Spina bifida

Overview

Spina bifida (Latin: "split spine") is a birth defect where there is incomplete closing of the backbone and membranes around the spinal cord. There are three main types: spina bifida occulta, meningocele, and myelomeningocele. The most common location is the lower back but rarely they may occur in the middle back or neck. Occulta has no or only mild signs. Signs of occulta may include a hairy patch, dimple, dark spot, or swelling on the back at the site of the gap in the spine. Meningocele typically causes mild problems with a sac of fluid present at the gap in the spine. Myelomeningocele, also known as open spina bifida, is the most severe form. Associated problems include poor ability to walk, problems with bladder or bowel control, hydrocephalus, a tethered spinal cord, and latex allergy. Learning problems are relatively uncommon.

Symptoms

The most common location of the malformations is the lumbar and sacral areas of the spinal cord. The lumbar nerves control the muscles in the hip, leg, knee and foot, and help to keep the body erect. The sacral nerves control some of the muscles in the feet, bowel and urinary bladder, and the ability to have an erection. Some degree of impairment can be expected in these areas, resulting in varying degrees of paralysis, absence of skin sensation, and poor or absent bowel and/or bladder control as well as curvature of the spine (scoliosis) (depending on the severity and location of the lesion damage on the spine). These individuals are rarely intellectually disabled. Children with spina bifida often have hydrocephalus, which consists of excessive accumulation of cerebrospinal fluid in the ventricles of the brain.

Tethered Spinal Cord syndrome, (with symptoms such as lower body pain, leg weakness, incontinence, scoliosis, numbness) is a common problem associated with spina bifida. Indeed, all spina bifida myelomeningocele patients have Tethered Cord on imaging studies such as Magnetic resonance imaging, but not all will develop symptoms. A tethered cord is thought to result from scar tissue which forms following the initial surgery to close the open defect. Symptoms caused by a tethered cord are rare in infancy and early childhood. Once symptoms develop it is important to make the diagnosis early, before permanent damage is done to the spinal cord and nerves

Causes

Spina bifida is believed to be due to a combination of genetic and environmental factors. After having one child with the condition or if a parent has the condition there is a 4% chance the next child will also be affected. Not having enough folic acid during pregnancy also plays a significant role. Other risk factors include certain antiseizure medications, obesity, and poorly controlled diabetes.

Prevention

There is neither a single cause of spina bifida nor any known way to prevent it entirely. However, dietary supplementation with folic acid has been shown to be helpful in reducing the incidence of spina bifida. Sources of folic acid include whole grains, fortified breakfast cereals, dried beans, leaf vegetables and fruits.

Folate fortification of enriched grain products has been mandatory in the United States since 1998. The U.S. Food and Drug Administration, Public Health Agency of Canada and UK recommended amount of folic acid for women of childbearing age and women planning to become pregnant is at least 0.4 mg/day of folic acid from at least three months before conception, and continued for the first 12 weeks of pregnancy. Women who have already had a baby with spina bifida or other type of neural tube defect, or are taking anticonvulsant medication should take a higher dose of 4–5 mg/day.

Certain mutations in the gene VANGL1 are implicated as a risk factor for spina bifida: These mutations have been linked with spina bifida in some families with a history of spina bifida.

Diagnosis

Open spina bifida can usually be detected during pregnancy by fetal ultrasound. Increased levels of maternal serum alpha-fetoprotein (MSAFP) should be followed up by two tests - an ultrasound of the fetal spine and amniocentesis of the mother's amniotic fluid (to test for alpha-fetoprotein and acetylcholinesterase). AFP tests are now mandated by some state laws (including California). and failure to provide them can have legal ramifications. In one case a man born with spina bifida was awarded a $2 million settlement after court found his mother's OBGYN negligent for not performing these tests. Spina bifida may be associated with other malformations as in dysmorphic syndromes, often resulting in spontaneous miscarriage. In the majority of cases, though, spina bifida is an isolated malformation.

