urinary problems. Most patients are put on intermittent catheterization programs in which the catheter is placed into the bladder several times a day to ensure complete emptying. Some medications to lower bladder pressure may be used with the catheter to keep the bladder at very low pressures. This will preserve kidney function and decrease the chance of having a kidney infection if the urine backs up into the kidneys.
Integrative therapies
Note: Currently, there is insufficient evidence available on the safety and effectiveness of integrative therapies for the prevention or treatment of spina bifida. The integrative therapies listed below should be used only under the supervision of a qualified healthcare provider, and should not be used in replacement of other proven therapies or preventive measures.
Strong scientific evidence:
Folic acid: Folate, also known as folic acid, is a water-soluble B vitamin. Folate occurs naturally in food and folic acid is the synthetic form of this vitamin. Folic acid is well tolerated in amounts found in fortified foods and supplements. Studies have shown that folate consumption during pregnancy prevents deficiency and anemia in pregnant women. Low folate levels during pregnancy may contribute to birth defects and pregnancy loss. A high dietary intake of folate and taking folic acid supplements during pregnancy reduces the risk of neural tube birth defects, like spina bifida, in the infant.
Folic acid supplements should be avoided with allergy to any of the ingredients in various folate products. Common side effects at large doses may include, but are not limited to, bad taste in the mouth, nausea, confusion, irritability, and disturbances in sleep patterns.
Good scientific evidence:
Cranberry: Cranberries are tart, red, edible berries that are harvested from small evergreen shrubs. The berries are used in sauces, jellies, and drinks. Some patients with spina bifida have problems fully emptying their bladders, which may lead to urinary tract infections (UTIs). While no single study convincingly demonstrates the ability of cranberry to prevent UTIs, the sum total of favorable evidence combined with laboratory research tends to support this use.
Avoid if allergic to cranberries, blueberries, or other plants of the Vaccinium species. Sweetened cranberry juice may affect blood sugar levels. Use cautiously with a history of kidney stones. Avoid more than the amount usually found in foods if pregnant or breastfeeding.
Unclear or conflicting scientific evidence:
Iodine: Iodine is an element that the human body needs to make thyroid hormones. Some patients with spina bifida have problems fully emptying their bladder, which may lead to urinary tract infections. These patients may be on intermittent catheterizations, which can also allow bacteria into the urinary tract. Povidone-iodine bladder irrigation has been suggested as a way to prevent infections before catheters are removed. There is limited research in this area.
Reactions can be severe and deaths have occurred with exposure to iodine. Avoid iodine-based products if allergic or hypersensitive to iodine. Do not use for more than 14 days. Avoid lugol solution and saturated solution of potassium iodide (SSKI, PIMA) with hyperkalemia (high amounts of potassium in the blood), pulmonary edema (fluid in the lungs), bronchitis, or tuberculosis. Use cautiously when applying to the skin because it may irritate or burn tissues. Use sodium iodide cautiously with kidney failure. Avoid sodium iodide with gastrointestinal obstruction. Iodine is safe in recommended doses for pregnant or breastfeeding women. Avoid povidone-iodine for perianal use during delivery or postpartum antisepsis.
Physical therapy: The goal of physical therapy is to improve mobility, restore function, reduce pain, and prevent further injury. A variety of techniques, including exercises, stretches, traction, electrical stimulation, and massage, are used during physical therapy sessions. A physical therapist is able to show parents and children certain exercises for the child to improve balance and motion. They are also able to teach parents and children how to properly use walking aids, like crutches, braces, walkers, and wheelchairs. Although there seems to be a benefit for patients with spina bifida in clinical practice, there is not enough scientific evidence supporting this benefit.
Not all physical therapy programs are suited for everyone, and patients should discuss their medical history with qualified healthcare professionals before beginning any treatments. Based on the available literature, physical therapy appears generally safe when practiced by a qualified physical therapist. However, physical therapy may aggravate some pre-existing conditions. Persistent pain and fractures of unknown origin have been reported. Physical therapy may increase the duration of pain or cause limitation of motion. Pain and anxiety may occur during the rehabilitation of patients with burns. Both morning stiffness and bone erosion have been reported in the literature, although causality is unclear. Erectile dysfunction has also been reported. All therapies during pregnancy and breastfeeding should be discussed with a licensed obstetrician/gynecologist before initiation.
Prevention
Folic acid: Folate, also known as folic acid, is a water-soluble B vitamin. Folate occurs naturally in food and folic acid is the synthetic form of this vitamin. Folic acid is well-tolerated in amounts found in fortified foods and supplements.
