Rewiring of nerves gives movement to paralyzed arms and hands

By Dr. Ananya Mandal, MDJul 5 2019

Researchers from Australia have successfully “rewired” the nerves within the paralyzed arms of some accident survivors and provided them with successful movement of arms and hands.

The results of the study titled, “Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series”, were published in the latest issue of the Lancet.

The team of surgeons explain that certain injuries as suffered by these patients stopped their spinal cord from transmitting messages to their brains resulting in paralysis. For this study the team included patients who had had such injuries in the past rendering them quadriplegic – paralyzed in both arms and legs. Some of their upper arm muscles were still functional though because of some of the still functional nerves from the spinal cord. The team rewired these functioning nerves to the muscles. The process of rewiring involved cutting these functional nerves and attaching them to the muscles that were not working. This rewiring led to functioning of the nerves that could help open or close the hands.

Dr Natasha van Zyl from Austin Health in Melbourne, in a statement said, “We believe that nerve transfer surgery offers an exciting new option, offering individuals with paralysis the possibility of regaining arm and hand functions to perform everyday tasks, and giving them greater independence and the ability to participate more easily in family and work life.”

One of the beneficiaries of this experimental but successful procedure was Paul Robinson, a 36 year old from Brisbane. He had been injured after a fall from his dirt bike in 2015. The spinal cord at his neck was damaged leading to paralysis in his arms and hands. He was operated upon in December 2015. Following the rewiring operation, he underwent rigorous physiotherapy to be able to move his arms and hands. Slowly he regained movement and since then has become more independent. He plays wheelchair rugby he said and is also studying to become an engineer. He can now not only feed himself but can also write at his University, he said.

Dr van Zyl explained that full function of the hands cannot be restored with this surgery. She added that their focus is to allow the patient to open and close the hands and to be able to open and stretch their elbows to reach for something. Dr van Zyl added, “So you can get your hand open, get it around something and then grasp and pinch. We are not trying to restore the very fine co-ordination of the hand.” “It allows you to reach above your head, which you need to be able to do because the world is designed for standing-up people. So you can switch a light off, you can get something off a shelf. Hand function is everything you use your hand for. You would just need to tape your hands up for five minutes to experience how frustrating life would be without your hands, without your fingers,” she said. However the level of achievement with the surgery could restore quality of life say the researchers.

Dr Natasha van Zyl said that around 250,000 people around the world annually suffer from spinal cord injuries that lead to paralysis of arms and legs. For this study the team operated on 13 patients on whom 59 nerve transfers were performed. In two patients, there was a permanent reduction in sensation and the surgery failed on four occasions, the team wrote. The team explains that after six months to a year after the injury, the surgery tends to fail. Initially 16 patients were recruited. One of them died due to unrelated causes and two dropped out of the treatment programme.

For these patients, nerves were taken from the shoulders and transplanted onto the paralyzed arm muscles. Of the 13, ten had a transplant of nerves to one arm and tendon transplants on the other arm. While four of the nerve transplants in three patients were unsuccessful, the tendon transplant was a backup plan.

According to Van Zyl, nerve transfers are not a new procedure. They have been performed earlier in nerve injuries. This procedure however has never before been tried on paralyzed patients with spinal cord injury, she explained. In 2014, she and her team had designed a triple nerve transplant that was performed successfully.

The team wrote that two years after the surgery the patients, with regular physiotherapy showed significant improvements in their hand function. They could now grasp and hold something in a pinch to perform most of their daily activities and tasks.

Van Zyl went on to say that some of her patients had been successful before their accidents. One of them, she said was a CEO of three different companies that he had set up before he met with a boating accident. “He told me, after he’d had his surgery and had enough of a result from it, that he had decided that he would try this surgery but if it didn’t work he was going to exit. He didn’t want to live any more. His was a very high level of injury but he got enough out of what we did for him, which was a combination of tendon and nerve transfers, for him to start to work again at home, to be able to take a young family member out to the movies independently and handle the money, get the tickets, get the popcorn,” she said.

Van Zyl said that she and her team have till date performed around 16 nerve transfers. She concluded, “We are all dedicated to this cause and absolutely love this work. All around the world there are surgeons – we all know each other – some of them waiting for patients, frustrated that they don’t get enough.”

Dr Ida Fox from Washington University, wrote a commentary along with the study saying, “Stem cells and neuroprostheses could change the landscape of regenerative medicine in the future. For now, nerve transfers are a cost-effective way to harness the body’s innate capability to restore movement in a paralysed limb.”

This study was funded by Institute for Safety, Compensation, and Recovery Research (Australia).