Scientists have found that rerouting nerves during amputation can reduce debilitating phantom limb and stump pain in amputees even before it starts. Doctors at Ohio State University are pioneering the use of primary targeted muscle reinnervation (TMR) to prevent or reduce phantom limb pain.
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. Residual nerves from the amputated limb are transferred to restore new muscle targets that have lost their function. These muscles then serve as amplifiers of the nerve’s motor signals, allowing for more control of advanced prosthetic arms.
A study published in the journal “Plastic and Reconstructive Surgery” showed that primary TMR greatly reduces phantom limb and residual limb pain. The research describes how to perform this technique in below-the-knee amputations and documents the benefits of primary TMR for preventing pain.
Over the course of three years, the surgeons performed 18 primary TMR surgeries on below-the-knee amputees. None of the patients have developed symptomatic neuromas and only 13 per cent of patients reported having pain six months later. Patients were also able to significantly reduce or sometimes stop using narcotics and other nerve pain related medications, which can greatly improve their quality of life.
“A significant amount of pain in amputees is caused by disorganized nerve endings, ie symptomatic neuromas, in the residual limb. They form when nerves are severed and not addressed, thus they have nowhere to go,” said Ian Valerio, division chief of Burn, Wound and Trauma in Ohio State. “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. 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,”
The researchers believe primary TMR is a reliable technique to prevent the development of disorganized 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.
Source: The Week Magazine