Human head transplants coming soon, doctor believes

It may sound like science fiction, but an Italian surgeon believes that the technology needed to transplant a person's head onto a new body could exist in just two years.

Dr. Sergio Canavero, a doctor in Turin, Italy, says the procedure could revolutionize medicine by helping extend the lives of people with terminal diseases, and allowing those with spinal cord injuries to abandon a body that is no longer working for one that is.

Canavero tells New Scientist magazine that all the medical technologies needed for such an operation are either already available or not far off in the future.

He's even sketched out a proposal for how it could be performed, and is scheduled to present the plan at a large orthopedic surgery conference this June, where he hopes to begin rallying the support and expertise to begin planning a first attempt.

But Canavero's proposal is already drawing scorn and skepticism from others in the medical community. They say such a surgery would be so complicated, the notion that it is just around the corner is absurd.

According to the procedure Canavero envisions, outlined this month in Surgical Neurology International, the first step would be finding the right candidate, as well as a suitable donor body from a brain-dead patient.

Then, the patient's spinal cord would need to be cut cleanly to minimize nerve damage, Canavero writes. (He offers several suggestions for this, including using a "diamond microtomic snare blade" or a "nanoknife made of a thin layer of silicon nitride with a nanometer sharp cutting edge.")

The recipient's head would then be moved onto the donor body and the blood vessels and muscles stitched together.

The most challenging part would be fusing the two ends of the spinal cords, which resemble packed bundles of fibre optic cables. Canavero proposes using a chemical called polyethylene glycol, which would encourage the fat in the spinal cord cell membranes to glue together.

Afterwards, the patient would need be kept in a coma for several weeks, to be sure they don't move during recovery. To strengthen the new nerve connections, surgeons would implant electrodes into the neck to provide regular electrical stimulation.

The patient would then be slowly revived. Canavero believes, if all goes well, the patient should be able to feel their face, speak with their normal voice and eventually move their bodies after several months of physiotherapy. Patients would also need to stay on medications to prevent their bodies from rejecting their new heads.

While the proposal sounds complicated, Canavero notes that head transplants have been attempted in animals, albeit with poor results.

A research team from Case Western Reserve University in Cleveland, Ohio, transplanted the head of one monkey onto the body of another in 1970, although they didn't attempt to fuse the spinal cords.

The monkey was never able to move its body, but was able to breathe with artificial assistance. After nine days, though, the monkey's immune system rejected the head and the animal died.

Canavero says with advances in immunosuppression, science has progressed enough since 1970 to attempt the surgery in a human. But his plan is being met with skepticism.

Dr. Harry Goldsmith, a professor of neurological surgery at the University of California, Davis, who performed one of the few surgeries allowing someone with a spinal cord injury to walk again, told the New Scientist the surgery would be so intensive, "the possibility of it happening is very unlikely."

He said even trying to keep someone healthy in a coma for four weeks would be hard enough.

"I don't believe it will ever work, there are too many problems with the procedure," he said.

But Dr. William Mathews, a spinal surgeon and the chairman of the American Academy of Neurological and Orthopaedic Surgeons (AANOS), told the magazine he believes the idea of a spinal fusion is possible. But he said it's highly unlikely such a surgery could be attempted within two years.

"He thinks it's ready, I think it's far into the future," he said.