Syringomyelia is a disorder in which a cyst forms within a person's spinal cord. The cyst, referred to as a, 'syrinx,' expands and elongates over a period of time and destroys a part of a person's spinal cord from its center and expands outward. As a syrinx widens it compresses and inures a person's nerve fibers that carry information from their brain to their extremities.
Syringomyelia is defined as a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord. This cyst, called a syrinx, can expand and elongate over time, destroying the spinal cord. The damage may result in pain, paralysis, weakness, and stiffness in the back, shoulders, and extremities. Syringomyelia may also cause a loss of the ability to feel extremes of hot or cold, especially in the hands. The disorder generally leads to a cape-like loss of pain and temperature sensation along the back and arms. Each patient experiences a different combination of symptoms. These symptoms typically vary depending on the extent and, often more critically, to the location of the syrinx within the spinal cord.
Damage to the person's spinal cord many times leads to progressive weakness in their legs and arms, stiffness in the person's arms, shoulders or legs, as well as chronic and severe pain. Additional symptoms might include:
Each person experiences a different combination of symptoms, depending on the location of the syrinx in their spinal cord and how far it extends. Signs of the disorder often develop slowly, although sudden onset might happen with straining or coughing.
Several disorders share the early symptoms of syringomyelia, which may also occur in association with other conditions. Estimates of the number of Americans with syringomyelia differ greatly, yet a conservative estimate is that around 40,000 people in America are affected, with symptoms commonly starting in young adulthood. At times, syringomyelia occurs in more than one member of the same family, although it is rare.
A watery and protective substance known as, 'cerebrospinal fluid (CSF),' usually flows around a person's spinal cord and brain, transporting nutrients and waste products. CSF also acts as a cushion to protect the spinal cord and brain. In early development, CSF also fills a small canal that runs through the center of a person's spinal cord, the central canal, which then collapses over time.
Several medical conditions may cause an obstruction in the usual flow of CSF and redirect excess fluid into a person's spinal cord and central canal. The redirected CSF accumulates within the tissue of the person's spinal cord and forms a fluid-filled syrinx. Pressure differences along the person's spine cause the fluid to move within the syrinx and outside the spinal cord. Doctors believe the continual movement of fluid in and around the spinal cord results in cyst growth and additional damage to the person's spinal cord tissue.
In general, there are 2 forms of syringomyelia. Most of the time, the disorder is related to an abnormality of the brain called a, 'Chiari I malformation,' named after one of the doctors who first characterized it. The anatomic abnormality causes the lower part of a person's cerebellum to protrude from its usual location in the back of the head into the cervical or neck portion of their spinal canal. A syrinx might then develop in the cervical region of the person's spinal cord.
Due to the relationship that was once believed to exist between the brain and spinal cord of this form of syringomyelia, doctors at times refer to it as communicating syringomyelia. Symptoms commonly start between the ages of 25-40 and might worsen with straining or any activity that causes CSF pressure to fluctuate suddenly. Some people; however, might experience extended periods of functional stability. Others with this form of the disorder also have hydrocephalus, in which CSF accumulates in the brain, or a condition called, 'arachnoiditis,' in which a covering of the spinal cord is inflamed.
The second major form of syringomyelia happens as a complication of meningitis, trauma, a tumor, hemorrhage, or arachnoiditis. With this form, the syrinx or cyst develops in a segment of a person's spinal cord that has been damaged by one of these conditions. The syrinx then begins to expand. At times this is referred to as, 'non-communicating syringomyelia.' Symptoms might appear months or years after the initial injury beginning with pain, weakness and sensory impairment originating at the site of trauma.
The main symptom of post-traumatic syringomyelia is pain unfortunately, which might spread upward from the site of injury. Symptoms such as numbness, pain, weakness and disruption in temperature sensation can happen on one or both sides of a person's body. Syringomyelia may also adversely affect a person's sweating, sexual function, bladder and bowel control.
Syringomyelia might also involve a part of the brain called the brainstem. The brainstem controls a number of our vital functions such as heartbeat and respiration. When syrinxes affect a person's brainstem, the condition is referred to as, 'syringobulbia.'
