I’m doing a little research on a problem I’ve developed over the years called spinal stenosis. I’ve had X-rays and MRIs and they could find nothing to account for my back and leg pain. I finally had exploratory surgery. Lo and behold they discovered cysts had formed inside the ligament inside my spinal canal. Once they took them out, I was perfectly fine. Is this a common problem? What are my chances that I’ll form more of these pesky beasts?

Spinal stenosis refers to a narrowing of the spinal canal where the spinal cord is located. Many things can contribute to stenosis but the most common are the degenerative changes that occur with aging. One of the major causes of synovial cysts in the spine is degenerative spondylolisthesis.

Spondylolisthesis is the forward slippage of one vertebral body over the one below it. As the vertebra moves forward, the spinal canal narrows. Anything that narrows the spinal canal can cause pinching (impingement) or compression of soft tissue structures such as the spinal cord and spinal nerve roots.

The shift in the bodies of the vertebral bones also changes the normal alignment of the spinal (facet) joints. Any change in joint alignment can contribute to uneven wear and tear. Eventually, bone spurs form, joint integrity is disrupted, and joint fluids escape, leading to cyst formation. So you can see, one thing leads to another and another and another.

The incidence of synovial cysts within the spine hasn’t been calculated but reports that it is linked with degenerative spondylolisthesis suggest it is more common in older adults. Recurrence rates are also unreported. Since this occurs as a result of osteoarthritis, which doesn’t go away when the cysts are removed, it’s possible that the cysts can reform or more likely, new cysts can develop.

A recent finding has opened up discussion around this topic. It appears that there are channels leading from the spinal joints called facet joints that are present even in the normal spine without stenosis and in the absence of any cysts. The purpose of these channels remains a mystery. Clearly, they are used to transport synovial fluid out of joints damaged by osteoarthritis because that’s how these cysts form. Now that these channels have been identified, researchers will study them more closely.