What is a ganglion cyst?
A ganglion cysts is a benign gel filled cyst that forms around the joints or tendons. They are the most common soft tissue swellings seen around the wrist and hand. The most common location is on the back of the wrist. They are made up of a thick jelly-like fluid, called synovial fluid, which normally surrounds joints and tendons.
Why do they occur and who gets them?
It is not known why ganglion cysts form but they may be related to the ageing process or to injury to the joint or tendon. Normal joints in the human body contain a fluid called synovial fluid. This fluid is also found surrounding tendons. In some people, for unknown reasons, the fluid can collect and form a swelling beneath the skin. They are more common in women and the majority occur between the age of 20 and 40 years. They occur rarely in children.
Are they harmful?
Ganglions are harmless and are usually painless. However they can vary in size and may cause mild pain, especially if they lie next to a nerve.
How are they diagnosed?
Ganglion cysts are usually easy to diagnose on the basis of their clinical features. They usually look and feel like a smooth soft lump under the skin. Sometimes, however, they feel very firm and can be mistaken for a bony lump. They are usually non-tender. Wrist ganglions can be associated with aching discomfort in the wrist. They are fixed to the underlying structures and do not move with flexion or extension of the wrist or fingers. If there is any doubt about diagnosis and ultrasound scan may be ordered.
How are ganglion cysts treated?
Ganglion cysts are harmless and do not require treatment. They tend to fluctuate in size and some disappear spontaneously when left untreated. If a ganglion becomes very large and unsightly or is causing discomfort, then treatment may be indicated.
What treatments are available?
- Aspiration: this involves draining the fluid with a syringe after injecting a small amount of local anaesthetic to numb the area. This can be done in the outpatient clinic at the first appointment. It usually takes approximately 5 minutes to do. In most cases it is possible to completely empty the cyst of its gelatinous contents. Sometimes however the fluid is too thick to be aspirated through a needle. There is a recurrence rate of up to 50% following aspiration. (Patients should not attempt to aspirate these swellings themselves as this can damage to surrounding structures such as blood vessels or cause infections of the underlying joint.)
- Surgery: This involves complete surgical removal of the cyst. This usually requires a general anaesthetic. Some smaller ganglions on the fingers can be removed under local anaesthetic. Most ganglions however extend quite deep and connect to the underlying joint therefore a significant amount of surgical dissection is required. It is therefore better that the surgery be performed under a general anaesthetic as a day case. Ganglions can still reappear following surgical removal. The recurrence rate is approximately 15 to 20%.
What does surgery involve?
During the operation an incision is made into the skin that is at least as wide as the lump. The ganglion is then excised. That wound is stitched up using dissolvable sutures. A bulky bandage will be placed over the area for protection and to apply compression .This bandage can be removed at 24 to 48 hours after the surgery. The underlying adhesive dressing should be left alone until the first follow-up consultation with the surgeon. Painkillers are given to the patient to take home but these are usually not required.
Patients are able to go home the same day once the effects of the anaesthesia have worn off and they have been seen by their surgeon. A sling may be used for the first couple of days to help reduce swelling and discomfort. The fingers are mobilised straightaway to keep them mobile. Most tasks are possible but those requiring two hands may be difficult. The wound and the dressings should be kept dry for at least 10 days. The amount of time required of work depends upon the nature of the profession. Most people can return to work within a few days. For heavy manual professions 4 to 6 weeks may be required however.
What are the possible complications?
- Recurrence of the cyst 15-20%
- Infection 1%
- Damage to a significant blood vessel- under 1%
- Numbness around the scar- this is not uncommon due to damage to the small cutaneous nerves in the skin.
- Scar tenderness or hypersensitivity.
- Finger stiffness- this is uncommon and is usually treatable with physiotherapy. Rarely some people may get more troublesome swelling and stiffness in the hand known as a RSD.
- Anaesthetic complications. General anaesthesia carries a very small risk of complications. The consultant anaesthetist will discuss these risks with the patient prior to the operation.