While most people have heard of carpal tunnel syndrome, a condition in which the nerves going through the carpal tunnel in the wrist are pinched, another condition called cubital tunnel syndrome also exists. With cubital tunnel syndrome, the pressure is on the back of the elbow onto the ulnar nerve – where your “funny bone” is. It can cause pain, weakness, or numbness of the hand. It can also cause numbness or a pins-and-needles sensation on the ring finger or small finger (pinky).
Cubital tunnel syndrome can be caused by a few things, with the most common cause being repetitive bending and straightening of the elbow, such as reaching for something and pulling down. Other people develop it by leaning on their elbow either at their desk, in the car, or elsewhere. Other causes include something that is in the elbow that shouldn’t be, like a cyst, that takes up space and puts pressure on the nerve. Of course, like with striking your “funny bone,” if you hit the ulnar nerve hard enough to cause an injury, it could also result in cubital tunnel syndrome.
Diagnosis of cubital tunnel syndrome includes patient history of pain or numbness in the fourth (ring) finger and small finger. Some patients may have weakness in their hand as well as a duller sensation compared to the other hand. Studies have found that 40 percent of patients with cubital tunnel syndrome also have atrophy, or wasting away of muscles, in the hand.
When examining the hand, the doctor will check for the sensation on the tip of each finger, as well as strength in the fingers. The doctor may also apply pressure to the ulnar nerve, check the patient’s ability to bend the elbow, and performing the Tinel’s sign, which involves lightly tapping over the nerve to see if the tapping causes tingling.
In one study, performed by Novak and colleagues, of 32 patients with cubital tunnel syndrome and 33 control patients who didn’t have an elbow problem, researchers found that the elbow bending test was twice as effective (sensitive) if it was done for 60 seconds when compared to only 30 seconds. The problems with such tests is the margin of error that exists – if they are done correctly and for a long enough period. The authors of this article wrote that using electrodiagnostic tests, tests that use electrical currents, may be more effective and help avoid the subjective nature of tests like the elbow test. However, some doctors don’t care to use electrodiagnostic tests because they, too, have given false negative results.
Other tests that can be done are ultrasounds and magnetic resonance imaging (MRI). Ultrasounds use sound waves to make an image on a screen. This can help find if there are any cysts, tumors or other masses in the elbow that may be causing the problem, as well as tell if there are any abnormalities. MRIs, which make images using magnets, can show if the nerve has become larger than it should be and it can also tell if there are any masses in the elbow space.
Treatment for cubital tunnel syndrome varies according to the doctor. Surgery has been a common treatment, but the type of surgery may differ. Some surgeons decompress the area so there is no more pressure on the nerve, while others move the nerve so that it’s not so vulnerable to pressure. Studies have shown that there doesn’t seem to be a difference between the two techniques in how successful the surgery is. And, because there is no difference in outcome, researchers recommend that surgeons choose to do the decompression because it’s less invasive than the other.
Following surgery, it’s possible that the patients still feel pain in the elbow. This may be caused by damage to the nerve during surgery. The solution for this could be injection of an anesthetic directly to the painful area.
In conclusion, the authors wrote that researchers are still trying to determine the best way to treat cubital tunnel syndrome. In order to be more exact, however, more trials will need to be done on larger patient populations.