Table of ContentsView AllTable of ContentsHistoryPossible UsesDonor SelectionRecipient ClearanceProposed ProcedureAfter SurgeryComplicationsPrognosis
Table of ContentsView All
View All
Table of Contents
History
Possible Uses
Donor Selection
Recipient Clearance
Proposed Procedure
After Surgery
Complications
Prognosis
It may sound like science fiction, but as medical science advances, a head transplant might one day be possible. With over a century of advances inorgan transplantation, some scientists have begun to look at head transplantation as a potential solution toprogressive diseasesthat become terminal over time but do not impact the function of the brain.
But is a head transplant even possible?
Along with the uncertainties of the medical benefits of a head transplant, there are also likely risks, including the rejection of donor tissues, a loss of cognitive function. chronic neuropathic pain, and the toxicity of immunosuppressant drugs used toprevent organ rejection.
This article explores what is needed to make head transplants a reality, including the current scientific barriers and possible drawbacks.
Ruben Earth / Getty Images
What Is a Head Transplant?
A head transplant would theoretically involve surgically removing the head of someone with a terminal illness and connecting their nerves, blood vessels, muscles, trachea (windpipe), esophagus (feeding tube), and other structures to those of the deceased donor body.
To date, there has been minimal success with head transplants performed on mice, dogs, and monkeys. Many experts have been critical of the animal models and argue that gaps in our current understanding of such procedures make studies like these not only premature but unethical.
Back in the 1970s, a head transplant performed on a rhesus monkey highlighted the challenges yet to overcome if the procedure is ever to be viable. Although the monkey survived for eight days, the restoration of functions was only limited to smell, taste, hearing, and muscle movements of the face.
Despite the setbacks in research, investigational surgeons like Xiaoping Ren, Sergio Canavero, and others have announced plans to attempt the first human head transplant within the next few years. To date, head transplants in humans have only been limited to human cadavers.
No head transplant has been performed with a living human recipient.
Early Head Transplant Attempt Aborted
Reasons for a Head Transplant
Theoretically speaking, a head transplant can be used for any medical condition in which a person’s survival is severely shortened due to a disease affecting the body but not thecentral nervous system(the brain and spinal cord). This is more or less how organ transplants are currently managed and regulated.
Conditions for which a head transplant may be indicated include:
A head transplant would not extend to someone whose body fails from natural aging.
Donor Recipient Selection
A head transplant donor would be someone who has sufferedbrain death, likely from a catastrophic injury, yet can remain on life support until the head transplant can occur. This would preserve the health and function of the tissues.
Because multiple organs are involved, the evaluation will likely be more extensive than a single organ transplant. This includes checking for chronic conditions that may impact the life of the recipient, such asHIV,diabetes, heart disease, lung disease, thyroid disease, or kidney disease.
Some of these conditions, in turn, could impact not only recovery from the transplant but also the success of the transplant.
The donor tissue and blood type would also need to match the recipient’s tissue and blood type to avoidorgan rejection.
Current law would suggest that the selection process would begin onlyafterthe recipient has died. Most ethnicists argue that waiting for a still-living donor to die—even with their approval—may alter how that person is treated and lead to the withholding of life-sustaining treatments.
Currently, there is no index or donation system set up for head transplantation.
Transplant Recipient Approval
As with any organ transplant, the recipient of a head transplant would require extensive evaluation before they can be cleared for surgery. This would include a comprehensive medical and psychiatric evaluation to confirm that the transplant is both necessary and the only option left to that individual.
The transplant team would also need to ascertain if the recipient can withstand high doses ofimmunosuppressantsused to prevent organ rejection prior to the surgery as well as abone marrowtransplant used to replace theimmune systemof the donor,
It is difficult to anticipate who may or may not be an ideal candidate for a head transplant given that the potential risks and complications are as of yet unknown.
Using today’s dollar value, some experts suggest that a head transplant would cost no less than $13 million, not including the cost of long-term aftercare.
Head Transplant Procedure
No head transplant has yet been performed on a human. Nevertheless, surgeons interested in the procedure have prepared preliminary protocols planning the steps of a future head transplant.
Moreover many of the proposed tools and techniques—such as spinal cord transection, chemicals called fusogens (used to fuse nerve cells), and spinal cord stimulation—are largely theoretical in the context of a head transplant.
In the proposed protocol, four surgical teams would work simultaneously on the recipient and donor.
Donor Preparation
Surgical preparation of the donor begins with atracheotomy(a surgical opening in the windpipe) and amechanical ventilatorto stabilize the body once the head is detached. Blood oxygen, body temperature, and blood pressure are monitored to ensure vital signs are maintained.
Major blood vessels are then connected with plastic tubes to anextracorporeal membrane oxygenation (ECMO) machinethat replaces the function of the heart and lungs, delivering oxygen to and taking carbon dioxide away from tissues.
Recipient Preparation
While the donor is prepared, the recipient is anesthetized to put them to sleep. Brain activity is monitored with anelectrocardiogram (EEG)to ensure their brain function is stable.
