2016-05-02 02:34:11 UTC
One Autumn day in 1974, when he was 9, Sergio Canavero visited his regular newsstand on a bustling street in Turin, Italy, to buy a comic book.
As a bullied schoolboy, the man who now claims he can complete the first human head transplant was dismally aware of his pitiable social status - "cookie-cutter nerd" - and sought fictional escape. His attachment to Spider-Man's Peter Parker, another dweeb, lured him deep into the comic book world of Marvel, with its dose of futuristic medicine. That fateful day, he bought Issue 51 of Marvel Team-Up, in which Dr. Strange boasts to Spider-Man and Iron Man, "I myself have surgically rejoined severed neurolinkages.... The nerve endings have been fused, the healing process begun." This marked Canavero's first encounter with the idea of spinal cord fusion. And he wanted more.
Three years ago, Canavero, now 51, had his own Dr. Strange moment when he announced he'd be able to do a human head transplant in a two-part procedure he dubs HEAVEN (head anastomosis venture) and Gemini (the subsequent spinal cord fusion). Valery Spiridonov, a 31-year-old Russian program manager in the software development field, soon emerged from the internet ether to volunteer his noggin. He suffers from Werdnig-Hoffman disease, a muscle-wasting disorder, and is desperate. Canavero likens Spiridonov's willingness to venture into a new medical frontier to cosmonaut Yuri Gagarin's bold resolution to become the first human to travel to space, back in 1961.
But many dismiss Canavero's plans as fantasy. And if he has a comic book-like nemesis - or maybe he's the hero here? - it is Arthur Caplan, founder of the Division of Bioethics at New York University's School of Medicine. "I think he's a charlatan, a quack and a self-promoter," says Caplan, who also labels Canavero a "Looney Tune" who's "peddling false hope." Those judging Canavero generally assign him to one of two categories: either an outlandish Dr. Frankenstein seeking fame without regard for risk or an innovator willing to try what others consider impossible.
Meanwhile, Canavero claims his detractors publicly denounce him but then approach him to learn more. And in a world of heart, lung, kidney, uterus and hand transplants, he wonders why we can't yet transplant the human head. After all, back in 1970 American neurosurgeon Dr. Robert White conducted the first successful transplant of a head to another body when he operated on a rhesus monkey. Modern spinal cord fusion technology had not yet been developed, and the monkey lived only a few healthy days. But in 1999, White predicted that what "has always been the stuff of science fiction - the Frankenstein legend - will become a clinical reality early in the 21st century."
Canavero has a plan, delineated in a June 2013 paper in the peer-reviewed journal Surgical Neurology International and presented in 2015 as the keynote address of the American Academy of Neurological and Orthopaedic Surgeons's 39th annual conference. It's a 36-hour, $20 million (£14 milion) procedure involving at least 150 people, including doctors, nurses, technicians, psychologists and virtual reality engineers.
In a specially equipped hospital suite, two surgical teams will work simultaneously - one focused on Spiridonov and the other on the donor's body, selected from a brain-dead patient and matched with the Russian for height, build and immunotype. Both patients - anesthetized and outfitted with breathing tubes - will have their heads locked using metal pins and clamps, and electrodes will be attached to their bodies to monitor brain and heart activity. Next, Spiridonov's head will be nearly frozen, ultimately reaching 12 to 15 degrees Celsius, which will make him temporarily brain-dead.
Doctors will then drain his brain of blood and flush it with a standard surgery solution. A vascular surgeon will loop sleeve-like tubes made of Silastic (a silicone-plastic combination) around the carotid arteries and jugular veins; these tubes will be tightened to stop blood flow and later loosened to allow circulation when the head and new body are connected. Then the two teams, working in concert, will make deep incisions around each patient's neck and use color-coded markings to note all the muscles in both Spiridonov's head and that of the donor, to facilitate the reconnection.
Next comes the most critical step of all. Under an operating microscope, doctors will cleanly chop through both spinal cords - with a $200,000 diamond nanoblade, so thin that it is measured in angstroms, provided by the University of Texas. Then the rush is on: Once sliced, Spiridonov's head will have to be attached to the donor's body and connected to the blood flow within an hour. (When the head is transferred, the main vessels will be clamped to prevent air from causing a blockage.) Surgeons will quickly sew the arteries and veins of Spiridonov's head to those of his new body. The donor's blood flow will then, in theory, re-warm Spiridonov's head to normal temperatures within minutes.
