Lumbar radiculopathy is irritation of a nerve root as it exits the spine. Radiculopathy: "Radic-" is just Latin for "nerve root" and "-opathy" is "pathology.” So it’s pathology of a nerve root. Commonly, people refer to it as a pinched nerve in the back.
Lumbar radiculopathy comes from a variety, can arise from a variety of factors within the spine. You can have a herniated disc, there can be some arthritis in the facet joint, you can have bone spurs, you can have spondylolisthesis, where the bones in the spine actually slip on top of one other, you can have the ligamentum flavum buckling. All of these things can contribute to narrowing of the space where the nerve exits the spine. Essentially, if you think of the hole where the nerve comes out, and as that hole gets encroached upon, there’s less room for give within the hole. It doesn't have to be a mechanical constriction of the nerve, but there‘s just less room within that hole for the nerve to exist and there becomes more of a propensity towards an inflammatory response. That inflammatory response can cause pain, numbness, weakness in the leg. Often the pain will be radiating into the leg, and that's what we call lumbar radiculopathy.
Diagnosing lumbar radiculopathy, just like we diagnose most things medically, begins with a good history and a good physical examination. This is really Medicine 101. Often from the history and the physical examination, we can tell whether or not a lumbar radiculopathy is present. And we'll typically get an MRI to be able to look at the anatomy to see what anatomical processes are contributing to that radiculopathy—a herniated disc, spinal stenosis, foraminal stenosis, facet joint arthropathy. All of these things can contribute to it, so we look at the anatomy to get a sense of which level and what the underlying pathophysiologic process is that’s actually going on.
Sometimes, if the diagnosis is in doubt, or if we want to get a sense of the extent of the radiculopathy, we may also get a nerve test, which basically looks at, which is a way of testing the nerves to see where the inflammation is coming from a little more exactly and to what extent the inflammation is there and to help rule out also more peripheral causes that can sometimes mimic a lumbar radiculopathy. Nerve testing is commonly referred to as an EMG.