Targeted muscle reinnervation to improve electromyography signals for advanced myoelectric prosthetic limbs: a series of seven patients

Abstract

BackgroundUpper limb amputation is a devastating injury. Patients may choose to use a passive prosthesis, a traditional body‐powered prosthesis or a myoelectric prosthesis driven by electromyography (EMG) signals generated by underlying muscles. Targeted muscle reinnervation (TMR) aims to surgically create strong and reliable signals to permit the intuitive use of a myoelectric prosthesis with the greatest number of movements possible. We review the Alfred Hospital experience of using TMR to improve upper limb prosthesis control.MethodsA retrospective review of all cases of TMR performed at the Alfred Hospital was undertaken. Patient demographics, injury, surgical complications and outcomes were examined. Comparison was made to preoperative prosthesis use.ResultsSeven patients have undergone TMR to improve upper limb prosthesis control at the Alfred Hospital between 2015 and 2018. Within the patient group, pre‐TMR EMG signal numbers ranged from 1 to 2, and post‐TMR signal numbers ranged from 3 to 5. Six patients were able to achieve six degrees of freedom post‐operatively, and one patient achieved four degrees. No patients required the use of co‐contraction to switch function post‐operatively. There were no significant surgical complications.ConclusionThe use of TMR to improve and increase the number of EMG signals has been successful in generating more degrees of freedom for upper limb amputees with myoelectric prostheses.

Agonist-antagonist muscle strain in the residual limb preserves motor control and perception after amputation

“…To enhance neuroprosthetic control, amputation paradigms seeking further reconfiguration of residual limb soft tissues have been developed, including Targeted Muscle Reinnervation (TMR) 17 – 20 , Regenerative Peripheral Nerve Interfaces (rPNIs) 21 – 23 , and the Agonist-antagonist Myoneural Interface (AMI) 24 – 27 . Each of these techniques have been demonstrated in combination with neuroprostheses 17 , 19 , 22 , 24 for the enhancement of prosthetic control. Nevertheless, neuroprosthetic performance is a system-level evaluation that depends on multiple factors such as subject-specific inherent capacities of residual limb motor control and phantom limb perception, engineered functional feedback, presence of visual feedback, and choice of the neuroprosthetic control paradigm.…”

The Current State of Targeted Muscle Reinnervation: A Systematic Review

“…Those that did not achieve greater degrees of freedom postoperatively reported smoother control of their prosthesis and avoided the need for cocontraction. 9 Only one patient—the only transradial amputation in the series—did not achieve six degrees of prosthetic freedom postoperatively. 9 A study by Hebert et al similarly demonstrated improved myoelectric prosthesis control following delayed TMR, as well as restoration of cutaneous sensation.…”

“…9 Only one patient—the only transradial amputation in the series—did not achieve six degrees of prosthetic freedom postoperatively. 9 A study by Hebert et al similarly demonstrated improved myoelectric prosthesis control following delayed TMR, as well as restoration of cutaneous sensation. 5 All patients in this series has transhumeral level amputations.…”

“…16 In a retrospective series by Myers et al, seven patients with upper extremity limb loss underwent delayed TMR for improved myoelectric prosthesis control, on average 131 months following index amputation. 9 All patients increased their number of EMG signals; 80% doubled the signals that could be used for prosthesis control and therefore achieved greater degrees of freedom. Those that did not achieve greater degrees of freedom postoperatively reported smoother control of their prosthesis and avoided the need for cocontraction.…”

“…The existing literature highlights a myriad of clinic indications and patient populations for which TMR has been utilized. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] However, although multiple studies have reported experience with TMR, review articles of the existing literature are limited; to our knowledge, the present study is the largest comprehensive review of the literature to date. 16 Furthermore, a majority of the literature utilizes outcomes measures including PROMIS (patient-reported outcomes measurement information system), NRS (numeric rating scale), orthotics prosthetics user survey, and neuro-quality of life scores; however, while these tools are validated metrics, they are neither specific to the outcomes relevant for amputee patients nor standard reporting measures in this area of investigation.…”