- An Italian scientist details how technology might now be available to allow for the first human head transplants to treat paralysis or diseases like muscular dystrophy.
- Such a head transplant was done on a monkey in 1970 and this latest paper builds on that research.
- Several ethical issues, including that of a person’s personality, quality of life and the donor patient come into play with such a suggested procedure, called HEAVEN.
- “Just to do the experiments is unethical.”
Organ transplants have made huge strides in the last few decades and the advent of 3D printing is even beginning to transform where replacement parts might come from. But, according to an Italian scientist, one frontier that hasn’t been broached yet might soon be a possibility — a whole human head transplant.
A paper published in Surgical Neurology International describes how some of the challenges that have prevented a complete head exchange from taking place for humans might now be overcome.
In addition to scientific challenges, the ethical considerations of such a procedure are now being discussed with another scientist saying it “should never happen.”
Dr. Sergio Canavero with the Turin Advanced Neuromodulation Group in Italy wrote that technology now exists to reconnect the head of a donor to the spinal cord of the recipient. He calls the procedure HEAVEN.
This type of transplant was conducted in a rhesus monkey in 1970. The animal lived only eight days afterward, but during that time, functioned normally, according to the Canavero.
Canavero pointed to the words of the scientist, Robert White, who completed this feat in the monkey:
In 1999, he predicted that “…what has always been the stuff of science fiction – the Frankenstein legend, in which an entire human being is constructed by sewing various body parts together – will become a clinical reality early in the 21st century… brain transplantation, at least initially, will really be head transplantation – or body transplantation, depending on your perspective… with the significant improvements in surgical techniques and postoperative management since then, it is now possible to consider adapting the head-transplant technique to humans.”
In his paper, Canavero describes how he believes this is now possible.
It first starts off with cooling the “body-recipient (R)’s head to such a low temperature to allow the surgeons to disconnect and reconnect it to the donor (D)’s body.” This temperature would be between 12°C and 15°C (54.6°F and 59°F).
When it comes to separating the heads from each body for transfer, the surgeons use an ultra-sharp blade for a clean cut that is “the key to spinal cord fusion, in that it allows proximally severed axons to be ‘fused’ with their distal counterparts. This fusion exploits so-called fusogens/sealants.”
It’s this reconnection where Canavero’s proposal differs from others. He suggests using polyethylene glycol (PEG), a plastic, to help fuse the two spinal cords.
In addition to main technical description of the procedure, Canavero also provides a “possible scenario in order to give the reader a feel for the whole endeavor.” Here are parts of it, which are a bit more readable:
Donor is a brain dead patient, matched for height and build, immunotype and screened for absence of active systemic and brain disorders. If timing allows, an autotransfusion protocol with D’s blood can be enacted for reinfusion after anastomosis.
R’s head is subjected to PH (ca 10°C), while D’s body will only receive spinal hypothermia; this does not alter body temperature. This also avoids any ischemic damage to D’s major organs. R lies supine during induction of PH, then is placed in the standard neurosurgical sitting position, whereas D is kept upright throughout. The sitting position facilitates the surgical maneuvers of the two surgical teams. In particular, a custom-made turning stand acting as a crane is used for shifting R’s head onto D’s neck. R’s head, previously fixed in a Mayfield three-pin fixation ring, will literally hang from the stand during transference, joined by long Velcro straps. The suspending apparatus will allow surgeons to reconnect the head in comfort.
Under the operating microscope, the cords in both subjects are clean-cut simultaneously as the last step before separation. Some slack must be allowed for, thus allowing further severance in order to fashion a strain-free fusion and side-step the natural retraction of the two segments away from the transection plane. White matter is particularly resistant to many of the factors associated with secondary injury processes in the central nervous system (CNS) such as oxygen and glucose deprivation and this is a safeguard to local manipulation.
Once R’s head is separated, it is transferred onto D’s body to the tubes that would connect it to D’s circulation, whose head had been removed. The two cord stumps are accosted, length-adjusted and fused within 1-2 minutes: The proximal and distal cord segments must not be accosted too tightly to avoid further damage and not too loose to stop fusion. A chitosan-PEG glue, as described, will effect the fusion. Simultaneously, PEG or a derivative is infused into D’s blood-stream over 15′-30′. A few loose sutures are applied around the joined cord, threading the arachnoid, in order to reinforce the link. A second IV injection of PEG or derivative may be administered within 4-6 hours of the initial injection.
Various components then would be reconnected, like the esophagus, nerves, blood vessels, muscles, etc., and the skin would be sewn back together. The recipient would then remain sedated in intensive care for three days, wearing a brace, according to the scenario description, and physiotherapy would occur afterward for recovery.
You might be wondering who would benefit from such a procedure. QZ noted paraplegics or muscular dystrophy patients could be candidates to regain function that was lost. QZ also reported that the cost, as estimated by Canavero, for such a procedure would be at least $13 million.
Ethical considerations, including issues of personality and other components of the brain have come into play with White’s research in the past, but the donor patient presents an issue as well. Canavero described the donor as brain dead, which brings up problems regarding the ethics of harvesting organs before a person is officially dead.
The Daily Telegraph reported Dr. Calum Mackellar with the Scottish Council on Human Bioethics saying,”This sounds like something from a horror movie.”
Canavero admits in the paper that he doesn’t address ethical considerations of the procedure.
“On the whole, in the face of clear commitment, HEAVEN could bear fruit within a couple of years,” Canavero wrote.
Other less invasive research to help treat spinal cord conditions include a recent, successful study of rats that regained bladder function. Nerve cells combined with what the BBC described as a “cocktail of chemicals” were able to take hold in the injured area of the rats’ spinal cords in ways previously prevented by scar tissue, giving hope for further research for this method to treat paralysis.
CBS News reported Dr. Jerry Silver with Case Western Reserve University, who was part of the team that successfully reconnected the severed spinal cords in rats, remembering what it was like to see White’s monkey with a transplanted head and believes such research “should ever be done again.”
“Just to do the experiments is unethical,” he said, according to CBS. “This is bad science, this should never happen.”
He also said the proposal by Canavero is “light years away” from every actually being feasible.
“It’s complete fantasy, that you could use [PEG technology] in such a traumatic injury in an adult mammal,” Silver says. “But to severe a head and even contemplate the possibility of gluing axons back properly across the lesion to their neighbors is pure and utter fantasy in my opinion.”
Featured image via Shutterstock.com.
(H/T: The Next Big Future)