Targeted Muscle Reinnervation

Today we will be talking about targeted muscle reinnervation or TMR.  TMR is a technique developed by Dr. Gregory Dumanian and Dr. Todd Kuiken in the last decade. More than just the bone is cut in an amputation: muscles, tendons, ligaments, soft tissue, and nerves. Sometimes the nerves become "irritated" when they no longer have a muscle to innervate and control. This can make it challenging to use a prosthesis that operates based on nerve signals, as without a muscle to innervate, the signal may not be as strong as before the amputation.

This type of prosthesis, called a myoelectric prosthesis, uses electrodes that read muscle signals to operate a component of the prosthesis.  By using the technique of targeted muscle reinnervation, the nerves that no longer communicate with the original muscle are buried in a different muscle. Once the nerve grows into the new destination muscle, the signals it produces are stronger than prior to the procedure.

It was also discovered during the development of this procedure that  TMR may be used to address phantom limb pain. When nerves no longer have a muscle to communicate with, they can send signals to the brain that are registered as phantom limb pain. TMR has been shown to help with phantom limb pain, in addition to improving signals for use with myoelectric prostheses. The procedure is complex, and is ideally timed with the amputation, which can be challenging based on the situation and type of amputation. However, there is also the option to pursue this procedure after the amputation has been completed.

For more information on this topic you can visit the US National Library of Medicine and the National Institute of Health reference by clicking here. Or, this reference from the Journal of the American Medical Association by clicking here.