Surgical innovations for managing residual and phantom limb pain after amputation
In the relatively short time that Dr. Jhade Woodall has been performing reconstructive plastic surgeries at Eastern Idaho Regional Medical Center, he has treated severe injuries caused by motorcycles, ATVs, and farm equipment. It’s just part of practicing medicine in a state where people play and work hard.
Occasionally, such accidents require an amputation procedure when reconstruction fails or is impossible. Amputations can also be the result of diabetes, vascular disease, or other health conditions. Regardless, at least 50% of amputees experience residual or phantom limb pain.
Phantom limb pain (PLP), according to the Amputee Coalition, is “ongoing painful sensations that seem to be coming from the part of the limb that is no longer there. The limb is gone, but the pain is real.” And residual limb pain (RLP) is “pain that originates in the remaining part of [an amputated] limb.”
Dr. Woodall has special training in surgical procedures that can either reduce the chance of developing PLP and RLP in new patients or help those who already have one or both conditions.
Preventing residual limb pain in some patients
According to Dr. Woodall, treating the nerves during the initial amputation surgery is the best way to prevent PLP and RLP from developing. When planning an amputation, the goal is to create a stump that can heal properly and accommodate a prosthetic limb if desired. Every patient is unique, as are their circumstances, and Dr. Woodall takes this into account before surgery.
“We have to consider the situation. If the patient is younger, then it’s a question of how active they will be afterward and which prosthetic will work best. If the patient is older, then the biggest concern is just getting the surgery to heal. In either case, I use special surgical techniques to bury or reroute the nerves at the point of amputation, and I leave a lot of thick tissue to cover the bone. This can lessen the occurrence of phantom and neuroma pain.”
One of surgical treatments Dr. Woodall uses is regenerative peripheral nerve interface (RPNI). This involves implanting the end of a peripheral nerve into a muscle graft, which can prevent the abnormal growth of scar tissue on the nerve, called a neuroma. Neuromas are the primary cause of residual limb pain.
Additionally, when the graft and nerve are implanted in just the right spot, it can help the patient control a mechanical prosthetic. As Dr. Woodall puts it, RPNI “gives the nerve a place to go and something to do.”
Help for patients with existing residual limb pain and phantom limb pain
Targeted muscle reinnervation (TMR) is a second surgical procedure to treat nerve pain. It involves cutting the affected sensory nerves and attaching them to motor nerves. If there is a neuroma at the site, the surgeon removes it at the same time. This treatment is primarily used for upper extremities, and, says Dr. Woodall, “the success rate when using RPNI and TMR together is pretty good.”
Both TMR and RPNI can change the lives of amputees who suffer from RLP and PLP. Again, thorough pre-operative evaluation is critical for determining the risks and benefits of surgery versus more conservative options like physical therapy.
“There are lots of things we consider before surgery: How old is the patient? Is the patient a healthy candidate for surgery? What component of their pain is residual and what is phantom, and how big of a problem is the pain? If they only experience pain once or twice a year, then surgery may not be worth the risk. On the other hand, if that pain sends them to the hospital for treatment a couple times a year, then surgery would be beneficial.”
A physical exam and imaging tests are also part of Dr. Woodall’s pre-op assessment.
“We check the length of the remaining bone to see if shortening it could add more padding to the end. If there’s too much scar tissue or too much time has elapsed since the injury, then TMR may not be possible. Neuromas, however, are easy to find, so RPNI would work well. We match the surgery to the type of pain they have and what their goals are for prosthetic use.”
Surgical outcomes
The outcome of any surgery to treat nerve pain is unpredictable and variable. One patient may experience complete relief of all pain and gain the ability to use a sophisticated prosthetic. Another patient may only get partial pain relief. And because nerves take a long time to heal and regrow, it can take months before patients see results.
But, as Dr. Woodall points out, even a reduction in pain is a big improvement for a patient who has been in a lot of pain.
“If we can reduce their pain by half and get them off some of their pain medications, then that’s a win. It improves their overall quality of life. That’s worth the risk.”