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Syringomyelia (sear-IN-go-my-EEL-ya) is a disorder in which a cyst forms within the spinal cord. This cyst, called a syrinx, expands and elongates over time, destroying a portion of the spinal cord from its centre and expanding outward. As a syrinx widens it compresses and injures nerve fibres that carry information from the brain to the extremities. Damage to the spinal cord often leads to progressive weakness in the arms and legs, stiffness in the back, shoulders, arms, or legs, and chronic, severe pain. Other symptoms may include headaches, a loss of the ability to feel extremes of hot or cold (especially in the hands), and loss of bladder and other functions. Each individual experiences a different combination of symptoms depending on where in the spinal cord the syrinx forms and how far it extends. Signs of the disorder tend to develop slowly, although sudden onset may occur with coughing or straining. Many disorders share the early symptoms of Syringomyelia, which also can occur in association with other conditions such as multiple sclerosis and Fibromyalgia. Estimates of the number of Americans with Syringomyelia vary widely, but a conservative estimate is that over 100,000 people in the United States are affected, with symptoms usually beginning in young adulthood.
In some individuals it may be necessary to drain the syrinx, which can be accomplished using a catheter, drainage tubes, and valves. This system is known as a shunt. Shunts are used in both the communicating and non-communicating forms of the disorder. First, the surgeon must locate the syrinx. Then, the shunt is placed into it with the other end draining the syrinx fluid into a cavity, usually the abdomen. This type of shunt is called a syringoperitoneal shunt. A shunt of CSF from the brain to the abdomen is called a ventriculoperitoneal shunt and is used in cases involving hydrocephalus. By draining syrinx fluid or CSF, a shunt may halt the progression of symptoms and relieve pain, headache, and tightness. Without correction, symptoms generally continue.
How is Syringomyelia diagnosed?
Diagnostic imaging has significantly increased the number of Syringomyelia cases detected in the beginning stages of the disorder. Physicians primarily use magnetic resonance imaging (MRI) to diagnose Syringomyelia. Computer-generated radio waves and a powerful magnetic field produce images of body structures, such as the brain and spinal cord, in vivid detail. This test will show the syrinx in the spine as well as other conditions, such as the presence of a tumor. Images taken in rapid succession can be used for “dynamic imaging” (in “cine mode”) to observe the fluid flowing around the spinal cord and within the syrinx. Computed tomography (CT), which uses x-rays and a computerized scanner to produce cross-sectional images of the body or an organ structure, may reveal the presence of tumors and other abnormalities such as hydrocephalus. Another test, called a myelogram, takes x-ray-like pictures and requires a contrast medium or dye to do so. Since the introduction of MRI this test is rarely necessary to diagnose Syringomyelia.
What research is being done?
Scientists at the National Institute of Neurological Disorders and Stroke (NINDS) in Bethesda, Maryland, and at grantee institutions across the country continue to explore the mechanisms that lead to the formation of syrinxes in the spinal cord. For instance, Institute investigators have found that as the heart beats, the syrinx fluid is abruptly forced downward. They have also demonstrated the presence of a block to the free flow of CSF that normally occurs in and out of the head during each heartbeat. In the past decade, clinicians and researchers used this new understanding to improve the standard of care for people who experience loss of function due to expanding syrinxes. They are now studying how syrinxes first form in disorders known to produce Syringomyelia. In some cases, chronic enlargement or tethering of the spinal cord and other changes might be detected earlier than is currently the case, allowing surgical treatment before loss of function becomes permanent.
NINDS scientist-physicians are conducting clinical studies at the NIH to learn more about the mechanisms of Syringomyelia, for example, how abnormal CSF flow contributes to the progression of the disorder. In these studies individuals with progressive Syringomyelia undergo clinical procedures and research tests as well as standard surgical care for the disorder. Studies are under way to better understand the genetic factors related to a Chiari I malformation. Individuals with a Chiari I malformation who also have a family member with either the abnormality or Syringomyelia are being studied to discover the location of the gene(s) responsible for the malformation. It is also important to understand the role of birth defects in the development of hindbrain malformations that can lead to Syringomyelia. Learning when these defects occur during the development of the fetus can help us understand this and similar disorders, and may lead to preventive treatment that can stop the formation of many birth abnormalities. Dietary supplements of folic acid during pregnancy have been found to reduce the number of cases of certain birth defects. Diagnostic technology is another area for continued research. MRI has enabled scientists to see conditions in the spine, including Syringomyelia, even before symptoms appear. A new technology known as dynamic MRI allows investigators to view spinal fluid pulsating within the syrinx. Other diagnostic tests have also improved greatly with the availability of new, non-toxic, contrast dyes. Improved techniques are expected to become available in the future from the research efforts of scientists today.
What causes Syringomyelia?
A watery, protective substance known as cerebrospinal fluid (CSF) normally flows around the spinal cord and brain, transporting nutrients and waste products. It also acts as a cushion to protect the brain and spinal cord. In early development, CSF also fills a small canal that runs through the centre of the spinal cord—the central canal—which then collapses normally over time. A number of things can cause an obstruction in the normal flow of CSF, redirecting excess fluid into the spinal cord and central canal. This redirected CSF accumulates within the tissue of the spinal cord and forms a fluid-filled syrinx. Pressure differences along the spine cause the fluid to move within the syrinx and outside the spinal cord. Physicians believe that this continual movement of fluid in and around the spinal cord results in cyst growth and further damage to the spinal cord tissue.
How is Syringomyelia treated?
Surgery is an option for some but not all cases will result in surgery. Patients are monitored until surgery is required. The type of surgery and its location depend on the type of Syringomyelia. In Chiari malformation, the main goal of surgery is to provide more space at the base of the skull and upper neck, without entering the brain or spinal cord. This may result in the primary cyst becoming much smaller. Surgery may result in stabilization or modest improvement in symptoms for most individuals with Chiari malformation. Delay in treatment may result in irreversible spinal cord injury. Recurrence of Syringomyelia after surgery may make additional operations necessary; these may not be completely successful over the long term.
Syringomyelia Facts Sheet
The decision to use a shunt requires extensive discussion between the surgeon and the individual, as this procedure carries with it the risk of injury to the spinal cord, infection, blockage, or hemorrhage and may not necessarily work for all people. If a tumor is causing Syringomyelia, removing the tumour is the treatment of choice and almost always eliminates the syrinx.In the case of trauma-related Syringomyelia, the preferred surgical approach is to operate at the level of the initial injury to expand the space around the spinal cord and decrease fluid volume.This operation is performed outside the spinal cord. An alternate operation is to place a shunt in the syrinx, which requires a hole to be made in the spinal cord. Shunts may injure the spinal cord and may require replacement if they clog over time. Many surgeons now consider shunt placement only as a last resort. Instead, surgeons usually choose to expand the space around the spinal cord. This is done by removing scar tissue that “tethers” the cord in place and prevents the free flow of CSF around it, and adding a patch to expand the “dura,” the membrane that surrounds the spinal cord and contains the CSF (a procedure called expansive duraplasty). In some cases, the vertebrae may need to be realigned to correct spinal deformity that is narrowing the spinal column. Many spinal cord-injured individuals have a cyst at the site of the original injury. These cysts do not always require treatment, although treatment may be warranted if a cyst grows larger or begins to cause symptoms. Drugs have no curative value as a treatment for Syringomyelia but may be used to manage pain. In the absence of symptoms, Syringomyelia is usually not treated. In addition, a physician may recommend not treating the condition in individuals of advanced age or in cases where there is no progression of symptoms. Whether treated or not, many individuals will be told to avoid activities that involve straining.