Logo for the Journal of Rehab R and D

Volume 46 Number 3, 2009
   Pages 447 — 462

Abstract – Development of hybrid orthosis for standing, walking, and stair climbing after spinal cord injury

Rudi Kobetic, MS;1* Curtis S. To, MS;2 John R. Schnellenberger, MS;1 Musa L. Audu, PhD;2 Thomas C. Bulea, MS;2 Richard Gaudio, CO;3 Gilles Pinault, MD;1 Scott Tashman, PhD;4 Ronald J. Triolo, PhD1,5

1Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH; 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH; 3Orthotics and Prosthetics Specialties, Cleveland, OH; 4Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA; 5Department of Orthopaedics, Case Western Reserve University, Cleveland, OH

Abstract — This study explores the feasibility of a hybrid system of exoskeletal bracing and multichannel functional electrical stimulation (FES) to facilitate standing, walking, and stair climbing after spinal cord injury (SCI). The orthotic components consist of electromechanical joints that lock and unlock automatically to provide upright stability and free movement powered by FES. Preliminary results from a prototype device on nondisabled and SCI volunteers are presented. A novel variable coupling hip-reciprocating mechanism either acts as a standard reciprocating gait orthosis or allows each hip to independently lock or rotate freely. Rotary actuators at each hip are configured in a closed hydraulic circuit and regulated by a finite state postural controller based on real-time sensor information. The knee mechanism locks during stance to prevent collapse and unlocks during swing, while the ankle is constrained to move in the sagittal plane under FES-only control. The trunk is fixed in a rigid corset, and new ankle and trunk mechanisms are under development. Because the exoskeletal control mechanisms were built from off-the-shelf components, weight and cosmesis specifications for clinical use have not been met, although the power requirements are low enough to provide more than 4 hours of continuous operation with standard camcorder batteries.

Key words: assistive technology, bracing, functional electrical stimulation, gait, hybrid systems, mobility, neuroprostheses, orthotics, paralysis, rehabilitation engineering, spinal cord injury, stair climbing, standing, stepping.

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