I saw a hand surgeon for what I thought was carpal tunnel syndrome. My ring finger and baby finger were both going to sleep all the time. But she says I have something else called cubital tunnel syndrome. I was told diagnostic testing isn't all it's cracked up to be. So they may treat it with medications and physical therapy. Should I get a second opinion? Is an actual diagnosis important?
Carpal tunnel and cubital tunnel syndrome are very similar problems. They both involve pressure, traction, or loss of blood flow to a nerve in the forearm. In the case of carpal tunnel syndrome, the median nerve is affected as it travels through the carpal (wrist) bones. Those carpal bones are lined up to form a tunnel through which the nerve passes. Anything that alters the alignment or shape of that tunnel can put pressure on the nerve causing carpal tunnel syndrome.
The cubital tunnel is also an anatomic location only this time in the elbow. A natural groove in the bone keeps the ulnar nerve along the inside of the elbow on track as it travels from the upper arm through the elbow area and down to the hand. Symptoms of finger numbness and tingling develop but affect different fingers depending on which nerve is compresses or pinched.
Symptoms affecting the ring and little fingers point to the ulnar nerve as the problem. That leads the physician to examine the cubital tunnel for any signs of nerve impairment. For example, palpation while moving the elbow is performed. This technique may show that the nerve moves in and out of the natural groove (cubital tunnel) in the bone where it should remain all the time. This type of nerve subluxation (partial movement out of the groove) or dislocation (nerve displaced out of the groove completely) can contribute to the problem.
Although physicians rely on these tests to diagnose cubital tunnel syndrome, studies show they aren't all that reliable or dependable. One of the biggest problems in coming to any conclusions about testing for cubital tunnel syndrome is how much variation there is in conducting the tests. Judging the results (called interrater reliability) is another important factor. The lack of interrater reliability is one reason why these tests can't be used alone to make the diagnosis.
There are electrodiagnostic tests that can be done. Nerve conduction studies check the speed at which the nerve transmits signals. Damaged, compressed, or irritated nerves may have abnormal conduction times. But studies of the validity and reliability of nerve conduction tests show limited sensitivity for these tests.
What about imaging studies such as ultrasound, MRI or CT scans? There haven't been a lot of studies in this area. So far, it looks like MRIs show nerve compression before it is evident using electrodiagnostic testing.
The best imaging choice may be ultrasound. Bouncing sound waves off the tissues creates a picture on a computer screen. It allows the surgeon to see any changes in the cubital tunnel. Ultrasound images reveal bone spurs or ganglions that are pressing on the nerve. Ultrasound also provides a view of the nerve to see if it is subluxed or dislocated from the cubital tunnel.
You can always get a second opinion but first you may want to ask your surgeon to reconfirm her diagnosis with an ultrasound scan. It can't hurt and it may help offer some additional information. Unless a tumor or other unusual mass is found in the area, it's likely that the initial treatment will be the same: conservative (nonoperative) care. Conservative care usually consists of antiinflammatory medications, an elbow splint at night to keep the elbow straight, and modifications to your daily activities to give the elow (and the ulnar nerve) a rest. If your symptoms do not improve with this approach, then further diagnostic testing may be ordered.
Richard L. Hutchinson, MD, and Ghazi Rayan, MD. Diagnosis of Cubital Tunnel Syndrome. In The Journal of Hand Surgery. September 2011. Vol. 36A. No. 9. Pp. 1519-1521.
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