Spina Bifida Occulta

What Is It?

Spina Bifida Occulta is a congenital malformation of the developing spinal column which usually is asymptomatic and does not present medical problems.

The developing nervous system forms from a sheet of cells in the embryo which fold on themselves to form a tube, the neural tube. Normally, this tube closes off completely. However, in some cases the closure and normal development of the neural tube does not proceed correctly. In general, the malformations that result from this abnormality in development are termed spina bifida. However, the resulting malformation can vary from mild and innocuous to very severe and life-threatening. Spina bifida occulta represents the most mild form of spina bifida.

Occulta comes from the same word root as occult, which can mean "cut off from view by interposing something". This form of spina bifida is called occult because it is not obvious by just examining a patient. More severe forms of spina bifida are far from occult, being very obvious on physical examination of the patient's back. Therefore, this term is used to describe these most mild and hard to detect forms of spina bifida.

This form of spina bifida involves just the bony part of the spine. The actual nervous system structures, the spinal cord and spinal nerves, and the coverings of the spinal cord, all develop normally. The only malformation is an incomplete closure of the bone overlaying the back side of the spinal canal. This defect in the bone generally just occurs at one small level in the lower back.

What Types of Symptoms Are Typical?

In true spina bifida occulta, the patient generally has no symptoms. As mentioned above, the malformation does not involve the spinal cord or spinal nerves.

Some patients who learn they have it worry that they will be paralyzed by damage to the spinal cord through the opening in the bone. They worry that pushing too hard on their back will cause injury. However, the spinal cord and spine are not right at the surface. There is muscle and other soft-tissues separating the skin of the back from the spinal column. Additionally, these openings are generally very small. As a generalization, injury associated with these malformations is very rare.

In rare cases the bony abnormality may be more severe and/or associated with other abnormalities of the spine. For example, a spinal cord lipoma (a fatty tumor) or cyst can present along with the bony defect. These cases are generally termed an occult spinal dysraphism rather than spina bifida occulta.

How Is The Diagnosis Typically Made?

Spina bifida occulta is relatively common. However, most people never know they have it unless they have imaging studies of the back for some other reason. It is often diagnosed when a patient, child or adult, has an x-ray, CT scan or MRI scan of the lower back. The opening in the bone can be visualized on most of such imaging studies.

In some cases, particularly those with more severe malformations such as a spinal dysraphism, some small stigmata of the disorder will be visible on the skin of the back over the area. This can be a small dimple, a tuft of hair or other abnormality. However, in many cases of pure spina bifida occulta there is no obvious superficial mark.

What Are Some Common Treatments?

True, pure spina bifida occulta which does not cause any symptoms generally does not require any treatment.

In the case of more severe malformations of the spine or spinal cord, treatment may be necessary to deal with the deformity or to prevent deterioration of neurological functioning. Each case should be assessed and discussed with the patient with a qualified physician.

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Important Note: 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.

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