Around 25% of all amputees develop chronic pain in the remaining portion of the limb that has done. This can include phantom limb pain syndrome–which is pain that perceived in the portion of the limb that has been amputated. The pain often prevents amputees from using prostheses.
A Chicago hospital is leading a four year study, funded by the Department of Defense to evaluate a surgical method known as targeted muscle reinnervation (TMR) to treat the chronic pain that can result from amputation.
Northwestern Memorial Hospital is the lead site. Other participating sites include Water Reed National Military Medical Center, the University of Washington Medical Center, Harborview and the San Antonio Military Medical Center.
The current standard of care for a painful amputee neuroma is to remove the nerve growth and then place the nerve ending into a nearby muscle for extra cushioning. While this treatment can reduce neuroma pain, it is not always successful and still leaves the nerve active and disconnected to inevitably create a new neuroma.
The TMR therapy’s goal 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.”
Like many chronic pain patients, amputees that are unable to control the pain suffer greatly.
Several years ago, we got to know the late Mike Roman, a St. Louis area man who lost his leg after a staph infection set in following a routine knee operation. The phantom limb pain that he suffered tormented him for a decade, as he struggled to manage the pain with pain medication.
Roman, who had a life-long ambition to be race car driver, had a spinal cord stimulation device implanted which helped him return to a normal life. He became a spokesperson for Boston Scientific, which manufactured the device and was the centerpiece in the “Race Against Pain” that the Company still conducts to promote spinal cord stimulation. The one-legged man raced cars and became a symbol for amputees around the country. He worked with many veteran organizations.
Roman died of lung cancer in 2012.
We mention Roman’s work with military veterans in association with this story because a press release from Northwestern Memorial Hospital points out more than 1,000 active military personnel have had a major limb amputation due to combat-related injuries in recent conflicts.