Symptoms and diagnosis of a synovial cyst

A synovial cyst is most commonly found in patients who are older than 65 years old. This type of cyst is benign (non-malignant) and the symptoms may remain stable and not progress for long periods of time.

Symptoms
Spinal stenosis from a synovial cyst can cause pain in the lower back that travels down to the legs.

Typically, there is minimal or no pain if the patient is seated, because in the seated position the spinal canal opens up and there is not as much pressure on the spinal nerves. When standing up straight or walking, however, the spinal canal closes down and creates more pressure on the nerves.

Diagnosis
The synovial cyst is best visualized on a MRI scan of the spine. It shows up as a hyperintense lesion that has the same signal intensity as water.

X-rays, including flexion/extension motion x-rays, are also important to rule out any spinal instability. It is important to check for spinal instability because the joint is undergoing degeneration and there is often an accompanying degenerative spondylolisthesis (vertebral body that slips forward), which indicates that the joint is unstable and incompetent.

It is very important to identify any instability before surgery for the synovial cyst, because if the instability is not addressed at the time of surgery, often a revision surgery will be required at a later date.