The idea of transplanting a human head (or a human body, depending on your point of view) sounds like something that would be done in the laboratory of Dr. Frankenstein. Italian surgeon Sergio Canavero, however, plans to do the procedure soon.
The idea of transplanting human heads has been around in science fiction for quite a while. Mary Wolstonecraft Shelley published her novel about Victor Frankenstein and his monster in 1818. The first Robocop movie came out in 1987. The Ghost in the Shell manga came out two years later.
Laboratory experimentation to develop the technique for transplanting a human head has also been around for quite a while. Here is the gruesome history:
- In 1908, Dr. Charles Guthrie decapitated a dog and transplanted its head onto another dog 20 minutes later, creating a two-headed creature. The transplanted head retained some basic movements and reflexes, such as pupil reaction to light.
- In the 1950's, Soviet transplantation researcher Dr. Vladimir Demikhov repeated the procedure creating two-headed dogs with 20 puppies, minimizing the amount of time the donor head was without oxygen by using a "sewing machine" to connect blood vessels. The transplanted heads acted independently of the dogs to which they were attached, barking, drinking water and milk, and in one case biting the dog to which the head had been attached.
- In 1970, a team of scientists led by Dr. Robert J. White of Case Western Reserve University in the United States successfully attached the head of one monkey to another monkey's body. The head retained sight, hearing, smell, taste, and aggression, biting one of the doctors.
- In 2002, Japanese researchers transplanted heads of rats. In 2012, German researchers transplanted a section of spinal cord to enable a paraplegic rat to move again.
None of these experiments resulted in long-term viability. Usually the animals die in a week or less due to organ rejection. No experiments, as far as we know, have been conducted on humans.
Nonetheless, the idea that a human's brain could be transferred into another human's body or into a robot or virtual reality simulator has captured the imagination of billions of people. However, for one man in Russia, the idea is more of a desire than a fantasy.
Who Would Ever Volunteer for a Head Transplant, and Why?
In 2015 thirty-year-old Valerii Spiridonov, a 30-year-old computer scientist from Vladimir, Russia became the first person ever to volunteer and be accepted for a head transplant. Spiridonov suffers from Werdnig-Hoffman disease, a rare genetic condition that causes deterioration of the spinal nerves and of the part of the brain near the spine. Diagnosed at the age of 1, he has already lived 10 years longer than most people who have the disease, and he is increasingly incapacitated. His only hope for continued life is a head transplant. The only doctor in the world publicly willing to perform the operation is a man named Sergio Canavero, a surgeon in Turin, Italy.
What Kind of Doctor Would Attempt to Perform a Head Transplant?
Dr. Canavero confidently believes that advances in technology will make a head transplant possible by 2017. In a locally organized TED event, Canavero disputes the traditional idea that the impulses for motion arise in the brain and have to transmitted through a spaghetti-like bundle over over 1,000,000 nerve fibers in the base of the brain, and that for movement to occur, all of these tiny fibers are necessary. Canavero believes that instead only 10 to 20 percent of the nerve fibers need to be functioning for movement to be possible, and 10 to 20 percent of the fibers feeding the spinal can be spared by using much less pressure during the severing of the spinal cord. Neurons will regenerate their connections over a short distance in a short time, although spinal cord stimulation will still be required. He plans to sever the "spaghetti" at the base of the brain, but to spare the spinal cord except for one point of reconnection.
What Could Possibly Go Wrong with a Head Transplant?
Dr. Canavero's critics point out that the reconnection of the spinal cord, even if that is enough to restore the ability to the lower body to move, is similar to connecting two ends of a strand half as wide as a human hair. To make the reconnection possible, Canavero plans to use an "ultra-sharp" blade that does minimal damage to either of the two spinal cords (donor and recipient) that have to be merged. Once the spinal cords are reattached, then a team of 100 surgeons operating for 36 hours will attach the blood vessels and muscles of the neck of the recipient to the donor body.
Chemicals such as chitosan and polyethylene glycol will be used to encourage the new connection. The spinal cord will be electrically stimulated for three to four weeks while the patient is kept in a coma. Canavero believes that his patient will be able to walk within a year.
What does Spiridonov think about this? "Of course, I am afraid," he told the British publication Daily Mail Online. "You have to understand that I don't really have many choices," he added. "If I don't try this chance my fate will be very sad. With every year my state is getting worse."
Is It Possible the Head Transplant Will Actually Work?
Proponents of the experiment point out that other procedures that require reconnecting the nervous systems of donor and recipient have been at least partially successful:
- Approximately 100 hand transplants have been performed world-wide, with many successes.
- At least 20 face transplants have been performed world-wide, with only one rejection.
Neurosurgeons argue that it is not possible simply to stick the ends of nerves together and to hope that they work. Canavero, however, argues, that it is only necessary to get a small number of nerves into a functional state for the spinal cord to become functional.
What About Other Complications of the Head Transplant Procedure?
Critics of Canavero are also skeptical that someone can be kept in a coma for a month without complications, and that rejection of the head by the donor body's immune system is avoidable. They argue that if the spinal cord has to regenerate itself, it is likely to grow at the rate of 1 mm per month, so anything less than the most extremely precise surgical technique will fail.
Canavero, however, compares the proposed surgery to the first airplane flight. "This won't be a 787," he says. "It will be more like the flight at Kitty Hawk." Canavero recognizes that the procedure will be enormously complicated and require unprecedented resources and the coordination to use them. In the future, however, he believes the procedure will become commonplace as a means of extending life for both the brain-injured and the bodily impaired.
Sources & Links
- Canavero S. HEAVEN: The head anastomosis venture Project outline for the first human head transplantation with spinal linkage (GEMINI). Surg Neurol Int. 2013 Jun 13. 4(Suppl 1):S335-42. doi: 10.4103/2152-7806.113444. eCollection 2013.
- Photo courtesy of theglobalpanorama: www.flickr.com/photos/121483302@N02/14417362179
- Photo courtesy of umjanedoan: www.flickr.com/photos/umjanedoan/496720453