Cubital tunnel syndrome and radial tunnel syndrome aren't as familiar as their better-known relative -- carpal tunnel syndrome -- but they also can cause severe pain, numbness, tingling, and muscle weakness in the hands and arms.
The common cause of all these nerve compression syndromes is increased pressure -- usually from bone or connective tissue -- on a nerve in the wrist, arm, or elbow. In most cases, cubital tunnel syndrome and radial tunnel syndrome can be managed with conservative treatments. But more severe cases may require surgery to reduce pressure on the affected nerve.
Cubital Tunnel Syndrome: Causes and Symptoms
Cubital tunnel syndrome -- also known as ulnar neuropathy -- is caused by increased pressure on the ulnar nerve, which passes close to the skin's surface in the area of the elbow commonly known as the "funny bone." You're more likely to develop cubital tunnel syndrome if you:
- Repeatedly lean on your elbow, especially on a hard surface
- Bend your elbow for sustained periods, such as while talking on a cell phone or sleeping with your hand crooked under your pillow
Sometimes, cubital tunnel syndrome results from abnormal bone growth in the elbow or from intense physical activity that increases pressure on the ulnar nerve. Baseball pitchers, for example, have an increased risk of cubital tunnel syndrome, because the twisting motion required to throw a slider can damage delicate ligaments in the elbow.
Early symptoms of cubital tunnel syndrome include:
- Pain and numbness in the elbow
- Tingling, especially in the ring and little fingers
More severe symptoms of cubital tunnel syndrome include:
- Weakness affecting the ring and little fingers
- Decreased ability to pinch the thumb and little finger
- Decreased overall hand grip
- Muscle wasting in the hand
- Claw-like deformity of the hand
If you have any of these symptoms, your doctor may be able to diagnose cubital tunnel syndrome by physical examination alone. He or she also may order a nerve conduction study and a test called electromyography. Electromyography is a procedure in which electrodes placed into muscles and on the skin measure the health of muscles and the nerve cells that control them, to confirm the diagnosis, identify the area of nerve damage, and determine the severity of the condition.
Radial Tunnel Syndrome: Causes and Symptoms
Radial tunnel syndrome is caused by increased pressure on the radial nerve, which runs by the bones and muscles of the forearm and elbow. Causes include:
- Noncancerous fatty tumors (lipomas)
- Bone tumors
- Inflammation of surrounding tissue
Symptoms of radial tunnel syndrome include:
- Cutting, piercing, or stabbing pain at the top of the forearm or back of the hand, especially when you try to straighten your wrist and fingers.
In contrast to cubital tunnel syndrome and carpal tunnel syndrome, radial tunnel syndrome rarely causes numbness or tingling, because the radial nerve principally affects the muscles.
Just as with cubital tunnel syndrome, if you have any of these symptoms, your doctor may be able to diagnose radial tunnel syndrome by physical examination alone. He or she also may order electromyography to confirm the diagnosis, identify the area of nerve damage, and stage the severity of the condition.
Treatments for Cubital Tunnel Syndrome and Radial Tunnel Syndrome
Cubital tunnel syndrome often can be managed conservatively, especially if electromyography reveals that there is minimal pressure on the ulnar nerve.
Mild cases of cubital tunnel syndrome often respond to physical therapies such as:
- Avoidance of undue pressure on the elbow during daily activities
- Wearing a protective elbow pad over the "funny bone" during daily activities
- Wearing a splint during sleep to prevent over-bending of the elbow
In cases where splinting doesn't help or nerve compression is more severe, about 85% of patients respond to some form of surgery to release pressure on the ulnar nerve. These include surgeries that:
- Result in simple decompression of the ulnar nerve
- Shift the nerve to the front of the elbow
- Move the nerve under a layer of fat, under the muscle, or within the muscle
- Trim the bump of the inner portion of the elbow -- the medial epicondyle -- under which the ulnar nerve passes
If you undergo surgery for cubital tunnel syndrome, recovery may involve restrictions on lifting and elbow movement, and rehabilitation therapy. Although numbness and tingling may or may not quickly improve, recovery of hand and wrist strength may take several months.
Conservative treatments for radial tunnel syndrome include medications such as nonsteroidal anti-inflammatory drugs to reduce soft tissue swelling, corticosteroid injections to relieve inflammation and pressure on the radial nerve, and wrist and/or elbow splints to reduce irritation of the radial nerve.
Some patients also may benefit from ergonomic education to reduce the effects of repetitive stress, nerve-gliding exercises, stretching/strengthening exercises, and other interventions such as heat, cold, and ultrasound.
If these conservative measures fail to provide relief after three months, your doctor may consider surgery to reduce pressure on the radial nerve. Surgery is often recommended in severe cases, particularly those in which the wrist becomes weak or droopy or it becomes difficult to extend the fingers.