Do you think a head transplant is science fiction or science fact? Italian neurosurgeon Sergio Canavero thinks it will be science fact. Canavero has a reputation for being a sensationalist in the global medical community. But is he?
The Animal Successes
Canavero and Chinese surgeon, Xiaoping Ren, published a study that showed monkeys and dogs could walk after their spinal cords were completely severed during surgery and then put back together again. According to USA Today, the study published in the magazine Surgical Neurology International included video evidence.
They applied a polyethylene glycol substance (PEG) to the nerve endings. They want to use PEG to transplant human heads.
Patients with incurable and fatal diseases would have a new body in which to live. Think of people with amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), people like physicist Stephen Hawking.
Canavero states that neurosurgeons have been “stuck to the view that a severed spinal cord cannot be mended in any way.” He completely rejects that view.
Is a Head Transplant Possible
There have been experiments involving animal head transplants since the early 1900s. None, not even the ones Cavanero and Xaioping did, have survived more than days.
Whole head transplantation must overcome four major technical challenges.
First Challenge
The brain, like any organ, depends on a continuous flow of blood to provide oxygen, nutrients, and to remove waste products. Damage sets in quickly at normal temperatures when the blood flow is cut off. Blood supply and preserving the brain after removal, before and during transplantation may benefit from techniques used for heart and lung and other organ transplants. The brain is perhaps the most sensitive of these organs to lack of oxygen. Will the same techniques work for the brain? Maybe.
Second Challenge
The nervous system in the head and body is complex. The central nervous system, governed by the brain stem, controls life-sustaining functions like breathing and heart beating. There are nerves that control motor function, allow voluntary movement of your muscles, and peripheral nerves that allow you to feel pressure, temperature, and proprioception. All these nerves would have to reconnect and do so appropriately. Today, amputees often suffer neuropathy or phantom pain. These pains can be debilitating.
Third Challenge
There are major structures in the head and neck. Surgeons have reattached the trachea and the esophagus on a smaller scale. The neck muscles that hold up and move the head are more structures to reattach. All of these at once has never been done. And all of these must be successful for the surgery to be considered a success.
Fourth Challenge
Transplant rejection is when the body rejects the “foreign” tissues of another body. Medical science has made great advances in managing transplant rejection using medications. However, transplant rejection still causes an overall mortality that is much higher than in the general population. There are many transplant rejection challenges that could occur with a whole head transplant.
The Head Transplant Procedure
Canavero estimates the procedure “would cost up to $100 million and involve several dozen surgeons and specialists. He said the donor would be the healthy body of a brain-dead patient matched for build with a recipient’s disease-free head.”
The recipient’s head would be cooled to deep hypothermia.
The procedure would last more than twenty-four hours. And after surgery the patient would be kept in a coma for a time. Then the long road to recovery would begin.
The First Volunteer
Spiridonov has Werdnig-Hoffman disease (a spinal muscular atrophy disease). One can’t blame Spiridonov for wanting a new body. But can is he fully aware or informed of the risks?
The Risks
Obviously, the first risk is death. But there are many more.
Imagine that you undergo a head transplant to escape paralysis and end up with facial paralysis, paralysis of one body part, or the whole body? How would you cope?
Neuropathy in the whole body could become unbearable.
Transplant rejection symptoms are often flu-like meaning fever, aches, pain and tenderness, and fatigue, plus symptoms of the transplanted organ failing such as decreased urine output in a kidney transplant. We can assume that in the whole head transplant there would be more than a headache.
Beside the risk of whole body neuropathy and transplant rejection, there are psychological risks. Will his personality, his memories survive the transplant? Would all the adjustments to new chemicals, connections, and even body image drive him insane?
Science or Science Fiction
Many people’s first reaction to the idea of a whole head transplant is revulsion, shock, or rejection. They think of Mary Shelley’s Frankenstein and recoil.
There were similar reactions to the first hand, heart, and face transplants. In 1954, many people probably felt “creeped out” by the first human organ transplant, a kidney.
The Future
Xaioping feels that human trials should begin soon.
Science or science fiction isn’t the real question. As in previous posts about the ethics of science (see The Good, the Bad, and the Ugly), science will march forward. The real question is, are we ready for it?