Genetic counseling and further genetic testing, such as amniocentesis, may be offered during the pregnancy, as some neural tube defects are associated with genetic disorders such as trisomy 18. Ultrasound screening for spina bifida is partly responsible for the decline in new cases, because many pregnancies are terminated out of fear that a newborn might have a poor future quality of life. With modern medical care, the quality of life of patients has greatly improved.

Prognosis

The prognosis for individuals with spina bifida depends on the number and severity of abnormalities. Prognosis is poorest for those with complete paralysis, hydrocephalus, and other congenital defects. With proper care, most children with spina bifida live well into adulthood.

Treatment

There is no known cure for nerve damage caused by spina bifida. To prevent further damage of the nervous tissue and to prevent infection, pediatric neurosurgeons operate to close the opening on the back. The spinal cord and its nerve roots are put back inside the spine and covered with meninges. In addition, a shunt may be surgically installed to provide a continuous drain for the excess cerebrospinal fluid produced in the brain, as happens with hydrocephalus. Shunts most commonly drain into the abdomen or chest wall.

Childhood

Most individuals with myelomeningocele will need periodic evaluations by a variety of specialists:

  • Physiatrists coordinate the rehabilitation efforts of different therapists and prescribe specific therapies, adaptive equipment, or medications to encourage as high of a functional performance within the community as possible.
  • Orthopedists monitor growth and development of bones, muscles, and joints.
  • Neurosurgeons perform surgeries at birth and manage complications associated with tethered cord and hydrocephalus.Neurologists treat and evaluate nervous system issues, such as seizure disorders.
  • Urologists to address kidney, bladder, and bowel dysfunction - many will need to manage their urinary systems with a program of catheterization. Bowel management programs aimed at improving elimination are also designed.
  • Ophthalmologists evaluate and treat complications of the eyes.
  • Orthotists design and customize various types of assistive technology, including braces, crutches, walkers, and wheelchairs to aid in mobility. As a general rule, the higher the level of the spina bifida defect, the more severe the paralysis, but paralysis does not always occur. Thus, those with low levels may need only short leg braces, whereas those with higher levels do best with a wheelchair, and some may be able to walk unaided.
  • Physical therapists, occupational therapists, psychologists, and speech/language pathologists aid in rehabilitative therapies and increase independent living skills.

Although the standard treatment is postnatal treatment ( after delivery), there is increasing evidence of the efficacy of prenatal treatment ( before delivery, whilst the baby is inside the womb). A recent large study suggested there was some benefit in operating on the baby inside the womb by open surgery. These 'open' operations are largely carried out in the United States with a few units in Europe. There can be serious complications to the mother from the 'open' procedure. There is also the fetoscopic approach ( akin to 'keyhole') surgery. The fetoscopic operation is mostly carried out in Giessen, Germany. The fetoscopic approach is purported to have less complications to the mother.

Transition to adulthood

Although many children's hospitals feature integrated multidisciplinary teams to coordinate healthcare of youth with spina bifida, the transition to adult healthcare can be difficult because the above healthcare professionals operate independently of each other, requiring separate appointments and communicate among each other much less frequently. Healthcare professionals working with adults may also be less knowledgeable about spina bifida because it is considered a childhood chronic health condition. Due to the potential difficulties of the transition, adolescents with spina bifida and their families are encouraged to begin to prepare for the transition around ages 14–16, although this may vary depending on the adolescent's cognitive and physical abilities and available family support. The transition itself should be gradual and flexible. The adolescent's multidisciplinary treatment team may aid in the process by preparing comprehensive, up-to-date documents detailing the adolescent's medical care, including information about medications, surgery, therapies, and recommendations. A transition plan and aid in identifying adult healthcare professionals are also helpful to include in the transition process.

Further complicating the transition process is the tendency for youths with spina bifida to be delayed in the development of autonomy, with boys particularly at risk for slower development of independence. An increased dependence on others (in particular family members) may interfere with the adolescent's self-management of health-related tasks, such as catheterization, bowel management, and taking medications. As part of the transition process, it is beneficial to begin discussions at an early age about educational and vocational goals, independent living, and community involvement.

Pregnancy

If spina bifida is detected during pregnancy, then open or minimally-invasive fetal surgery can be performed.