EMG is a two-part test: nerve conduction studies and the needle EMG.
With the nerve conduction study, we check the integrity of the nerves. We put a couple of little leads on the nerves, depending on what nerves we’re checking in the upper or lower extremities. Once we do the test, the information it gives us is whether or not there is a pinched nerve somewhere in the distribution of the nerve we checked, as well as where the injury is and what the prognosis is.
For the needle EMG component, we use a small needle, kind of like an acupuncture needle, and we check a couple muscles to see if there is any muscle damage related to the nerves. The test is very important because it helps the hand doctor determine what kind of treatment they’re going to do if there is a nerve injury in the upper extremity. It also helps the spinal surgeon know whether or not the patient needs surgery, based on the findings of the examination.
Reasons for ordering an EMG include numbness, tingling or pain in the hands, wrists, elbows, knees, ankles or feet, and if there’s any kind of weakness or atrophy or muscle loss in the upper or lower extremities. The most common study we do is for carpal tunnel syndrome or for a radiculopathy or pinched nerve in the upper or lower extremities. An EMG can also be used to look for ALS or neurologic conditions, so this information is very helpful for hand, wrist, elbow and shoulder specialists and again for the spine surgeons.
When we walk people through, they usually tend to tolerate the procedure very well. There are really hardly any complications or risk with the EMG. If there’s an active infection going on, we’ll hold off and do the EMG on a different day. There might be a little bit of bruising associated with the needle component…more a discomfort with the needle component and the nerve conduction portion. Like I said before, we really walk the patients through every step, so there are no surprises at all during the procedure.
An EMG will take roughly 15-20 minutes, depending on the test results. Once we start doing the examination, if we see some abnormal findings it might take a little bit longer, but in general, it takes about 15-20 minutes.