What is a Spinal Synovial Cyst?
A synovial cyst is a rare and benign fluid filled sac that can cause spinal stenosis by creating a narrowing within the spinal canal. It is caused by degeneration in the lower back (lumbar spine) that generally occurs after age 50 and is more common in even older patients. Synovial cysts grow over years and symptoms may remain stable for years as well. Synovial cysts may be painless but can progress to a sharp or pain dull that can be chronic and worsens with activity. You may have numbness or tingling or even weakness of muscles as well. In severe cases, your neurosurgeon may recommend surgery to enlarge the spinal canal to reduce pressure on the spinal cord and nerves.
Your symptoms will depend on the cyst size and how it is pressing on adjacent structures. Pain is usually the first sign of a synovial cyst. Lower back pain may or may not be present. You may have sciatica, which is irritation of the sciatic nerve, which causes pain, weakness and numbness extending from your back to your buttocks, thighs, and down to your calves. You may have aching, tingling or burning sensations in the affected area. If the synovial cyst causes severe lumbar stenosis you may have bowel or urinary incontinence, sexual dysfunction, or numbness in the groin and buttocks area. The pain is usually only on one side of the body but may be both. Movement, walking sitting and certain bending or twisting movements may worsen the pain. Pain tends to improve with sitting and worsens with standing and walking. Rarely, a large synovial cyst can cause cauda equina syndrome which requires immediate medical attention. When you are unable to perform your normal daily activities then it is time to see your doctor.
The facets of the spine are where 2 consecutive vertebrae connect on both sides of the bony spinous process. Degeneration of this joint can cause a fluid filled sac (synovial cyst). This almost always occurs in the lower lumbar spine, L4-L5. Normally the spinal facets slide over each other smoothly. As wear and tear causes joint degeneration, more fluid is produced which forms the fluid filled cyst. The synovial cyst can press on the sensory or motor nerves of the spinal cord causing symptoms. Because the facets stabilize the spine, a synovial cyst can also cause spinal instability.
Your doctor will take a complete history. A physical exam will evaluate you for the source of your pain and discomfort. Your nerve function will be evaluated along with and muscle strength and skin sensation. Imaging tests can help your doctor identify injured areas of spinal bones and muscles. X-rays including those taken bending forward and backward will look for spinal instability. A magnetic resonance imaging (MRI) uses powerful magnets and radio waves to create a detailed picture of soft tissue of the spine, spinal cord and spinal nerves and the synovial cyst will be easy to see as a bright white space. A computed tomography (CT) scan uses the electromagnetic energy of X-rays to provide a detailed look at the bony anatomy spine and tissue around it.
Just changing positions may provide relief from a spinal synovial cyst. Being seated is the most comfortable position. If the synovial cyst is not causing problems for you then you may not require medical management. Pain relief can sometimes be achieved with heat or cold against the area. Resting can allow your back to heal. Over-the-counter medications like ibuprofen (Advil, Motrin) or naproxen (Aleve) are NSAIDs (nonsteroidal anti-inflammatory drugs) that can decrease pain and swelling. If pain of a herniated disc lasts more than 10 days you should talk to your doctor as the side-effects of long term NSAID use rarely include stomach ulcers, circulation problems and heart failure. Muscle relaxants and nerve pain medications can also be used. Stretching and exercises may help improve the symptoms. A physical therapist can show you which exercises you should perform.
Injections may help with the pain of a synovial cyst. Facet injections involves draining the cyst inside the facet joint with a needle before injecting steroids into the joint to decrease inflammation. An epidural steroid injection is the injection of steroids around the cyst which can temporarily reduce inflammation and pain but does not reduce the cyst size. Steroid injections are limited to 3 per year but may prevent the need for surgery.
If conservative treatments do not provide relief then surgery may be necessary. Any instability must be diagnosed before surgery as that can be corrected at the same time the cyst is drained. If there is no instability then a Microdecompression Spinal Surgery can drain the cyst and relieve the pressure on the spine, but this may not prevent the cyst from refilling. This may be most appropriate for younger and more active patients or before a larger and more invasive procedure is performed. To prevent the cyst from filling again, a Decompression with Spinal Fusion Surgery may be indicated. The spine segments are permanently attached which decreases spine function in this area, but, the synovial cyst is very unlikely to recur. This has a higher success rate but is a larger surgery and spinal fusion may take 6 or more months to heal.
The neurosurgeons of Norelle Health are highly trained and skilled in the diagnosis, management, and treatment of synovial cysts. Our neurosurgeons can provide the optimal treatment. Neurosurgery is considered essential by insurances and should be covered with your plan. As out-of-network providers, we will check your benefits for you and let you know what they are so there are no surprises. We use an individualized treatment plan for your concerns to provide a personalized holistic plan of care. If you would like assistance, please feel free to contact us (link to contact page) or call our office (link to phone number).