MIRA for Amputation

(MIRA Trial)

Overseen By Debbie Harrington, BS

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Pittsburgh

Must not be taking: Steroids, Immunosuppressants, Anticoagulants, Chemotherapy

Disqualifiers: Severe phantom pain, Active infection, Uncontrolled diabetes, Active psychiatric concerns, others

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

Compensation: Varies

Number of Visits: 1

5 Participants Needed

Trial Summary

What is the purpose of this trial?

The purpose of this research study is to see how well a new type of myoelectric prosthesis works. A myoelectric prosthesis is a robotic limb for amputees that is controlled by sensing the activity of muscles in the body above the amputation level. This study involves a medical procedure to implant the Myoelectric Implantable Recording Array (MIRA) in the residual limb. The procedure will be performed under sedation by a physician. When muscles contract, they generate an electrical signal that can be sensed by MIRA and used to control the prosthetic limb. Myoelectric prosthetic limbs normally use electrodes that are placed on the surface of the skin to control different movements. However, MIRA is implanted under the skin, which could improve the ability to control the myoelectric prosthesis. After the MIRA is implanted, training will occur to learn how to control the prosthesis using the muscles in the residual limb. The device can stay implanted for up to one year. The device will be removed (explanted) by a physician.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but you cannot participate if you are on medications that affect blood coagulation, chronic steroids, or immunosuppressive therapy.

What data supports the effectiveness of the treatment Myoelectric Implantable Recording Array (MIRA) for amputation?

The Myoelectric Implantable Recording Array (MIRA) is a novel implant designed to improve prosthetic control by providing a high-bandwidth interface between the nervous system and prosthetic devices, as shown in animal and cadaver studies. Additionally, similar systems like the Myo Plus and the Agonist-antagonist Myoneural Interface (AMI) have demonstrated improved functionality and control in prosthetic use, suggesting potential benefits for MIRA in enhancing prosthetic performance for amputees. ^{1 2 3 4 5}

Is the Myoelectric Implantable Recording Array (MIRA) safe for human use?

The Myoelectric Implantable Recording Array (MIRA) has been tested in animals and cadavers, showing it can be implanted without issues for a period of four months in animal studies. However, there is no specific safety data available for its use in humans. ^{1 2 3 6 7}

How is the MIRA treatment different from other treatments for amputation?

The MIRA treatment is unique because it is the first fully implantable system designed for prosthetic interfacing with a high number of channels, using 32 intramuscular electrodes to improve control of prosthetic limbs by directly recording muscle signals, unlike current surface-based systems. ^{1 8 9 10 11}

Research Team

Robert Gaunt, PhD

Principal Investigator

University of Pittsburgh

Eligibility Criteria

This trial is for adults aged 22-70 with a single lower arm amputation, who can understand and follow study instructions. They must be at least one year post-amputation, able to control forearm muscles independently, and not pregnant or planning pregnancy within the next 25 months. Exclusions include severe visual impairment, certain medical conditions like heart arrhythmias or infections, ongoing substance abuse (excluding limited cannabis use), recent cancer treatments outside of specific skin cancers, uncontrolled diabetes, and those needing MRI or similar procedures.

Inclusion Criteria

I have had an amputation at or above my wrist on one arm.

It has been over a year since my amputation.

I understand the study's goals and can follow simple instructions.

Exclusion Criteria

I have no history of blood vessel problems that could affect healing.

I do not need routine MRI, ultrasound, or diathermy for my care.

I am not taking any blood-thinning medications.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Implantation

Participants undergo a medical procedure to implant the Myoelectric Implantable Recording Array (MIRA) in the residual limb

1 day

1 visit (in-person)

Training and Rehabilitation

Participants learn to control the prosthesis using the muscles in the residual limb, with regular progress checks and remote monitoring

12 months

Regular remote monitoring and in-person assessments

Follow-up

Participants are monitored for safety and effectiveness after the device is explanted

4 weeks

Treatment Details

Interventions

• Myoelectric Implantable Recording Array (MIRA)

Trial Overview The trial tests a new myoelectric prosthesis called MIRA that's implanted under the skin to improve control over robotic limbs by sensing muscle activity in the residual limb. Participants will undergo surgery to implant MIRA and receive training on using it to control their prosthetic limb. The device remains implanted for up to a year before removal.

Participant Groups

Group I: MIRA Device Experimental Treatment 1 Intervention

All participants enrolled in the study and who meet eligibility criteria will be implanted with the MIRA device in their residual limb. There is no control group.

Who Is Running the Clinical Trial?

University of Pittsburgh

Lead Sponsor

Trials

1,820

Recruited

16,360,000+

Boninger, Michael, MD

Lead Sponsor

Trials

1

Recruited

5+

National Institute of Neurological Disorders and Stroke (NINDS)

Collaborator

Trials

1,403

Recruited

655,000+

Ripple Therapeutics Corporation

Industry Sponsor

Trials

1

Recruited

5+

Findings from Research

The Myoelectric Implantable Recording Array (MIRA) is a novel fully implantable system with 32 intramuscular electrodes that shows promising biocompatibility and functionality for prosthetic interfacing in upper extremity amputations, as demonstrated in studies involving rabbits and large animals.

