Release date: 2015-03-25
Organ transplantation is the process of transferring a healthy organ of a meat to another meat that needs it, in order to extend the life of the latter. So far, people often accept transplants of organs such as heart, lung, kidney, and liver. If you transplant your head, I am afraid that many people will shake their heads and think that it is "impossible."
In early March of this year, an Italian neurosurgeon announced that he planned to complete a head transplant in the last two years. According to some media, Sergio Canavero of the Senior Neuromodulation Group in Turin, Italy, will perform the operation in 2017 without moral condemnation and restraint.
"Dark Science"
Just like the two sides of a coin, the impact of science on people's lives is also two-sided. Those scientific experiments that have been in the history of right and wrong, between right and wrong, have been called "dark science." These included a head-changing operation performed by Dr. Robert White in a monkey in 1970.
The operation was terrible. Robert transplanted the head of one monkey to another monkey. Although the monkey survived the experiment, it could not control the new body. Jerry Silver of Case Western Reserve University remembers the scene of the experiment: "The monkey's head woke up, but its expression reflected the pain, confusion, anxiety of the animal... This is very bad, I think such an experiment is not It should reappear." But Robert is convinced that such an experiment can be done in humans. In 1999, he thought that human head transplant research could begin.
Although Dr. Sergio Canavero of Italy claimed that they had overcome the last part of the spinal cord transfer, until today, head transplant surgery is still limited to animal testing. Moreover, Jerry Silver does not believe that this successful test in mice, pigs or dogs can be applied to people. Silver believes that it is whimsical to couple the axons between the damaged tissues after cutting off the head, and such surgery is very unethical.
A few years ago, Wu Yusen's "Change Face" tells the story of a policeman who was replaced by a villain. This story involves the social attributes of the organ on the face and the individual's psychological identity. Today, it is not just the face but the entire head. Then how does its social attribute confirm, whether the brain and the body can identify with each other, and whether the progeny gene of the reproduction belongs to the brain or the body? What is more, some people are worried that if such a test is successful, it will become another life-selling business. way.
"If the head transplant operation is successful, then the integrity of the person is destroyed." Wang Mingxu, a professor at Xi'an Jiaotong University School of Medicine, told the Journal of the Chinese Journal of Science and Technology, "And even if the transplant is successful, the surviving is the head provider. The provider of the body? If it involves the problem of the offspring, it will lead to the question of who decides whose genetic attribute is." But whether there will be criminals using this operation for personal gain, I hope that I will live forever or prolong my life, and then The phenomenon of arbitrarily depriving others of their lives, Wang Mingxu said that the possibility is not great, after all, there are more involved in head-changing surgery, and even if some people are eager to continue life, whether it is to replace the old head with a healthy body, or vice versa, Can not stop the pace of the body's various organs to synchronize aging. Unless there is a serious illness in the body and limbs, failure to replace will result in death or a serious impact on the quality of life.
Predicted head change
Of course, all moral and ethical issues are based on successful head transplants and successful graft survival. So, where does Carnavello's confidence in setting the surgery time within two years come from?
Canavelo published a paper in the recently published Surgical Neurology International, which listed the key steps of “head-changingâ€: first, it must be done for head transplants. Patients and donors are cooled down to slow the rate of cell death; their heads are cut and the main blood vessels are attached to the pre-prepared tubes; finally, the spinal cord is severed and the wounds are as clean as possible.
The Atlantic magazine also revealed details of the surgery that Canavelo prepared. The donor for the first surgery was from a brain-dead patient. Because of identity problems, we refer to a person with organ failure and quadriplegia as A, and a donor with brain death but normal body function is called B.
They will be placed on a special operating table. The first thing to do is to freeze the head of A, so that it can be cut and then attached to B's body. Canavelo said that the key to this operation is to simultaneously cut off the neck tissue and spine of the donor and recipient, and cleanly cut their head and body.
Canavelo explained in the article that the bone marrow must be cut with a sharp scalpel and "mechanically connected" to other bodies. He further explained: "This clean and decisive cutting is the key to bone marrow fusion, which allows the proximally cut axons to fuse with the distal axons."
The next step is to quickly transplant the patient's head to the donor's neck and use a medical "glue" to connect the spine together. Next, the dura mater is sewed, and the spine is stabilized according to the method determined by the exercise on the corpse. The trachea and esophagus are connected, the vagus nerve and the diaphragm nerve are connected, the muscle tissue is connected, and the plastic surgeon sutures the skin. After the operation is completed, the patient is still comatose for up to 4 weeks in order to allow the wound to heal as much as possible. In the process, the doctor will also use weak current to stimulate the nerves in the cervical spine and strengthen the connection between the head and the body. After that, the patient AB is sent to the intensive care unit, and when the patient wakes up, he/she is sent to see the psychiatrist.
Canavelo said that once the operation is successful, the patient will learn to walk within a year with the help of physical therapy, and learn to adapt to his new body, including feeling the face, and even speak with the original voice.
At the same time, doctors will use powerful immunosuppressive drugs to suppress new body rejection of the head.
Suspected surgery
The above surgical procedures are all envisioned by Canavelo and his team, and it will take two years to complete the surgery. However, Zhu Tongyu, deputy dean of Zhongshan Hospital affiliated to Fudan University and director of the Shanghai Key Laboratory of Organ Transplantation, believes that the timing of head transplant surgery is not mature. The biggest difficulty is the "spinal cord link."
The spinal cord is part of the central nervous system and is located in the spinal canal of the vertebrae. Its activity is controlled by the brain and is responsible for transmitting various sensory impulses from the trunk and limbs. If the spinal cord is acutely transected, it can be paralyzed. Even today, when science is so developed, paraplegia is still incurable.
"The blood vessels, trachea, and muscles can be sutured, but how the spinal cord is connected is a difficult point. If the spinal cord cannot be successfully connected, the trunk and limbs will not move." Zhu Tongyu said. In addition, the brain cells of the brain can only survive for 8 minutes without the supply of blood oxygen. But it is well known that "even in kidney transplants, the suture of the renal artery takes 5 to 7 minutes at the earliest, which is achieved in the hands of a very skilled doctor." Zhu Tongyu said, "In the head transplant operation. It is not only a blood vessel that needs to be sutured. Then, it takes 10 minutes to suture the aorta connecting the head and the trunk. After that, it is necessary to suture the two middle cerebral arteries as well as the internal and external carotid arteries and various veins. Hours are hard to succeed."
Some people may solve the problem of oxygen supply and blood supply to the brain, but then they will face the problem of brain stem connection. "Because the heart's respiratory center is on the brainstem, if the brain stem can't be connected, or the signal can't be transmitted, how can the breathing recover?" Zhu Tongyu questioned.
Source: Chinese Journal of Science
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