Medically Speaking - Syringomyelia
What you should know
Syringomyelia stems from the Greek word syring meaning tube or fistula and Latin myel and its first known use dates back to 1880. Syringomyelia is a chronic and progressive disease of the spinal cord and is found not only in persons who have suffered a spinal cord injury. However in those who have suffered a traumatic spinal cord lesion, Post Traumatic Syringomyelia can be a worrying complication and needs urgent attention.
What is Syringomyelia?
The condition is seen where cerebro spinal fluid, the clear fluid bathing the brain and spinal cord but separated from the brain and cord by membranes, enters into a small cyst in the spinal cord causing cavitation and pressure on the spinal cord and nerves.
Why does this happen?
There are many theories as to why this develops and although nobody really knows the exact mechanisms, the most commonly agreed theory is that after a vertebral injury to the cord, damage to the cord ultimately results in the nervous cells in that area to liquefy. Enzymes and chemical mediators released by damaged cells results in further liquefaction and a cavity or cyst remains as this mass of destroyed tissue is resorbed. The resultant cavity then becomes filled with cerebro spinal fluid. At the same time there may be very small adhesions which form around this damaged area (arachnoiditis) and this may play a part in causing traction on the damaged cord further increasing the size of the cavity. There does not appear to any clear correlation between the mechanism of injury, the method of treatment of the injury (either surgical or conservative) or the level at which the cord is injured and the incidence of Post Traumatic Syringomyelia (PTS).
The incidence of Syringomyelia.
Syrinx is a relatively rare complication of traumatic spinal cord injury. The reported incidence of PTS is between 0.3 to 3.2%, with a mean of 1.3%. However only 0.5% of patients with a syrinx have symptoms.
There are three commonly reported symptoms. Pain is the commonest initial symptom of PTS. It can be described as dull aching and constant, or stabbing, burning and intermittent in nature. Pain is usually located at or above the site of the original spinal injury, and may radiate to the neck or the upper limbs.
The natural progression of the syrinx is to expand both up and down the cord. Expansion of into normal cord will result in the second of the most common presentations – that of ascending sensory loss. The sensory loss may be patchy and may exhibit daily variations. The areas of loss may be one or both sides of the body.
Finally, sensory loss and pain may be accompanied by weakness in muscle groups previously normal. This is the most devastating of all symptoms particularly in the high spinal lesions where upper limb function is already compromised to a greater or lesser degree.
After the suspicion of a syrinx is raised clinically, the only effective way of making a diagnosis is by MRI scan. This will show the size of the cavity and also whether it is a single cavity or loculated one which helps with planning treatment.
As PTS can continue to extend upward compressing normal spinal cord and causing increasing pain, loss of sensation and deteriorating motor function, neurosurgical drainage of the cavity is essential. This involves the insertion of a small drain into the cavity. The fluid is drained off into the chest or abdominal cavity. The drain remains in as continuous production of cerebral spinal fluid would result in the cavity refilling should the drain be removed. Unfortunately the drain has been known to block and therefore a repeat operation is sometimes required.
In a nutshell
If you have suffered a traumatic spinal cord lesion and notice increasing pain, spasm, sensory loss or power loss above your injury level, alert your doctor immediately as these may indicate a syrinx. Left untreated, the cyst will continue to expand and compress the spinal cord and the subsequent loss of function might be irreversible.