Unfortunately, it’s not abnormal to experience chronic pain after an amputation. The good news? There are promising new treatments to help those experiencing phantom limb pain.
The moment someone undergoes an amputation, their first thoughts are: ‘what function will I lose,’ ‘how can I get it back’ and ‘will I feel pain?’
Painful amputations happen for several reasons. Often, the soft tissue is badly injured, or the residual amputation stump has a prominent bone and therefore doesn’t fit well into a prosthetic. And at least 25% of amputation patients experience painful neuromas, which occur due to nerve damage.
“[Pain] can happen when nerves are cut in the process of performing an amputation,” said Jed Ian Maslow, M.D., assistant professor of Orthopaedic Surgery, Division of Hand and Upper Extremity Surgery, Vanderbilt Orthopaedic Institute, and a physician at the new Orthopaedic Limb Loss Clinic in Belle Meade. “The natural response is for the nerves to scar at the end, which can lead to inflammation, persistent pain and an inability to wear prostheses.”
Treatment and care
“If we give the nerve something to do and somewhere to go, it is less likely to form a neuroma and be persistently painful.”
Recent advances in nerve surgery, however, have “taught us that if we give the nerve something to do and somewhere to go, it is less likely to form a neuroma and be persistently painful,” said Maslow, adding that some studies have shown that up to two-thirds of patients with symptomatic neuromas will ultimately require a procedure to address them. The good news is viable strategies are available: targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI), which Maslow says are two of the “newest and most exciting methods” for treating phantom limb pain.
“TMR involves re-wiring nerves that have been injured or cut during an amputation to healthy muscle,” he said. “This gives a nerve somewhere to go and something to do, and has been shown to reduce incidence of neuroma and also allow for an increased number of signals that myoelectric prosthetic limbs can interpret.”
The other strategy, RPNI, uses muscle wrapped around a nerve ending to allow them to sprout into the muscle and, like TMR, find somewhere to go and something to do. Some researchers are putting sensors in these grafts to send more signals to prosthesis than ever thought possible, reducing phantom limb pain and increasing function.
Other techniques involve removing neuromas and burying nerves deep into healthy bone or muscle to make them less likely to cause pain, Maslow said, or incorporating synthetic nerve wraps, caps or tubes to help prevent neuromas.
Treating the whole patient
“In treating the whole patient, not just the limb, we are learning how to integrate mental health care, primary care providers and families into amputee care.”
Vanderbilt’s new Limb Loss Clinic is utilizing these new techniques to address nerve-related pain after amputation, significantly advancing the ability to improve patients’ function and quality of life after surgery. Onsite occupational therapists, prosthetists, surgeons, fellows and residents are also participating in this care, and on-site radiology and procedural rooms are available where Maslow and his colleague, Dr. Mihir Desai, can perform testing during visits.
“Our vision is to have a one-stop shop,” Maslow said, “where amputee patients are triaged by a team of providers and can receive prosthetic care, therapy and surgical planning in one visit.”