Outcomes, Challenges, and Pitfalls after Targeted Muscle Reinnervation in High-Level Amputees: Is It Worth the Effort?

Abstract

Background: Although the distal targets have been lost in proximal upper limb amputees, the neural signals for intuitive hand and arm function are still available and thus can be incorporated into more useful prosthetic function using targeted muscle reinnervation technique. In this article, the authors present their outcomes and range of indications in addition to experiences and pitfalls after 30 targeted muscle reinnervation cases at above-elbow and shoulder disarticulation level of amputation. Methods: Thirty patients with above-elbow or shoulder disarticulation amputations were enrolled between 2012 and 2017. Indications for targeted muscle reinnervation surgery differed between improvement of prosthetic function (n = 19) and/or pain (n = 11). Functional outcome was evaluated with the Action Research Arm Test, the Southampton Hand Assessment Procedure, and the Clothespin-Relocation Test. Functional evaluation was performed at least at 6 months after final prosthetic fitting. Results: All nerve transfers were successful and provided independent myoelectric signals. The 10 patients available for final functional evaluation showed Action Research Arm Test scores of 20.4 ± 1.9 and Southampton Hand Assessment Procedure scores of 40.5 ± 8.1. The Clothespin-Relocation Test showed a mean time of 34.3 ± 14.4 seconds. Conclusions: Targeted muscle reinnervation has improved prosthetic control and revolutionized neuroma treatment in upper limb amputees. Still, the rate of abandonment even after targeted muscle reinnervation surgery has been shown high, and several advances within the biotechnological interface will be needed to improve prosthetic function and acceptance in these patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Bionic Upper Limb Reconstruction: A Valuable Alternative in Global Brachial Plexus Avulsion Injuries—A Case Series

“…These few motor axons may then be used to re-innervate a free muscle transplant transferred to the patient s arm, which will not have the functional capacity or power of a biological muscle but instead serve as an additional EMG signal for future prosthetic control (given that a sufficient number of axons regenerate into the transferred muscle target). Since the dexterity of prosthetic control increases with the number of available EMG signals [18,19], free functional muscle transfers have previously been used to increase the number of these muscle signals [16].…”

Therapy Interventions for Upper Limb Amputees Undergoing Selective Nerve Transfers

“…As described by Salminger et al 9 , assessment of the 10 patients after TMR surgery revealed a SHAP score of 40.5 ± 8.1 (with a healthy upper extremity having a score of about 100) and ARAT score of 20.4 ± 1.9 (with 57 being the maximum score and 0 representing no upper extremity function) (Table 1). In the CPRT, patients were able to complete the tasks within 34. wearing their prosthesis daily with a wearing time ranging from 3-10 hours per day.…”

“…12. Perform the TMR surgery (surgeon) 9 . NOTE: In some cases, a re-fitting of the socket might not be feasible.…”

Rehabilitation of high upper limb amputees after Targeted Muscle Reinnervation

“…The initial draft of the protocol as well as its subsequent modifications were continuously guided by the concurrent patient care experience at the first author's clinical centre, the results of which were recently reported elsewhere 21 .…”

“…When evaluating the rehabilitation protocol proposed in the Delphi study, the authors could demonstrate its feasibility in clinical practice and present good functional outcomes 21 . Thus, while controlled studies are still needed to further evaluate the effect of the proposed rehabilitation protocol, it may contribute to improving the rehabilitation process for individuals with amputation undergoing TMR.…”