Post-Amputation Pain

Eric H. Williams MD
Specializing in reconstructive surgery and pain relief in the Greater Baltimore area.

Did you know that, according the U.S. Department of Health and Human Services, there are approximately 185,000 new extremity amputations performed annually in the United States?

Out of all those amputation procedures, roughly 86 out of every 100 involve lower extremities (legs, feet). Naturally, this means the other 14 out of that 100 involve upper extremities (arms, hands). Regarding procedures for lower limbs, amputations below the knee constitute a vast majority—with this applying to slightly more than 7 out of every 10.

One more interesting amputation statistic:

Roughly 2 million Americans are currently living with some form of limb amputation.

In general, limb amputation is performed in an effort to provide better function or address disease and resolve painful or life-threatening illnesses. Therefore, it is especially frustrating and disheartening when you have postoperative pain after the difficult decision was made to undergo an amputation.

And that decision wasn’t even necessary an easy one—even though it was likely the right call—in the first place. After all, losing a limb can already be challenging in both physical and psychological ways. To have pain on top of that is like being kicked when you’re down.

Accordingly, your frustration for this situation is completely understandable!

In fact, it’d be a little strange if you weren’t at least somewhat upset about this outcome—but there’s a chance you don’t have let this become a permanent state in your life.

We have been fortunate to help other patients who came to us experiencing post-amputation pain, and we may be able to do the same for you!

Physical Pain After Limb Amputation

Amputation performed to treat pain—and/or save your life—can present its own unique challenges in some patients. When it does, the associated pain can fall into one of three general categories:

  1. Phantom limb pain (PLP)
  2. Residual limb pain or “stump pain” (RLP)
  3. Phantom sensations

Reported statistics on this vary, but the number of amputees who experience at least one of these three conditions may be as high as 95%.

Let’s take a closer look at each of these:

PHANTOM LIMB PAIN is a painful or unpleasant sensation in the distribution of the missing body part. This type of pain is often described as a burning, sharp, shooting, aching, pressure, and electrical in nature. It may be perceived as affecting the whole limb or just one region of the missing limb.

PLP usually occurs within 6 months of the loss of the limb and may present at 2-3 years post amputation in as many as 85% of amputees. In addition, it can persist for years after surgical amputation.

RESIDUAL LIMB PAIN is usually localized to the remaining body part after amputation. It is frequently described as sharp, dull, aching, burning, and shocking in nature. It can be perceived to involve just the distal end of the stump or throughout the entire residual limb.

The pain can be located deep within the residual limb but it can also be superficial in nature, often involving the skin, making it very painful to touch or rub. This is a major reason for patients not being able to tolerate wearing a prosthetic limb. The incidence of stump pain is reported to be as high as 75%.

PHANTOM SENSATIONS are defined as non-painful perceptions in the distribution of the lost body part that may be perceived as movement of the missing body part, size, shape or position of the missing body part, or sensations such as touch, pressure, vibration, tingling, itch, or temperature. This phenomenon occurs in as many as 2/3 of major limb amputees.

Although there are all kinds of ways to categorize and describe post-amputation pain, it can be difficult to distinguish one category of pain from another.

Where Your Post-Amputation Pain Comes From

Traditionally, both phantom pain and stump pain have been very difficult to treat. When peripheral nerves are cut, they will invariably form neuromas as they try, and fail, to reconnect with the end of the nerve which has been removed (along with the amputated limb).

These “stump” neuromas, along with potential compression neuropathies, can be responsible for both the pain in the residual limb, as well as at least some types of phantom pain. Phantom pain is theorized to involve processes which occur at the level of the brain and spinal cord in addition to peripheral mechanism which can make it more difficult to treat.

When a nerve is cut, there is sprouting of the nerve fibers (axons) on the “live” end of the nerve (the end which is still attached to the spinal cord). If the nerve is not repaired surgically, the live end of the nerve may form a painful structure known as a “neuroma.”

