After rehabilitation, the 27-year-old will be able to control her entire artificial arm in thought

15 June 2018 - Holding an apple or bringing a cup of coffee to your mouth: a mirage for the over 700 people who every year in Italy lose a upper limb. Over time, thousands of patients in our country have undergone this form of amputation, which prevents them from performing even the most seemingly trivial movements, but impossible for those who no longer have an arm. And that instead could soon become possible again, after lsurgery performed on Friday 15 June at the Campus Bio-Medico University Hospital by Professor Vincenzo Denaro, Ordinary Emeritus of Orthopedics and Traumatology of the University, supported by his team and by Professor Oskar Aszmann, a Viennese surgeon who has already performed operations of this type.

It will be so, hopefully, for Daniela (the name is fictitious), a 27-year-old woman who a year and a half ago lost her right arm following a serious road accident and, until now, has only been able to wear a cosmetic prosthesis unable to perform any movement.

Reinnervation surgery or NMR

Following the complex operation performed today on her, amputated at the shoulder, in about six months an upper limb prosthesis will be fitted  which, moved by sensitive surface electrodes, activated by the various bundles of the pectoralis major muscle and by other suitably re-educated trunk muscles, will allow her to pick up and manipulate objects. “This is thanks to the impulses that will reach the muscles from the brain – explains Denaro, clinical project manager – where special surface electrodes will transmit brain impulses to the bionic arm, with an intensity a thousand times higher than the actual nerve". "Conversely, stimulators applied to the skin will allow the tactile sensations on the consistency of the objects held by the artificial limb to be transmitted to the brain, allowing them to be gripped and manipulated more effectively".

THEThe objective of the experimentation is the creation of a highly specialized center for this type of intervention which, for the first time in Italy, can open up a similar prosthesis path to all other subjects with the same type of amputation.

Targeted muscle reinnervation o Targeted Muscle Reinnervation it is a complex method, which has the objective of exploiting a muscle such as the pectoralis major, which has become no longer useful in a subject amputee at the shoulder, re-innervating its bundles through the endings of the nerves which once reached up to the hand of the patient and moved muscles that he no longer has, transforming these muscle bundles into 'biological amplifiers' of the nerve signals that originally controlled the amputated area. Thus, the myoelectric signal taken from the muscles, after re-innervation, will allow simultaneous and intuitive control of a prosthesis with a large number of active joints.

"The operation – adds the Dr. Giovanni Di Pino, head of the Neurophysiology and Neuro Unitingengineering of human-technology interaction and co-responsible for the project – it was particularly delicate, because it was first necessary to denervate the pectoralis major muscle and other muscle fascias, then take the three large residual nerves, radial, median and ulnar, which move the hand and wrist, from the brachial plexus and apply them to the muscle fibres”.

"A futuristic intervention, with very few precedents in the world and which represents the first stage of a process that now involves the study of stimulation processes, followed by the application of surface electrodes and finally the intelligent prosthesis”, adds the teacher Vincenzo Di Lazzaro, Professor of Neurology at UCBM and also co-responsible for the experimentation. “If the functional re-education of these bundles goes as we hope, when the command to grip an object or bend the arm comes from the brain, the three major nerves will generate contractions of the respective muscle bundles that the surface electrodes will interpret and transform into impulses able to move the prosthesis”, he clarifies Di Lazzaro.

The train phaseing intensive treatment necessary to teach the patient to move the bionic limb appropriately should last approximately three months and start after the first 4-6 months of rehabilitation, useful for completing the muscle reinnervation process. For the first time, a patient operated in Italy with an amputation of this type will also be able to check the prosthesis that will be applied by the Inail Prosthetic Center at the level of the shoulder joint.  

The bionic prosthesis and the prospects for amputees

"The prosthesis - highlights Loredana Zollo, Associate of Bioingengineering at UCBM Is responsable ingengineering of the project – it is modular in type, or made up of several modules for the restoration of the elbow, wrist and hand joints and, in the experimental phase, also of the shoulder. Advanced classification techniques based on self-learning algorithms applied to the muscle signal will then be used to coordinate the motion of the different prosthetic modules and make prosthesis control as natural and intuitive as possible".

"This intervention – dichiara Angelo Andretta, director of the Inail Prosthetic Center – constitutes a crucial point of the research project that we are carrying out in partnership with theUniversità Campus Bio-Medico di Roma and which aims to develop clinical practices that allow full use of the most advanced prosthetic solutions made available today by new technologies, using innovative methods in the treatment of limb amputations. In fact, as the Inail Prosthetic Center – continues Andretta – the ultimate goal of our numerous research projects is to find solutions to improve techniques and devices, to make innovative prostheses more usable and positively influence the quality of life of our injured people at work".

An experiment, therefore, which sees the Inail Prosthesis Center alongside theUniversità Campus Bio-Medico di Roma, to guarantee the immediate application of new technologies to the many workers and non-workers who have been amputated up to the entire arm and who have so far been forced to have practically no movement due to traditional prostheses.