The history of head transplantation: a review

Abstract

BackgroundSince the turn of the last century, the prospect of head transplantation has captured the imagination of scientists and the general public. Recently, head transplant has regained attention in popular media, as neurosurgeons have proposed performing this procedure in 2017. Given the potential impact of such a procedure, we were interested in learning the history of the technical hurdles that need to be overcome, and determine if it is even technically possible to perform such a procedure on humans today.MethodWe conducted a historical review of available literature on the technical challenges and developments of head transplantation. The many social, psychological, ethical, religious, cultural, and legal questions of head transplantation were beyond the scope of this review.ResultsOur historical review identified the following important technical considerations related to performing a head transplant: maintenance of blood flow to an isolated brain via vessel anastomosis; availability of immunosuppressive agents; spinal anastomosis and fusion following cord transfection; pain control in the recipient. Several animal studies have demonstrated success in maintaining recipient cerebral perfusion and achieving immunosuppression. However, there is currently sparse evidence in favor of successful spinal anastomosis and fusion after transection. While recent publications by an Italian group offer novel approaches to this challenge, research on this topic has been sparse and hinges on procedures performed in animal models in the 1970s. How transferrable these older methods are to the human nervous system is unclear and warrants further exploration.ConclusionsOur review identified several important considerations related to performing a viable head transplantation. Besides the technical challenges that remain, there are important ethical issues to consider, such as exploitation of vulnerable patients and informed consent. Thus, besides the remaining technical challenges, these ethical issues will also need to be addressed before moving these studies to the clinic.

Modern techniques in organ transplantation

“…Team Carrel-Guthrie przeprowadził transplantacje głów psich w 1908 roku. Podczas tych eksperymentów głowy pozostawały bez dopływu krwi przez 20 minut i choć bezpośrednio po przeprowadzeniu przeszczepu zwierzęta reagowały na zadawane bodźce, ich stan pogarszał się gwałtownie i usypiano je w kilka godzin po zabiegu [3]. Mimo braku efektów eksperymentów transplantacji Alexis Carrel przysłużył się całemu środowisku transplantologicznemu dzięki dwóm wynalazkom -nowoczesnej metodzie zespolenia trójkątnego naczyń, zwanego w nauce o anastomozach "manewrem Carrela", ułatwiającej szybkie i stabilne zaszywanie naczyń, przeciwdziałającej również krwawieniom i zakrzepom pooperacyjnym, jak również pompie perfuzyjnej, co umożliwiło dalsze badania nad maszyną płuco-serca i w konsekwencji przyczyniło się do rozwoju kardiochirurgii i chirurgii transplantacyjnej [4].…”

“…Następnie eksperymenty w dziedzinie przeszczepu głowy przeprowadzał w latach 50. Vladimir Demikhov, którego badania przyniosły dłuższą przeżywalność psów (do 29 dni) oraz lepszą reakcję na bodźce [3]. Prawdziwą inspiracją dla teamu Canavero-Ren stały się w latach 70. doniesienia amerykańskiego neurochirurga Roberta White'a, który dokonał zakończonych sukcesem przeszczepów głowy oraz mózgu u małp i psów.…”

The EANS Ethico-legal Committee finds the proposed head transplant project unethical

“…Recently, the procedure has regained attention as an Italian team has suggested to perform a head transplant in the near future. However, as pointed out by Lamba et al [2], there are still many unanswered (technical, biological, ethical, psychological, etc.) questions related to head transplantation.…”

“…For first-inman procedures, there should be ample evidence from animal experiments and other models that all aspects of the procedure have been studied and that there are no remaining questions to be answered. As demonstrated in this issue of Acta Neurochirurgica [2], there remain many unsolved questions. There are no reports of head transplants performed in animals with long-term survival and normalisation of neurological function, and no evidence that all of the technical issues, such as functional cord re-anastomosis, can be successfully achieved in humans.…”

“…The risks involved for the patient undergoing a head transplant is enormous, including this risk of death. There is no solid evidence base for all steps of the procedure; for some, there is even lack of proof of concept [2]. The risk-benefit ratio for a head transplant is currently extremely unfavourable.…”