Editing Head transplant (section)

==History==
[[File:Bundesarchiv Bild 183-61478-0004, Kopftransplantation durch Physiologen Demichow.jpg|thumb|Transplantation of a dog-head performed in the [[Soviet Union|USSR]] by Vladimir Demikhov on 1954]]

[[Alexis Carrel]] was a French surgeon who had developed improved surgical methods to [[Circulatory anastomosis|connect blood vessels]] in the context of [[organ transplantation]]. In 1908, he collaborated with the American [[Charles Claude Guthrie]] to attempt to graft the head of one dog on an intact second dog; the grafted head showed some reflexes early on but deteriorated quickly and the animal was killed after a few hours.<ref name=Lamba2017rev/><ref name = "stiffy">{{cite book| last =Roach| first =Mary| date = 2004| title = Stiff: The Curious Lives of Human Cadavers| publisher = W. W. Norton & Co.| isbn = 978-0393324822| pages = 206–210}}</ref> Carrel's work on organ transplantation later earned a Nobel Prize; Guthrie was probably excluded because of this controversial work on head transplantation.<ref name=Furr2017rev>{{cite journal|last1=Furr|first1=A|last2=Hardy|first2=MA|last3=Barret|first3=JP|last4=Barker|first4=JH|title=Surgical, ethical, and psychosocial considerations in human head transplantation.|journal=International Journal of Surgery |date=May 2017|volume=41|pages=190–195|doi=10.1016/j.ijsu.2017.01.077|pmid=28110028|pmc=5490488}}</ref>

In 1954, [[Vladimir Demikhov]], a [[Soviet Union|Soviet]] surgeon who had done important work to improve [[coronary bypass surgery]], performed an experiment in which he grafted a dog's head and upper body including the front legs, onto another dog; the effort was focused on how to provide blood supply to the donor head and upper body and not on grafting the nervous systems. The dogs generally survived a few days; one survived 29 days. The grafted body parts were able to move and react to stimulus. The animals died due to [[transplant rejection]].<ref name=Lamba2017rev/>

In the 1950s and '60s, [[immunosuppressive drug]]s and [[organ transplantation]] techniques were developed that eventually made transplantation of kidneys, livers, and other organs standard medical procedures.<ref name=Lamba2017rev/>

In 1965, [[Robert J. White]] did a series of experiments in which he attempted to graft only the vascular system of isolated dog brains onto existing dogs, to learn how to manage this challenge. He monitored brain activity with EEG and also monitored [[metabolism]], and showed that he could maintain high levels of brain activity and metabolism by avoiding any break in the blood supply. The animals survived between 6 hours and 2 days. In 1970, he did four experiments in which he cut the head off of a monkey and connected the blood vessels of another monkey head to it; he did not attempt to connect the nervous systems. White used [[Deep hypothermic circulatory arrest|deep hypothermia]] to protect the brains during the times when they were cut off from blood during procedure. The recipient bodies had to be kept alive with mechanical ventilation and drugs to stimulate the heart. The grafted heads were able to function - the [[Eye movement|eyes tracked]] moving objects and it could chew and swallow. There were problems with the grafting of blood vessels that led to blood clots forming, and White used high doses of immunosuppressive drugs that had severe side effects; the animals died between 6 hours and 3 days after the heads were engrafted.<ref name=Lamba2017rev/> These experiments were reported and criticized in the media and were considered barbaric by animal rights activists.<ref name=Furr2017rev/> There were few animal experiments on head transplantation for many years after this.<ref name=Furr2017rev/>

In 2012, [[Xiaoping Ren]] published work in which he grafted the head of a mouse onto another mouse's body; again the focus was on how to avoid harm from the loss of blood supply; with his protocol the grafted heads survived up to six months.<ref name=Lamba2017rev/>

In 2013, [[Sergio Canavero]] published a protocol that he said would make human head transplantation possible.<ref name=NS>{{cite news|title=Sergio Canavero: Will His Head Transplants Roll? - Neuroskeptic|url=http://blogs.discovermagazine.com/neuroskeptic/2017/05/13/canavero-head-transplants/|work=Neuroskeptic|date=13 May 2017|access-date=August 5, 2017|archive-date=November 20, 2019|archive-url=https://web.archive.org/web/20191120030703/http://blogs.discovermagazine.com/neuroskeptic/2017/05/13/canavero-head-transplants/|url-status=dead}}</ref><ref name=":0">{{cite journal|last1=Canavero|first1=S|title=HEAVEN: The head anastomosis venture Project outline for the first human head transplantation with spinal linkage (GEMINI).|journal=Surgical Neurology International|date=2013|volume=4|issue=Suppl 1|pages=S335–42|pmid=24244881|doi=10.4103/2152-7806.113444|pmc=3821155|doi-access=free}}</ref> In 2016, he announced his plans to do the procedure on Valeriy Spiridonov, a disabled Russian software engineer suffering from [[spinal muscular atrophy]], who volunteered for the surgery. Canavero claimed that there is a 90% chance of success.<ref>{{Cite news |date=2016-09-20 |title=The surgeon who wants to perform a head transplant by 2017 |language=en-GB |work=BBC News |url=https://www.bbc.com/news/newsbeat-37420905 |access-date=2023-07-28}}</ref> However, Spiridonov later cancelled his participation after getting married and having his first child.<ref>{{Cite web |last=Stewart |first=Will |date=2018-12-18 |title=Man set for world's first head transplant cancels surgery after falling in love |url=https://www.mirror.co.uk/news/world-news/man-set-worlds-first-head-13748350 |access-date=2023-07-28 |website=mirror |language=en}}</ref>

In 2015, Ren published work in which he cut off the heads of mice but left the brain stem in place, and then connected the vasculature of the donor head to the recipient body; this work was an effort to address whether it was possible to keep the body of the recipient animal alive without life support. All prior experimental work that involved removing the recipient body's head had cut the head off lower down, just below [[Axis (anatomy)|the second bone in the spinal column]]. Ren also used [[Targeted temperature management|moderate hypothermia]] to protect the brains during the procedure.<ref name=Lamba2017rev/>

In 2016, Ren and Canavero published a review of attempted as well as possible neuroprotection strategies that they said should be researched for potential use in a head transplantation procedure; they discussed various protocols for connecting the vasculature, the use of various levels of hypothermia, the use of [[blood substitutes]], and the possibility of using [[hydrogen sulfide]] as a neuroprotective agent.<ref name=Lamba2017rev/><ref>{{cite journal|last1=Ren|first1=X|last2=Orlova|first2=EV|last3=Maevsky|first3=EI|last4=Bonicalzi|first4=V|last5=Canavero|first5=S|title=Brain protection during cephalosomatic anastomosis.|journal=Surgery|date=July 2016|volume=160|issue=1|pages=5–10|doi=10.1016/j.surg.2016.01.026|pmid=27143608}}</ref>