Nerve compression other than carpal tunnel syndrome

“Yeah runnin’ down a dream that never would come to me, working on a mystery, goin’ wherever it leads, runnin’ down a dream”

Tom Petty “Runnin’ Down a Dream”

Well I took a little sabbatical here to get some new ideas and add to the blog.  In honor of the late great Tom Petty, who died this month, our topic song is from his great album “Full Moon Fever”.  Everyone seems to know about Carpal Tunnel Syndrome, but there are actually a couple of other areas in the upper extremity where nerves can be compressed and cause problems such as numbness or weakness.

There are three major nerves in the arm and all three of them have specific areas where they can be compressed.  The most common area of course is carpal tunnel syndrome where the median nerve is compressed at the wrist.  However a more rare form of compression of the median nerve can occur further up the arm closer to the elbow.  Near the elbow the median nerve passes between a pretty big muscle called the pronator teres.  Very rarely the nerve can be pinched as it passes through the pronator and cause pain and discomfort in the arm.  The pain is usually pretty vague and does not always occur at night.  Occasionally patients will have numbness and tingling as well that can mimic carpal tunnel syndrome.  If the patient has carpal tunnel like symptoms of numbness and tingling and also has pain in the forearm near the elbow, then I have to think about the possibility of the median nerve being compressed further up the arm rather than at the carpal tunnel in the wrist.  There are ways of examining a patient to help make the diagnosis and occasionally a nerve conduction study will reveal the area of compression.  This problem may well get better on its own with rest and a cortisone shot may or may not help.  Rarely surgery is indicated to try and release the pressure on the nerve.

There is a variation of this problem where the thumb and index finger may quit bending due to irritation of a branch of the median nerve call the anterior interosseous nerve.  This is a scary problem because the patients can’t bend the tip of the thumb or the index finger.  Unfortunately there’s not much that can be done for this problem other than waiting for it to resolve.  Most of the recent studies don’t seem to show much improvement with surgery which is done to try and release pressure on the nerve.  It can sometimes take 6 months or longer for the nerve to recover so this takes a lot of patience from both the patient and the physician.

The ulnar nerve is another nerve that can be compressed.  This is your “funny bone” on the inside of your elbow, and pressure on the nerve at the elbow is the second most common area of compression in the upper extremity.  The latin word for elbow is “cubital” so this is known as cubital tunnel syndrome.  The most common symptom of cubital tunnel syndrome is numbness and tingling the pinky and the ring finger (carpal tunnel usually involves the thumb, index and middle fingers).  Patients may also notice weakness or clumsiness when using their hands because the ulnar nerve goes to the small muscles in the hands which contribute to our dexterity.  The most common cause of this problem is compression on the nerve as it passes around the elbow and goes through a tunnel of muscle.  A lot of the time this problems just goes away on it’s own.  It’s really hard to splint the elbow and cortisone shots don’t seem to do much good.  If the symptoms are really causing a problem or if numbness or muscle weakness have occurred then sometimes surgery is indicated.  There are a number of procedures than can be done, from simply releasing the nerve from the constricting areas to moving the entire nerve to get it away from the places where it is getting pinched.

Very rarely the ulnar nerve can be compressed in the wrist as well in an area right next to the carpal tunnel called guyon’s canal.  I’ve found in a significant number of patients who have this problem they usually have a small cyst or mass that is pressing on the nerve which needs to be removed as well as releasing the compression on the nerve.

The third major nerve to the arm is called the radial nerve and a branch of this nerve called the posterior interosseous nerve can be compression near the elbow.  This is usually on the top outside part of the elbow and can mimic tennis elbow.  This problem is known as radial tunnel syndrome.  The pain is usually not as specific as tennis elbow and the area that is really sore is a different from tennis elbow.  If I suspect the nerve is compressed I usually recommend an injection of cortisone and a numbing agent.  The problem will usually improve with an injection, although this may be temporary and the problem may need surgery to remove pressure from the nerve.

Fortunately these problems are pretty rare.  I will occasionally see patients with both carpal and cubital tunnel syndrome, and I see a fair number of patients with cubital tunnel syndrome, but the other problems are things that I see only a couple of times a year.  A good hand surgeon will be aware of these rare problems and hopefully can help guide you through if you develop one of these problems.