This case report describes a novel nerve transfer procedure in a bilateral shoulder disarticulation amputee. The median, radial, ulnar, and musculocutaneous nerves were transferred onto segments of the pectoralis muscles to serve as biological signal amplifiers. The question: can surgically created muscle segments give a high-level amputee intuitive, simultaneous control of multiple prosthetic joints?
The core mental model: after amputation the brain still sends motor signals down the peripheral nerves, but they are too weak to detect at the skin. Transferring the nerve onto a denervated muscle segment turns that muscle into a biological amplifier, producing a strong surface EMG signal.
When you map each transferred nerve to the prosthetic function it originally controlled, control becomes intuitive. Thinking "flex elbow" flexes the prosthetic elbow. Two technical pearls worth carrying: separate muscle segments by at least 2 cm and defat the overlying skin to minimize EMG cross-talk. Reinnervation failure tracks with poor muscle vascularity and inadequate nerve debridement.
This is a single-patient case report, so it is preliminary evidence. Weight it as proof of concept, not as an outcome study.
This case report describes a novel nerve transfer procedure in a bilateral shoulder disarticulation amputee. The median, radial, ulnar, and musculocutaneous nerves were transferred onto segments of the pectoralis muscles to serve as biological signal amplifiers. The question: can surgically created muscle segments give a high-level amputee intuitive, simultaneous control of multiple prosthetic joints?
The core mental model: after amputation the brain still sends motor signals down the peripheral nerves, but they are too weak to detect at the skin. Transferring the nerve onto a denervated muscle segment turns that muscle into a biological amplifier, producing a strong surface EMG signal.
When you map each transferred nerve to the prosthetic function it originally controlled, control becomes intuitive. Thinking "flex elbow" flexes the prosthetic elbow. Two technical pearls worth carrying: separate muscle segments by at least 2 cm and defat the overlying skin to minimize EMG cross-talk. Reinnervation failure tracks with poor muscle vascularity and inadequate nerve debridement.
This is a single-patient case report, so it is preliminary evidence. Weight it as proof of concept, not as an outcome study.