An Italian neurosurgeon has unveiled plans to perform the first human head transplant by the end of 2017.
Dr Sergio Canavero announced his plan at the annual meeting of the American Academy of Neurological and Orthopaedic Surgeons in the US state of Maryland on Friday, saying he believes he has a 90 percent chance of success.
He said his patient will be a 30-year-old Russian man, Valery Spiridonov, who has the muscle-wasting disease, Werdnig-Hoffmann.
"Of course there is a margin of risk, I cannot deny that," Canavero said.
"I made the announcement only when I was pretty sure I could do it."
Both men, who have been in regular contact through video chats, believe the controversial procedure is Spiridonov's best hope, the Reuters news agency reported.
"If it goes good, I think I will get rid of the limits which I have today and I will be more independent and this will much improve my life," Spiridonov said.
"We are making a huge step forward in science and I hope it will be OK."
Canavero is quick to point out that few with Werdnig-Hoffmann disease reach adulthood.
"He is a brave man and he is in horrible condition. You have to understand - for him, Western medicine has nothing to offer. Western medicine has failed."
Surgical team of 100
Canavero will need the support of his peers in order to move forward on the operation which could cost around $15m.
Cardiothoracic surgeon, Dr Raymond Dieter, a former president of the International College Of Surgeons, said one of the biggest concerns with the procedure was keeping the brain alive during the surgery.
"When you think you are doing a heart transplant, or a kidney transplant, or a liver transplant, you have to cool those organs to give you a longer period of … surgical time before you reconnect all the vessels and you start reperfusion," Dieter said.
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"We've seen several professors criticising Dr Canavero's work but you know, there was criticism for the first heart transplant as well and now it's commonplace."
The operation, which would require a team of more than 100 medical workers and could take 36 hours to complete, could take place in the US or China.
Canavero plans to carry out the procedure in December 2017.
"I prepared myself not only scientifically, but also psychologically which is equally important in order to tackle all of these attacks from several fronts, in order to justify what you want to do, why you want to do, you have to prepare yourself," Canavero said.
"This is a frontier, the final frontier. It's not space. This is it because it has implications that go well beyond religion, culture, the future, everything."