What is a synovial cyst?

What causes a synovial cyst?

Synovial cysts are rare, non-cancerous, and most often develop as a result of wear and tear, or arthritic degeneration, of the facet joint over time. Therefore, they are rarely seen in patients younger than 45, and are most common in those 65 or older. Synovial cysts are rarely dangerous.

Facet joints are joints located between the bony projections at the back of your vertebrae (the bones in your spine). Synovial fluid, contained in a membrane called the synovial sac, lubricates the facet joints and helps them move smoothly. When facet joints age and start to wear down, cartilage, the body’s natural lubricant, deteriorates. In response, the body may produce more synovial fluid in an attempt to keep the joints moving smoothly. It is thought that synovial cysts form when this extra fluid builds up inside one section of the synovial sac.

What does a synovial cyst feel like?

Many patients with synovial cysts experience no symptoms. Among those who do, common symptoms include:

• Lower back pain
• Leg pain, also called sciatica, which can occur in one or both legs, and may radiate down the back of the leg and into the foot
• Pain that improves when sitting and worsens with standing long periods of time
• Numbness, tingling, or muscle weakness in one or both legs
• May cause foot drop
• Pain, numbness, and weakness in the calves, buttocks, and/or thighs, called neurogenic claudication that worsens by walking or prolonged standing

What is the best treatment for a cynovial cyst?

If you have a cynovial cyst but you are not experiencing any discomfort, we will generally recommend that we watch the cyst to check if it is growing. Because large cysts can cause spinal stenosis. Spinal stenosis is narrowing of the spinal column that can result in pain and cramping in your lower back and legs. 

If you are experiencing discomfort or pain, we will most likely recommend restricting activities and other non-surgical therapies such as:

• Injections. A facet injection can be used to drain the fluid from the cyst, relieving the pressure on the nerve. Epidural steroid injections can provide temporary pain relief.
• Physical therapy. Your physician may suggest physical therapy, possibly along with pain-relieving steroid injections so that exercises can be done with minimal discomfort.
• Pain medications. Over-the-counter pain relievers, such as acetaminophen (Tylenol), and non-steroidal anti-inflammatory medicines such as ibuprofen or aspirin may be useful for chronic pain. Prescription pain relievers may be necessary during episodes of extreme pain but are not recommended for long-term relief.

When do I need surgery for a synovial cyst?

At Neurosurgery One, our expert neurosurgeons take a conservative approach and recommend surgery for synovial cyst only when patients experience ongoing pain that is not relieved with other treatments. If you’ve experienced pain for many years and it is harming your physical or emotional health, we will discuss surgery with you.

The goal of synovial cyst surgery is to remove the cyst to provide more room for the spinal column to eliminate pressure on the nerve roots. The surgery is similar to a microdiscectomy. It is a not a difficult surgery but you will need time to recover. Our spine surgeons perform this procedure using minimally invasive techniques through small incisions, which reduces pain and recovery time.

To prevent the cyst from reforming, especially in cases where there is associated spondylolisthesis, your surgeon may opt to fuse the affected joint. This type of surgery is called a lumbar fusion.