The ulna nerve is well known to anyone who has hit their ‘funny bone’ – it is the nerve that you hit, and the reason you experience pins + needles in the hand following the injury. Such an injury is only a temporary insult to the nerve, but in some patients, the nerve can be caught and compressed for longer periods, resulting in longer lasting altered sensation and weakness. The nerve forms in your axilla, and runs the entire length of your arm, supplying a number of muscles and areas of skin along the way. The site of any symptoms you have can be a clue as to where along its path the nerve is being damaged.
The most common site is in the cubital tunnel, which is where your ‘funny bone’ is. As you bend your elbow, the space the nerve sits in is reduced, and you can get nerve dysfunction. Some people have narrowing of the space even with the arm out straight, such as from inflammation, arthritis or scar tissue formation. This will lead to symptoms that are more frequent or permanent. Others have a failure of the roof of the tunnel, which allows the nerve to subluxate out of the groove behind the elbow. As it moves, the nerve can become irritated and its function impeded. It also moves into a less protected position and is more prone to damage from direct impacts.
Other sites where the nerve can be compressed are just above the elbow where the nerve passes from the front of the arm to the back, in the forearm as the nerve passes under muscles, and at the wrist where it passes through a bony and fibrous tunnel.
What symptoms will I have if my ulna nerve is being compressed?
The first symptom is usually altered sensation, and it is often described as the same feeling as hitting your ‘funny bone’. Classically the numbness and tingling will affect the little finger and half of the ring finger, but this can be variable. With higher nerve compression, the palm and inside of the forearm will also be affected. If the nerve is tightly compressed motor function will also be impaired, with the ulna nerve controlling muscles involved in grip strength and finger coordination/fine movement. This can lead to weakness of the fingers and wrist, and eventually wasting of the hypothenar eminence (little finger side of the palm) and small muscles of the hand. As the other nerves are still working, an ulna clawed hand can develop.
How can I find out if I have ulna nerve neuropathy?
If you suspect you have a problem with your ulna nerve, seek review with your local doctor. They will take a detailed history and examine you. If your story and signs fit, you will be referred to an orthopaedic surgeon for review. Nerve conduction studies and EMG studies are used as a tool to identify where along the nerve the problem is, and what sort of problem is occurring. You will usually be referred for these prior to any surgery being contemplated. Plain X-rays or an MRI scan may also be ordered depending on the suspected cause of the problem.
Who does this condition affect?
Anyone can develop the problem, and those with a family history of the same condition are at increased risk. This is likely due to similar anatomy or inherited connective tissue defects. Diabetics are also at increased risk, as their nerves are more prone to compression. Those patients who have an underactive thyroid gland are also at risk, as are those whose sports or occupation involve prolonged leaning on the elbow, or prolonged or repetitive flexion of the elbow.
How can it be treated?
Many patients will have resolution of their symptoms and return of function with avoidance of prolonged or repetitive elbow flexion, and avoidance of leaning on the elbow. To assist in recovery of the nerve, a night time elbow extension splint can be worn. This allows the nerve to sit for an extended period in a non-compressed environment, encouraging healing of any damage and resolution of inflammation.
When these measures fail or symptoms are severe, surgical release of the nerve can be performed. The aim is to release the nerve from any and all sites of compression along its path, or in the case of a nerve that is hypermobile, moving it permanently in front of the elbow to stop it being irritated.
How long will I need to be in hospital?
The surgery can be performed as day surgery, or you can elect to remain in hospital overnight. If there are any complications following the surgery, you will be kept in hospital and managed appropriately.
What will happen to me after the surgery?
Once you have fully recovered you will be discharged home. Your wounds will be dressed with a heavy bandage over the arm, and a plaster splint applied to the area that was operated on to limit movement. For the wrist, this will be an extension wrist splint, leaving the elbow free. For a release at the elbow, this will a half plaster that immobilises the elbow at 90 degrees. A sling will be provided to support the weight. The sutures used are all dissolving, but you will be reviewed by Dr Host or your local doctor at the 2 week mark post surgery to ensure the wounds have healed well.
How long will I take to fully recover?
Most patients will have full recovery by 3-4 months after surgery, and will be functional for daily activities and light work by 1-2 months. The rate and degree of nerve recovery depends on how long and how severely the nerve was damaged, and in some cases nerve function will never fully recover. For those with only sensory changes, recovery tends to be complete. Those who have muscle weakness, and in particular wasting, often have incomplete recovery.
What should I be concerned about following surgery?
If you have any of the following signs or symptoms, please contact Dr Host or your local GP for review:
- Increased redness, heat or swelling around your wounds.
- Raised temperature/fever.
- Persistent ooze from your wounds.
- Worsening of your nerve symptoms