Researchers are pioneering the use of primary targeted muscle reinnervation (TMR) to prevent or reduce debilitating phantom limb and stump pain in amputees.
Primary TMR — the rerouting of nerves cut during amputation into surrounding muscle — greatly reduces phantom limb and residual limb pain, according to a study published in Plastic and Reconstructive Surgery.
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 symptomatic neuromas and/or phantom limb pain.
In the current paper, Ian Valerio, MD, Burn, Wound and Trauma, Ohio State University Wexner Medical Center, Columbus, Ohio, and colleagues provide a detailed description of TMR in below-the-knee amputees and document the benefits of primary TMR for preventing pain.
“This paper provides a blueprint for improving patient outcomes and quality of life following amputation,” said K. Craig Kent, MD, Ohio State University College of Medicine.
Over the course of 3 years, the surgeons performed 22 TMR surgeries on below-the-knee amputees (18 primary and 4 secondary). None of the patients have developed symptomatic neuromas and only 13% of patients who received primary TMR reported having pain 6 months later.
“A significant amount of pain in amputees is caused by disorganised nerve endings,” said Dr. Valerio. “They form when nerves are severed and not addressed, thus they have nowhere to go. 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.”
He said that patients who’ve had TMR significantly reduce or sometimes stop using narcotics and other nerve pain related medications, which can greatly improve their quality of life.
“TMR has been shown to reduce pain scores and multiple types of pain via a variety of validated pain surveys,” said Dr. Valerio. “These findings are the first to show that surgery can greatly reduce phantom and other types of limb pain directly.”
The researchers believe primary TMR is a reliable technique to prevent the development of disorganised nerve endings and to reduce phantom and other limb pain in all types of amputations. When done at the time of initial amputation, there is minimal health risk and recovery is similar to that of traditional amputation surgery.