An unnamed 71-year-old quadriplegic man, who was paralyzed from the waist down and had lost all movement of both hands after a car accident, has regained the motor function in his fingers thanks to an experimental surgery that bypasses the damaged nerves.
The patient was paralyzed after a car accident in 2008 and has limited arm, elbow, and shoulder movement. The C7 vertebrae in his spinal cord had been crushed in the accident, and the nerve circuits that send signals from the brain to the muscles in the hands were severed, leaving him without the fine motor movements of the fingers.
“The circuit [in the hand] is intact, but no longer connected to the brain,” Ida Fox, MD, an assistant professor of plastic and reconstructive surgery at Washington University, explained. “What we do is take that circuit and restore the connection to the brain.”
Luckily, the nearby nerves had not been damaged. Surgeons in the study cut an undamaged nerve from the elbow and rewired it to the damaged nerve that is responsible for moving the muscles of the hand that grasp objects. The undamaged nerve that was cut controlled the man’s brachialis, an arm muscle that helps the elbow to bend.
“We had to sacrifice something that’s ‘sacrificable,'” said Fox.
The surgery was not meant to create an instant fix. By resurrecting the connection between the brain and the hand, the nerve established a new connection to the brain. After the connection was completed, it took nine months of intense physical therapy for the man to regain the ability to use his hands for simple tasks like feeding himself and writing.
“The brain has to be trained to think, ‘OK, I used to bend my elbow with this nerve, and now I use it to pinch,'” said Dr. Fox. “We’re not changing any of the biomechanics; we’re just changing the wiring. So it’s more of a mental game that patients have to play with themselves.”
The procedure takes advantage of the ability in lower, peripheral nerves to regenerate after being cut, which is not possible in spinal cord nerves.
“Despite years of research, we haven’t figured out how to make the spinal cord work again,” added Fox. “But we know nerves in the peripheral nervous system can regenerate, and that’s what we’re trying to exploit here.”