Once the recipient’s head and donor’s spinal cord have reached a low enough temperature (called profound hypothermia), the transplantation can begin.
Phases of Surgery
A head transplant surgery would theoretically involve the following steps:
After the underlying tissues and skin are sutured and bandaged, the recipient is wheeled to the intensive care unit (ICU) to begin the long recovery process.
It is only after consciousness returns that the surgeons can assess what is needed to rehabilitate the functional organs in the body.
As recovery progresses, physical therapy similar to that for quadriplegia would be used to promote neural connections between the brain and the new body.
The most likely complication of a head transplant would be the failure of a stable connection between nerves and blood vessels. This can lead to severe brain damage,stroke, or brain death.
If the nerves fail to fully connect, there will likely be a loss of sensations (such as taste, hearing, sounds, or taste), partial or complete paralysis, a loss of muscle control, and organ dysfunction or failure.
The immune system may also reject the transplanted tissue, the consequence of which is life-threatening.
Identity Challenges
It is unknown if and how a head transplant might affect intellectual abilities, consciousness, moods, or personality. While it is presumed that preserving the brain will preserve the recipient’s identity, ethicists argue that identity involves more than just nerve connections in the brain but those of the body as a whole.
As such, a person who undergoes a head transplant may be faced with serious mental health challenges, includingpsychosis,dementia, personality or mood disorders, and an increased risk of suicide.
There is no reliable information to predict how a human would do after a head transplant. Animals that received head transplants survived for only a limited time, from several hours to 29 days at most.
Lifelong immunosuppression would be necessary to prevent organ rejection. This could pose serious health concerns as the level needed for a head transplant could damage donor organs, such as the kidneys or liver.
Summary
It is unlikely that a head transplant will be successfully performed in humans anytime soon. To date, attempts in animals have not been successful, and the only attempts in humans have been limited to cadavers. Even if an attempt were made and a matched donor and recipient were found, scientists have no idea of the complications that might arise in the short or long term.
5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Gkasdaris G and Birbilis T.First human head transplantation: Surgically challenging, ethically controversial and historically tempting–an experimental endeavor or a scientific landmark?Mædica2019;14(1):5. doi:10.26574/maedica.2019.14.1.5People.Man set to undergo world’s first head transplant backs out after finding love and becoming a dad.Parr Center for Ethics.Head transplant.Farjud DD.Ethical, social & psychological challenges of head transplantation in human.Iran J Public Health.2018 Sep;47(9):1232–1234.Ren XP, Ye YJ, Li PW, Shen ZL, Han KC, and Song Y.Head transplantation in mouse model.CNS Neuroscience & Therapeutics. 2015;(8):615-8. doi:10.1111/cns.12422
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Gkasdaris G and Birbilis T.First human head transplantation: Surgically challenging, ethically controversial and historically tempting–an experimental endeavor or a scientific landmark?Mædica2019;14(1):5. doi:10.26574/maedica.2019.14.1.5People.Man set to undergo world’s first head transplant backs out after finding love and becoming a dad.Parr Center for Ethics.Head transplant.Farjud DD.Ethical, social & psychological challenges of head transplantation in human.Iran J Public Health.2018 Sep;47(9):1232–1234.Ren XP, Ye YJ, Li PW, Shen ZL, Han KC, and Song Y.Head transplantation in mouse model.CNS Neuroscience & Therapeutics. 2015;(8):615-8. doi:10.1111/cns.12422
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Gkasdaris G and Birbilis T.First human head transplantation: Surgically challenging, ethically controversial and historically tempting–an experimental endeavor or a scientific landmark?Mædica2019;14(1):5. doi:10.26574/maedica.2019.14.1.5People.Man set to undergo world’s first head transplant backs out after finding love and becoming a dad.Parr Center for Ethics.Head transplant.Farjud DD.Ethical, social & psychological challenges of head transplantation in human.Iran J Public Health.2018 Sep;47(9):1232–1234.Ren XP, Ye YJ, Li PW, Shen ZL, Han KC, and Song Y.Head transplantation in mouse model.CNS Neuroscience & Therapeutics. 2015;(8):615-8. doi:10.1111/cns.12422
Gkasdaris G and Birbilis T.First human head transplantation: Surgically challenging, ethically controversial and historically tempting–an experimental endeavor or a scientific landmark?Mædica2019;14(1):5. doi:10.26574/maedica.2019.14.1.5
People.Man set to undergo world’s first head transplant backs out after finding love and becoming a dad.
Parr Center for Ethics.Head transplant.
Farjud DD.Ethical, social & psychological challenges of head transplantation in human.Iran J Public Health.2018 Sep;47(9):1232–1234.
Ren XP, Ye YJ, Li PW, Shen ZL, Han KC, and Song Y.Head transplantation in mouse model.CNS Neuroscience & Therapeutics. 2015;(8):615-8. doi:10.1111/cns.12422
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