Targeted Muscle Reinnervation - Rehabilitation Institute of Chicago

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Targeted Muscle Reinnervation: 
Control Your Prosthetic Arm With Thought

RIC Patient, Claudia, in therapy after TMR surgeryTo say loss of an arm changes your life is an understatement. Tasks you once took for granted now pose a significant challenge. Prosthetic devices help, but they can be quite difficult to control, requiring unnatural movements of small chest muscles.

Scientists at the Rehabilitation Institute of Chicago (RIC) have developed a surgical procedure to reassign nerves that once controlled the arm and hand you lost, to your pectoral muscles. By reassigning these nerves, doctors can make it possible for people who have had upper-arm amputations to control their prosthetic devices by merely thinking about the action they want to perform. Once experimental, this innovative procedure is now available to the public.

People who undergo this "targeted muscle reinnervation" (TMR) surgery will be fitted with and trained to use a commercially available myoelectric prosthetic arm. No experimental “bionic” arms are available at this time.

Who Might Benefit from TMR Surgery?

Those interested in undergoing the procedure to reassign their nerves allowing them to better control their prosthetic arm must undergo a rigorous medical review process to determine their viability. In general, patients must meet the following criteria:

  • Amputation above the elbow or at the shoulder within the last 10 years. Ideal candidates will have had their amputations in the last five years
  • Children must be at least 14-years old and meet a minimum weight requirement
  • Those born missing part or all of their arm and those suffering nerve damage, degeneration or paralysis are not candidates for this procedure
  • Successful use of a powered device is beneficial

Clinical information about TMR for surgeons, prosthetists, occupational therapists, and patients can be found here

What is Involved in TMR Surgery?

The process from the start until you return home with your new device can take about a year or longer. There are four phases involved, and then we consider you to have a “lifelong partnership” with RIC for follow-ups or necessary therapy or repairs.

You can expect your experience to reflect the following sequence.

Phase One: Viability Review

RIC experts will review your medical records and, if appropriate, physically examine you to determine if this procedure is right for you. This can take one to two months, depending on the arrival of medical records and scheduling.

Phase Two: Financial and Medical Clearance

We will ensure that you are medically sound to undergo the surgery procedure. We also will work with you to secure insurance approvals for both the procedure and the prosthetic device. Once the insurance approvals are in, then you will need to decide whether to move forward, based on your ability to pay your portion of the hospital costs as well as the medical equipment cost. This can take from two weeks to six months, depending on your insurance plan.

RIC's "Bionic Man", Jessie, having wires attached

Phase Three: Surgery and Muscle Reinnervation

Surgery will be scheduled a minimum of six weeks from the time a decision is made to proceed. Assuming the surgery goes smoothly, you can expect a two-day stay at Northwestern Memorial Hospital.

You will then go home and wait five to six months for the nerves to regrow, at which point you will return to RIC for an evaluation of the nerve development. You also may meet with a prosthetist for revisions to your current prosthetic device if the fit has changed after surgery. The time allotted for this entire phase is six to eight months.

Phase Four: Device Fitting and Training

Once you have healed and the nerves have had a chance to grow, your prosthetic arm will be custom-built to correspond to your newly reinnervated muscles. You will undergo several fittings as the arm is built, as well as physical and occupational therapy to develop the muscles in your chest and your core so you can support the new prosthetic. This process takes about two months, and generally consists of two or three two-week visits.

Once your arm has been fitted and you return home with it, we recommend you see a prosthetist every six months for maintenance. If you do not live in Chicago, you can do that in your hometown. An RIC prosthetist will address socket repairs and mechanical issues, depending on the problem. We will recommend that you call RIC to discuss any problems you have to determine if you need to come in.

How Do I Start the TMR Process?

To find out if you are a candidate for targeted muscle reinnervation, call our dedicated line at 1-800-354-7342 (or 312-238-1000 locally) and ask for the TMR office, ext. 6035.