So many activities of daily living require the use of a functional upper extremity. People who lose an arm due to amputation can modify their activities somewhat to adapt, but return to the pre-injury condition may not be feasible.

Until recently, a prosthesis that functioned similarly to the lost extremity was theoretical at best. However, it is now sometimes possible to restore function to a large degree with a myoelectric prosthesis. For this to be successful, the patient must first undergo a surgical procedure called targeted muscle reinnervation.

What does TMR do?

An amputation involves cutting across some of the motor nerves of the upper extremity. Motor nerves are those that send signals to the muscles from the brain telling them to move. According to the National Center for Biotechnology Information, targeted muscle reinnervation involves attaching those nerves to existing motor nerves still present in the trunk of the body or the remainder of the amputated limb. TMR makes it possible to control the new prosthesis with thought, just as one does with one’s natural arm.

Who is a candidate for TMR?

Johns Hopkins Medicine explains that if a patient has paralysis or damage to the nerves, he or she is not a candidate for TMR. The amputation must have occurred at the shoulder or the elbow, and it cannot have occurred more than 10 years prior. Following the procedure, the patient must be willing to participate in the necessary rehabilitation. Additionally, the soft tissues at the amputation site must be stable. A doctor can determine a patient’s eligibility with a medical review.