What is a Synovial Cyst?
Synovial cysts or ganglion cysts refer to a small fluid-filled lump that arises from joints or tendon sheaths. These mucin-filled lesions with a fibrous capsule (approximately 0.5- to 2-cm in size) may occur at many joints along the spine (Splavski et al., 2019). Synovial cysts may remain asymptomatic for a long time and occur as a consequence of rheumatoid arthritis or neuropathic arthropathy. These cysts typically non-malignant (benign) in nature and non-cancerous. Synovial cysts sometimes located extradural in the lumbar spine and produce symptomatic radiculopathy and back pain. Management of these lesions usually conservative, but sometimes the physician performs percutaneous aspiration or lumbar decompression procedure and fusion to improve the condition.
These cysts may develop anywhere in the body around any joint. But research estimates almost 90 percent of synovial cysts develop in the facet joints of the lumbar spine. Most of the synovial cysts occur among adults older than 65 years of age due to the degeneration of the facet joint in their spine (Splavski et al., 2019). In some reports, patients with certain joint conditions like rheumatoid arthritis develop a synovial cyst, and a history of trauma causes cyst enlargement or hemorrhage into the synovial cyst cavity. This ultimately results in epidural compression of the spinal cord.
What are the Common Symptoms and Causes of Synovial Cysts?
Symptoms of a synovial cyst depend on the size and location of the cyst. Some patients may remain asymptomatic, which means they won’t experience any signs or symptoms. However, many patients suffer from back and leg pain while standing and walking. Although they feel good while sitting (Acharya et al., 2006). This results in a fully upright posture in patients that additionally pressures the spinal disc and nerve roots during standing and walking. But while sitting, the spinal canal naturally expands a bit, and this helps to relieve the excess pressure from spinal stenosis and improves the condition.
Besides these, patients with a synovial cyst may experience one or more of the following symptoms (Trummer et al., 2001):
- Severe pain which may radiate in the lower back, one or both legs and foot, causing sciatica
- Difficulties in walking and standing
- Muscle weakness and soreness in both legs
- Cramping, weakness, or heaviness feeling in one or both legs occur with the loss of motor function when spinal nerve pinched in the lumbar (lower) spine resulting in a condition named neurogenic claudication
- In case of a large synovial cyst, spinal stenosis occurs and causes numbness, or tingling in one or both legs
- Sometimes, cauda equina syndrome may develop in which the compressions of cauda equina–the sac of nerves and nerve roots at the base of the spinal cord occur
- Pain in the temporomandibular region with difficulties in mouth opening may occur because of the development of a cyst in that particular region
The actual pathogenesis of synovial cysts remains unclear. But scientists believe the formation of synovial cysts occurs due to the degenerative changes in the spine along with trauma or fracture, metaplasia, the presence of developmental rests, mucinous degeneration in the connective tissues excess stress with the herniation of synovial tissue, etc. They found that a damaged facet joint produces more synovial fluid than a healthy joint. Synovial fluids inside the joint usually provide lubrication and prevent friction between 2 adjacent joints. A cyst usually forms when extra fluid production occurs inside the synovial sac of the joint.
How do Spinal Specialists Diagnose Synovial Cysts?
The initial diagnosis of a synovial cyst includes a brief clinical presentation and pain patterns of patients. Spinal specialists perform further tests to confirm the diagnosis, which includes (Weiner, Torretti, & Stauff, 2007):
- X-ray: This imaging test uses electromagnetic energy beams (X-rays) to produce images of bones. X-ray provides an overall assessment of the bone anatomy and alignment of the vertebral column with any kins of abnormalities like spinal dislocation or slippage (also known as spondylolisthesis), kyphosis, scoliosis, etc.
- Magnetic resonance imaging (MRI): This imaging test uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of soft tissues and bones.
- Computed tomography (CT) scan: This scan uses a computer and X-rays to produce images of bones and soft tissues.
How do Neurosurgeons Treat a Synovial Cyst?
Physicians prefer conservative non-surgical options rather than surgical treatment while treating a synovial cyst. The non-surgical treatment protocol may include (Epstein & Baisden, 2012):
- Observation and activity modification: In case of an asymptomatic case causing no pain, physicians suggest ignoring this and recommend no treatment for this condition.
- Mediations: Several pain relievers like NSAIDs such as ibuprofen and acetaminophen help to reduce the pain.
- Application of hot or cold therapy helps to reduce the swelling.
- Rest for one or two hours can help the patient for a short time
- Injection of steroids relieves the pain temporarily and facet injection helps to drain the excess synovial fluid.
Neurosurgeons go for surgical options when the treatment becomes ineffective. Surgical treatment helps to remove the cyst permanently and decompress the spinal cord and nerve roots, just like a microdiscectomy technique. After removing the cyst, neurosurgeons fuse the affected joint to prevent the recurring of the cyst by performing a lumbar fusion surgery.
If You Think You May Be Suffering From a Synovial Cyst in the Fort Worth Area, Contact Longhorn Brain & Spine Immediately To Get a Consultation.
Acharya, R., Patwardhan, R. V, Smith, D. R., Willis, B. K., Fowler, M., & Nanda, A. (2006). Intraspinal synovial cysts : A retrospective study. 54(23), 38–41.
Epstein, N., & Baisden, J. (2012). The diagnosis and management of synovial cysts: Efficacy of surgery versus cyst aspiration. Surgical Neurology International, 3(4), 157. https://doi.org/10.4103/2152-7806.98576
Splavski, B., Rotim, A., Brumini, I., Koprek, I., Gajski, D., Božić, B., & Rotim, K. (2019). Lumbar Spine Synovial Cyst: a Case Series Report and Review of Surgical Strategies. Acta Clinica Croatica, 58(3), 491–496. https://doi.org/10.20471/acc.2019.58.03.13
Trummer, M., Flaschka, G., Tillich, M., Homann, C. N., Unger, F., & Eustacchio, S. (2001). Diagnosis and surgical management of intraspinal synovial cysts : report of 19 cases. 74–77.
Weiner, B. K., Torretti, J., & Stauff, M. (2007). Microdecompression for lumbar synovial cysts : an independent assessment of long term outcomes. 5(Figure 1), 3–7. https://doi.org/10.1186/1749-799X-2-5