If all that goes as planned, Canavero can then make good on his Dr. Strange inspiration with Gemini. The lengths of the transected spinal cord stumps will be adjusted so they're even, and the myelinated axons, the spaghetti-like parts of nerve cells, will be fused using a special type of glue made of polyethylene glycol, an inorganic polymer that Canavero says is the procedure's true magical elixir. In this way, spinal cord function will be established by enabling the cytoplasm of adjacent cells to mix together.
Then it's time to make sure the spinal fusion is secure with a few loose sutures applied around the joined cord and threaded through the thin membrane surrounding the brain and spinal cord. To finish securing Spiridonov's head, the previously exposed vertebral arteries of the donor and Spiridonov will also be linked to achieve proper blood flow. In addition, the dura, the tough outermost membrane covering the brain and spinal cord, will be sewn watertight with wires and clamps. Doctors will similarly reconnect the trachea, esophagus, vagi and phrenic nerves, along with all of the severed muscles, and plastic surgeons will sew the skin for optimal cosmetic results.
Throughout, doctors will ensure a suppressed immune system through medication, and after the transplant, doctors will regularly screen Spiridonov's blood for anti-donor antibodies while he lies in a drug-induced coma for four weeks to allow his brain to recover. During that time, doctors will electrically stimulate the spinal cord to promote communication between neurons and improve Spiridonov's motor and sensory functions.
Once he awakens, Spiridonov will start his rehabilitation, including virtual reality training. Canavero predicts his patient will be able to walk three to six months after surgery.
Despite the thoroughness of the presentation at the Annapolis, Maryland, conference, Canavero and Spiridonov faced vitriol and doubt. Spiridonov fielded a question about the ethics of this surgery by asking if anyone would like to be in his shoes: needing assistance with defecation and urination and living a life without sex. A hush fell over the audience. The Russian said he would rather risk death in this experimental surgery to achieve a higher quality of life than suffer the burdens of his current existence. "If he is going to die," Canavero said later, "he is the only one who can decide."
Canavero understands. A self-described womanizer who says he studied German-language Spider-Man comics as a bachelor to seduce German-speaking women, he is a hedonist who wants his patients to experience all of life's pleasures.
Canavero's collaborator, Xiaoping Ren of Harbin Medical University in China, recently completed a monkey head transplant. And Canavero's colleague, C-Yoon Kim of the Konkuk University School of Medicine in South Korea published a study in the journal Spinal Cord showing how his team re-established motor movements in mice whose neck spinal cords had been severed and re-fused.
Dr. Michael Sarr, professor emeritus of surgery at the Mayo Clinic and co-editor-in-chief of Surgery, recently accepted one of Canavero's head transplant papers for his publication. "He's a little bit fantastic, but he's a serious guy," Sarr says. "He's not just a showboat. This is not science fiction. This is now science. There's experimental work that supports the concept of nerve membrane fusion." Sarr is particularly interested in how this technique could be applied more widely to treat traumatic spinal cord injury patients. Of course, he admits the surgery has serious risks and wonders about how well Spiridonov will be able to function - should he survive.
"Conceptually, much of this could work, but the most favorable outcome will be little more than a Christopher Reeve level of function," says Dr. John Adler, a neurosurgeon and professor emeritus at Stanford University's School of Medicine, referring to the Superman actor who was left paralyzed from the neck down after a horse-riding accident. In other words, Spiridonov might end up with a body that functions not much better than the one he left. Adler says each piece of Canavero's method is viable from a strictly technical sense, but together there's too much risk of failure--paralysis or death for Spiridonov. The challenges range from whether the axons in the joined section of the spinal cords will form any sort of meaningful connections to the possibility that Spiridonov's brain will suffer irreparable damage when it is without blood flow.
Some skeptics are more outspoken. "In my opinion, this procedure has no feasibility at all," says Dr. Lorenzo Pinessi, director of the Neurology Clinic at Italy's University of Turin. "It is demented."