I recently read with interest the work of Dr. Oskar Aszmann and colleagues in Vienna, Austria regarding bionic reconstruction of the hand (The Lancet , February 2015). I have been listening to Oskar speak about this work for the past several years at our annual meetings and it is great to finally see it in publication. My hope is that this research will raise awareness of the possibilities for nerve reconstruction in the near future as well as what we are capable of doing today.
For those that haven’t seen or heard about this paper, it describes three patients who had severe brachial plexus injuries. The brachial plexus is the network of nerves in the neck and shoulder regions that mediate all of our upper extremity function and sensation. All three patients had failed traditional reconstruction methods and the patients were left with minimally functioning upper extremities. Something else had to be done. To simplify it, the wiring of the remaining upper extremity was reconfigured using a combination of nerve transfers and bringing in muscles from other parts of the body along with their nerves so that the remaining, functional nerves could intuitively and predictably innervate the upper extremity muscles. Then, by following a specific rehabilitation protocol, the patients re-learned how to use this re-wired musculature. This protocol included the use of a hybrid myoelectric (i.e. robotic) prosthetic which was attached to the native, non-functional hand so that the patients could appreciate how much additional function they had with the robotic hand as compared with their native hand which was often minimally functional and insensate. After adequately learning how to control this myoelectric (i.e. robotic) hand, each patient underwent elective amputation of the native hand and permanent fitting of the same myoelectric prosthetic which they had been learning to use. Post-operatively all three patients demonstrated significantly improved upper extremity function, decreased pain as well as improvements in quality of life according to well established measures.
Oskar’s work is exciting for a number of reasons. First of all, it wonderfully demonstrates the degree to which we are able to restore function in the upper extremity for those with previously devastating injuries that were once thought to be irreparable. Secondly, while these surgical procedures are not for everyone and can be complex, the technical challenges that we face in the operating room are being greatly aided by improvements in electronic prosthetic development. Already in the works are myoelectric prosthetics with vastly more degrees of freedom (i.e. independently moveable joints) and signal processing capabilities which will ultimately allow a very precise level of function at the wrist, hand and finger levels beyond those which are available today. Third, I believe that in the not too distant future, we will see prosthetics that can actually be surgically implanted and will not need to be taken on and off as we have today, thereby removing a psychological downside to prostheses in general. Fourth, such procedures and prosthetics may ultimately provide us with a level of functionality that even a “normal person” doesn’t have. While there are certainly moral and ethical implications to consider with these possibilities, the concepts and potential are exciting indeed.
In many ways, this type of work represents the ultimate melding of computer science/engineering and modern medicine/surgery. Dr. Darrell Brooks and I have performed several similar procedures, so far with very encouraging results. We sincerely hope that the publication of this paper and hopefully soon others like it will encourage peripheral nerve surgeons to pursue even greater achievements. I believe that in time and in collaboration with our engineering/biomedical colleagues, devastating injuries suffered by those returning from war or after accidents will no longer mean a lifetime of dysfunction.