A synovial cyst is generally a noncancerous or benign cyst commonly seen in the joints of the spine. The joints have a thin layer of tissue known as the synovium, which produces liquid to protect them. The fluid may build up as the joints degenerate or break down with age. As a result, fluid-filled sacs or growths may form. These cysts are typically located in the lower portion of the back.
Back pain is the most prominent symptom of this condition. There may also be muscle weakness and pain in the legs, thighs and buttock area. The pain may be more intense upon standing and walking for an extended period of time. Generally, sitting will lessen the pain, as this will relieve pressure of the cyst from the spine. Some individuals with a synovial cyst do not experience any symptoms.
Sometimes a synovial cyst can lead to spinal stenosis. This is a narrowing in areas of the spine, which may be caused by tumors, cysts, arthritis and injury. Significant pressure may be placed on nerves of the spinal cord due to the narrowing. In severe cases, the disorder can cause problems with the bladder or bowel. Most commonly, it causes pain, numbness and weakness in the lower back, hips and legs in addition to a loss of sensation in those areas as well.
If a doctor suspects a patient may have this type of cyst, he will generally order a diagnostic imaging test. A magnetic resonance imaging (MRI) may be used to diagnose the condition, as this specialized test can not only produce a clear image of the spine, but its surrounding ligaments and disks as well. Computerized tomography (CT) scans may also be used to make cross sectional images of the back and will provide more detailed imaging than a traditional X-ray. Many patients will undergo more than one imaging test.
Treatment will not be necessary for everyone with this condition. Generally, synovial cysts appear in older individuals and symptoms may not develop until later in life. Conservative treatments are generally used to treat individuals with problematic symptoms. This may include taking anti-inflammatory medications for pain and inflammation. Physical therapy may also be prescribed to strengthen the spine.
If an individual is very symptomatic, more advanced treatment may be needed. In this event, the cyst may be drained. The patient can also receive a steroid injection into the spine to relieve pain. If walking and maintaining balance becomes particularly problematic, the cyst may be removed by surgery. Usually, extreme treatment methods are not commonly needed and most people with a synovial cyst lead active lives.