Overview
Targeted muscle reinnervation (TMR) is a surgical technique developed so that people who have undergone upper limb amputation can use their prostheses in a more natural and intuitive way. The basic idea is to transfer the nerves that carried signals to the natural arm to other muscles, so that these muscles can be used for prosthetic control.
How does TMR work?
After an upper limb amputation, the nerves largely retain their function up to the amputation site. Under suitable conditions, these nerves can integrate into another muscle and produce contractions in that muscle. TMR is based on triggering this natural repair mechanism surgically in a targeted way:
- A muscle that has lost its function after amputation is surgically divided into several sections.
- The original nerve supply of this muscle is cut.
- The repositioned nerve endings are integrated into these muscle sections, establishing new connections.
The process of connecting nerve endings to new muscles in a targeted way is called targeted reinnervation. Thanks to these new connections, when the person thinks of a movement, the corresponding muscle is activated and this signal can direct the corresponding movement of the prosthesis.
Possibilities it may provide
The signals produced after TMR may contribute to prosthetic control in various ways:
- More independent signals: With an appropriate rehabilitation process, up to six independent muscle signals can be generated; this may increase control options.
- Intuitive use: When the person thinks of a natural movement (for example, making a fist), the corresponding muscle is activated and the corresponding movement of the prosthesis takes place.
- Simultaneous movements: More than one prosthetic movement can be performed at the same time and more smoothly.
- Compatibility with multi-grip hand prostheses: When used together with multi-grip bionic hand prostheses, the signals may support a wider range of movements.
TMR is regarded as an established approach that is considered in clinical practice for above-elbow arm prosthesis applications at the upper arm (transhumeral) level or for higher-level losses such as those requiring shoulder disarticulation prostheses.
The role of rehabilitation
The surgical procedure alone is not sufficient; targeted motor training is required for results to emerge. Comprehensive motor training carried out throughout the rehabilitation process enables the reinnervated muscles to be activated selectively and appropriately. This training may contribute to a marked improvement in prosthetic control. The process is carried out under the guidance of the rehabilitation team.
Who is it suitable for?
Whether TMR is suitable for a person depends on factors such as the amputation level, general health and individual goals. This assessment and the procedure are carried out in line with the specialist physician's examination, medical report and prescription. The decision on suitability can only be made by the relevant healthcare team.
This content is for informational purposes only; for diagnosis and treatment, you should consult your physician.
