Head Transplant Update

A few years ago we commented here at Viewpoint on news from Italy wherein a surgeon by the name of Sergio Canavero was striving to develop a technique that would allow him to transplant a human head onto another human being's body.

Part of the process would involve severing and restoring spinal cord function. If this could be done it would offer hope to accident victims whose spinal cords had been severed.

An article in USA Today suggests that progress is being made. Here's the lede:

Surgeons from China and Italy claimed that two studies published Wednesday add evidence to their ability to treat "irreversible" spinal-cord injuries and a related controversial aspiration to perform the world’s first human head transplant.

Xiaoping Ren and Sergio Canavero said the new work they published in a scientific journal showed that monkeys and dogs were able to walk again after their spinal cords were "fully transected" during surgery and then put back together again. The neurosurgeons described the results as medically "unprecedented."

The article goes on to say that,

While the researchers have tested head transplants, with some success, on small animals including mice and dogs, it's a concept that raises profound ethical, psychological and surgical questions.

It's interesting to speculate as to how a brain that has developed for decades in tandem with a particular body would accommodate itself to another body that has entirely different capacities and abilities. How much would have to be relearned? How psychologically jarring would the change be to the patient?

Would the resulting individual be a new person or would he/she be the same person that provided the head?

Canavero intends to eventually perform the extraordinarily expensive operation in China since America and Europe won't permit it: "The Americans did not understand," Canavero told USA TODAY two years ago as he announced that he would soon perform the world’s first human head transplant in China because medical communities in the United States and Europe would not permit him to do it there. From space exploration to climate-change science, China has indicated it intends to lead, not follow, the U.S. in all the major scientific and technological frontiers over the coming decades.

Canavero estimated the procedure would cost up to $100 million and involve several dozen surgeons and specialists. He said the donor would be the healthy body of a brain-dead patient matched for build with a recipient's disease-free head.

The procedure itself is described in the USA Today piece:

The researcher said he would simultaneously sever the spinal cords of the donor and recipient with a diamond blade. To protect the recipient's brain from immediate death before it is attached to the body, it would be cooled to a state of deep hypothermia.

Michael Sarr, a former surgeon at the Mayo Clinic in Minnesota, and editor of the journal Surgery, told USA TODAY in 2017 that....Doctors "have always been taught that when you cut a nerve, the 'downstream side,' the part that takes a signal and conducts it to somewhere else, dies," he said.

"The 'upstream side,' the part that generates the signal, dies back a little – a millimeter or two – and eventually regrows. As long as that 'downstream' channel is still there, it can regrow through that channel, but only for a length of about a foot."

This is why, he said, if you amputate your wrist and then re-implant it and line the nerves up well, you can recover function in your hand. But if your arm gets amputated at the shoulder, it won't be re-implanted because it will never lead to a functional hand.

"What Canavero (would) do differently is bathe the ends of the nerves in a solution that stabilizes the membranes and put them back together," Sarr said. "The nerves will be fused, but won't regrow. And he will do this not in the peripheral nerves such as you find in the arm, but in the spinal cord, where there's multiple types of nerve channels."

Are Canavero and Xiaoping Ren quacks or are they medical pioneers? A hundred years ago no one thought that hearts, livers, kidneys, hands or faces could ever be transplanted, but today they are being transplanted frequently. Perhaps it's just a matter of time before someone whose body is dying but whose brain is healthy can be given a new body.

If they have $100 million to spend on it.