Syringomyelia (SM) is a generic term referring to a condition where a syrinx (fluid filled cyst or cavity) develops in a segment of the spinal cord. This cyst can expand or elongate over time destroying the center of the cord. SM can be due to a congenital condition or as a result of trauma, meningitis, hemmorage or tumor. There are two forms of SM called communicating and noncommunicating.
SM and it’s Relation to Chiari Malformation
This type of syringomyelia called communicating SM develops as a result of a Chiari 1 malformation. Chiari, in which the cerebellar tonsils (lower part of the cerebellum) descend into the foramen magnum, causes obstruction to the flow of cerebrospinal fluid (CSF). The CSF is redirected to the spinal cord. Pressure differences along the spine cause the fluid to move within the cord. It is believed this movement can cause a syrinx due to the blockage of CSF. It is called communicating because of the relationship that was once thought to exist between the brain and spinal cord in this type of Chiari.
Noncommunicating SM occurs as a complication of trauma, meningitis, hemorrhage or tumor. The cyst or syrinx develops in a segment of the spinal cord damaged by one or more of these conditions.
Syringomyelia and Scoliosis
According to Robert P. Stanton, M.D., it is not known at this time the way in which SM produces a scoliosis. Many patients with SM do not have scoliosis and most with scoliosis do not have SM.
There are, though, interesting signs that can help in alerting to the possibility of SM if one has a scoliosis. The first is rapid progression of the curve, another is a left thoracic scoliosis. In most cases the curves of scoliosis are concave to the right which means the spine deviates toward the right side of the body. In the case of SM the opposite deviation, that is to the left, is the most common. As was mentioned above, another complication of syringomyelia and scoliosis is Chiari. Before the advent of MRI, SM and Chiari were difficult to diagnosis. Fortunately now, before surgery for scoliosis an MRI is performed to rule out SM and Chiari. In some cases treatment of scoliosis without recognition of SM and Chiari could and can lead to paraplegia.
The treatment in these cases is decompression of the Chiari which in some cases halts the progression of the scoliosis and reduces the size of the SM.
Symptoms of Syringomyelia
Symptoms of SM include back pain; headache (especially if straining, sneezing or coughing); stiffness, weakness or pain in the back, shoulders, arms and/or legs; loss of the ability to feel extremes of hot or cold especially in the hands.
Diagnosis of Syringomyelia is made with an MRI.
Treatment: Surgery, Shunts and Other Options
Doctors will consider the severity of the symptoms the patient is experiencing, as well as the type/cause of SM. The usual treatment of choice is surgery. Another method involves placement of a shunt or tube to redirect the flow of CSF.
In the absence of symptoms SM is usually not treated. The patient is monitored with an MRI and physical exam. With symptoms a physician may recommend not treating due to advanced age or in cases without progression of symptoms. Whether treated or not, many patients are told to avoid activities that involve strain.
Removal of the tumor (cyst) through surgery is the treatment of choice and this is usually successful in eliminating the syrinx (cavity).
In the case of trauma related SM as far as shunts are concerned, the neurosurgeon operates at the level of the initial injury. Until the 1990’s the most common approach was to collapse the cyst in surgery and then insert a tube or shunt to prevent its re-expansion. Because shunts routinely become clogged and require multiple operations, however, many surgeons now consider this option only as a last resort. In some patients it may be necessary to drain the syrinx, which can be accomplished using a catheter, drainage tubes and valves. This is shunting and is used for both communicating and noncommunicated SM. The placement of the shunt goes from the syrinx and down into a cavity, usually the abdomen and is called a syringoperitoneal shunt. Shunts are also used for hydrocephalus and are called ventriculoperitoneal shunts.
Instead surgeons now expand the space around the spinal cord by “realigning” (removal of bone and/or tissue) the vertebra, or discs, that are narrowing the spinal column around the cord. They then add a patch to expand the dura, the membrane that surrounds the spinal cord and contains the CSF, a procedure called duraplasty. It is also considered important to remove scar tissue that “tether” the cord in place and prevent the free flow of CSF around it.
With these procedures risks are of injury to the spinal cord, infection, blockage or hemorrhage and it may not be successful in reducing the original symptoms.
For specifics about the surgical procedure, and duraplasty go to the Diagnosis and Treatment of Chiari.