New Electrode for Prosthetic Limb Control in Amputees

Overseen By Mona Moore

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Michigan

Disqualifiers: Severe pain syndrome, Untreated mental health, Recent myocardial infarction, Uncontrolled diabetes, Others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 4

10 Participants Needed

Trial Summary

What is the purpose of this trial?

The device, a bipolar percutaneous intramuscular electromyography electrode, is intended for use in upper-limb amputation patients who have received the regenerative peripheral nerve interface surgical procedure, in order to enable the use of advanced prosthetic arms and hands.

Will I have to stop taking my current medications?

The trial protocol does not specify whether you need to stop taking your current medications. However, if you have an autoimmune condition, it must be well controlled by medication to participate.

What data supports the effectiveness of the treatment Bipolar Percutaneous Intramuscular Electromyography Electrode for prosthetic limb control in amputees?

Research shows that intramuscular electrodes, like the ones used in this treatment, can effectively record muscle signals for controlling prosthetic limbs, as they provide better signal fidelity compared to other types of electrodes. Additionally, studies have demonstrated the long-term stability and performance of similar electrode systems in human participants, suggesting their potential effectiveness in improving prosthetic control. ^{1 2 3 4 5}

Is the new electrode for prosthetic limb control safe for humans?

The electrode has been studied in humans, showing a high rate of staying intact in the body, with 95% intact at 6 months and 91% at 1 year. Some participants experienced infections or small lumps (granulomas), but these were treated successfully with antibiotics or minor procedures. ^{2 3 4 6 7}

How is the new electrode treatment for prosthetic limb control different from other treatments?

The new electrode treatment for prosthetic limb control is unique because it uses a fully implanted intramuscular bipolar myoelectric signal recording electrode, which allows for more precise and stable control of prosthetic limbs by capturing muscle signals directly from within the muscles. This approach differs from traditional methods that rely on surface electrodes or external devices, offering potentially improved long-term performance and functionality for amputees. ^{1 2 3 8 9}

Eligibility Criteria

This trial is for adults over 22 with an upper-limb amputation who are in good health and low surgical risk. They must have reliable transport, attend at least two visits per month, not use tobacco, and cannot be pregnant or have severe mental health issues without approval.

Inclusion Criteria

I have had an amputation above my wrist.

It has been over 6 months since my amputation.

I am 22 years old or older.

Exclusion Criteria

Participants must not have used tobacco for at least one month prior to enrollment in the study

Participants must agree to not use tobacco for the duration of the study

Participants must not be suffering from any untreated mental health disorders and if they have any DSM-5 diagnoses, they must receive approval to participate from their mental health professional

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Surgery and Initial Recovery

Participants undergo surgery to implant RPNI grafts and electrodes, followed by a recovery period

3 months

1 visit (in-person) for surgery, followed by recovery

Prosthetic Control and Sensory Feedback Experiments

Experiments with prosthetic control and sensory feedback are conducted

Up to 7 years

Minimum of 2 visits per month (in-person)

Follow-up

Participants are monitored for safety and effectiveness after electrode explantation

1 week

1 visit (in-person)

Treatment Details

Interventions

• Bipolar Percutaneous Intramuscular Electromyography Electrode

Trial Overview The study tests a bipolar intramuscular electromyography electrode in patients with upper-limb amputations post nerve surgery to improve control of advanced prosthetic arms and hands.

Participant Groups

Group I: New Grafts Experimental Treatment 1 Intervention

In this arm, participants will have an initial surgery to place partial muscle grafts on the amputated nerves. After a healing period, the participant will have a shorter surgical procedure to implant the electrodes onto the muscle grafts and in residual muscles. After another healing period, experiments with prosthetic control and sensory feedback will begin.

Group II: Existing Grafts Experimental Treatment 1 Intervention

In this arm, participants have already had partial muscle grafts placed on the amputated nerves to control neuroma growth. The participant will have a short surgical procedure to implant the electrodes onto the muscle grafts and in residual muscles. After a healing period, experiments with prosthetic control and sensory feedback will begin.

Who Is Running the Clinical Trial?

University of Michigan

Lead Sponsor

Trials

1,891

Recruited

6,458,000+

National Institute of Neurological Disorders and Stroke (NINDS)

Collaborator

Trials

1,403

Recruited

655,000+

Findings from Research

Epimysial patch electrodes recorded larger muscle signals and caused less tissue injury compared to intramuscular hook electrodes in a study involving 10 rats over 4 months.

Using a bipolar configuration with the patch electrodes significantly reduced signal noise compared to a monopolar configuration, enhancing the fidelity of muscle signal transduction for myoelectric prosthesis control.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Regenerative Peripheral Nerve Interface for Prostheses Control: Electrode Comparison. Sando, IC., Leach, MK., Woo, SL., et al.[2016]

A new fully implanted bipolar intramuscular myoelectric signal (IM-MES) recording electrode was successfully developed, allowing for effective functional electrical stimulation (FES) and prosthetic control.

In vivo testing showed that the IM-MES electrode recorded myoelectric signals comparable to existing electrodes, and initial clinical applications demonstrated its effectiveness in providing command signals for individuals with spinal cord injuries.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A fully implanted intramuscular bipolar myoelectric signal recording electrode. Memberg, WD., Stage, TG., Kirsch, RF.[2023]

The study involved three human participants with chronic implantation of Utah Slanted Electrode Arrays (USEAs) and intramuscular recording leads (iEMGs) to restore sensorimotor function after transradial amputations, showing that neural recordings from USEAs can persist for over 500 days in one subject, indicating long-term viability.

