Modern medical technology has granted doctors the ability to transplant many of the body’s organs, extending the life of people suffering from chronic diseases. But what about replacing all the organs at once along with the body they are in? That’s science fiction right now, but Italian neurosurgeon Sergio Canavero (pictured, top) says he plans to do the first human head transplant next year. This isn’t the first time he’s made this claim, but now he’s got a volunteer lined up and has explained in more detail how he thinks the procedure will go.

If this sounds suspicious, there’s good reason. There’s plenty of reason to be skeptical.

It’s easy to see the appeal of a head transplant in theory. If it were possible and reasonably safe, you could cure almost any disease, except for neurological ones. You’d be replacing a person’s entire complement of organs, their immune system, their joints, and everything else that causes problems as we age. Canavero’s first volunteer, Valery Spiridonov, has appeared with Canavero several times to talk about his desire to undergo the operation. Spiridonov is 31 and suffers from a muscle-wasting disease called Werdnig-Hoffman’s. It leaves him wheelchair bound and dependent on others for basic needs. Canavero wants to put his head on a body that doesn’t have Werdnig-Hoffman’s, but finding such a body will be the first hurdle.

According to Canavero, the donor body will come from someone who is brain dead and whose organs would be considered acceptable for transplantation. Things get wild when Canavero explains the process of disposing of the old body. The patient would be cooled in order to slow damage to brain cells, then surgeons would sever the soft tissue in the neck. Tubes would be affixed to all the arteries and veins to maintain blood flow. Then, Canavero plans to use a diamond knife to sever the spinal cord.

Being able to surgically remove the head in an orderly fashion should allow surgeons to then reattach all the nerves and blood vessels to the new body, once that pesky donor head is removed. A special bio-compatible glue will hold the spinal cord together so it can fuse with the donor body. The patient will then be put in a drug-induced coma for four weeks while the connection between the head and body heals. It’s the reattachment process that’s the most unlikely part of all this. There’s never been a successful procedure that reattached a fully severed primate spinal cord.

Canavero says all the technology he needs is available, and estimates the procedure will take about 36 hours and require the services of 150 medical professionals. He expects a 90% chance of success, as in a 90% chance the patient is up and walking around a few months after the surgery. This is… suspiciously high for a completely new procedure.

This all still sounds like science fiction, and medical professionals are mostly skeptical of Canavero’s plan. He seems set to try, though. And who knows? Maybe it’ll work. A few years ago face transplants seemed like science fiction. Even if this does work, the process will be obscenely expensive. Plus, it will give an entire body full of transplantable organs to a single person. It’s unclear if this would be considered ethical when there are so many people waiting for transplants.