A synovial cyst is a fluid-filled sac that develops as a result of degeneration in the facet joint of the spine. The fluid-filled sac creates pressure inside the spinal canal, which can cause pain. The pain usually results from compression of passing nerves.
Synovial cysts, which nearly always develop in the lower back, or lumbar spine, create pressure inside the spinal canal. If synovial cysts grow large enough, they can result in spinal stenosis, a condition in which the spinal canal becomes too narrow for the spinal nerves to move freely.
The experienced neurosurgeons at Neurosurgery One (formerly South Denver Neurosurgery), are expert at both surgical and non-surgical synovial cyst treatment.
Risk Factors of 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.
Facet joints are joints located between the bony projections at the back of the vertebrae. Synovial fluid, contained in a membrane called the synovial sac, lubricates the facet joints and helps them move smoothly. When facet joints age and degenerate, 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.
Common Symptoms of Synovial Cyst
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
- Numbness, tingling, or muscle weakness, in one or both legs
- Weakness possibly including foot drop
- Pain, numbness and weakness in the calves, buttocks, and/or thighs, called neurogenic claudication. This may be worsened by walking or prolonged standing
Non-Surgical Treatment of Synovial Cyst
Patients not experiencing symptoms from a synovial cyst can be treated with careful observation to determine whether the cyst is becoming larger and could possibly result in spinal stenosis.
For patients experiencing discomfort, initial treatment may include restricting activities that cause symptoms.
Other non-invasive therapies that may provide relief include:
- Steroid injections. A steroid injection 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.
Learn more about non-surgical treatments.
Surgery to Relieve Pain Caused by 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 treatment options, especially if it has been going on for years.
The goal of surgical treatment of synovial cyst is to remove the cyst in order to provide more room for the spinal cord and nerve roots and eliminate pressure. This surgery is similar to a microdiscectomy.
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. Learn more about spinal fusion, including lumbar fusion.