Nerve Rerouting at Time of Amputation Could End Phantom Limb Pain

By DocWire News Editors - Last Updated: December 29, 2018

A group of doctors at Ohio State University have recently used targeted muscle reinnervation (TMR) to reduce or eliminate phantom limb and stump pain in amputees. This procedure reroutes amputated nerves and can prevent these often debilitating pains from occurring at the time of amputation.

An article written by Dr. Ian Valerio, division chief of Burn, Wound and Trauma at Ohio State’s plastic and reconstructive surgery department, and fellow plastic surgeon Dr. J. Byers Bowen, describes the TMR technique in below knee amputations. Published in Plastic and Reconstructive Surgery, Valerio and Bowen’s work not only describes the procedure, but analyzes benefits of TMR in preventing pain. These researchers are from The Ohio State University Wexner Medical Center and College of Medicine.

“This paper provides a blueprint for improving patient outcomes and quality of life following amputation,” said Dr. K. Craig Kent, dean of The Ohio State University College of Medicine.

In the past three years, the two Valerio and Bowen have performed 22 TMR surgeries on below-the-knee amputees, with 18 of which being primary and 4 secondary. Primary and secondary amputations differ in that the latter follows a failed attempt at revascularization, whereas the former does not come after an attempt to salvage the limb. None of the 22 patients have experienced symptomatic neuromas and a mere 13% of the primary TMR patients report having pain after 6 months. The procedure involves the rerouting of nerves severed during amputation to the surrounding muscle tissue.

“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,” said Valerio. “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 was conceived to allow amputees to have better control of their upper limb prosthetics, and the procedure is commonly performed months, even years, after initial amputation. Surgeons discovered that this procedure can also reduce pain associated with the amputation, and began to use it in treating disorganized nerve endings known as symptomatic neuromas and/or phantom limb pain.

Valero noted that the patients who undergo TMR show significant reduction and sometimes full cessation in use of narcotics and other nerve pain medications after the procedure. Reducing these patients’ need to use these painkillers improves their quality of life and reduces unnecessary narcotic prescription.

“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 stated.

Bowen adds that those who had upper extremity amputations performed display better use and control of prosthetics and improved pain outcomes with TMR.

“TMR allows for more individual muscle unit firings through the patient’s thoughts,” said Bowen. “It provides for better intuitive control resulting in more refined functional movements and more degrees of motion by an advanced prosthetic.”

The researchers conclude that primary TMR holds utility in avoiding formation of disorganized nerve endings, as well as reducing phantom limb pain and other amputation pains. In addition, minimal health risks are seen when TMR is done at the time of the amputation and the recovery is similar to that of an amputation without TMR.

Research ➡️ Targeted muscle reinnervation (TMR) surgery to reroute amputated nerves ⤵️
– Reduced phantom/residual limb pain
– Prevented it, when done with amputationhttps://t.co/2QEd7Cl5zl #chronicpain #Veteran pic.twitter.com/YoSwr7Fndu

— Sandra Woods, CIPP/C (@SandraWoodsMtl) December 29, 2018