Managing spina bifida

In this video, you'll learn the critical elements of caring for children with spina bifida and when to seek specialist support.

Gary R. Simonds, MD MHCDS FAANS
Gary R. Simonds, MD MHCDS FAANS
14th Dec 2020 • 6m read

Spina bifida is a bit of a catch-all term for an array of disorders related to embryonic spinal development. But it's important to differentiate between these disorders in order to manage severe cases and recognize more subtle ones. In this video, you'll learn the critical elements of caring for children with spina bifida and when to seek specialist support.

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Video transcript

Spina bifida is a bit of a catch all term that encompasses an array of disorders of embryonic spinal development. It's important however to understand how to manage severe cases, and to recognize more subtle ones. Spina bifida, or spinal dysraphism encompasses a span of disorders that involve the incomplete development of the spine and its contents.

In its most severe form the entire neuroaxis may be poorly formed, and completely without any of its coverings. That is dura, bone, muscles, subcutaneous tissue and skin. This is incompatible with life. In a somewhat less severe form of spina bifida, a myelomeningocele occurs when the most distal portions of the spine in the spinal cord have not fully formed, and the baby is born with the distal end of the spinal canal open, and often leaking spinal fluid.

With the advent of prenatal vitamins, and prenatal testing, myelomeningoceles are less common than they once were decades ago. But it's still an entity that most pediatricians and primary care practitioners will encounter. Below the spinal cord level of the malformation, there is no neurological function.

Thus, the larger the deformity and the higher it extends up the back, the greater the neurological deficits. Myelomeningoceles must be repaired surgically to cover the exposed spinal cord. This is usually performed within 36 hours of birth, or in rare cases, prenatally. This does not restore neurological function, but prevents progressive loss of function, meningitis, and a high likelihood of death.

The least severe forms of spina bifida involving complete formation of the spinous process, and, or lamina of the vertebrae, in a small section of the spine. This is known as spina bifida occulta and occurs in five to 10 percent of the population, and is not associated with any neurological signs or symptoms.

There's a whole spectrum of other disorders between spina bifida occulta and myelomeningocele. The care of a child or adult with a history of myelomeningocele is complicated, and most efficiently provided through multidisciplinary spina bifida clinics. But primary care physicians should be aware of the following considerations.

The myelomeningocele defect is closed surgically at, or prior to birth, but may be problematic through the years. Particularly during growth spurts due to sticking down of the spinal cord to the surrounding tissues at the level of the repair. A phenomenon known as tethering of the spinal cord. In every visit, ask about increasing back pain, and progressive loss of lower extremity function.

Both potential signs of tethering. Assume that a patient who goes from ambulatory with braces to needing a wheelchair has a tethered spinal cord until proven otherwise. Examine and record strength in the upper and lower extremities, and compare this with previous visits. Also, look for progressive foot deformities such as clubfoot, pes cavus, or pes valgus.

These can be signs of a tethered spinal cord. Consult neurosurgery if you're concerned. The cord can be surgically detethered, and progressive loss of neurological function can be halted. Patients with myelomeningocele will have baseline neurological and urological deficits, such as a neurogenic bladder. Repeated straight catheterization is the rule.

They should be followed by specialized urologists, and may need diversion procedures. Make sure they routinely see physical and occupational therapists. Patients frequently require adjustments and upgrades of adaptive equipment. Most patients with myelomeningocele will have a ventriculoperitoneal shunt in place for hydrocephalus. Get to know the shunt and its history.

Often shunt failure is less dramatic than in other hydrocephalus patients, and may manifest itself as diminished school performance, diminished overall function and, or complaints of pain. An old adage is that no matter what a myelomeningocele patient is complaining of, suspect the shunt. Obtain imaging of the brain when in doubt. Myelomeningocele patients all have Chiari malformations at the craniovertebral junction.

