An Italian doctor recently revealed the completion of his outline for the world’s first head transplant. The operation involves taking a living head and transplanting it to a donor body, a feat he hopes may help those living with neurodegenerative diseases. Although the surgery sounds impossible, the doctor claims the steps needed to complete such a task are not out of reach; the operation may be available in as little as two years.

For years, Dr. Sergio Canavero has both fascinated and appalled those in the medical community with his aspirations to complete the world’s first head transplant, which he calls the GEMINI project. Recently the doctor published an outline in the journal Surgical Neurology International of exactly how the surgery would be completed.

The operation involves removing the recipient's head and cooling it along with the donor body, The Guardian reported. Tissues around the neck are dissected and major blood vessels are joined using tiny tubes. After this, the spinal cord is cut and the recipient's head is then completely moved onto the donor’s body. Once this is completed, the head’s remaining spinal cords are fused together with the spinal cord of the body, using a chemical called polyethylene glycol. In order to prevent injury during the process, the person would be kept in a coma for around four weeks. However, Canavero is confident that after around a year of rehabilitation, the individual would be able to move, speak, and walk.

While his method may be questionable, his intentions are honest. Canavero hopes that his surgery can help those left with limited mobility due to neurodegenerative diseases, such as muscular dystrophy.

"These are a source of huge suffering, with no cure at hand," wrote Canavero in a previous paper on the procedure.

From his initial introduction of his operation to the world in 2013, Canavero’s proposal was met with sharp criticism. Neuroscientist Jerry Silver of Case Western Reserve University told CBS News that, in his opinion, Canavero’s plans contain far more fiction than facts.

"It's complete fantasy, that you could use [PEG technology] in such a traumatic injury in an adult mammal," Silver said. "But to sever a head and even contemplate the possibility of gluing axons back properly across the lesion to their neighbors is pure and utter fantasy in my opinion."

Dr. Harry Goldsmith, a professor of neurological surgery of the University of California, Davis, shared his similar beliefs with The Guardian: “This is such an overwhelming project, the possibility of it happening is very unlikely.”

Of course, there is also the ethics issue. Many transplant recipients seriously reject their new appendages. For example, NBC News reported that the wife of the recipient of the world’s first penis transplant rejected his new body part so much that he eventually requested that it be removed. Another man requested that his hand transplant be removed because he felt “mentally detached” from the new limb. It’s unknown what a drastic change such as waking up in a completely new body will do to a person.

Canavero is well aware of his critics, but recently told New Scientist that he won’t let public opinion stop him from getting the procedure to those who truly want it.

“If society doesn’t want it, I won’t do it. But if people don’t want it, in the U.S. or Europe, that doesn’t mean it won’t be done somewhere else,” he said.

While head transplants have never been done (or at least never been documented) on humans, there have been cases of head transplants on various animals throughout history. In 1970, doctors in the U.S. attempted head transplants on monkeys. The animals lived for about eight days with no notable complications, but unfortunately were not able to complete the spinal cord transfer, and the operation left the primates paralyzed.

"I remember that the head would wake up. The facial expressions looked like terrible pain and confusion and anxiety in the animal," Silver told CBS News.

A more recent attempt involving mice head transplantation in China saw slightly better results, with researchers succeeding in more long-term brain stem survival post-surgery.

Source: Canavero S. The “Gemini” spinal cord fusion protocol: Reloaded. Surgical Neurology International. 2015.