Mucous Cyst

A mucous cyst is a sac filled with fluid that appears on the finger above the joint located next to the nail (the distal interphalangeal joint). The cyst can often thin the skin around the nail. The mucous cyst somewhat resembles a balloon on a stick due to its fluid-filled appearance and a stalk attached to this that connects the cyst to a joint.
The texture of the cyst is firm and is not easily malleable under the skin. Due to its nature, the cyst is often painful for the patient and is in danger of breaking open, increasing the chances of infection.
As a result of the mucous cyst growing so close to the fingernail, the nail can grow with an indentation towards its base or grow irregularly.

Unless a cyst seems to be in danger of rupturing or is causing pain to the patient, it can be left alone without any harm caused to the patient.

Who does it affect and why does it occur?

Usually females over 40 years.

It is a fluid-filled sac that occurs at the end finger joint (DIP joint), on its back surface to one side or the other. They are caused by a small extra bit of bone around the joint (osteophyte) that occurs as a result of arthritis in the joint. The cyst and bone can cause pressure on the nail bed to cause uneven nail growth.

A small lump that develops on the back of the joint to one side. The joint itself may be stiff and tender. The outline is quite smooth and may feel tense, like a small ball or balloon (cystic). The overlying skin may become thin and even break down.

Clinical Examination

A mucus cyst has quite typical features both in its location and appearance. In the clinical photograph, the finger shows a classic large mucus cyst. The finger is seen to be bending to one side as a result of more cartilage wear on one side than the other seen in the X-ray images.

Investigations

An x-ray will usually show wear and tear (osteoarthritis) in the joint. There is often a sharp spike of bone called an osteophyte that is caused by osteoarthritis.

Non-operative treatment

If it does not cause a problem, we recommend leaving it alone.

Operative treatment

If causing problems, we usually recommend surgery. The surgery is a day case procedure usually under local anaesthetic and takes about 10 minutes. A finger tourniquet is used, which is a small compressive ring around the finger that prevents blood from obscuring the surgeons’ view. 
Local anaesthetic is infiltrated at the base of the finger. 

Once numb, the skin is incised, and the skin flap elevated. The ganglion is dissected, taking care not to puncture it. The base of the ganglion is identified and excised. A small extra bony area (osteophyte) is seen and needs to be removed. The skin is sutured, and a bulky dressing is applied.

Post-operative rehabilitation

The patient is fit to go home soon after the operation. The anaesthetic will wear off after approximately 6 hours. Simple analgesia usually controls the pain and should be started before the anaesthetic has worn off. The hand should be elevated as much as possible for the first five days to prevent the hand and fingers from swelling. Gently bend and straighten the fingers from day 1. My preference is to remove the dressing for two days. The wound is cleaned and redressed with a simple dressing. The sutures are dissolvable and do not need removing.
Prof Imam usually sees patients at 6-8 weeks after surgery to assess the early result.
Return to activities of daily living
It is my advice to keep the wound dry until the wound has healed at 7-10 days.
Return to driving:
The hand needs to have full control of the steering wheel and left hand the gear stick. It is probably advisable to delay returning to driving for a few days until a car can be operated in a safe manner in the event of an emergency.
Return to work:
Everyone has different work environments.
Returning to heavy manual labour should be prevented for approximately 4 to 6 weeks. Early return to heavy work may cause the tendons and nerve to scar into the released ligament. Please ask your surgeon for advice on this.

Complications

Overall, greater than 95% are happy with the result. However, complications can occur.
There are complications specific to Mucus Cyst surgery and also general complications associated with hand surgery.

Specific complications:
Recurrence: We are not sure whether it is the same ganglion recurring or simply another one forming nearby. The joint is arthritic and may need treatment in the future.
Nail injury: The nail is very close to the site of the ganglion. Indeed the ganglion can cause pressure on the nail and cause ridging. Surgery can damage the nail and also cause abnormal nail growth but it is extremely rare.