Understanding Spinal Synovial Cysts: Symptoms & Causes

Individuals that have gone through a back injury may develop a synovial spinal cyst as a way to protect the spine that could cause pain symptoms and sensations. Can knowing the signs help healthcare providers develop a thorough treatment plan to relieve pain, prevent worsening of the condition and other spinal conditions?

Spinal Synovial Cysts

Spinal synovial cysts are benign fluid-filled sacs that develop in the spine’s joints. They form because of spinal degeneration or injury. The cysts can form anywhere in the spine, but most occur in the lumbar region/lower back. They typically develop in the facet joints or junctions that keep the vertebrae/spinal bones interlocked.

Symptoms

In most cases, synovial cysts don’t cause symptoms. However, the doctor or specialist will want to monitor for signs of degenerative disc disease, spinal stenosis, or cauda equina syndrome. When symptoms do present, they typically cause radiculopathy or nerve compression, which can cause back pain, weakness, numbness, and radiating pain caused by the irritation. The severity of symptoms depends on the size and location of the cyst. Synovial cysts can affect one side of the spine or both and can form at one spinal segment or at multiple levels.

Effects Can Include

• Radiculopathy symptoms can develop if the cyst or inflammation caused by the cyst comes into contact with a spinal nerve root. This can cause sciatica, weakness, numbness, or difficulty controlling certain muscles.
• Neurogenic claudication/impingement and inflammation of spinal nerves can cause cramping, pain, and/or tingling in the lower back, legs, hips, and buttocks. (Martin J. Wilby et al., 2009)
• If the spinal cord is involved, it may cause myelopathy/severe spinal cord compression that can cause numbness, weakness, and balance problems. (Dong Shin Kim et al., 2014)
• Symptoms related to cauda equina, including bowel and/or bladder problems, leg weakness, and saddle anesthesia/loss of sensation in the thighs, buttocks, and perineum, can present but are rare, as are synovial cysts in the middle back and neck. If thoracic and cervical synovial cysts develop, they can cause symptoms like numbness, tingling, pain, or weakness in the affected area.

Causes

Spinal synovial cysts are generally caused by degenerative changes like osteoarthritis that develop in a joint over time. With regular wear and tear, facet joint cartilage/the material in a joint that provides protection, a smooth surface, friction reduction, and shock absorption begins to waste away. As the process continues, the synovium can form a cyst.

• Traumas, large and small, have inflammatory and degenerative effects on joints that can result in the formation of a cyst.
• Around a third of individuals who have a spinal synovial cyst also have spondylolisthesis.
• This condition is when a vertebrae slips out of place or out of alignment onto the vertebra underneath.
• It is a sign of spinal instability.
• Instability can occur in any spine area, but L4-5 are the most common levels.
• This segment of the spine takes most of the upper body weight.
• If instability occurs, a cyst can develop.
• However, cysts can form without instability.

Diagnosis

• Cysts are generally diagnosed through MRI. (Nancy E, Epstein, Jamie Baisden. 2012)
• They can sometimes be seen with ultrasound, X-ray, or CT scans.

Treatment

Some cysts remain small and cause few to no symptoms. Cysts only need treatment if they are causing symptoms. (Nancy E, Epstein, Jamie Baisden. 2012)

Lifestyle Adjustments

• A healthcare professional will recommend avoiding certain activities that worsen symptoms.
• Individuals might be advised to begin stretching and targeted exercises.
• Physical therapy or occupational therapy may also be recommended.
• Intermittent use of over-the-counter nonsteroidal anti-inflammatories/NSAIDs like ibuprofen and naproxen can help relieve occasional pain.

Outpatient Procedures

• For cysts that cause intense pain, numbness, weakness, and other issues, a procedure to drain fluid/aspiration from the cyst may be recommended.
• One study found that the success rate ranges from 0 percent to 50 percent.
• Individuals who go through aspiration usually need repeat procedures if fluid build-up returns. (Nancy E, Epstein, Jamie Baisden. 2012)
• Epidural corticosteroid injections can reduce inflammation and could be an option to relieve pain.
• Patients are recommended to receive no more than three injections per year.

Surgical Options

For severe or persistent cases, a doctor may recommend decompression surgery to remove the cyst and surrounding bone to relieve pressure on the nerve root. Surgical options range from minimally invasive endoscopic procedures to larger, open surgeries. The best surgical option varies based on the severity of the situation and whether associated disorders are present. Surgical options include:

• Laminectomy – Removal of the bony structure that protects and covers the spinal canal/lamina.
• Hemilaminectomy – A modified laminectomy where a smaller portion of the lamina is removed.
• Facetectomy – The removal of part of the affected facet joint where the synovial cyst is located, usually following a laminectomy or hemilaminectomy.
• Fusion of the facet joints and vertebra – Decreases vertebral mobility in the injured area.

1. Most individuals experience immediate pain relief following a laminectomy or hemilaminectomy.
2. Fusion can take six to nine months to heal completely.
3. If surgery is performed without fusion where the cyst originated, the pain could return, and another cyst could form within two years.
4. Surgery Complications include infection, bleeding, and injury to the spinal cord or nerve root.

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References

Wilby, M. J., Fraser, R. D., Vernon-Roberts, B., & Moore, R. J. (2009). The prevalence and pathogenesis of synovial cysts within the ligamentum flavum in patients with lumbar spinal stenosis and radiculopathy. Spine, 34(23), 2518–2524. doi.org/10.1097/BRS.0b013e3181b22bd0

Kim, D. S., Yang, J. S., Cho, Y. J., & Kang, S. H. (2014). Acute myelopathy caused by a cervical synovial cyst. Journal of Korean Neurosurgical Society, 56(1), 55–57. doi.org/10.3340/jkns.2014.56.1.55

Epstein, N. E., & Baisden, J. (2012). The diagnosis and management of synovial cysts: Efficacy of surgery versus cyst aspiration. Surgical neurology international, 3(Suppl 3), S157–S166. doi.org/10.4103/2152-7806.98576