A neuroma is simply a tangled mass of these sensitive nerve endings stuck in a ball of scar tissue. Each axon in our body is programmed into the brain to identify a specific area of the body. When something touches the bottom of your big toe, those nerve fibers transport a signal to the brain that lets the brain know that the big toe has been touched. In effect, those particular nerve fibers “represent” the bottom of your big toe in the brain.

If you were to cut across those nerve fibers just below the level of the knee joint as part of a below knee amputation, it doesn’t change the way the brain identifies them. To the brain, the injured nerve fibers are still identified with the bottom of the big toe.

Now, supposing those fibers end up becoming stuck in a neuroma that is right down nerve the end of the amputation stump. Any time something pushes or stimulates the neuroma, the axons mapped to the bottom of the big toes can send a painful signal to the brain which may make you feel like the bottom of your big toe is being stabbed with a pin, shocked, or even burned with a hot coal.

Neuromas can also produce painful sensations in the ends of the stumps or even pain which can radiate throughout the remaining part of the limb as well.

If nerves which have been partially amputated also go to areas of skin, or of the prosthesis rubs or puts pressure on these nerves, this can result in a situation where the skin itself can become painful to even the lightest touch. This can make wearing a prosthesis nearly impossible.

Post-Amputation Pain Treatments: Old and New

Where in the past, many have suffered while choosing life-saving options like limb amputation, there are now a variety of techniques and treatment methods used to provide relief for painful symptoms. For example, pain management teams have a continued interest in neuromodulation and spinal cord stimulations.

We are going to switch our focus to surgical options, but keep neuromodulation in mind (since it will be coming back up in a moment).

One popular approach in the past to treating stump neuromas was to make small incisions down at the end of the residual limb, try and find the neuroma within all the remaining scar tissue (a rather difficult task, as you can likely imagine), and then simply cut the nerve back slightly and hope for the best.

This approach has not always been as successful as we’d hope because, even if your surgeon can find the neuroma (or all the multiple neuromas, which is often the case), it is only a matter of time before a new neuroma will grow back or the end of the nerve is still located in a superficial location, and the problem starts all over again.

Recent work has been showing promise, however, for a better approach to treating both phantom and stump pain that can arise from peripheral nerve neuromas following amputation.

With a more detailed understanding of peripheral nerve anatomy and mapping of nerve locations, incisions can be made remotely from the end of the residual limb in healthy tissue (without scarring) and used to find the specific nerve responsible for the symptoms. Once located, we may be able to disconnect them so you can find relief.

Subsequently, newer techniques are then employed to prevent another painful neuroma from developing. This can include implanting proximal ends of affected nerves in muscle, or attaching nerve grafts. With grafting, this may allow native nerves to grow into them, and then essentially “burn out” before a painful neuroma can be formed.

There is also promising research being performed on various techniques to improve post-amputation pain. A particularly noteworthy one entails attaching the “free” nerve end to a muscle graft, thus “closing the circuit” and giving the nerve something useful to do, thereby eliminating the unresolved signal that the brain misinterprets as painful. This also removes the end of the nerve away from the area where it can be irritated by the prosthesis or stretched by movement across the knee joints.

Where there was previously little hope for amputees, there are now good options to relieve both stump and potentially phantom pain. This can allow the amputee to resume wearing a prosthesis comfortably, restoring greater mobility and independence, as well as provide a major psychological boost.

There’s been continued efforts in neuromodulation and peripheral nerve stimulation to control these symptoms and turn off pain signals electronically as well, and we suspect that we will see improved outcomes in the future if these techniques can be used in a coordinated fashion.

At our Baltimore office, we have a unique interest in combining techniques to improve outcomes for more patients. By integrating surgical and other techniques, we are hopeful to see this happen for the simple reason that both surgical and neuromodulation approaches have their respective limitations. Combining them, however, may reduce those limitations and capitalize on their respective strengths—and this can potentially lead to improved results for those who have been suffering.

Remember, it’s okay to be frustrated with this situation, but keep in mind that you do have options!

If you are suffering with pain following your limb amputation, simply give us a call today at (410) 709-3868 and we will be happy to schedule you for a consultation at our Baltimore office. Together, we can discuss potential options and determine your next steps in finding the relief you deserve.

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