Cubital Tunnel Syndrome

Numbness and tingling in your hand can be the result of a number of problems. A common cause of tingling and numbness in the ring and small finger is cubital tunnel syndrome. Cubital tunnel syndrome refers to a problem related to compression of the ulnar nerve at the level of the elbow in the cubital tunnel region. Compression of the ulnar nerve will cause tingling and numbness in the small and ring finger, coordination disturbances in the small muscles of your hand, and weakness of hand grip and of pinch strength.

The ulnar nerve runs behind the elbow in a bony groove of the humerus (the longest bone of the upper arm, extending from the shoulder to the elbow) with a ligament over the top, forming the cubital tunnel. Just past the elbow, the nerve then goes through the flexor carpi ulnaris muscle into the forearm and continues into the hand, giving both sensation and muscle function to the hand. Increased pressure on the ulnar nerve is produced by bent elbow positions, and the nerve is further compressed when you lean on the elbow.

You probably have felt the effects of nerve compression – when your foot falls “asleep” or when you hit your “funny bone.” The changes in the nerve produced by pressure will progress with increased force of compression and/or length of time of compression.

The changes that occur in the nerve will be reflected in the symptoms that you feel in your hand. In the early stages of nerve compression, your symptoms will be relatively mild and occur only occasionally. It will take more pressure on the nerve for a longer period of time before you feel any symptoms. At the beginning, you may feel only tingling and/or numbness at night after you have been sleeping with your elbows bent for a long time. As the nerve compression progresses, the tingling and/or numbness to your small and ring finger will occur more often with less time in irritating positions. You also may feel pain on the inside of your elbow and aching of the muscle along the inside of the forearm. When the nerve compression is severe, the numbness will be fairly constant, and you may have weakness or wasting of the muscles supplied by that nerve.

The ulnar nerve at your elbow is exposed to increased pressure when the elbow is bent. Some conditions such as diabetes, hypothryroidism, rheumatoid arthritis, alcoholism, anorexia and obesity can increase your risk of developing cubital tunnel syndrome. Some people have a hereditary tendency toward developing nerve compression problems.

The first strategy of treatment is to understand the activities and positions that irritate your symptoms and then try to avoid these positions. By changing how you do things, you will take pressure off the ulnar nerve. Positions that place the elbow in bent postures (flexion) will increase pressure on the ulnar nerve, and elbow-straight positions (extension) will decrease the pressure. Most people sleep with their arms and hands in curled-flexed positions, and therefore, usually the first step of non-operative treatment is to protect the ulnar nerve at night. Wearing an elbow pad at night cushions the ulnar nerve from direct pressure, and most patients find this pad comfortable. If you spend a lot of time on the telephone, a head set is recommended to decrease the amount of time spent in elbow flexion. Stretching exercises at the elbow/forearm/wrist may be helpful in patients with tightness of the flexor carpi ulnaris muscle.

If nonoperative treatment is going to be successful in relieving symptoms, you will notice a decrease in your symptoms within four to eight weeks. However, it may take many months to completely relieve your symptoms. If you do not notice any relief or if you have muscle wasting, surgical management is recommended.

There are many surgeries for the treatment of cubital tunnel syndrome to take pressure off the ulnar nerve. If surgery is not performed, pressure on the ulnar nerve will continue, causing more numbness to your ring and small finger. Eventually, the small muscles of your hand will become weak, particularly in your pinch strength. These more severe changes will take many months and probably years to develop. Therefore, there is no urgency to have surgery for cubital tunnel syndrome unless you have severe ulnar neuropathy (degeneration of the nervous system), especially with muscle wasting.

The anterior transmuscular transposition of the ulnar nerve is the operation that we recommend. This operation to decompress the ulnar nerve involves releasing all tight soft tissue bands that are pressing on the nerve, moving the nerve to a position in front of the elbow within the flexor pronator mass and performing a flexor pronator muscle tendon lengthening procedure. The operation usually is done on an outpatient basis (or may require an overnight stay in the hospital) with an anesthetic to your arm. An incision is made behind your elbow. For your comfort, a long-acting anesthetic is placed at the incision site; this may cause increased numbness for up to a day after surgery. A drain is placed in the incision to help remove any blood from collecting at the operative site. After the incision is closed, a bulky dressing is placed on your arm to keep your elbow bent and wrist in a neutral position for two to three days.

As with any surgery, there are risks and complications that can occur with cubital tunnel surgery. There will be a scar behind your elbow that may extend into your upper arm or forearm. Occasionally, some patients will develop scar sensitivity or stiffness to the hand or arm. You may have excessive bleeding that may result in a hematoma (collection of blood underneath the skin). In most cases, this will reabsorb without any treatment, but sometimes it may be necessary to aspirate the hematoma. There is a risk of infection. There also is the risk of injury to the ulnar nerve or one of the surrounding nerves.

Your hand, wrist and elbow will be placed in a bulky dressing that extends from your hand to above your elbow, leaving your thumb and fingers free to move. Two to three days after surgery, the bulky dressing is removed, and you will be instructed in range-of-motion exercises for your hand, wrist, elbow and shoulder. The majority of patients will regain full function of their hand within a couple of months, although the incision may remain tender for many months while the scar tissue at the incision matures.

To make an appointment with a Washington University plastic and reconstructive surgeon, call 314-362-7388.

More information on treatment of peripheral nerve injuries is available on the Center for Nerve Injury & Paralysis website.