readings> head transplants
Fancy a bit of extreme surgery? Then what about a head transplant?
You've got a patient whose body is riddled with cancer or wasting away
with a degenerative disease. There's also a suitable donor down at the
local head trauma unit. So snip, snip; stitch, stitch - problem solved.
Old head, new body!
For several decades, Robert J White, a professor of neurosurgery at
Case Western Reserve University, Cleveland, Ohio, has been the man most
likely to give this history-making operation a go. He has openly talked
about it as an option for the likes of quadriplegic Superman actor,
Christopher Reeves, or amyotrophic lateral sclerosis sufferer, Stephen
Hawking. And he has the skills.
White pioneered many surgical techniques including extracorporeal
hypothermic perfusion where brains are chilled to 10 degrees Celsius to
allow blood flow to be interrupted for up to an hour. But he became
famous - notorious in vivisection circles - for his experiments in the
1970s in which he transplanted the heads of rhesus monkeys. It took a
team of thirty doctors, nurses and technicians. Chalk marks on the
floor were used to choreograph the procedure beforehand. After a monkey
eventually survived the 18 hour operation, a cheer went up when it
immediately bite the finger of the nearest assistant.
Of course, White's monkeys were left paralysed from the neck down.
There was no chance of knitting together the sectioned spinal cords and
so it was mostly a technical exercise in swapping over blood supplies
and sewing muscles. Immuno-rejection and other complications also meant
that none of the animals lasted more than nine days. But in the early
1990s, White began to prepare for a similar operation on a human. He
went down to the mortuary to practice on cadavers. His procedure
involved cutting through the neck at the fourth vertebra, dissecting
out blood vessels and exposing the spinal cord. Metal plates would be
used to mate the two halves. First the carotids and jugulars would be
connected, then if all went well, the vertebral arteries. As a fall
back, White had his brain cooling equipment to buy extra time during
the switching of blood supplies. His main concern, he said, was not the
operation itself but handling tissue-rejection afterwards.
White had a medical rationale for the procedure. He admitted the
patient would end up a "head on a pillow", paralysed and with no longer
even the breath control to speak. The donor body would have to be
ventilated and drip-fed. Yet a terminally-ill cancer sufferer or a
quadriplegic with multi-organ failure might take this extreme option -
at least they would still be able to watch Oprah on the TV or listen to
Mozart, White commented. He indicated the only thing really holding him
back was the need to raise several million dollars to pay for the
operation. White was not so concerned about the blessing of hospital
authorities as he had colleagues in Kiev and elsewhere eager to take
part in this ground-breaking neurosurgery.
Well, the years have come and gone and it hasn't happened yet. White is
nearing 80 and long-retired. However, while it is unlikely he will now
ever wield the knife himself, his associates could still spring a
surprise on us one of these days.
It does make one wonder what the future has in store. Some think head
transplants will become routine just as soon as can also manage spinal
cord regeneration. Who could object if we knew how to join the two
halves properly? But this seems a pipe dream. There is no reason to
expect that the spinal tract of one body could ever form a functional
connection with another. Even with intensive physiotherapy to retrain
the brain's somatosensory organisation, a patient would likely remain
just a spastic twitch or two better off than paralysed.
Without a functional connection there is also the obvious problem of
the survival of a decapitated body. Once cut-off from the brain-end of
its autonomic, endocrine, immune, and who knows what other control
systems, just how long could a torso survive?
Perhaps a transplant of a patient's entire CNS - brain and spinal cord
- might work. But if society really has the stomach for this kind of
surgical intervention, then why not go the whole hog and simply hook up
a severed head to a bionic life support machine? Dump the donor body
with all its own medical complications and just clamp a head to a rack
of blood pumps, oxygenating and feeding equipment, a dialysis unit, and
other necessary kit. These days you could disguise the machinery in a
latex prosthetic body and stick the whole lot in a motorised wheel
chair. Well, what's to stop the really ambitious neurosurgeon? Apart
from the raising the cash?