Cubital Tunnel Syndrome

What is it?

A nerve called ulnar nerve supplies the index and ring fingers.It runs underneath the inside part of bone in the elbow(medial epicondyle) and tip of elbow(olecranon).It can get compressed in this tunnel and this is known as Cubital tunnel syndrome..

What is the cause?

In most of cases no underlying cause can be found. In some patients it is due to sustained stretch , or pressure on inside of elbow for prolonged periods of time which can cause thickening of tissue over the tunnel(Osborne’s ligament). This can cause compression of nerve.

This condition is also found more in people who have diabetes, Rheumatoid arthritis, elbow arthritis, or previous elbow fracture.

What are the symptoms and how is the condition diagnosed?

Patients usually complain of pins and needles in ring and little fingers .This is because of compression of nerve in tunnel at the elbow. The tingling is worse when the elbow is bent and for this reason most people experience worse symptoms at night time.(as most people keep their elbow bent over had while sleeping)

In later stages patients notice weakness in grip, and may drop things frequently. Muscle weakness in hand muscles can occur if left untreated and can cause deformity.

How is it diagnosed?

Testing of hand muscles and Elbow will be done by Specialist Elbow surgeon and he can determine whether the compression is minimal or severe. The diagnosis is mostly made on clinical examination but usually supplementary nerve testing is required.

Will further tests or investigations be needed?

The diagnosis of cubital tunnel syndrome is made clinically but you will nearly always be referred for electrical tests (nerve conduction studies). The tests may be to confirm the diagnosis in patients in whom the symptoms and signs are not typical and also to confirm that the nerve is not compressed elsewhere (usually in the neck from where it begins or rarely on the front of the wrist).  Other medical conditions like diabetes or thyroid disease need to excluded using lab investigations.

What is the treatment?

Initial treatment consists of Splints to elbow to help in reduction of symptoms. Night time splinting is achieved with a custom made long arm splint that the patient will wear at night time and as often as possible during the day. Unfortunately it is cumbersome to keep the arm out straight all the time and therefore this is usually used only at night.

If symptoms persist even after conservative measures Surgery can be done to relieve the symptoms.

The procedure is described below

Decompression of the ulnar nerve: This is a standard operation advised and is an open

surgical release of the cubital tunnel. A skin incision of 5 cm is required and at surgery the  roof of the cubital tunnel is opened, thereby decompressing the ulnar nerve. The  procedure can be carried out under local or general anaesthesia, as a day case. After the  operation, a sticky dressing is applied over the surgical wound. A bulky supportive cotton wool dressing then goes on top of that. This supportive dressing is reduced after a couple  of days. The small sticky dressing should be left for 10 -12 days when the stitches will  need to come out.

Light use of the limb should be  possible immediately after the day of surgery. Active movements of the fingers/ wrist/  shoulder are recommended soon after surgery.

Other surgical procedures like transpositions of Ulnar nerve or medial epicondylectomy are done for resistant  cases.

When certain other conditions like (rheumatoid) arthritis are present, clearing of the soft  tissue lining (synovectomy) or excision of any bony spurs, may be needed.

What happens if it is not treated?

If left untreated the tingling and numbness may become progressively worse. Compression of nerve for prolonged time can result in weakness of  hand muscles, wasting and can result in deformity.

What is the success of surgical treatment?

The operation has a very good success rate in the early stages. It results in good resolution of  night pain and tingling within a few days. However if the condition has been present for a long  time, then recovery from symptoms of constant numbness and muscle weakness is unpredictable. However one of the aims and benefits of surgery is to stop the nerve from  deteriorating due to constant compression. Thus even if the procedure does not reverse the  symptoms, it will help to prevent progressive worsening of the nerve function.

What are the complications of surgical treatment?

1. Infection of the wound is possible and in the early stages can be successfully treated with antibiotics.  If pain increases after surgery infection needs to be ruled out.

2. Damage to the ulnar nerve is possible but very rare when the open surgical technique is used

When can I do various activities?

Return to work depends on many factors including the nature of the job and hand dominance.

Generally patients can return to a desk job within a few days and perform reasonable tasks with the hand.

References