|The Doyle family.|
Four-year-old Michael Doyle of Phoenix, Maryland, races his twin brother Christopher around the local zoo, and long after Christopher's energy fades, Michael asks to go see the polar bears. As Christopher sinks into the oversized stroller, Michael, braced with an AFO, beelines to the ice caps.
Their mother Helen recaps this story as her seven-month-old son naps and the twins are occupied in another room. After several years of unsuccessfully trying to conceive, Helen and her husband Tim, a physician, tried in-vitro fertilization and soon became pregnant with twin boys. In the first trimester, the Doyles learned that one of their boys would be born with spina bifida, a congenital birth defect associated with folic acid deficiency in the first days after conception. It was then that they understood that Helen's difficulties conceiving might have been linked to her body's inability to metabolize folate.
"At first I didn't get it. I asked, How does something like this happen?'" says Doyle. "By the time they were born, we were very educated."
The Doyles educated themselves on the disorder by reading books, speaking with other parents of children with spina bifida, and by visiting the Kennedy Krieger Institute in Baltimore, Maryland. Though some advisors suggested a selective reduction of the pregnancy, Doyle says, "We knew from day one that we were keeping [the baby]. We were cautiously optimistic for the rest of the pregnancy."
|Eric Levey, MD|
"There's a lot we can do for this population," says Eric Levey, MD, director, Center for Spina Bifida & Related Conditions at Kennedy Krieger Institute. "We have pediatrics, neurosurgery, urology, orthopedics, physical therapy, occupational therapy, neuropsychology, social work, and nursing. We also invite an independent orthotist and podiatrist to participate in our clinic. We refer patients to Johns Hopkins Hospital for other specialty consultations, including pulmonary, cardiology, opthalmology, and nephrology. All can help educate families."
Levey continues, "There are misconceptions that spina bifida is a life-threatening disorder, when in reality 95 percent of children survive into adulthood. I occasionally do prenatal consultations, and I like to give parents a realistic view of what it's like to have a child with spina bifida. Most of them just need to be told their child can do well."
Developmental Neurobiology of NTDs
Folic Acid Vital during Pregnancy
Because 95 percent of NTDs occur in women with no personal or family history, all women of childbearing age are at risk for this type of pregnancy. According to the Centers for Disease Control (CDC), a woman who previously has had a NTD-affected pregnancy is 20 times more likely to have a second. Maternal insulin-dependent diabetes, use of certain anti-seizure medications, obesity, and high temperatures in early pregnancy also are risk factors.
However, studies have shown that the incidence of NTDs can be reduced by up to 70 percent by supplementing folic acid intake. Because the neural tube is formed early, when many women have yet to learn of their pregnancy, the CDC recommends that all women of childbearing age consume 400 micrograms of folic acid daily to prevent these serious birth defects. Furthermore, in 1998 the US Food and Drug Administration (FDA) mandated fortification of cereal-grain products with folic acid.
"Because I'd had a previous pregnancy affected by a NTD, when I was ready to get pregnant with my third child, I was given four milligrams of folic acid, a thousand times more than the average woman," Doyle explains. Her third son was born without abnormalities.
Foods that contain folate (natural folic acid) include orange juice, leafy green vegetables, beans, and whole-grain products. Multivitamins, fortified breakfast cereals, and enriched grain products contain a synthetic form of folic acid that is more easily absorbed by the body than the natural form.
Michael is one of more than 70,000 people in the United States who are currently living with spina bifida, the most common form of neural tube defect (NTD). The central nervous system—brain and spinal cord—develops from a hollow structure called the neural tube. A process called neurulation forms the neural tube on gestational day 20, when the neural plate folds. When the folds contact each other, a fusion begins at the dorsal midline at what will become cervical levels of the spinal cord and proceeds, zipper-like, in rostral (towards the nose) and caudal (towards the tail) directions. Much like a kink in a zipper, defective neurulation in which the neuropore fails to close sometimes results in congenital malformations called dysraphic defects. Failure of the anterior neuropore to close causes anencephaly in which the brain is not formed, the meninges and skull may be absent, and there may be facial abnormalities. Defects in the closure of the posterior neuropore cause a range of malformations known collectively as myeloschisis.
Spina bifida ranges in severity. When the vertebral arches fail to completely form and fuse to cover the spinal cord, yet the skin is closed over it, the condition is called spina bifida occulta. In this mild form, though there may be no motor or sensory impairments evident at birth, neurological deterioration may materialize later in childhood or adulthood. Therefore occulta may be diagnosed at any age.
