A new procedure has been developed that can reduce crippling phantom limb and stump pain in amputees. Doctors from the Ohio State University Wexner Medical Center and College of Medicine have created the procedure that uses primary targeted muscle reinnervation (TMR) as a way to assist amputees to live without pain.
Upwards of 75 percent of amputees suffer from phantom limb and stump pain in the US. Primary TMR reduces this pain by rerouting the nerves that were cut during amputation into surrounding muscle.
Targeted surgery reduces pain and assists with prosthetics
A recent journal article from Dr. Ian Valerio, division chief of Burn, Wound and Trauma in Ohio State’s Department of Plastic and Reconstructive Surgery, and Dr. J. Byers Bowen, a former resident who is now in private practice in details the procedure the January 2019 issue of Plastic and Reconstructive Surgery using a below-the-knee amputation as an example.
TMR was first used to assist amputees to have better control of prosthetics; the surgery was typically done months or even years after the initial amputation.
Doctors eventually discovered that the surgery also significantly improved certain experiences of pain and the procedure began to be developed to treat disorganized nerve endings called symptomatic neuromas and/or phantom limb pain. The new paper details 22 TMR surgeries completed on below-the-knee amputees, 18 primary and four secondaries.
Tangled nerve endings can cause ongoing distress
In every case, none of the patients have developed symptomatic neuromas and only 13 percent of patients who received primary TMR reported having pain six months later.
“A significant amount of pain in amputees is caused by disorganized nerve endings, i.e. symptomatic neuromas, in the residual limb. They form when nerves are severed and not addressed, thus they have nowhere to go,” Valerio said.
“Attaching those cut nerve endings to motor nerves in a nearby muscle allows the body to re-establish its neural circuitry. This alleviates phantom and residual limb pain by giving those severed nerves somewhere to go and something to do.”
The pain reduction has been so significant for some patients that they have been able to reduce or stop pain medication completely.
“TMR has been shown to reduce pain scores and multiple types of pain via a variety of validated pain surveys. These findings are the first to show that surgery can greatly reduce phantom and other types of limb pain directly,” Valerio explained.
The surgery doesn’t only reduce pain it also significantly assists amputees to better use and control their prosthetics.
“TMR allows for more individual muscle unit firings through the patient’s thoughts. It provides for better intuitive control resulting in more refined functional movements and more degrees of motion by an advanced prosthetic,” Valerio continued.
Early surgery means a better quality of life
The surgery can be done at the time of the amputation in many cases, the researchers belive the TMR surgery is a reliable way to reduce pain for amputees. TMR was first developed to allow amputees better control of upper limb prosthetics.
Traditionally doctors perform the surgery months or years after the initial amputation. When surgeons discovered the procedure also improves certain causes of pain, they started using it to treat disorganized nerve endings called symptomatic neuromas and/or phantom limb pain.