Synovial cysts are fluid-filled sacs that develop in joints, most commonly in the spine, particularly the lumbar (lower back) region. These sacs are benign, meaning they are non-cancerous. They form from the synovial membrane, which lines joints and produces a lubricating fluid to help them move smoothly. While they can occur in various spinal areas, the lower back is the most frequent site of development due to age-related degeneration of the facet joints, which are small joints connecting vertebrae.
Do Synovial Cysts Go Away on Their Own?
The spontaneous resolution of synovial cysts, especially those in the spine, is a rare occurrence. While some smaller cysts might fluctuate in size or even disappear, spinal synovial cysts are less likely to resolve completely without intervention. Spinal synovial cysts are generally associated with underlying degenerative changes and instability within the facet joints.
Factors that might influence the rare instances of spontaneous resolution include the extrusion of the cyst’s contents, the reabsorption of the cyst wall, or changes in the local forces that initially contributed to their formation. For example, reduced inflammation or decreased micro-traumatic events might lead to some cysts shrinking. Despite these possibilities, observation is typically the initial approach if symptoms are mild or absent.
There have been documented cases of symptomatic lumbar synovial cysts resolving spontaneously, though these are considered sporadic events in medical literature. This suggests that while possible, complete resolution without active treatment is not the most common outcome for symptomatic spinal synovial cysts.
Managing Synovial Cysts
When synovial cysts do not resolve on their own or begin to cause symptoms such as pain, numbness, or weakness, various management approaches are considered. Initial strategies often involve conservative, non-surgical methods to alleviate discomfort and improve function. These include rest, modifying activities to avoid aggravating movements, and using anti-inflammatory medications like NSAIDs (non-steroidal anti-inflammatory drugs) to reduce pain and swelling.
Physical therapy is also a common conservative treatment, focusing on exercises that can help improve spinal stability and reduce pressure on affected nerves. Injections can be used, such as epidural steroid injections, which deliver anti-inflammatory medication to the area around the cyst for temporary pain relief. A facet injection can sometimes be used to aspirate, or drain, the fluid directly from the cyst, which may provide immediate relief, though cysts can sometimes refill.
If conservative treatments prove insufficient or if the cyst causes persistent pain, neurological deficits, or spinal cord compression, surgical intervention may be considered. The primary goal of surgery is to remove the cyst and decompress the spinal cord and nerve roots by creating more space. This procedure can be performed using minimally invasive techniques, which typically lead to smaller incisions, less post-operative pain, and faster recovery times.
In some cases, particularly when there is underlying spinal instability or spondylolisthesis (a slippage of one vertebra over another), a spinal fusion might be performed after cyst removal. Fusion involves joining or fusing the affected vertebrae to stabilize the joint and reduce the likelihood of the cyst recurring.
Understanding Synovial Cyst Formation
Synovial cysts in the spine typically arise from degenerative changes within the facet joints. These small joints, located at the back of the vertebrae, allow for spinal movement while providing support. They are lined by a synovial membrane that produces fluid to lubricate the joint and minimize friction during motion.
As a person ages, or due to repetitive stress and wear and tear, the cartilage in these facet joints can degenerate, a process often linked to osteoarthritis. In response to this degeneration, the body may produce excess synovial fluid in an attempt to protect the joint. This additional fluid can then escape through small tears or weaknesses in the joint capsule, forming an out-pouching that becomes a synovial cyst.
The development of these cysts is also associated with spinal instability, where excessive movement or micro-trauma in the facet joints contributes to the herniation of the synovial lining.