It has been shown that when pregnant women take multivitamins containing folic acid, they have a 70% lower risk of having children with neural tube defects. Because many pregnancies are unplanned, it is recommended that all women of childbearing age take a supplement containing 400 micrograms of folic acid. Women who are planning to get pregnant should consume 1 milligram of folic acid daily, the amount found in prescription prenatal vitamins. Over-the-counter prenatal vitamins contain the standard 400 micrograms. If a woman has already had a child with spina bifida or any other neural tube defect, or has spina bifida herself, it is recommended that she take 4,000 micrograms (4 milligrams) of folic acid. This is only available by prescription and should be taken one to three months before getting pregnant and throughout the first trimester of pregnancy. In addition to dietary supplements, folic acid can be found in many foods. Many breakfast cereals, breads, flours, pastas, and grains are fortified with 100% of the recommended daily allowance (RDA) of folic acid (400 micrograms). Other foods containing folic acid are dark, green vegetables, egg yolk, and some fruits. Synthetic folic acid found in supplements has been reported to be absorbed better than folate found in food.
It is also important to remember that folic acid supplementation will not guarantee a healthy baby, but it will significantly decrease the risk of neural tube defects.
Author information
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
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Causes
The cause of spina bifida is not known. It is believed that a combination of genetic, environmental, and nutritional factors play a role in the development of spina bifida.
Risk factors
General: Spina bifida can occur in any child. About 95% of neural tube defects (NTDs), including spina bifida, occur when there is no family history. There are some risk factors associated with an increased chance of a child having spina bifida.
Family history: If a woman has a child with spina bifida there is a 4% chance she will have another child with spina bifida. Also, if the mother has spina bifida, there is a 4% chance that her child will have it. Couples with family histories of spina bifida or any NTD can discuss the risks of having a child with a NTD with a genetic counselor.
Folic acid deficiency: If a pregnant woman is deficient in folic acid, a fetus may not be able to develop properly. There is evidence indicating that a lack of folic acid (vitamin B-9) increases the risk of NTDs, including spina bifida.
Gender: More females are born with spina bifida than males. The reason for this is unknown.
Genetics: The 5-methyltetrahydrofolate-homocysteine methyltransferase reductase gene, also known as the MTRR gene or MTR gene, gives instructions for making the methionine synthase reductase enzyme. This enzyme ultimately helps to make methionine, an important amino acid. A specific version of the MTRR gene has been associated with an increased risk of having a child with spina bifida. However, researchers do not know the reason for this association.
High body temperature: A rise in body temperature, even by about 3-4 degrees, during the early months of a pregnancy may increase the risk of spina bifida and other NTDs. This could be caused by a prolonged fever or the use of hot tubs and saunas.
Medical conditions: Pregnant women with diabetes may have an increased risk of neural tube birth defects. This is especially evident when a woman's blood sugar levels are elevated during pregnancy. Careful blood sugar level management should be practiced while pregnant. Obesity has also been linked to an increase in NTDs. The reason is unknown but it may have to do with poor nutrition or it may be because obese women are more likely to have diabetes.
Medications: Anti-seizure medications, such as valproic acid (Depakene?), have been shown to cause NTDs if taken during pregnancy. Scientists theorize that these medications interfere with the body's ability to use folic acid. Other anti-seizure medications associated with spina bifida include divalproic acid (Depakote?) and carbamazapine (Tegretol?).
Ethnicity: Hispanic women have the highest risk of having a child with spina bifida. This is followed by Caucasian (especially those of European descent), American Indian/Alaskan Native, and African American, in descending order. Asians/Islanders have the lowest risk of having a child with spina bifida.
Types of the disease
Spina bifida occulta: Spina bifida occulta (meaning "hidden") is the most common and the mildest form of spina bifida. It occurs in about 3-5% of patients and the malformation is usually covered by the skin. The defect is usually a minor gap in a few of the vertebrae, which are the small bones that make up the spine. In later childhood or adulthood, progressive neurological deterioration may become apparent; however, it can be so mild that there is no disturbance in spinal function. Some signs may be seen with close examination of the back. These include dimpled, thickened, pigmented (colored), or hairy skin where the defect is covered or soft swelling over the spine (composed of fatty tissue). It may be diagnosed at any age, and some people with occulta may go their whole lives without ever knowing they have it.
Spina bifida meningocele: This type, along with myelomeningocele, is collectively known as spina bifida manifesta. Meningocele accounts for 4% of all spina bifida manifesta cases. In this type, the coating that protects the central nervous system, known as the meninges, is pushed through an open part of the spine. There is usually a sac filled with cerebrospinal fluid (the fluid found around the spinal cord and brain), and it may or may not be covered by skin. Usually, there is no nerve damage and a person may have minor disabilities.
Spina bifida myelomeningocele: Myelomeningocele is also a type of spina bifida manifesta and accounts for 96% of manifesta cases. This form of spina bifida is the most serious and causes nerve damage and more severe disabilities. Like meningocele spina bifida, there is a sac that pushes through an open part of the spine. This sac contains meninges, spinal nerves, and can even contain the spinal cord itself. It can cause partial or complete paralysis to any part of the body below the opening. Some patients are unable to walk and may experience urinary and bowel problems.