Syringomyelia is a condition in which a syrinx (a cyst, or collection of fluid) forms in the spinal cord.
The fluid inside the syrinx is called cerebrospinal fluid. Normally, cerebrospinal fluid flows around the outside of the brain and spinal cord, bathing and cushioning them. When the flow of cerebrospinal fluid is blocked, however, some of the excess fluid can enter the spinal cord. This is the beginning of a syrinx. Untreated, syrinxes tend to expand over time, though some remain stable or even disappear. Unfortunately, it is not always clear which course a syrinx will follow.
Syringomyelia is also known as hydromyelia.
A syrinx can compress the nerves of the spinal cord. Specific symptoms depend on where the syrinx is located and how much it compresses the nerves. Possible symptoms include weakness of hands and arms, numbness to temperature, pain in the back and neck, scoliosis (curvature of the spine), stiffness, pain, and incontinence. Symptoms usually appear gradually.
Symptoms may also appear because of the underlying cause of the syrinx. For instance, a syrinx may be caused by a Chiari Malformation, which can cause headaches or neck pain..
Causes and Risk Factors
Syringomyelia can also be caused by damage to a previously healthy spinal cord. This damage can be caused by trauma, meningitis (an infection in the spinal cord membranes), arachnoiditis (inflammation and scarring of the spinal cord membranes), hemorrhage (bleeding), or other problems.
In some cases, there is not a clear cause. These are called cases of “idiopathic” syringomyelia.
Tests and Diagnosis
If a patient presents with symptoms associated with syringomyelia, the surgeon may order a magnetic resonance imaging (MR) scan. MR scans use a combination of large magnets, radio waves, and a computer to produce detailed images of organs and structures within the body. A special type of MR called a cine MR may also be useful. More like a video than a still image, the cine MR can show the movement of cerebrospinal fluid. Computed tomography (CT) scan can also be useful. They use a computer and multiple X-rays to produce detailed images of bones and soft tissues. They can help diagnose syrinxes, tumors (occasionally a cause of syringomyelia), or hydrocephalus (a buildup of cerebrospinal fluid in the brain).
In many cases, a syrinx causes no symptoms and may need no treatment. But if the syrinx causes problems such as injury to the spinal cord or progressive scoliosis, it must be treated surgically.
The following courses of treatment are options in treating syringomyelia:
- Treat the underlying cause. In the cases where hydrocephalus or Chiari malformation are causing the syrinx, the surgeon will treat the underlying cause and the syrinx will usually shrink or disappear. For patients with spinal cord tumors, removal of the tumor will usually also result in resolution of the syrinx.
- Drain the syrinx. To drain the syrinx, the surgeon may choose to use either a stent or a shunt. A stent will drain the fluid from inside the syrinx to the cerebrospinal fluid space just outside the spinal cord. A shunt will drain the fluid to another body cavity, such as the chest or abdomen.
- Treat the underlying cause and drain the syrinx. The surgeon may choose to combine the above options by treating the underlying cause and draining the syrinx during the same operation.