When Can Foot Drop Be Reversed?

A foot drop represents a patient's inability to dorsiflex the foot (flex the foot towards the sky). There are a number of reasons it happens, and this article discusses foot drop that occurs from any reason outside of spine surgery. For instance, it can be the result of a spinal cord injury, stroke, tumor, or compression/injury to either the peroneal nerve or the lumbar nerve root itself.

When a patient develops a foot drop, the first important consideration is to figure out the cause. The primary contributor to a person being able to dorsiflex the foot is the L5 nerve root. Other nerve roots may help as well, such as L4, which can sometimes explain a partial foot drop. If the cause ends up being farther down the leg (more distal), it can be the peroneal nerve.

An electromyographic exam is a vital test to determining the level of the problem, whether it's in the back or in the leg. Along with this, an MRI can be vital to seeing if there is a herniated disc pushing on the L5 nerve root. That would be the most common cause, but in certain instances even something rare like a spinal cord tumor may show up. One should have an extremely low threshold for ordering an MRI for evaluation of a foot drop.

If the electromyography and MRI are consistent with a herniated disc compressing a nerve root, then the answer is clear. But what's the solution? There is no definitive answer as to how long it is acceptable to watch a foot drop. However, the current theory is that over 3 to 6 months it may be a permanent situation despite fixingthe problem. This means that if it is observed 6 months for improvement, none occurs, and then surgery is undertaken, it may never get better even with a perfectly done procedure.

So what's the answer? Patients are different in healing capacities, so it's not a black and white answer. But if a foot drop has been present for 3 months, heavy consideration should be given to decompressing the problem area. If this means a herniated disc on the L5 nerve root, a discectomy should be accomplished. If this means a compressed peroneal nerve, it is a short procedure to free it up.

It should never be ignored. The cause should be figured out, and then an action plan put into place. That may mean an observation period to see if it resolves, but after a certain point the risk of a permanent situation makes it prudent to take away the compression despite the surgical risks.