http://www.digitaljournal.com/article/353719

Human head transplants within reach, says neuroscientist

Posted Jul 4, 2013 by Jordan Howell
Face transplants, the human genome map, and the cure for HIV—within one generation all three have made the leap from science fiction to science fact. Could head transplants some day also make that leap? One scientist thinks so.
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Credit: Movie still from: The Brain That Wouldnt Die (1962)
In a study published in the June 2013 issue of Surgical Neurology International, Dr. Sergio Canavero of the Turin Advanced Neuromodulation Group outlines the feasibility of such a procedure as well as the logistics of performing the surgery, which would require both bodies to be in the operating room at the same time.
Canavero’s proposal, known as the head anastomosis venture project, or HEAVEN for short, is largely based on data collected from prior head transplants conducted on rhesus monkeys in 1970. At the time, Dr. Robert White and his colleagues kept a monkey alive for 8 days following the head transplant and were able to maintain normal organ functions.
However, Dr. White was unable to reconnect the spinal cord, leaving the monkey paralyzed from the neck down.
“The greatest technical hurdle to such endeavor is of course the reconnection of the donor’s (D)’s and recipients (R)’s spinal cords. It is my contention that the technology only now exists for such linkage,” says Canavero in his paper.
Such a surgery may one day look like the following. Make note: the recipient is the head receiving the body, and the donor is the body that will receive the replacement head.
First, the surgical teams would need to induce hypothermia by lowering the recipient’s body temperature to about 15 degrees Celsius.
At this reduced temperature, the surgeons would then induce full cardiac arrest and remove the head.
The recipient’s head must be attached to the donor’s circulatory system within one hour, which is currently the maximum amount of time a body can be in full cardiac arrest without any discernible neurological damage.
Once the head is connected, the donor’s heart would then be re-started at which time the surgeons could proceed with the reconnection of the spinal cord.
According to Christopher Mims, since this has never been done successfully Canavero’s paper “must be taken as an exercise in speculation.”
The next part of Canavero’s paper is where things get interesting.
Successfully reconnecting a spinal cord will depend entirely on how the head is first detached.
Using an “ultra-sharp blade,” surgeons should be able to cut the cooled spinal cord in such a way as to inflict minimal damage and scarring.
“It is this ‘clean cut’ the key to spinal cord fusion, in that it allows proximally severed axons to be ‘fused’ with their distal counterparts,” Canavero notes in slightly broken English.
If the cut is as clean as Canavero hopes, then the spinal cord should be able to heal naturally, with corresponding nerves and tissue held together with inorganic polymers, likely polyethylene glycol or PEG, that will act as a “sealing mechanism” to “immediately reconstitute (fuse/repair) cell membranes damaged by mechanical injury.”
However, some are already questioning the reasoning behind such a procedure. Could anyone ever be certain that the doctor or hospital performing the surgery acted ethically to reduce patient suffering as opposed to acting out of a desire for money or fame?
Mims notes that such a procedure could cost upwards of US $13 million. However, such a price seems trivial when compared to the possibility of a patient with muscular dystrophy getting a second chance on life.
For some ethicists, the surgery also poses a philosophical question of what it is to be human.
“What is the donor and what’s the recipient?” asked Dr. Christopher Scott, bioethicist and regenerative medicine expert at Stanford University. “We all have an idea of personhood, right? Of what a person is. You know, a baby or a human becomes a person. And this procedure turns it on its head. Is this a person that the body belongs to, or the person the head belongs to? It’s a chimera, a hybrid person.”
Canavero, to his credit, is unapologetic about the HEAVEN project.
“[H]orrible conditions without a hint of hope of improvement cannot be relegated to the dark corner of medicine.”
Read the full paper here.
Find a short movie about the 1970 rhesus monkey head transplant below.