It started in 1950 when Vladimir Demikhov transplanted one dog’s head onto another’s body. Sixty years on and a full head human transplant could happen as soon as December 2017 (1).
Dr. Sergio Canavero, the neurosurgeon proposing the head transplantation venture, told ‘New Scientist’ magazine “I think we are now at a point when the technical aspects are all feasible” (2). His paper, published in June 2015 in ‘Surgical Neurology International’, outlines the procedure, with the first step being to create hypothermic conditions to extend the life span of the cells, prevent coagulopathy, and ultimately brain damage (1). At low temperatures, mammals can be kept alive for one hour without oxygen. Thus, once the head had been initially disconnected from its original body, blood flow would need to be reconnected within the hour. Canavero explains that the key to successful spinal cord fusion is a ‘clean cut’ so an ultra-sharp blade would need to be used to prevent scarring and damage (3).
The next proposed step is to flush the body with polyethylene glycol, a cell-cell fusogen which aids the fusion of fatty membranes. This will encourage spinal cord growth by connecting axons and sealing neurons. Muscles and blood vessels will then have to be stitched and sealed before the implantation of electrodes. These would provide electricity-accelerated recovery as it is shown to strengthen new nerve connections and therefore accelerate axonal and dendritic regrowth (1).
Lastly, the recipient will be put into a coma for 3-4 weeks post-surgery to prevent excessive movement, with the final recovery steps being physiotherapy, antibiotic coverage, and an extensive course of immunosuppressive drugs.
The major hurdles in this venture have been identified by Canavero to be the spinal cord fusion as there are worries that the recipient could become quadriplegic, as well as the risk of rejection of the donor body. If the use of polyethylene glycol as a fusogen is unsuccessful in prompting spinal cord growth Canavero aims to use olfactory ensheathing cells, stem cells, or failing that, stomach membranes to bridge the spinal cord gap (3).
The candidate for the procedure, that will take thirty six hours and one hundred surgeons, is Valery Spiridonov, a thirty year old Russian man who suffers from Werdnig-Hoffman disease, a rare form of muscular wasting. Werdnig-Hoffman disease is an infantile disease caused by a mutation which results in the degeneration of motor neurons, causing muscular atrophy. Due to this, respiratory failure is usually the cause of death and babies diagnosed with this disease do not normally live past the age of two (2).
Canavero further told ‘New Scientist’ that “the real stumbling block is the ethics”. If the procedure was successful and the recipient wished to reproduce, the offspring would have the genetic inheritance of the donor. Additionally, although it would be primarily used to help people with severe muscle and nerve degeneration as well as people suffering from cancerous organs; eventually Canavero hopes to be able to replace our old, used bodies with cloned, younger bodies of ourselves (2). There are undoubtedly mixed opinions from both the medical community and the general public on this matter, and the question to ponder is this: is this an example of medical advances gone too far or is it the future for human longevity?
By Olivia Meadowcroft
- Canavero, S. 2013. HEAVEN: The head anastomosis venture Project outline for the first human head transplantation with spinal linkage (GEMINI). Surgical Neurology International [online]. 13(4). [Accessed: 13-9-15]. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3821155/
- T, Helen. 2015. First human head transplant could happen in two years. New Scientist. 28 February.
- Canavero, S. 2015. The “Gemini” spinal cord fusion protocol: Reloaded. Surgical Neurology [online]. 6 (18). [Accessed: 13-9-15]. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4322377/