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Contacts and TMR Centers

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Do you have further questions? Please use the contact form or send us an e-mail to tmr@ottobock.com.

Erik Andres, registered orthopaedic technician
Head of the "Upper Limb Prosthetics" department, Competence Center, Otto Bock HealthCare GmbH

Why is TMR so fascinating for you?

For one thing, I've always been interested in technical solutions and also in the anatomy of the structural wonder that is the human body. For me, orthopaedic technology in general is an exciting synthesis of technology and medicine. I find TMR prostheses particularly fascinating because the movements of the prosthesis approach those of the natural biological model.

Why isn't a TMR prosthesis suitable for every prosthesis user?

First, a thorough examination by a physician is needed to check the medical suitability. In addition, the potential user must be able and willing to learn and practice how to control the prosthesis in daily training sessions for several months. Interested persons should have good cognitive understanding and body perception. After the operation, it can take up to 2 years until the prosthesis is finished. Because the re-innervation process – that is, growing into the "new" muscle – can take up to two years after the transfer, the prosthetic socket may have to be changed several times during this time until the final prosthesis is finished.

What can a TMR user do better or differently than a person with a conventional myoelectric prosthesis?

The nerve transfer that is performed makes intuitive control with an arm prosthesis possible for the first time. And after a familiarisation phase of a few weeks or months, simultaneous control of the prosthesis functions is possible. Simultaneous control of the prosthesis functions results in fluid movements that approach those of a natural arm.

With conventional myoelectric prostheses, an unnatural switching movement (such as tensing the biceps and triceps together) must be used to switch between the prosthesis functions. And prosthesis control does not follow an intuitive pattern, because individual muscles must sometimes control multiple functions in the prosthesis.

Hans Oppel, registered orthopaedic technician

What is challenging about a TMR fitting for an prosthetist?

In terms of socket design, the fitting must be such that the components can be controlled immediately. Having to don the prosthesis several times is unacceptable.

The bandage technique plays a much greater role in TMR fittings; motion artifacts substantially reduce the use of the prosthesis, which is why it was completely redeveloped by Ottobock.

How many test and training sockets do you produce on average before the user receives his/her definitive fitting? And why is this necessary?

This is why we developed the so-called therapeutic socket, to shorten the process, because it lets us make a huge number of adaptations. The key aspect of this development is that the therapist can work without the prosthetist.

The following number of sockets, in general, must be produced in the course of a fitting:

3    Therapeutic sockets

1-2   Test sockets

1     Definitive socket

What sort of patient information is helpful to the prosthetist during the fitting?

It’s very important for the prosthetist to know which activities the prosthesis will be used for most frequently. But it will always be a compromise, because:

  • A high degree of prosthesis functionality in the upper extremity always comes at the expense of symmetry on the healthy side.

  • It is necessary to position the joints asymmetrically to enable the user to obtain a very high flexion angle, such as for making a phone call.

  • Is the visual appearance important to the user? Or does he/she need the prosthesis for heavy work? 

These requirements are all taken into account when fabricating the socket.