motor control for trauma and advanced prosthetics

Albert Chi, MD, MS, FACSAssociate Professor, Division of Trauma and Critical Care

Research and Exploratory Development, Johns Hopkins Applied Physics LabCommander, Medical Corps, IRR USN

Motor Control for Traumaand

Advanced Prosthetics

Background• 82% majority of trauma that currently occurs in Iraq and

Afghanistan involves the upper and lower extremities – Wearing of protective body armor – MRAP (Mine resistant Ambush Protected Vehicle)– IED (Improvised Explosive Devices)

• Iraq – 155 artillery rounds• Afghanistan – nitrogen based bombs

During the 1980s, 11 of 469 (2.3%) amputees returned to active duty

The number of amputees returning to duty has increased significantly, from 2.3% to 16.5%, due to advancements in combat casualty care and the establishment of centralized amputee centers

J Trauma. 2010 Jun;68(6):1476-9.

Applied Physics LabModular Prosthetic Limb

• Designed for modularity and 50% male• The robotic arm itself weighs 9 lbs• Capable of 17 degrees of freedom

– Able to move each individual finger and full range of motion of the wrist

– Able of curling 50 Ibs

• Sensory feedback able to measure temperature, pressure, velocity and position

March 29, 2018 7

Modular Prosthetic Limb

DARPA – Revolutionizing Prosthetics Program

• Benefit individuals at all levels of injury– Spinal Cord injury

• Control Strategies– Cortical Control

Bruce Lee an American born martial artist, philosopher and the founder of the Jeet Kune

Do martial arts system

Pete Rose best known for his years with the Cincinnati Reds is the all-time Major

League leader in hits, games played, at bats and outs

Moe Howard was one of The Three Stooges comedy team

who starred in motion pictures and television

5th grade

6th grade

4th grade

Jennifer Chiborn

September 30, 1973

Cortical Control

“Breakthrough”Aired December 21, 2012

• Benefit individuals at all levels of injury– Spinal Cord injury

• Control Strategies– Cortical Control

“Breakthrough”Aired December 21, 2012

• Within 48 hours of injury– Text to speech– Social Media– YouTube– Email– Environmental

Controls

Robotic Eye Control

Activities of Daily Living

Autonomous Grasping

HARMONIE Conceptual Demo(Hybrid Augmented Reality Multimodal Operation Neural Integration Environment)

DARPA – Revolutionizing Prosthetics Program

• Benefit individuals at all levels of injury– Missing upper extremity

• Control Strategies– Surface EMG Control

Targeted Muscle Reinnervation

Pre and Post TMR – Above ElbowCommercially Available Prosthetics

Residual FunctionsMusculocutaneous -> Lateral biceps Elbow flexionProximal Radial -> Long head Triceps Elbow extension

Transfers FunctionsMedian -> Medial head Biceps Hand CloseDistal Radial –> Lateral Triceps Hand OpenUlnar -> Brachialis Wrist/Hand

Pre and Post TMR – ShoulderCommercially Available Prosthetics

Targeted Muscle ReinnervationAdvanced Algorithms

28

• Virtual Interactive Environment Real-time control and feedback– Confusion Matrix Performance Feedback – Able to classify multiple grips and finger control

JPO Journal of Prosthetics & Orthotics: January 2013

Virtual Rehabilitation

• Virtual Tasks– Performance

Evaluation• Box and Blocks• Clothespin• Positional• Weight

– Gaming• Strengthening

Exercises

• Pattern Recognition• Intuitive individual

finger control• Accurate prediction

of position and duration in real time

Air Guitar Hero

Bilateral MPL Shoulder Fitting

Pattern Recognition Experience

• Diversity of Patients– Studied all amputation levels– Including all levels of congenital limb loss

• All achieve control which exceeded expectations– Multiple grip classifications– Intuitive control strategies– Individual finger control

• Take home pattern recognition prosthesis using commercial available devices

Osseointegration / October 2015

Targeted Sensory Reinnervation

MPL Sensory Feedback

• Finger discrimination : four trials of 25 repetitions with 91% accuracy

• Object density: Four trials of 27 repetitions was able to distinguish between hard, soft, and no object with 95 % accuracy

Walter Reed – MPL Phase 2

Walter Reed – MPL Phase 2

• Take home MPL study for 1 year

• Goals• Enrolled for wireless

sensory feedback study

• Piano lessons• Feel the sensation of

holding his wife’s hand again

• Open Source designs• Biodegradable Polylactic Acid

polymer derived from corn resin• To print costs around $20US• Tensile Strength 57.8 MPa (8,383 psi)

– The force required to break the plastic exceeds the strength of the human hand

• Melting Temperature 170°C

E-nabling the FutureA network of passionate volunteers using 3D printing to give the World a "Helping Hand"

• Kennedy Krieger Institute / JHH Children’s Center– Fitting patient’s with congenital limb loss

• Enables gross grasp capabilities and stabilization• Psychosocial benefits• Strengthening and prosthetic acceptance

E-nabling the FutureA network of passionate volunteers using 3D printing to give the World a "Helping Hand"

E-nabling the FutureA network of passionate volunteers using 3D printing to give the World a "Helping Hand"

E-nabling the FutureA network of passionate volunteers using 3D printing to give the World a "Helping Hand"

Future Directions

• Surgery– Change surgical approach to upper extremity amputation

• Local Reinnervation and pattern recognition evaluation – TMR approaches for both upper and lower limb loss

• Research– Ossteointegration – Socketless and wireless designs– Sensory Cuff Electrode– IMES (Implantable Myoelectric Sensors)– HARMONIE (Hybrid Augmented Reality Multimodal Operation Neural Integration Environment)

• Center for Neuroprosthetics– Continuum of surgical and prosthetic options– Virtual and physical rehabilitation

Questions?

Johnny MathenyProsthetic Champion

“Testing Arms for a Better Life”