New Electrode for Prosthetic Limb Control in Amputees

Overseen By Jenni Hamill, MPH

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

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new device designed to assist individuals with upper-limb amputations in using advanced prosthetic arms and hands. The device, known as a Bipolar Percutaneous Intramuscular Electromyography Electrode, works with special muscle grafts to enhance control and feedback. The trial includes two groups: one for participants needing new muscle grafts and another for those who already have them. Suitable candidates are individuals who have had an arm amputation above the wrist, are in good health, and are at least six months post-amputation. The trial aims to make prosthetic limbs more effective and easier to use. As an unphased trial, it offers a unique opportunity to contribute to groundbreaking research that could improve prosthetic technology for future patients.

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 prior data suggests that this electrode is safe for use in upper-limb amputation patients?

Research has shown that the bipolar percutaneous intramuscular electromyography electrode is designed for safety. One study focused on ensuring the safety of these electrodes. This study involved a small group of people and found no major safety issues.

These electrodes are often used in prosthetic limbs to send and receive signals between the body and the prosthetic limb. This technology is not entirely new and has been used similarly before.

Overall, while this is a new application, the electrode itself has a history of being well-tolerated. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores a new technique for controlling prosthetic limbs using bipolar percutaneous intramuscular electromyography electrodes. Unlike traditional methods that primarily rely on surface electrodes or mechanical sensors, this approach involves implanting electrodes directly onto muscle grafts and residual muscles. This could potentially offer more precise control and natural sensory feedback for amputees. By integrating with existing or new muscle grafts, this innovative method aims to improve the functionality and user experience of prosthetic limbs, potentially transforming the standard of care for individuals with limb loss.

What evidence suggests that this electrode is effective for prosthetic limb control in amputees?

Research shows that special devices called intramuscular electrodes can successfully record muscle signals to help control prosthetic limbs. In this trial, participants will join one of two groups: the "New Grafts" group, where partial muscle grafts are newly placed before electrode implantation, or the "Existing Grafts" group, where participants already have muscle grafts. Studies have demonstrated that these electrodes can match hand movements with 100% accuracy, allowing precise control of prosthetic hands and arms. The electrodes pick up electrical signals from muscles, which then move the prosthetic limb. This method has shown promise in making advanced prosthetics easier to use and control for people with upper-limb amputations. ^{1 3 4 6 7}

Who Is on the Research Team?

Paul Cederna, M.D.

Principal Investigator

University of Michigan

Are You a Good Fit for This Trial?

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 for a Trial Participant

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)

What Are the Treatments Tested in This Trial?

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.

How Is the Trial Designed?

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+

Published Research Related to This Trial

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]

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 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]

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]

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]

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]

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]

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]

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT03260400

NCT03260400 | Short-term Implanted Electrodes Following ... The device, a bipolar percutaneous intramuscular electromyography electrode, is intended for use in upper-limb amputation patients who have received the ...

2. withpower.com withpower.com/trial/phase-neuroma-6-2017-8a672

New 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 ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6868792/

Stable, three degree-of-freedom myoelectric prosthetic ... Both the EMG-based KNN controller and the intact hand-based controller had 100% hand posture matching success rates, but the intact hand-based ...

4. trialx.com trialx.com/clinical-trials/listings/273515/short-term-implanted-electrodes-following-regenerative-peripheral-nerve-surgery-for-improving-prosthetic-limb-control-signals/

Short-term Implanted Electrodes Following Regenerative ... The device, a bipolar percutaneous intramuscular electromyography electrode, is intended for use in upper-limb amputation patients who have ...

5. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1050641114001370

On the usability of intramuscular EMG for prosthetic control Intramuscular and surface EMG signals were recorded concurrently from the right forearm. Five performance metrics (Throughput, Path efficiency, Average Speed, ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12086952/

Investigating the Feasibility and Safety of Osseointegration ... Electrode stimulation is most used in prosthetics, including monopolar, bipolar, cuff, and sieve electrodes to allow bidirectional communication ...

7. science.org science.org/doi/10.1126/scitranslmed.abq3665

Improved control of a prosthetic limb by surgically creating ... This proof-of-concept study indicates that motor neural commands can be increased by creating electro-neuromuscular constructs using distributed nerve ...