Ulnar Nerve Entrapment at the Elbow
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. Ulnar nerve entrapment occurs when the ulnar nerve in the arm becomes compressed or irritated. Depending upon where it occurs, this pressure on the nerve can cause numbness or pain in your elbow, hand, wrist, or fingers.
The most common place where the nerve gets compressed is behind the elbow, where the nerve travels through a tunnel of tissue called the cubital tunnel and runs under a bump of bone at the inside of your elbow. This bony bump is called the medial epicondyle. (The spot where the nerve runs under the medial epicondyle is commonly referred to as the “funny bone.”) When the nerve is compressed in this location it’s called cubital tunnel syndrome. The site of the compression can be above or below this location, in which case it is called “abnormal compression at the elbow.”
There are several things that can cause pressure on the nerve at the elbow, including repeatedly bending your elbow or bending it for a long period of time. When you bend your elbow, the ulnar nerve stretches around the boney ridge of the medial epicondyle and this can irritate the nerve. In some people, the nerve slides out from behind the medial epicondyle when the elbow is bent. Over time, this sliding back and forth may irritate the nerve. Sometimes a thickened ligament or extra muscle “belly” can compress the nerve.
Cubital tunnel syndrome can cause an aching pain on the inside of the elbow. Most of the symptoms, however, occur in your hand. These include: “falling asleep” in the ring finger and little finger, especially when the elbow is bent. In some cases, it may be harder to move fingers in and out, or to manipulate objects. You may also feel numbness and tingling in the ring finger and little finger as well as weakening of your grip and difficulty with finger coordination (such as typing or playing an instrument). If the nerve is very compressed or has been compressed for a long time, muscle wasting in the hand can occur.
To stop the condition from progressing, you should avoid activities that require you to keep your arm bent for long periods of time, and stop leaning on your elbow or putting pressure on the inside of your arm. It is best to keep your elbow straight at night when you are sleeping. (This can be done by wrapping a towel around your straight elbow or wearing an elbow pad backwards.)
Dr. Pianka recommends making a doctor’s appointment if your symptoms are severe, or if they are less severe but have been present for more than six weeks. He can use X-rays to determine if bone spurs or arthritis may be compressing the nerve, while nerve conduction studies can determine how well the nerve is working and help identify where it is being compressed. Nerve conduction studies can also determine whether the compression is causing muscle damage. During the test, small needles are put into some of the muscles that the ulnar nerve controls. Muscle involvement is a sign of more severe nerve compression.
Unless your nerve compression has caused a lot of muscle wasting, the doctor will most likely first recommend nonsurgical treatment, which includes non-steroidal and anti-inflammatory medicines, steroid injections, bracing/splinting, and nerve gliding exercises.
When surgery is necessary, it’s most often done on an outpatient basis, but some patients do best with an overnight stay at the hospital. Options include:
Cubital tunnel release. In this operation, the ligament “roof” of the cubital tunnel is cut and divided. This increases the size of the tunnel and decreases pressure on the nerve. After the procedure, the ligament begins to heal and new tissue grows across the division. The new growth heals the ligament, and allows more space for the ulnar nerve to slide through.
Ulnar nerve anterior transposition. More commonly, the nerve is moved from its place behind the medial epicondyle to a new place in front of it. Moving the nerve to the front of the medial epicondyle prevents it from getting caught on the bony ridge and stretching when you bend your elbow.
Medial epicondylectomy. Another option to release the nerve is to remove part of the medial epicondyle. Like ulnar nerve transposition, this technique also prevents the nerve from getting caught on the boney ridge and stretching when your elbow is bent.
Depending on the type of surgery you have, you may need to wear a splint after the operation. A submuscular transposition usually requires two weeks in a splint. In addition, Dr. Pianka may recommend physical therapy exercises to help you regain strength and motion in your arm.