Phantom pain can feel like cramps or burning where the limb used to be. Many patients still develop neuromas, where nerves can grow to form a lump of painful disorganized nerve tissue. The pain from neuromas can also make wearing a prosthetic device impossible. Recently, UC Davis surgeons began using a procedure called targeted muscle reinnervation, or TMR. The surgery reroutes severed nerves so that signals from the brain that once controlled the missing limb are picked up by a nearby muscle. Pereira said it’s like converting a dumb muscle into a smarter muscle. Amputees only need to think about making a fist or opening their fingers for the movement to occur. “It was originally done to increase the number of muscle signals that a patient could generate after an amputation so there could be more degrees of control of a prosthetic device,” said Andrew Li, an assistant professor in the Department of Surgery at UC Davis Health and UCNI scholar. “An unintended benefit was that those patients also tended to have reduced phantom pain and neuroma pain as well.”
David Brockman, a retired firefighter and hand amputee, shows off his new myoelectric prosthetic device. UC Davis surgeons performed targeted muscle reinnervation surgery and used smart prosthetics to provide better muscle control, improved sensory feedback and less limb pain for amputees. (Gregory Urquiaga / UC Davis)
Artificial Intelligence Now Used in Prosthetic Technology Brockman had TMR surgery at UC Davis Health and is now using a smarter prosthetic device. “They actually call it a bionic hand,” Brockman said. “It’s a working, functional hand. It has five fingers. It’s got like 13 sensors built into the sleeve. And it works off a muscle reaction in my arm. So, when I twitch my thumb nerve, which is still there, the prosthetic senses that and the thumb will move.” The prosthetic hand must first learn how to read these signals. This is where artificial intelligence, or AI, plays a role. The UC Davis researchers are examining the muscle firing patterns of Brockman and others who have had TMR surgery.
46 Impact Report 2023 - 24 | UC NI
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