In Hindu mythology, the almighty Shiva is said to have ‘transplanted’ an elephant’s head on Lord Ganesha, in what is the first recorded instance of a feat that has thus far failed to break out of the realms of science fiction.
Unfazed, however, visionary neurosurgeons around the world have spent whole lifetimes in pursuit of this seemingly impossible medical mission that, if ever achieved, will rank as the grandest scientific feat in human history, even higher than landing on the moon.
However, the prospect of transplanting a human head even now appears nearly as far-fetched as being able to move at the speed of light despite some exuberant claims notably by Dr Sergio Canavero from Italy who recently published an article saying he was ready to carry out the world’s first ever head transplant.
The earliest such attempt was made by Vladimer Deminkov who carried out the procedure on dogs. After recovering from anesthesia these dogs barked a bit and then died in a few hours. A subsequent attempt by Robert White, this time on monkeys too ended in failure owing to immune rejection.
The brain is an extremely complex organ where millions of electrically charged neurons function synchronously not only to sustain vital functions like blood flow and breathing but also to shape our thoughts, emotions and intellect that ultimately give each of us our unique identity and personality. In other words, getting someone else’s brain also means becoming a different person! The functioning of the brain involves point-to-point connectivity with the body and two-way signaling and feedback systems.
Cooling the body and the head, severing the neck, connecting blood vessels and other structures, aligning the spinal cord and patching with poly ethylene glycol as proposed by Dr Canavero appears interesting on paper but in practice this will not be easy to achieve. Having said this, we as neuro scientists must keep pushing back the frontiers and move towards making head transplant too a reality.
During my neurosurgical residency I was made to believe that neural regeneration will be impossible, which is no longer true. Knowing the complexity of the brain’s anatomy, physiology and neuro chemistry, transplanting the organ with its functional integrity intact is likely to remain beyond our reach in the foreseeable future, which is why the focus for many years has been on regeneration and cerebral protection. In this pursuit, stem cells have emerged as a major source of hope although thus far therapies using these cells have to be validated for their consistent clinical benefits. However, promoting regeneration by “cell transplantation” seems like a realistic option. Various options involving stem cells, their safety and efficacy are currently at the frontier of research.
Similarly, despite the hurdles one must relentlessly pursue innovations that may make it possible for us to carry out head transplantation safely. In this direction fixing the spinal cord especially in injuries will be the first step for success. Personally I have tried spinal regeneration using several methods over the last decade and many times felt like being on the verge of success. But clearly we still have many miles to go before we can sleep.