MIRA maintained stable EMG signal quality and telemetric communication over long-term implantation, indicating its potential for providing high-bandwidth control for prosthetic devices across all major levels of upper limb amputation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Feasibility of a Wireless Implantable Multi-electrode System for High-bandwidth Prosthetic Interfacing: Animal and Cadaver Study. Gstoettner, C., Festin, C., Prahm, C., et al.[2023]

A significant portion of Veterans (41.8% of unilateral and 40.6% of bilateral amputees) expressed willingness to consider surgery for implantable interfaces that restore touch, while 49.0% were interested in improved movement control, indicating a strong interest in enhancing prosthetic functionality.

Factors influencing willingness included age and mental health, with younger individuals (18-45) being more likely to consider surgery, and myoelectric users showing greater interest in control compared to body-powered users. Long-term risks were viewed as the most unacceptable, while durability and comfort were prioritized.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Patient perspectives on benefits and risks of implantable interfaces for upper limb prostheses: a national survey. Resnik, L., Benz, H., Borgia, M., et al.[2022]

The agonist-antagonist myoneural interface (AMI) was successfully implemented in 3 human subjects after below-knee amputation, showing promising results in controlling and interpreting proprioception from a bionic ankle.

All subjects experienced minor complications but reported a high degree of phantom limb position perception without phantom pain, suggesting that AMIs could enhance prosthetic control and sensory feedback for amputees.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Ewing Amputation: The First Human Implementation of the Agonist-Antagonist Myoneural Interface. Clites, TR., Herr, HM., Srinivasan, SS., et al.[2023]

The agonist-antagonist myoneural interface (AMI) is a new technology that allows amputees to control prosthetic limbs more naturally by connecting directly to their peripheral nervous system, enhancing both movement and sensory feedback.

Pre-clinical studies show that the AMI improves muscle-tendon proprioception and neuroprosthetic control, leading to benefits such as pain reduction, better range of motion, and improved control of the prosthetic limb.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Agonist-antagonist Myoneural Interface. Herr, H., Carty, MJ.[2021]

The Myo Plus system, which uses an 8-channel electromyograph, allows upper limb amputees to control their prosthesis more effectively and intuitively compared to traditional systems, leading to improved functionality and ease of use.

This advanced system reduces rehabilitation time and associated costs for patients, making it a more accessible option for those who might otherwise abandon prosthesis use due to complexity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Use of the Myo Plus system in transradial amputation patients]. Guirao Cano, L., Samitier Pastor, B., Peret Hernández, P., et al.[2022]

New data visualization techniques, including histograms and Archimedean spirals, provide a detailed and objective way to assess upper limb activity in prosthesis users, highlighting their real-world usage patterns.

In a study involving two prosthesis users and two anatomically intact participants, it was found that prosthesis users engaged in significantly less unilateral activity with their prosthesis (20-40 minutes per week) compared to the intact participants' unilateral activity (approximately 350 minutes per week), indicating a potential gap in prosthesis utilization.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Visualisation of upper limb activity using spirals: A new approach to the assessment of daily prosthesis usage. Chadwell, A., Kenney, L., Granat, M., et al.[2019]

The developed multichannel electromyography sensor system can process signals from up to 32 implanted myoelectric sensors, providing high-quality, cross-talk-free EMG signals directly from the source.

Animal testing in three cats showed that the implanted sensors remained fully operational four months after implantation, demonstrating the system's potential for long-term use without servicing and reducing risks associated with traditional percutaneous wires.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Implantable myoelectric sensors (IMESs) for intramuscular electromyogram recording. Weir, RF., Troyk, PR., DeMichele, GA., et al.[2021]

The updated upper-extremity prosthesis control system utilizes implantable myoelectric sensors, with a focus on a miniature injectable implant that includes a silicon chip and wireless communication coils.

Recent design improvements have enhanced the IMES implant's functionality and safety, providing better protection against electrical malfunctions and potential tissue damage, paving the way for human implantation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

IMES: an implantable myoelectric sensor. Troyk, PR., DeMichele, GA., Kerns, DA., et al.[2021]

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]

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]

References

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

Feasibility of a Wireless Implantable Multi-electrode System for High-bandwidth Prosthetic Interfacing: Animal and Cadaver Study. [2023]

2. England pubmed.ncbi.nlm.nih.gov

Patient perspectives on benefits and risks of implantable interfaces for upper limb prostheses: a national survey. [2022]

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

The Ewing Amputation: The First Human Implementation of the Agonist-Antagonist Myoneural Interface. [2023]

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

The Agonist-antagonist Myoneural Interface. [2021]

5. Spain pubmed.ncbi.nlm.nih.gov

[Use of the Myo Plus system in transradial amputation patients]. [2022]

6. France pubmed.ncbi.nlm.nih.gov

Visualisation of upper limb activity using spirals: A new approach to the assessment of daily prosthesis usage. [2019]

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

Implantable myoelectric sensors (IMESs) for intramuscular electromyogram recording. [2021]

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

IMES: an implantable myoelectric sensor. [2021]

9. 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]

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

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

11. 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]