Researchers at Northwestern Medicine, Chicago, have received a grant, OR120021, from the U.S. Department of Defense (DoD) Office of Congressionally Directed Medical Research to evaluate targeted muscle reinnervation (TMR) as a treatment for chronic pain resulting from limb amputation. Northwestern Memorial Hospital, Chicago, is the lead site for the four-year study and clinical trial, “Targeted Reinnervation as a Means to Treat Neuromas in Major Limb Amputation.” The other participating sites are Walter Reed National Military Medical Center, Bethesda, Maryland; University of Washington Medical Center, Seattle; Harborview Medical Center, Seattle; and San Antonio Military Medical Center.
The clinical trial will use an online pain questionnaire and MRI imaging of the nerves treated before and after surgery to compare the outcomes of TMR and the current standard surgical treatment for painful neuromas. The research will seek to enroll 200 individuals across all four centers, making it the largest neuroma study ever performed.
“The problem for amputees that experience chronic pain isn’t that the limb itself was removed,” said Gregory A. Dumanian, MD, Northwestern Medicine’s chief of plastic surgery and principal investigator for the study. “The problem is that the nerves that used to control the amputated limb are incomplete, but also remain active, constantly sending signals to the brain. These separated nerves cannot heal properly without the chance to connect to other nerve tissue, and end up creating painful growths called neuromas.”
The goal of TMR therapy is to transfer a nerve that has been cut off from the muscles it used to control and essentially plug it into a functioning muscle nearby. This is accomplished by removing the neuroma from the damaged nerve, and then surgically joining it with a healthy nerve that controls the existing target muscle. Joining these nerves together allows them to then grow into, or reinnervate, the target muscle and prevent the neuroma from reforming.
“TMR is a completely new approach to treating neuroma-induced pain for amputees,” said co-investigator Todd Kuiken, MD, PhD, a Northwestern Medicine physiatrist who is director of the Center for Bionic Medicine at the Rehabilitation Institute of Chicago (RIC) and professor of surgery at the Northwestern University Feinberg School of Medicine. “Instead of trying to treat a painful neuroma by burying it, this procedure provides damaged nerves with a new purpose. After TMR, patients can use these previously unable nerves to contract their target muscle and their repurposed signals can even be detected and used to control prostheses.”
“By giving an amputee’s damaged nerves a new purpose, we have seen TMR improve many lives,” said Dumanian, who is also a professor at the Feinberg School of Medicine. “Now we have the chance to test TMR in a large clinical trial which will allow us to take the next steps toward the possibility of making it a new standard of care.”
To learn more about the clinical trial, visit http://clinicaltrials.gov or call 312-695-5142.