Head transplantation aims to allow people who suffer from degenerative diseases to have access to a healthy body, thus improving their quality of life.
So far, the human head transplant has not yet been performed, but there are already several people who are applying for the transplant. However, since the 1950s, doctors and scientists have performed head transplants on animals, such as dogs and monkeys, but the results have not been very satisfactory.
The main risk of head transplantation is spinal cord involvement, since to perform the surgery it is necessary to interrupt the connection between the cord and the head. For this reason, scientists have been studying substances and ways to reconstruct this connection and prevent loss of movement in transplant patients.
First head transplants
The first head transplant was performed on a puppy in the 1950s by a Soviet doctor. The doctor created a two-headed dog, that is, transplanted a dog's head into a completely healthy one. The two-headed dog survived a few days after surgery. A few years later, an American doctor decided to transplant a monkey's head, however the animal's survival after surgery was very short, about a day and a half after the operation the monkey died.
In 2015 an Italian doctor said it was possible to perform a head transplant in humans, and that the first transplant would be performed in late 2017. The doctor also said that he had already performed a head transplant on cadavers and that it had been a success, however, as they are cadavers, it is not possible to assess the possible consequences of a head transplant. For this reason, the neurosurgeon has received several criticisms related to medical ethics.
How the transplant can be done
The head transplant proposed by the Italian doctor has the support of Chinese doctors and scientists and, theoretically, is done with the aim of allowing people who have degenerative diseases that cause muscle atrophy and make movement impossible, such as Werdnig-Hoffman Syndrome, for example, start to have a healthy body, without movement limitations. Learn more about Werdnig-Hoffman syndrome.
The head is transplanted into the body of a donor who had brain death, but who is healthy. Both the head and the spinal cord of the donated body are frozen between -10 and -15ºC to prevent cell death until they are rewired by means of a certain substance. In addition, the person must remain in an induced coma for 3 to 4 weeks, to avoid any movement, and make use of immunosuppressive medication to avoid any type of rejection and, thus, avoid death. After the induced coma, the person will need constant physiotherapy sessions in order to relearn the movements.
According to the neurosurgeon, the transplant would cost millions of dollars, would require a team of about 150 doctors and would last around 36 hours.
Human head transplantation has not actually been performed, so it is still a theoretical procedure. However, there are several people who are applying for a transplant in order to improve their quality of life.
Risks of head transplant
The greatest risk of head transplant, in addition to death, is the definitive loss of movement, since to perform the operation it is necessary to interrupt the connection between the spinal cord and the brain. To avoid this risk, scientists have discovered a substance that is capable of acting as a glue, polyethylene glycol or PEG, thus being able to connect the brain to the spinal cord.
PEG has already been used in experiments with dogs, monkeys and mice that have had their spinal cord compromised. These animals were treated with PEG and after 1 year they were able to walk normally. However, PEG has not yet been used for this purpose in humans, and therefore it is not known whether this substance is capable of regenerating, in fact, the connection between the spinal cord and the brain, which will be observed when the head transplant is performed.
