Ulnar nerve decompression

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Procedure

Decompression of the ulnar nerve at the level of the elbow. The nerve is explored through the same incision at three points where it can be trapped:

Just above the elbow where the nerve passes under a ligament (‘Arcade of Struthers’)

At the inner side of the elbow where it runs in a groove between the most prominent bone of the elbow (olecranon) and a bony prominence at the inner side (medial condyle). You can actually feel the nerve in this groove.

Just below the elbow where it goes deeper into the forearm between two muscles (two heads of flexor carpi ulnaris muscle).

There are variations of the operative technique. Some surgeons simply decompress the nerve at the three levels. In some cases, where the nerve despite decompression is still under pressure when bending the elbow (this can be assess during surgery) the nerve is moved in front of the medial epicondyle (above). This is called nerve transposition. A few surgeons remove the medial epicondyle to allow more space for the nerve to move when bending the elbow. In my own practice, a simple decompression produces satisfactory results in most cases but a transposition might be necessary depending on the findings during surgery.

Indication

Ulnar nerve syndrome which has not responded to non-operative treatment or is causing a significant or progressive hand weakness.

Risks

Bleeding, Infection, neurological deficit including paralysis resulting in permanent numbness or hand weakness (claw deformity -see Ulnar nerve syndrome ), no improvement of symptoms, recurrence of symptoms due to scarring. Overall, the risks, in particular the serious risks are very small (<5%).

Hospital stay

Most cases are done as a day case.

Anaesthesia

Usually general anaesthesia but can be done under a regional block or local anaesthesia

Outcome

The majority of patients (~80%) will have a good response to surgery. However, about 15% will not improve. Pain and sensory changes (pins and needles) respond much better than muscle weakness.

Recovery

The elbow will feel sore for a few days but unless there are complications, recovery is quick. Patients need to be careful with using the arm and should keep it elevated for a few days if possible. Any direct pressure on the wound should be avoided.

Commonly asked questions

When should I have a decompression?

In mild to moderate cases where the patient ‘only’ has pins and needles, conservative treatment should be tried first (see Ulnar nerve syndrome). However, best results are achieved if the symptoms have been present for less than one year, which is not to say that surgery should not be attempted for symptoms lasting longer than this. If there is any muscle weakness or wasting, the results from surgery are not as good but the nerve should be decompressed to avoid further damage.