Diagnostic imaging has significantly increased the number of people with syringomyelia detected in the beginning stages of the disorder. Doctors mainly use magnetic resonance imaging (MRI) to diagnose syringomyelia. Computer-generated radio waves and a powerful magnetic field produce images of a person's body structures, such as their brain and spinal cord, in exceptional detail. The test shows the syrinx in the spine and other conditions, such as the presence of a tumor.
Images taken in rapid succession may be used for, 'dynamic imaging,' to observe the fluid flowing around a person's spinal cord and within the syrinx. Computed tomography (CT), which uses x-rays and a computerized scanner to produce cross-sectional images of the person's body or an organ, may show 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. Since the introduction of MRI this test is rarely needed to diagnose syringomyelia.
Surgery is usually recommended for people with syringomyelia. The type of surgery and its location depend on the type of syringomyelia the person experiences. In Chiari malformation, the main goal of surgery is to provide more space at the base of the person's skull and upper neck without entering their brain or spinal cord. Doing so results in the primary cyst becoming much far smaller. Surgery results in stabilization or modest improvements in the symptoms most people with Chiari malformation experience. Delay in treatment might result in irreversible spinal cord injury. A recurrence of syringomyelia after surgery might make further operations necessary, although these may not be completely successful over the long-term.
In some people it might be necessary to drain the syrinx, which can be dome using a catheter, drainage tubes and valves. The system is known as a, 'shunt.' Shunts are used in both the communicating and non-communicating forms of the disorder. The surgeon must first locate the syrinx. The shunt is then placed into it with the other end draining the syrinx fluid into a cavity, usually the person's abdomen. A shunt of this type is called a, 'syringoperitoneal shunt.'
A shunt of CSF from a person's brain to the abdomen is called a, 'ventriculoperitoneal shunt,' and is used when hydrocephalus is involved. By draining syrinx fluid or CSF, a shunt may halt the progression of symptoms while relieving pain, tightness and headache. Without correction, the person's symptoms usually continue.
The decision to use a shunt requires extensive discussion between the surgeon and the person involved because the procedure carries the risk of injury to the person's spinal cord. It also presents the risk of infection, blockage, or hemorrhage and might not necessarily work for everyone. If a tumor is causing syringomyelia, removal of the tumor is the treatment of choice and nearly always eliminates the syrinx.
With trauma-related syringomyelia, the preferred surgical approach is to operate at the level of the initial injury to expand the space around the person's spinal cord and decrease fluid volume. The operation is performed outside the spinal cord. An alternate operation is to place a shunt in the syrinx itself, which requires a hole to be made in the person's spinal cord.
Shunts might injure the spinal cord and may require replacement if they become clogged over time. A number of surgeons now consider shunt placement as a last resort. Instead, surgeons commonly choose to expand the space around a person's spinal cord. They accomplish this by removing scar tissue that tethers the cord in place and prevents the free flow of CSF. In some instances, the vertebrae might need to be realigned to correct spinal deformity that is narrowing the person's spinal column.
A number of people with spinal cord injuries have a cyst at the site of their original injury. The cysts do not always require treatment, although treatment might be warranted if a cyst grows larger, or starts to cause the person symptoms. Drugs have no real curative value as a treatment for syringomyelia, although they may be used to ease pain. Radiation is rarely used and is of little benefit, except in the presence of a tumor. In these instances, it may stop the extension of a cavity and might help to alleviate the pain a person is experiencing.
If a person is not experiencing any symptoms, the syringomyelia they experience is usually not treated. A doctor might recommend not treating the condition in people who are older, or in instances where there is no progression of symptoms. Whether treated or not, many people will be told to avoid activities that involve straining.
Syringomyelia was once thought be extremely rare with early estimates of only 20,000 people in the U.S. having it. Increased use of MRI has since shown that syringomyelia is more common and, while there has not been a rigorous study to determine how many people have it, a Duke University analysis estimates that between 100,000 - 200,000 people in the US may have syringomyelia.