While the performance of USEAs generally declines over time, they still provide consistent sensory percepts and stable signal quality, suggesting that with further improvements, these devices could enhance the restoration of function in amputees.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Long-term performance of Utah slanted electrode arrays and intramuscular electromyographic leads implanted chronically in human arm nerves and muscles. George, JA., Page, DM., Davis, TS., et al.[2022]

In a study involving 6 paraplegic subjects over 38 months, temporary percutaneous intramuscular electrodes were successfully implanted to stimulate paralyzed muscles, allowing for improved gait training and energy-efficient movement.

While 35% of the 1025 electrodes failed within the first 4 months, the failure rate significantly decreased after this period, indicating that electrode stability improves with longer implantation times.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Implantation techniques and experience with percutaneous intramuscular electrodes in the lower extremities. Marsolais, EB., Kobetic, R.[2004]

The study successfully implanted a wireless electromyography system in 28 animals (24 rats and 4 Merino sheep), demonstrating its potential as a strong interface for controlling myoelectric prostheses, especially for high-level amputees.

Histological evaluations indicated good biocompatibility with minimal tissue response, and the device maintained stable electromyographic recordings over 4 months, suggesting reliable performance in real-world conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prosthesis Control with an Implantable Multichannel Wireless Electromyography System for High-Level Amputees: A Large-Animal Study. Bergmeister, KD., Hader, M., Lewis, S., et al.[2021]

The study demonstrated that bipolar electrode recordings provide reliable measurements of compound muscle action potentials (CMAPs) during voluntary wrist flexion contractions, with high reliability scores for RMS amplitude (R=0.89) and mean power frequency (MPF) (R=0.84).

However, normalizing the RMS amplitude can reduce the reliability of these measurements, indicating that careful consideration of electrode placement and data processing is crucial for accurate assessments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Flexor carpi radialis surface electromyography electrode placement for evoked and voluntary measures. Green, LA., McGuire, J., Gabriel, DA.[2015]

The study analyzed 858 electrodes implanted in 62 participants over 20 years, finding that 95% of electrodes remained intact after 6 months and 91% after 1 year, indicating a high rate of durability.

Infections or granulomas occurred in 16% of participants, but all adverse incidents were localized and manageable with treatments like antibiotics or minor surgical procedures, suggesting a generally safe profile for these electrodes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Electrode fracture rates and occurrences of infection and granuloma associated with percutaneous intramuscular electrodes in upper-limb functional electrical stimulation applications. Knutson, JS., Naples, GG., Peckham, PH., et al.[2007]

Using electromyographic (EMG) signals from residual muscles can significantly enhance the control of robotic lower limb prostheses, allowing for more natural and adaptable movement for amputee users.

This review identifies both the potential benefits and challenges of EMG-based control, emphasizing the need for collaboration among researchers and clinicians to develop advanced bionic limbs that improve motor function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Myoelectric control of robotic lower limb prostheses: a review of electromyography interfaces, control paradigms, challenges and future directions. Fleming, A., Stafford, N., Huang, S., et al.[2021]

Advanced upper limb prosthetics, like the Modular Prosthetic Limb (MPL), are being developed with a focus on improving control methods, particularly through the use of electrocorticographic (ECoG) signals, which may offer more stable long-term recordings compared to traditional microelectrode arrays.

Current research is exploring the effectiveness of ECoG for decoding limb movement and controlling prosthetic arms, highlighting its potential as a reliable interface for chronic brain-machine interaction (BMI) applications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Neuroprosthetic limb control with electrocorticography: approaches and challenges. Thakor, NV., Fifer, MS., Hotson, G., et al.[2020]

References

1. United States pubmed.ncbi.nlm.nih.gov

Regenerative Peripheral Nerve Interface for Prostheses Control: Electrode Comparison. [2016]

2. United States pubmed.ncbi.nlm.nih.gov

A fully implanted intramuscular bipolar myoelectric signal recording electrode. [2023]

3. England pubmed.ncbi.nlm.nih.gov

Long-term performance of Utah slanted electrode arrays and intramuscular electromyographic leads implanted chronically in human arm nerves and muscles. [2022]

4. United States pubmed.ncbi.nlm.nih.gov

Implantation techniques and experience with percutaneous intramuscular electrodes in the lower extremities. [2004]

5. United States pubmed.ncbi.nlm.nih.gov

Prosthesis Control with an Implantable Multichannel Wireless Electromyography System for High-Level Amputees: A Large-Animal Study. [2021]

6. United States pubmed.ncbi.nlm.nih.gov

Flexor carpi radialis surface electromyography electrode placement for evoked and voluntary measures. [2015]

7. United States pubmed.ncbi.nlm.nih.gov

Electrode fracture rates and occurrences of infection and granuloma associated with percutaneous intramuscular electrodes in upper-limb functional electrical stimulation applications. [2007]

8. England pubmed.ncbi.nlm.nih.gov

Myoelectric control of robotic lower limb prostheses: a review of electromyography interfaces, control paradigms, challenges and future directions. [2021]

9. United States pubmed.ncbi.nlm.nih.gov

Neuroprosthetic limb control with electrocorticography: approaches and challenges. [2020]