Ganglion cyst

Juxtafacet cyst lacking synovial lining as counterpart to synovial cyst.

A ganglion cyst is a cystic mass that usually occurs in close proximity to a tendon sheath or joint space. The etiology of spinal cysts is poorly understood. Several theories include extrusion of synovial fluid from a defect in the joint capsule, myxoid degeneration and cyst formation in collagen connective tissue, increased production of hyaluronic acid by fibroblasts, and non-specific proliferation of mesenchymal cells.

Trauma is generally thought not to play a significant role, even though several cases demonstrated evidence of hemorrhage in the lumbar cyst.

Several authors concluded that facet cysts are closely related to degenerative spinal instability including spondylolisthesis.

Furthermore, the development of post-operative intraspinal facet cysts was related to the presence of segmental spinal instability before and after surgery ¹⁾.