Electromyography is a complementary test that is sometimes called for by a doctor when he or she has doubts about the degree of involvement of a nerve in the body or when it is suspected that it is damaged. Nerves are the wires that the body has to carry information. A nerve can be damaged for many reasons. There are diseases like diabetes that damage the nerves with time or wounds where we hurt directly on the nerve such as a cut with a crystal, for example.
Back injuries can also damage nerves. The most frequent cause is the herniated disc, although nerve injuries can also occur due to fractures or dislocations of the vertebrae after a trauma. There are other causes but they are much less frequent.
In the case of the lower back (lumbar spine) the nerves that go to the legs are affected. These nerves will collect the sensitivity information in the legs and will transmit the signals to the muscles so they can move. Once a nerve is damaged, it has consequences. To simplify a little would be as follows:
– It can damage the nerves that carry the sensitivity and then we will notice pain in the form of cramps and tingling by the leg. We may even lose sensitivity in some areas.
– If you damage the nerves that bring the motor activity to the muscles, it will cause a loss of strength in the affected muscles.
These lesions can be detected with adequate physical examination by the physician, but sometimes there may be doubts or more data are required of the problem and then electromyography is used.
Electromyography as a test has two parts
– There is a part that focuses on analyzing the muscles. We are going to prick ourselves with a very fine needle in some muscles, for example, in the leg (in the case of sciatica). The needle has electrodes that will allow us to analyze the electrical activity of that muscle. The examiner will ask us to contract and relax the muscle while analyzing whether this electrical activity is correct or if there are signs that suggest disease.
– During the test also we can stick some stickers on the skin following the route of these nerves. Through electrical stimulation, which we will notice as cramps through the arm or leg, we will be able to analyze if these nerves conduct electricity as they should or if there are alterations during the tour.
As for the question of whether it can do harm, it is a very low risk test but it is still an invasive technique because we are pricking in the muscle. It therefore has the risk of a puncture: bleeding, infection or puncture in an unwanted area. But it is exceptional that significant problems occur. During the test it can be somewhat annoying to get a muscle but performed by expert staff hardly knows. They have a worse reputation for the electric shocks that occur during the test but almost everyone adapts well and the general comment after the test is usually a “not so much”.
These are the basics of how this test works. Electromyography is an aid to the doctor to tune in the diagnosis and to be able to recommend the most appropriate treatments, but it is a complementary test. In no case can this test replace a medical evaluation, nor will it be the only element of judgment to opt for a particular treatment.
Being a web that speaks of back I added two posts where I explain what we can provide this test in sciatica and another where I talk about what it means to have a normal electromyography. The latter is very disturbing and is a very frequent question that I receive in the comments.
You May Also Like this website.