The Chiari malformation is a malformation of the posterior fossa and its contents. It results in a series of findings, including kinking of the medulla, and a significant amount of cerebellar tissue projecting through the foramen magnum and compressing the brainstem and spinal cord to one degree or another. In infants, brainstem compression can cause severe brainstem and cranial nerve dysfunction.

Respiratory stridor, aspiration, and apneic spells may result. In such cases the Chiari malformation may be surgically decompressed, but prognosis can still be very guarded. In older children, and in adults, Chiari malformations are often asymptomatic. They can, however, cause cavitation of the spinal cord, known as the syrinx, potentially causing significant dysfunction.

When evaluating for symptomatic Chiari malformation in syrinx, look for signs of spinal cord and brainstem dysfunction. Ask about progressive upper extremity dysfunction, loss of coordination and progressive loss of lower extremity function. Ask about swallowing difficulties, and aspiration, indicating lower cranial nerve dysfunction.

Obtain an MRI of the cervical and thoracic spinal cord. The syrinx may extend well into the thoracic spine. Progressive scoliosis is not uncommon in myelomeningocele patients. This and other orthopedic considerations such as contractures, and hip dislocations makes it invaluable to have the patient evaluated periodically by a pediatric or adult orthopedist, and, or a scoliosis specialist.

Many myelomeningocele patients, both children and adults, have seizures or other neurological disorders. Routine follow up with neurologists is recommended. Patients with myelomeningocele may have associated pulmonary, cardiac, renal and gastrointestinal disorders. Follow their general medical conditions as well as their neurological conditions.

Latex allergy is common in patients with myelomeningocele, and can be severe. This can be particularly concerning at the time of any surgery. Avoid the use of latex around myelomeningocele patients at all times. What about the other forms of spina bifida that we discussed? Most will be asymptomatic, but some will be symptomatic.

Other forms of symptomatic spina bifida are less traumatic than myelomeningocele, that can be disabling. These entities will carry a risk of tethering of the spinal cord, which may result in progressive neurological dysfunction over time, particularly during growth spurts. Patients experiencing symptomatic cord tethering may present with progressive back pain, urinary dysfunction, numbness and, or weakness in the legs, progressive scoliosis, progressive foot deformities, trophic skin changes in the legs, gait difficulties, muscle atrophy in the legs, and shortening of the legs.

Any patients with suspected tethering of the spinal cord should undergo MRI of the lumbar spine. Children discovered to have tethering of their spinal cord by imaging should be referred to neurosurgery for detethering procedures, whether they are symptomatic or not. Adults may only require monitoring, if they're asymptomatic.

They won't have growth spurts to go through. If a tethered cord patient presents with urinary dysfunction, obtain a urology consult, and urinary dynamic evaluation. Of course, do a thorough general physical and neurological exam. Remember to inspect the patient's back. Most symptomatic spina bifida patients will have cutaneous clues. Look for a nontender lump of fatty tissue under the lumbar skin.

This would suggest a lipomyelomeningocele in which has subcutaneous fatty mass extends down through a defect in the lamina and the dura, and into the end of the spinal cord tethering it. If you observe a fatty mass under the lumbar skin, order an MRI of the lumbar spine. A cutaneous meningioma or discoloration in the lumbar midline skin, with or without a patch of hair, may signify spinal bifida and tethering.

Such a finding particularly if associated with signs and symptoms of tethered spinal cord, should precipitate an MRI evaluation of the lumbar spine, or an ultrasound of the same region if you're dealing with an infant. Also, look for a one to two millimeter wide dimple or sinus in the lower midline skin of the lumbosacral region.

There may be associated discoloration or hair growth. Do not probe this lesion. This may represent a dermal sinus tract that stretches all the way into the spinal cord. They are a direct communication with the nervous system and can result in nervous system infection. If you suspect a dermal sinus tract, retract the edges of the lesion. If it has no definable bottom or end, order an MRI or an ultrasound in a newborn. If the track proves to extend to the spinal cord, it needs to be addressed surgically by a neurosurgeon.