What is a ganglion cyst?
A ganglion cyst is the most common mass that develops in the hand. Ganglion cysts are benign lesions. A ganglion is a fluid-filled sac arising from an adjacent joint capsule or tendon sheath. A ganglion can form from almost any joint or tendon sheath in the wrist or hand. The following drawings describe the most common sites for presentation of a ganglion.
Ganglion cysts of the wrist.
What are the causes?
The exact cause of ganglions remains uncertain. The most popular theory is that ganglions form after trauma or degeneration of the tissue layer responsible for producing the synovial fluid which normally lubricates the joint or tendon sheath. The cyst arises from accumulation of this fluid outside the joint or tendon sheath in a sac or cyst.
What are the signs and symptoms?
Ganglions may limit motion in the adjacent joints, or produce discomfort from compression or distention of local soft tissues. Particularly large ganglions can be cosmetically unpleasant. Ganglion cysts of the distal interphalangeal (DIP) joint may produce deformities of the fingernail. Ganglion cysts arising from the flexor tendon sheath at the base of the finger may produce pain when grasping. On rare occasions, ganglion cysts (particularly those associated with the wrist) may cause changes in the bone.
Ganglion cysts can frequently be diagnosed simply by their location and shape. They are usually not adherent to the overlying skin and are firmly attached to the underlying joint or tendon sheath. Large ganglions may permit the passage of light through their substance (trans-illumination). X-rays are sometimes helpful in diagnosing ganglion cysts, particularly about the distal interphalangeal joint where associated degenerative arthritis is often found. The presence of a grooved nailbed is a classic finding with a mucous cyst. As other lesions can produce swelling in the same sites as ganglions, a 100% diagnosis cannot be provided without excision of the mass.
Ganglion involving the distal interphalangeal joint.
How is it treated?
Ganglion cysts often change in size and may even disappear spontaneously. For this reason, if the ganglion is asymptomatic, it may be best to simply observe the mass for a period of time. Ganglions about the wrist may respond well to a temporary period of immobilisation if diagnosed early.
Aspiration of a ganglion is rarely of long term benefit as the ganglion returns in greater than 50% cases.
The most reliable method of treating a ganglion cyst is by surgical excision. This is performed as day surgery. Ganglions in the fingers in the finger can be removed under local anaesthetic. However those cyst involving the wrist usually require regional or general anaesthetic. The ganglion is removed through an incision directly over the area of the swelling. Care is taken to attempt to identify its site of origin, and to excise a small portion of joint capsule or tendon sheath from which it has arisen. In the treatment of a mucous cyst at the distal interphalangeal joint, it is important to remove any osteophytes (bony spurs) that may be associated with the origin of this type of ganglion.
What about recovery?
Following ganglion cyst removal at the wrist level, a bulky dressing and plaster splint will be applied. You will be encouraged to move the fingers, which will be left free, to avoid stiffness. Wrist movement will be commenced in approximately 10-14 days. This may be supervised by a therapist. Between exercises the wrist may be rested in a splint. Usual recovery time following surgery for ganglion cysts ranges from 2-3 weeks for small ganglions of the finger, and 6-8 weeks for ganglions involving the wrist.