Spina bifida aerta is a more serious malformation in which the skin is not closed over the vertebral defect. "These babies are literally born with a hole in their back, that needs to be sewn up immediately to avoid further damage," explains Levey.
Spina bifida often is accompanied by a cystic mass (spina bifida cystica), a saccular structure that may contain meninges and cerebral spinal fluid (CSF). In this condition, called meningocele, there is usually no nerve damage and only minor disabilities, though new problems may develop later in life. Meningomyelocele, a condition in which the sac contains spinal neural tissue in addition to meninges and CSF, results in nerve damage and severe disabilities. The lower portion of the spinal cord or, more commonly, the "a" portion of the cauda equina are the neural tissues affected in meningomyelocele cases, resulting in paraplegia of the lower limbs, loss of bladder and bowel control, and an inability to perceive pain.
Five babies in 10,000 births are born with meningomyelocele. Infants with meningomyelocele also may have other congenital malformations such as hydrocephalus, which is a build-up of CSF within the skull, requiring shunting immediately after birth to relieve the pressure on the brain.
There is a wide spectrum of functional abilities among those with spina bifida.
"[A patient's] ambulatory potential is primarily determined by the lesion level," explains Don Katz, CO, FAAOP, administrative director of Orthotics and Prosthetics at Texas Scottish Rite Hospital for Children, Dallas. "For example, those with sacral lesions may only require foot orthoses due to weak foot intrinsic motor power, whereas those with lesion levels higher in the spine will require orthoses crossing more joints of the lower extremity. Regardless of functional levels, these kids are as motivated as other kids to run and play."
|Luciano Dias, MD, with spina bifida patient from Brazil, Pryscila Reis, wearing a RGO brace.|
Depending on the level of the lesion, patients can walk with little (lower lumbar/sacral lesions) or extensive (upper lumbar/thoracic lesions) bracing. However, Levey explains, "The functional level is not the same as the anatomical level of the lesion. Function is determined by a doctor's or therapist's observations."
Dias adds, "One misconception in spina bifida is that people try to put them all together in one group, when in reality the functional levels are different. Some are wheelchair users who can still have good quality of life, while others, who have more strength in their lower extremity are able to achieve significant mobility and levels of independence."
Children often are motivated to walk by their parents and a desire to keep up withtheir peers.
"One thing all children have in common is their incredible resilience," Katz observes. "They give it their best; they'll try anything. Some will stop walking by about age ten because it becomes clear to them that use of awheelchair is a much more energy-efficient form of mobility than use of orthoses that cross the knee or hip joints. We support that decision because it allows them tofocus on excelling in the classroom and at other things."
|Don Katz, CO, FAAOP, with young patient. Photo courtesy of Texas Scottish Rite Hospital for Children, Dallas.|
Spina bifida is considered to be the most complex birth defect that is compatible with human life. Therefore the resulting spectrum of problems requires a team of specialists to manage patient care.
"With our intervention—all of us working together—and the assistance of [the patient's] family, we can really make a difference in their quality of life," Dias comments. "I think a team approach to the management of spina bifida is imperative. These patients have orthopedic problems, neurological and urological problems, and 95 percent of them require the use of braces and very good physical therapy support. It [takes] everybody working together with the same goal in mind to maximize the [patient's] function."
Levey adds, "Parents can have trouble navigating the system. Coordination of care is critical." Because this often can be such a daunting task, multidisciplinary care centers offer much-needed relief.
"All of our centers are multidisciplinary," explains Elise Babbitt, Kennedy Krieger communications manager. "We have all the specialists under one roof, so parents don't have to take their child to five different places."
Similarly, "At Scottish Rite, ourteam that staffs our spina bifidaclinics is one of our most dynamic," says Katz. "It will not only include a physician (whichcould be an orthopedist, apediatrician, or urologist), and nursing staff who specialize in wound care management, but also dieticians (because obesity can be a real challenge), an orthotist, and physical therapist, as well as on-call psychologists."
Management Differs from Other Disabilities
Prenatal vs. Postnatal
Over the years, doctors have noticed that nerve function in fetuses with spina bifida seems to worsen throughout pregnancy as movements in the legs and feet occur less often. This suggests that there is ongoing damage to the open portion of the spinal cord, possibly from contact with amniotic fluid. Therefore, timely closure of the baby's spina bifida defect is important, though whether it is better to operate before or after birth has not been determined.
"The benefits of operating in utero aren't clear," Levey says. "Based on historical comparison, it doesn't make much difference in leg function, but it may result in less brain injury. The risks of the surgery include spontaneous abortion, premature birth, or infection."
