Hand Surgery #5: Ganglion Cysts

The most common tumor of the hand is not a cancer. It's a ganglion cyst....

Anatomy

Bones meet at joints. Joints are lubricated by synovial fluid. Escape of the fluid is prevented by a joint capsule.

Likewise, tendons are lubricated and nourished by synovial fluid from their surrounding tenosynovium.

Pathology - The Ganglion Cyst

If some of that synovial fluid escapes from a joint or tendon sheath, it stimulates an encompassing scar. The resulting fluid-filled sac is a ganglion cyst.

Gangions are common, and they are benign (meaning that they are not cancer).

A ganglion can arise from almost any joint or tendon sheath in the wrist and hand, but they are most common at the back of the wrist, on the front of the wrist below the thumb, along the palmar surfaces of the proximal fingers, and at the last knuckles of the fingers (the distal interphalangeal joints, which are just proximal to the nails; ganglion cysts at the distal interphalangeal joints are sometimes erroneously referred to as mucous cysts).

Causes

The exact cause of ganglions remains uncertain. Why does the fluid leak in the first place? The most popular theory is that ganglions form after trauma or degeneration of the capsule around the joint or tendon sheath.

Signs and Symptoms

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. X-rays are sometimes helpful in diagnosing ganglion cysts, particularly about the distal interphalangeal joint, where associated degenerative arthritis is often found. As other lesions can produce swelling in the same sites as ganglions, a 100% accurate diagnosis cannot be provided without aspiration or excision of the mass.

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 joint may produce grooving or ridging of the fingernails. 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.

Treatment

Conservative treatment:
- 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 immobilization.
- Aspiration of a ganglion may diagnose the lesion and may temporarily or permanently treat the condition. This consists of first numbing the area with a local anesthetic, and then inserting a needle to withdraw the clear, jelly-like fluid from the ganglion sac. A compressive dressing or splint may be applied following aspiration. Aspiration is extremely useful in minimizing symptoms when surgery is not desired. Recurrence of the ganglion can be expected in >50% of cases following aspiration.
When conservative treatment fails, or when symptoms are severe and/or longstanding, I usually recommend surgery....
- outpatient
- small incision over the ganglion cyst
- The cyst is carefully freed from the surrounding structures.
- Care is taken to identify its site of origin, and to excise a small portion of the joint capsule or tendon sheath from which it has arisen.
- In the treatment of a "mucous cyst" at the distal interphalangeal joint,I remove the osteophytes (bony spurs) that may be associated with the origin of this type of ganglion.

Recovery

Following ganglion cyst removal, a bulky compressive dressing is applied. Within 1-2 weeks, exercises are initiated to prevent the development of stiffness. 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.