Long-term implant of intramuscular sensors and nerve transfers for wireless control of robotic arms in above-elbow amputees.

Targeted muscle reinnervation (TMR) amplifies the electrical activity of nerves at the stump of amputees by redirecting them in remnant muscles above the amputation. The electrical activity of the reinnervated muscles can be used to extract natural control signals. Nonetheless, current control systems, mainly based on noninvasive muscle recordings, fail to provide accurate and reliable control over time. This is one of the major reasons for prosthetic abandonment. This prospective interventional study includes three unilateral above-elbow amputees and reports the long-term (2.5 years) implant of wireless myoelectric sensors in the reinnervation sites after TMR and their use for control of robotic arms in daily life. It therefore demonstrates the clinical viability of chronically implanted myoelectric interfaces that amplify nerve activity through TMR. The patients showed substantial functional improvements using the implanted system compared with control based on surface electrodes. The combination of TMR and chronically implanted sensors may drastically improve robotic limb replacement in above-elbow amputees.

Nerve grafts bridging the thenar branch of the median nerve to the ulnar nerve to enhance nerve recovery: a report of three cases.

We report a nerve graft procedure bridging the thenar branch of the median nerve to the ulnar nerve in three patients with ulnar nerve transection and defect at the mid-forearm. Ulnar nerve function was evaluated with electroneurography and quantitative sensory-motor testing before and after surgery, and at a 6-year follow-up. After surgery all patients showed electroneurographic evidence of median nerve innervation of the intrinsic muscles normally innervated by the ulnar nerve. The average strength was Grade 4 in the intrinsic muscles originally supplied by the ulnar nerve at the final follow-up. Our results indicate that the thenar branch of the median nerve may support ulnar nerve regeneration and so help prevent intrinsic muscles from irreversible atrophy, but our report is preliminary. This procedure should be validated by future clinical data, especially those with complete ulnar nerve transection at or above the elbow. LEVEL OF EVIDENCE: IV.

Hand Transplantation Versus Hand Prosthetics: Pros and Cons.

Composite tissue transplantation and new developments in the field of prosthetics have opened new frontiers in the restoration of function among upper limb amputees. It is now possible to restore hand function in affected patients; however, the indications, advantages, and limitations for either hand transplantation or prosthetic fitting must be carefully considered depending on the level and extent of the limb loss. Hand transplantation allows comprehensive hand function to be restored, yet composite tissue transplantation comes with disadvantages, making this method a controversial topic in the hand surgical community. Alternatively, prosthetic limb replacement represents the standard of care for upper limb amputees, but results in the known limitations of function, sensation, and usage. The indication for hand transplantation or prosthetic fitting strongly depends on the level of amputation, as well as on the extent (unilateral/bilateral) of the amputation. In this review, we discuss the advantages and disadvantages of hand transplantation and prosthetic replacement for upper limb amputees in general, as well as in regard to the different levels of amputation.

Prosthetic reconstruction to restore function in transcarpal amputees.

Mutilated hands at the distal level may pose a challenge for reconstruction. Biological treatment options may require multiple surgical interventions and a long rehabilitation course with little hope of good functional outcome. Standard hand prostheses are also not an ideal solution, as they are too long and cumbersome for partial hand injuries. This paper outlines the functional outcomes of prosthetic reconstruction with devices customized for the transcarpal amputation levels. The functional outcome was evaluated with the Action Research Arm Test (ARAT), Southampton Hand Assessment Procedure (SHAP), and the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). Functional evaluation was performed at least 12 months after final fitting. Psychological assessment was performed with the Short Form-36. The three patients achieved a mean ARAT score of 35.67 ± 0.58. The average SHAP score was 74 ± 7.81. The average DASH score was found to be 16.11 ± 12.03. The reconstructed hand achieved a score of 75.27 ± 8.16% in SHAP and 62.57 ± 1.02% in ARAT in relation to the healthy hand. All patients exhibited average physical and mental component summary scales in the Short Form-36. The majority of transcarpal amputations are seen in manual laborers due to work-related trauma. Returning to work is the main goal in such young and otherwise-healthy patients. As shown with this study, prosthetic fitting results in quick and reliable functional reconstruction. Therefore, this treatment should be considered as an option during the initial decision-making process of reconstructing difficult traumatic injuries of the hand.