Ulnar Nerve Entrapment

Ulnar Nerve

The ulnar nerve is one of the three main nerves in your arm. It travels from your neck down into your hand and can be constricted in several places along the way, such as beneath the collarbone or at the wrist.

Anatomy

The ulnar nerve controls most of the fine motor muscles in the hand as well as the bigger forearm muscles that help with making a strong grip. It gives feeling to both pinky fingers and half of the ring fingers on your hands. The ulnar nerve travels through a tunnel of tissue called the cubital tunnel that runs under a bump of bone called the medial epicondyle on the inside of your elbow. Commonly known as the “funny bone” is the spot where the nerve runs under the medial epicondyle and causes a shock sensation when bumping it. The ulnar nerve is more vulnerable to compression at the elbow because it must travel through a narrow space where there is very little soft tissue protecting it.

The ulnar nerve continues beyond the elbow traveling under forearm muscles and into your hands. When it enters the hand, the nerve travels through another tunnel of tissue called the Guyon’s canal.

Common Causes of Compression at the Elbow:

• Putting too much pressure on the nerve by leaning on your elbow or flexing it for a lengthy period.
• Swelling or cysts caused by fluid buildup in your elbow.
• Direct trauma to the inside of your elbow.
• Bone spurs/arthritis of your elbow.
• Repeated elbow bending for long periods of time can irritate the ulnar nerve. You may wake up in the middle of the night with your fingers asleep because you slept with your elbow bent.
• When the elbow is bent, in some cases, the ulnar nerve may slide out from behind the medial epicondyle. Over time, this continual sliding back and forth movement irritates the nerve.

Treatment

Nonsurgical Treatments

Nonsurgical treatments for ulnar nerve entrapment and cubital tunnel syndrome include the following:

• Bracing or splinting to keep your elbow in a straight position.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen to help reduce swelling around the nerve
• Avoiding activity that demand bending of your arm for a lengthy period. For example, do not drive with your arm resting on an open window.
• Modifying your chair position when using a computer so that you do not rest your elbow on the armrest.
• Modifying your sleeping position so that you keep your elbow straight. Wearing an elbow pad backward or wrapping a towel loosely around your arm with tape can help prevent you from bending your elbow through the night.
• Nerve gliding exercises if directed by Dr. Stowell.

If symptoms do not improve, your ulnar nerve is very compressed, or nerve compression has caused damage in your hand, surgery may be recommended by Dr. Stowell. At your appointment, Dr. Stowell will discuss your medical history and general health. He will thoroughly examine your arm and hand to determine which nerve is being affected and where it is compressed.  He may order X-rays to check for bone spurs, arthritis, or other places that the bone of your elbow or wrist may be compressing the nerve.

Dr. Stowell will then conduct a nerve study to help identify where the nerve is being compressed. Nerves are like electrical cables, carrying messages to your brain and muscles. When a nerve is damaged or not functioning well, it takes longer for it to communicate and conduct. Dr. Stowell may stimulate the nerve and measure the time it takes for a response. The area where a response takes too long is likely where the nerve is being compressed. During this study, Dr. Stowell can also determine if nerve compression is causing muscle damage. If muscles damage is present, it is usually a sign of more severe nerve compression.

Surgical Treatments

There are a few surgical procedures that will help relieve pressure on the ulnar nerve at the elbow. Dr. Stowell will discuss the option that is best for you. These procedures are most often done on an outpatient basis and include:

• Cubital tunnel release – Dr. Stowell cuts and divides the ligament roof of the cubital tunnel, increasing the size of the tunnel and decreasing pressure on the nerve. As the ligament heals, new tissue grows across the division, allowing more space for the ulnar nerve to slide through.
• Ulnar nerve anterior transposition – Dr. Stowell makes an incision along the inside of your elbow or back side of the elbow and moves the nerves from behind the medial epicondyle to a new place in front of it, preventing it from getting caught on the boney ridge when bending. There are three types of transpositions where the ulnar nerve can be moved to lie under the skin and fat, on top of the muscle called a subcutaneous transposition; within the muscle called an intermuscular transposition; or under the muscle called a submuscular transposition.
• Medial epicondylectomy – Dr. Stowell removes part of the medial epicondyle to release the nerve. Like an ulnar nerve transposition, this procedure also prevents the ulnar nerve from getting caught on the boney ridge when bending.

After your operation, Dr. Stowell may send you home in a splint. A submuscular transposition procedure usually requires about 3 to 6 weeks in a sling. Dr. Stowell may also recommend physical therapy exercises to help regain strength and mobility in your arm.

Surgical results are generally good for each method of nerve compression surgery. If there is significant nerve compression or muscle degeneration, the nerve may not be able to return to normal, leaving symptoms to continue even after surgery. Nerves recover slowly. Patience is required to know exactly how well the nerve does after surgery.