Head Transplants Continue to Progress


Italian neuroscientist Sergio Canavero is overcoming the nature of impossibility. In the past, certain events were immortalized as the epitome of science fiction by novel writers. The rocketship once seemed to be the ultimate goal, something that was so amazing that it was impossible. What would it mean to conquer such an invention? Mary Shelley in Frankenstein (1818) thus made monster-making a more flippant, more unreachable action simply by writing a piece of fiction about it. Canavero is broaching that barrier of the impossible. He has stated that despite failures in the past and the sense of complexity behind such events, he can perform a successful head transplant of a healthy head to a healthy body by 2017.

Past attempts at head transplanting have ultimately failed, but only because some of the necessary science did not yet exist. In the 1940s, Soviet surgeon Vladimir Demikhov created approximately twenty live two-headed dogs, as reported by Time. Demikhov started his career not in a focus on the brain or nervous system, but on the heart and lungs — his first experiments included replacing or implanting new mechanical hearts in dogs. He then moved on to surgically attaching the respiratory and circulatory systems of host dogs with the head, shoulders, and front legs of puppies.

These creatures responded to the same stimuli: when the host was hot, both panted and sweat; when the host was thirsty, both drank eagerly. However, as the digestive tract was not connected between the two, some efforts were meaningless. The ultimate failure of these creatures was immunorejection, or that the immune system labeled the segments as alien and attacked them rather than accepting them. No spinal attachment was necessary, but the host dog rejected the puppy’s cells, and none lasted longer than two and a half months.

The next attempt at this flavor of experimenting came with Robert White in the 1970s, who experimented on monkeys. He attempted the same idea as Demikhov, but instead of grafting new heads onto his monkeys, he decapitated two and attached one head to the other body, creating a whole monkey. White used cryotechnology, or freezing processes, to buy an extra hour while switching blood supplies from one head to another, slowing the process of decay. Still, such surgeries took eighteen hours of precise and choreographed surgery, and only after many trials did a monkey survive intact. However, the result was quadriplegic; White made no effort to reattach the spinal cord, so no signals from the brain could reach the body. Once again, immunorejection stopped life expectancy of the monkeys at nine days.

Canavero believes he has solved both the problem of immunorejection and that of spinal reconnection, and would like to begin such a thirteen-million-dollar surgery on a human. However, his plans are still flawed. To attach the spinal column, Canavero suggests as clean a cut as possible on either subject, then flushing the bonding area extensively with polyethylene glycol (PEG) which encourages the connection of fat tissues around cells. This, he believes, will reconnect the correct spinal systems together to form a capable attachment.

Furthermore, if the brain rejects the body, the subject can be injected with a routine of immunosuppressants until all is healed and functioning. Canavero plans on using the cooling technique of White to give his team of thirty doctors more time to reconnect blood and air passageways. He will overlay pieces of the two parts of the subject to encourage a stronger attachment. He also plans on keeping the subject in an induced coma for four weeks after the surgery to keep the subject from shifting and to aid in recovery.

The progression of such science may be seen as going from bad to worse by some critics. In the ethical department, one must realize that one donor body of healthy organs could save dozens of separate lives by itself, yet this surgery would save a single life. However, if it gave an important quadriplegic such as Stephen Hawking a chance to walk again, such progress could be deemed worthy.

Additionally, in order to have a living and healthy body, a living and healthy human would have to give their life for another. If the patient has serious head trauma and chooses not to live anyway, such a choice could be justified, but one should not be forced to give one’s entire being to the good of a stranger. Furthermore, a coma of four weeks could prove fatal unto itself — without activity of any kind, the body atrophies bit by bit, and the brain dies off very slowly. Nonetheless, it could be a necessary step to success.

All of that aside, flushing the spinal cord with PEG and hoping cells reconnect to the correct strains seems too uncontrolled to work as well as the purpose of the surgery demands. If, accidentally, the nerves responsible for wiggling the thumb are connected to those of contracting the bicep, for example, things would be extremely difficult for the recovering patient. Already, Canavero puts the time for being able to speak again with one’s own voice at a year. Adding the overriding of impulses to that would lengthen recovery time excessively.

Overall, White’s theory of human progress seems most fitting: nothing should put a limit on human progress if it means saving lives in the long term. Humanity has the capacity to conquer every aspect of scientific inquiry and event. There is so much potential for good, and this attempt by Canavero is simply a step in the process of perfecting the system of head transplant. In the future, if he or others continues to experiment, perhaps with the use of stem cells to seal the spinal cord if PEG fails; the healing time could decrease from a year to six months, or further. Canavero realizes the moral implications of his experiments, and will only run his tests if the public approves. However, as ability advances with technology, nothing should be a stopping-block for progress if good can come of it.

Sources & Further Reading