Transradial (below elbow) amputation is the most common form of major upper limb amputation, affecting several thousand individuals in the United States. Although transradial amputees have more residual muscles than higher level amputees, these individuals have at most only two residual muscles to control a prosthetic hand using conventional control. Using pattern recognition, transradial amputees cannot perform as many hand grasp movements as individuals with higher level amputations who have had TMR because transferred nerves carry control information for intrinsic hand finger, and thumb muscles, which is not available to individuals with a transradial amputation.
Performing transradial TMR, in which residual nerves from intrinsic hand muscles are transferred to remaining forearm muscles, provides individuals with intuitive control over prosthetic wrist and hand movements, and potentially allows for more intricate grasping patterns. This is significant given that advanced, multifunction hands and fingers are now commercially available. Thus transradial TMR could potentially benefit thousands of individuals.
Currently, we are evaluating ways to quantify the control information provided by intrinsic hand muscles to guide future transradial TMR procedures.