Exoskeleton Orthotics

Mikaila Foster & Tina Stough

“A prescribed device that is composed of an external, powered, motorized orthosis used for medical purposes that is placed over a person’s paralyzed or weakened limbs for the purpose of providing ambulation.” - FDA

These devices are believed to increase the quality of life for people with lower body paralysis or weakened legs by assisting or restoring mobility, while providing health

benefits across multiple physiological systems

What is a powered exoskeleton?1

How does it work? ReWalk- Argo Medical Technologies

● End-effector-based robot with footplates placed on a double crank and rocker gear system

● Battery powered, computer controlled, exoskeleton○ bilaterally controls the movements at the hip & knee ○ Ankles are articulated with spring-assisted dorsiflexion ○ Can be wireless or wrist control ○ Weight 50lbs

● Senses the patient's movement to control externally powered gait

○ Uses a closed loop control algorithms ○ Sensors to measure different body angles & ground contact

Types: ● AlterG Bionic Leg:

○ Unilateral robotic knee orthoses for individuals with asymmetric lower-limb motor impairments ○ For stability and safety, it is operated with a walker

● Hybrid Assistive Limb (HAL):○ 6 part bilateral lower-limb exoskeleton with 3 active degrees of freedom for actuating the hip,

knee, and ankle joints ○ Receives data from EMG, angle/acceleration, force sensors and computes the force necessary

for the action○ For stability and safety, it is operated with a walker or cane

● Wearable Power-Assist Locomotor Exoskeleton (WAPAL):○ 6 degrees of freedom for bilateral flexion and extension at the hip, knee and ankle joint○ Orthotic and robotic components are modular to allow personalization whereas robotic

components can be standardized and mass produced ○ For stability and utility, it is operated with a custom walker

Case Study: Meet John3

● 22 y/o male 1 year following traumatic SCI● ASIA Class C, Neurological level T11,

○ Motor function preserved below level

and more than half of key muscles below have muscle grade less than 3/5

● Initial goals ○ Walk further without involuntary interruption, gradually reduce support of accompanying

physiotherapist, perform donning + doffing of exoskeleton without assistance

● Short Term Goals○ Walking outdoors, around obstacles and without assistance

● Long Term Goal○ Walking independently in everyday life when accompanied by family or friends

● ReWalk training for 1 hr sessions, 5x/week for 6 months duration ● Let's Meet John!

Case Study Results3

● Outcome Measures○ SF-36 (QOL)○ Goal Attainment Scaling (GAS)○ Modified Berg-Balance Scale (BBS)○ Dynamic Gait Index (Reduced to 21)○ Functional Ambulation Category (FAC to document support needed by PT)

● John partly regained control of bowel and bladder function ● ASIA motor function improved from 52 to 54 points, sensory unchanged

○ John was able to use his hip flexors better than before and he could make his first movements of knee extension on his own

● John was able to walk independently outdoors with single PT supervision

Role of Physical Therapy with Exoskeletons3

● During the first phase, John received standard physiotherapy 3x per week

○ Including: standing and trunk stability exercises, balance work in parallel bars

● Physiotherapists helped John describe and achieve goals● Assessing skin integrity at beginning/end of every session to ensure

no tissue damage occurs from orthotic ● Standard physiotherapy used to prime and prepare patients for

exoskeleton gait training○ Functional Electrical Stimulation (FES) during cycling prior to ReWalk ○ Soft tissue techniques

○ Far-infrared heat therapy: expands capillaries which stimulates increased blood flow,

regeneration, circulation and oxygenation

Training with ReWalk3

● 1st session: Required 2 PTs, 2-point alternate crutch gait

● 10th session: 40 m nonstop walking, more autonomous initiation, 1 PT

● 19th session: 100 m nonstop● 29th session: 10 steps w/out PT contact● 37th session: Walking in darkness, 97

steps w/out PT contact● 50th session: Open doors, 4-point

alternate crutch gait● 70th session: 500 m walking non-stop

with single PT supervision

Benefits1

● Improve patient engagement & outcomes

● Provide short term rewards via immediate feedback of movement

● Empower patient with direct control of their health

● Falls● Changes in BP and HR● Lightheadedness ● Skin abrasions

○ Bruising ○ Pressure sores

● Increased spasticity

Risks1

Limitations1

● Little is known about how the level of injury affects the usage of the exoskeletons

● Specialized designs will be needed for C-level patients for safety

● No studies with children○ May have greater potential for neuro

recovery and should be investigated

● Heavy & Expensive ● Extensive training needed3

● Likely to achieve significant growth as powered exoskeletons are used inside rehabilitation centers, deployed in homes and outdoors

● Improve performance of artificial limbs + lessen loads carried by soldiers

● New materials for lighter + cheaper products like air compression or 3D printing

The Future

References 1. Contreras-Vidal, J. L., Bhagat, N. A., Brantley, J., Cruz-Garza, J. G., He, Y., Manley, Q., . . . Pons, J. L. (2016). Powered

exoskeletons for bipedal locomotion after spinal cord injury. J. Neural Eng. Journal of Neural Engineering, 13(3), 031001. doi:10.1088/1741-2560/13/3/031001

2. H. (2014). John's ReWalk Testimonial. Retrieved July 16, 2016, from https://www.youtube.com/watch?v=6LmmXU78YcE 3. Raab, K., Krakow, K., Tripp, F., & Jung, M. (2016). Effects of training with the ReWalk exoskeleton on quality of life in

incomplete spinal cord injury: A single case study. Spinal Cord Series and Cases, 1(1), 15025. doi:10.1038/scsandc.2015.25 4. White, H., Hayes, S., & White, M. (2015). The Effect of Using a Powered Exoskeleton Training Programme on Joint Range of

Motion on Spinal Injured Individuals: A Pilot Study. International Journal of Physical Therapy & Rehabilitation Int J Phys Ther Rehab, 1(1). doi:10.15344/2455-7498/2015/102

Questions?