The overall objective of this proposal is to perform a first-in-human home trial of the Electronic Osseoanchored Prostheses for the Rehabilitation of Amputees (e-OPRA) implant system in individuals with transhumeral amputations who have had Targeted Muscle Reinnervation (TMR) surgery and use a pattern recognition-controlled myoelectric prosthesis. The purpose of the study is to capture preliminary safety and effectiveness information on the e-OPRA device when used with the prosthetic systems. The investigators expect that the e-OPRA implant system will be safe and provide clinically and statistically significant improvements in control and comfort.
Specifically, the investigators hypothesize that the e-OPRA system will (1) allow for training of more functional prosthesis controllers, (2) provide more stable electromyographic (EMG) signals, reducing the need to recalibrate the prosthetic control system, and (3) be more comfortable, as it does not require a tethered arm-band to record surface EMG signals.
Phase 1: Perform TMR and e-OPRA surgeries in 8 persons with transhumeral amputations.
Phase 2: Perform a randomized cross-over study to compare the OPRA and e-OPRA system (without sensory feedback) in 8 transhumeral amputees who have received TMR.
Phase 3: Perform a randomized cross-over study to compare the e-OPRA system with and without sensory feedback in 8 transhumeral amputees who have received TMR.
Between the ages of 18 and 70 years old
Unilateral transhumeral level absence
Candidate for a myoelectric prosthesis (can generate mV level electromyographic EMG signals as detected by surface electrodes).
Candidate for TMR surgery as verified by surgical team
Significant new injury that would prevent use of a prosthesis: The ability to consistently wear a prosthesis and perform activities of daily living and specific performance tasks is necessary to evaluate the relative benefits of the interventions.
Cognitive impairment sufficient to adversely affect understanding of, or compliance with, study requirements, ability to communicate experiences, or ability to give informed consent: The ability to understand and comply with requirements of the study is essential in order for the study to generate usable, reliable data. The ability to obtain relevant user feedback through questionnaires and informal discussion adds significant value to this study. These cognitive impairments would be confirmed with the Mini-Mental State exam.
Proximal nerve injury that would prevent TMR or sensory feedback
Significant other comorbidity: Any other medical issues or injuries that would preclude completion of the study, use of the prostheses, or that would otherwise prevent acquisition of useable data by researchers. Examples include: injuries to the shoulder, cervical spine or sound side joint pain that would prohibit the participants from being able use a prosthesis. Medical conditions including unregulated high blood pressure or advanced heart disease that would exclude the participant as an appropriate surgical candidate.
Crossover
eOPRA
DeviceElectronic Osseoanchored Prostheses for the Rehabilitation of Amputees (e-OPRA) implant system for transhumeral amputees.
OPRA
DeviceOsseoanchored Prostheses for the Rehabilitation of Amputees (e-OPRA) implant system in individuals with transhumeral amputations
eOPRA with sensory feedback
DeviceElectronic Osseoanchored Prostheses for the Rehabilitation of Amputees (e-OPRA) implant system in individuals with transhumeral amputations with sensory feedback.
eOPRA without sensory feedback
DeviceOsseoanchored Prostheses for the Rehabilitation of Amputees (e-OPRA) implant system in individuals with transhumeral amputations without sensory feedback.
Safety related: Adverse Event reporting
The number/percentage of subjects that successfully demonstrate the absence of any Serious Adverse Device Effects will be summarized along with a 95% confidence interval.
Effectiveness related: EMG Signal to Noise Ratio Testing
The investigators will quantify the signal-to-noise ratio (SNR) of EMG signals by comparing activity recorded during maximum voluntary contraction (MVC) to that recorded during rest. SNR will be calculated as the ratio of EMG signal power during contraction to the signal power during rest, using a standardized protocol consistent with our preliminary data. Each trial will consist of three repetitions of three-second MVCs, interleaved with three-second rest periods. From each repetition, the central 30% of both the contraction and rest epochs will be extracted to minimize edge effects and ensure steady-state measurement. These extracted segments will then be concatenated across repetitions to create two signal arrays: one representing active EMG and the other representing baseline noise. This metric will be used to evaluate the quality of EMG signal acquisition from both surface and implanted electrodes, and to ensure adequate fidelity for pattern recognition control.
Effectiveness related: Somatosensory Mapping
The projected field-the region on the phantom limb where an electrically evoked sensation is perceived-for each contact on the implanted spiral nerve cuff electrodes. This mapping will be performed at three stimulation levels: the detection threshold (the lowest amplitude at which a sensation is first perceived) and two suprathreshold amplitudes that fall within a safe, physiologically relevant, and comfortably perceptible range. These amplitudes will allow us to assess the size, intensity, and location of the perceived sensation change with increased stimulation. Projected fields will be recorded on a schematic of the hand and used to build a subject-specific somatotopic map. This map will inform which sensor signals (from the TASKA CX hand) are routed to which nerve cuff contacts during the sensory feedback phases of the study. Contact-response stability will be evaluated over time, as these experiments will be repeated each time outcomes are collected in the study.
Effectiveness related: EMG Signal to Noise Ratio Testing
The investigators will quantify the signal-to-noise ratio (SNR) of EMG signals by comparing activity recorded during maximum voluntary contraction (MVC) to that recorded during rest. SNR will be calculated as the ratio of EMG signal power during contraction to the signal power during rest, using a standardized protocol consistent with our preliminary data. Each trial will consist of three repetitions of three-second MVCs, interleaved with three-second rest periods. From each repetition, the central 30% of both the contraction and rest epochs will be extracted to minimize edge effects and ensure steady-state measurement. These extracted segments will then be concatenated across repetitions to create two signal arrays: one representing active EMG and the other representing baseline noise. This metric will be used to evaluate the quality of EMG signal acquisition from both surface and implanted electrodes, and to ensure adequate fidelity for pattern recognition control.
Orthotics and Prosthetics User Survey-Upper Extremity Functional Status (OPUS-UEFS):
A 19-item, self-reported measure of an individual's ability to perform self-care and upper limb-based daily living tasks (e.g. button shirt, tie shoelaces) using a 5-point scale. Rasch analysis of the questionnaire ratings is used to calculate an overall measure of each subject's functional ability.
Jebsen Test of Hand Function
The Jebsen test includes seven subtests, including writing, turning over cards, picking up small objects, etc., in which the time taken to complete each subtask is recorded. The test has been validated for able-bodied subjects, but not for subjects with an amputation. The investigators have used this test previously for transhumeral and transradial amputees.
Clothespin Relocation Task
A test of prosthetic function that requires the user to move three clothespins from a vertical bar to a horizontal bar (thereby requiring use of the elbow, terminal device, and wrist rotator). This test has been in use by the Center for Bionic Medicine as a measure of prosthesis function for over a decade.
Modified Box and Block Test
This test involves counting the number of blocks a patient can move from one side of a box, over a barrier, to the other side of the box, usually in a 2-min test period. This test requires elbow and hand function.
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Shirley Ryan AbilityLab
Lead sponsor
Integrum
Collaborator
Northwestern Memorial Hospital
Collaborator
National Institute of Neurological Disorders and Stroke (NINDS)
Collaborator
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