What Is It?
Spinal dysraphism is a very general term for a family of congenital malformations of the spine and spinal cord. Most of these types of spinal anomalies are also known as neural tube defects
because they arise when the normal formation and development of the neural tube, which gives rise to the brain and spinal cord in development, does awry. These abnormalities of development generally occur at the early embryonic stages of development when the nervous system is first developing. Therefore, these are congenital malformations, meaning that patients are born with them.
The actual types of spinal malformations included in the general term spinal dysraphism vary quite dramatically. Their affect on an individual can vary tremendously as well. While some are very subtle anomalies which may go un-noticed and without causing symptoms, others can have severe, debilitating effects on the functioning of the spinal cord and lead to considerable dysfunction.
This class of disorders has several types. Some of the forms of spinal dysraphism include:
- Spina Bifida: Spinal bifida is a general term for malformations where the neural tube does not close completely and the lowest portion of the spine and/or spinal cord have abnormalities. It can vary from quite subtle and asymptomatic (spina bifida occulta) to severe with a major deformity and neurological symptoms (myelomeningocele).
- Spina Bifida Occulta: The most subtle and minor form of spina bifida, spina bifida occulta only results in a minor malformation of the back part of the spinal bones, the vertebra.
- Meningocele: A more severe form of dysraphism, the spinal cord is generally normal but the overlying coverings of the spinal cord develop abnormaly.
- Myelomeningocele: The most severe form of spina bifida, myelomeningocele represents abnormal development of all the coverings behind the end of the spinal cord as well as abnormalities of the spinal cord itself.
- Diastematomyelia: This form of spinal dysraphism results in a spinal cord which is split down the middle, usually in the lower back, into two "hemi-cords".
- Spinal Dermal Sinus: This is an abnormal connection between the skin and the deeper structures of the spine which can cause infection or other problems if it involves the spinal canal.
- Spinal Lipoma: Abnormal development of fat cells leads to a fatty mass (lipoma) in the spine which can involve the spinal cord itself.
- Tethered Cord: A tethered cord is a spinal cord which is tethered, or stuck, down toward the tail end of the spine and does not move up appropriately during development and growth. This can occur primarily because of abnormalities in the development in the end of the spinal cord, such as a thickened filum terminale or it may occur as the result of scarring or other tethering from other forms of spinal dysraphism in the area and/or its treatment.
What Types of Symptoms Are Typical?
The symptoms of spinal dysraphisms of the spine are quite varied and are therefore hard to generalize. They depend heavily on the type of malformation and the extent or severity of the malformation. In general, smaller malformations have less of an affect on neurological function. Spina bifida occulta is called "occult" because it is hidden. It generally has no symptoms and the individual does not even know if they have it.
More severe malformations may affect the function of the spinal cord. Most occur low in the spinal cord and therefore, if they cause symptoms, will primarily affect neurological functioning of the lower extremities (legs) and sometimes bowel and/or bladder function. In the most severe cases of myelomeningocele, spinal lipoma and others, there may be no neurological functioning of the legs, including a complete lack of sensation and motor function (paralysis). Bowel and bladder dysfunction can also cause incontinence and other problems with bowel and bladder function.
Besides the functional effects of these malformations, some may have physical effects as well which can be seen superficially. In some malformations which do not present significantly to the surface of the skin, there may be more subtle stigmata of the underlying dysraphism, generally in the lower back. This can include a pronounced dimple in the skin near the midline of the back, a patch of dense hair, a birthmark, or a visible or palpable lump. In the most severe malformations, such as significant meningocele and myelomeningocele, there is a large bulging sac hanging out of the back.
How Is The Diagnosis Typically Made?
The more severe spinal dysraphisms are generally obvious at birth. Meningocele and myelomeningocele generally have a hard defect and sac bulging from the back. Dermal sinuses, lipoma and diastematomyelia may be more subtle but will often present with some stigmata on the midline skin of the back superficial to the malformation, as discussed above. For this reason, physicians generally inspect the back of newborn infants for any suspicious findings in the area.
If an anomaly is seen visibly or suspected based on the presence of a stigmata or neurological symptoms in the legs, further work-up often involves imaging studies such as MRI to assess the deeper structures of the spine and the spinal cord itself. These can help to diagnose the dysraphism and distinguish the different types from each other. It can also help to guide treatment, if it is indicated.
What Are Some Common Treatments?
Treatments vary depending on the type and severity of the malformation. Very subtle malformations, such as spina bifida occulta will often require no treatment and do not cause symptoms. More severe malformations may require surgical treatment to prevent complications of the malformation (such as infection, further damage to the spinal cord, etc.) or to attempt to maximize and preserve neurological function. In some cases where tethering of the cord becomes an issue, un-teathering procedures may be required during the growth and development of the individual to prevent traction on the spinal cord and further injury.
Patients with significant spinal cord involvement may have long-lasting neurological problems and may need multiple treatments during their life. Bowel and bladder complications can be frequent and many patients, particularly those with myelomeningocele, also have Type II Arnold-Chiari Malformation and/or hydrocephalus, which may require separate treatments itself.
All these treatments are quite varied and depend heavily on the specifics of each case, the type of anomaly, its location and its extent. Therefore, general guidelines on treatment cannot be given. Each patient should consult their own treating physicians to be counseled about the management options that apply to their unique case.
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This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.