About Synovial Cysts
A synovial cyst is an out-pouching of the lubricating lining of the facet joint, a pair of joints that are between the vertebrae along the back of the spine. This out-pouching can project into the spinal canal and compress a nerve or the spinal cord. The synovial cyst is benign and is not cancerous. These cysts are degenerative and typically occur in the lower back, causing what is commonly called sciatica, or pain going down the leg.
Age related degeneration of the spine is usually the cause of synovial cysts. Systemic diseases that affect the joints (rheumatoid arthritis) can also be associated with this type of cyst. These cysts are usually most common in patients 65 years and older.
They can be treated with conservative care, such as physical therapy, but often once symptomatic they require surgical resection. Synovial cyst surgery often entails a focused removal of the cyst, but sometimes a fusion surgery is needed as well to stabilize the joint of origin. In either case, minimally invasive spine surgery can be an option.
Common Symptoms of a Synovial Cyst
The location and size of the cyst affect the symptoms experienced by patients. However some patients may not experience symptoms at all. When the cysts causes a problem, common symptoms include:
- Back pain that worsens when standing/walking
- Leg pain/numbness/tingling/ or weakness – known as sciatica or neurogenic claudication.
- Typically gets worse with standing and walking and improved with sitting or leaning forward.
Diagnosis of a Synovial Cyst
- X-ray – produce images of bones, and provide an overall assessment of bone anatomy and alignment of the spinal column. Spinal deformity,,overall spinal balance, and bony abnormalities can be assessed with X-rays.
- Magnetic resonance (MR) imaging – produces detailed images of soft tissues and bones.
- Computed tomography (CT) scan – uses a computer and X-rays to produce images of bones and soft tissues.
Treatment Options for a Synovial Cyst
The goal of surgery is to remove the cyst and decompress the spinal cord and nerve roots. The procedure used is similar to a microdiscectomy. Sometimes the affected joint will need to be fused after the procedure if the cyst or the resection of the cyst results in spinal instability.