The National Institute of Child Health and Human Development (NICHD), a part of the National Institutes of Health (NIH), is funding a study to compare how babies who have prenatal surgery do compared with those who have postnatal surgery. The study, called Management of Myelomeningocele Study (MOMS), is conducted at the University of California at San Francisco; The Children's Hospital of Philadelphia in Philadelphia, Pennsylvania; and Vanderbilt University Medical Center, Nashville, Tennessee.
"Parents can no longer opt to get the surgery prenatally," says Levey. "The surgery is now only being offered to women enrolled in the study." Two hundred women carrying babies with spina bifida will be enrolled during the five-year study. Half will be randomly selected to have prenatal surgery to be done between weeks 19 and 25 of the pregnancy and the other half will have postnatal surgery at 37 weeks of pregnancy.
For more information on this study, visit www.spinabifidamoms.com
According to Katz, it is important to appreciate the differences between the management of spina bifida and other disorders from a clinical perspective. "There are three key differences: the lack of sensation; bowel and bladder control; and joints, unbeknownst to the patient, that can be damaged due to lack of support," he says. "They may have the same muscle weakness as, for instance, a post-polio patient, but due to their lack of sensation, meticulous care of their skin can be an enormous challenge. Fighting infections can be a major concern."
Katz explains that because of the lack of sensation, it is easy for patients to damage their joints without knowing. "The gait deviationdue to weakness across the hip joint creates a gait pattern that can place a significant torque on the knee joint which can result in damagethat may not be fully realized until later in life." Observational gait analyses and checking for sores are important ways parents and physicians can help patients.
For Levey, increasing the quality of life for patients with spina bifida is as important as treating the medical condition. "Two key elements to their happiness and success are ambulation and bowel and bladder control," he explains. "Sometimes it's better for them to be in a wheelchair than to expend so much energy on walking. About 70 percent of adults with spina bifida say the number one thing that affects their quality of life is bowel and bladder control."
Levey explains, "There are multiple people involved in the decision about bracing. We all work together to provide stability and improve function while preventing deformity and accommodating a developing child."
Dias agrees, "The management of spina bifida is unique relative to that of cerebral palsy or other neuromuscular problems." He adds, "The most important problem they have from the orthopedic standpoint is muscle weakness—not spasticity. They don't have normal sensation, and they can develop deformities that affect function."
Though surgeries are similar to those that treat cerebral palsy patients, Dias says the post-operative care is much easier for spina bifida patients because they don't have to deal with balance or spasticity problems. "Most patients do quite well in regaining strength after surgery, and post-operative pain is not a factor since they lack normal sensation."
As a result of the unified efforts of several specialists and informed parents, Michael Doyle can make his way around his preschool without the use of a walker or crutches. He even plays baseball and can kick a soccer ball. "We balance making modifications for him with letting him make choices for himself," Helen says. He currently takes medication three times a day and is catheterized every three hours to help control his bladder and bowel function. By the time he is in kindergarten, he will be able to self-catheter.
Doyle summarizes, "Because this disease runs the gamut, everyone is different. We don't let his disability define him or get in the way of his goals."
Prevalence of Latex Allergies
Research has shown that up to 73 percent of children and adolescents with spina bifida are sensitive to latex. The cause of the allergy currently is unknown, though many think it is a result of early and repeated exposure to latex during corrective surgeries, doctor examinations, and bladder catheterizations.
Levey, in a joint effort with Robert Hamilton, PhD, D.ABMLI, a world expert on this type of allergy, is testing blood samples from children with spina bifida to determine the current prevalence of latex allergy and to determine whether there is a genetic predisposition to the allergy.
Because latex is found in a variety of everyday items, people with spina bifida and parents of children with the defect must take great precautions. Items that contain latex include medical and surgical gloves, urinary catheters, band aids, balloons, beach toys, art supplies, and pacifiers. Allergic reactions to latex include typical symptoms such as watery and itchy eyes, sneezing, coughing, rashes, swelling of the windpipe, and wheezing, but can also be more serious, even life-threatening.
"The incidence of latex allergy in spina bifida is so high that every surgery that is done—orthopedic, neurosurgical, urological—is done in a latex-free environment," says Luciano Dias, MD, chief of Orthopaedics in the Spina Bifida Clinic at Children's Memorial Hospital, Chicago, Illinois.
For more information on spina bifida, visit www.sbaa.org
, the official website of the Spina Bifida Association.
Sherry Metzger, MS, is a freelance writer with degrees in anatomy and neurobiology. She is based in Westminster, Colorado, and may be reached at firstname.lastname@example.org