Improving Shoulder Health for Persons with Spinal Cord Injury through an Ergonomic Wheelchair

Abstract

Background: Manual wheelchairs are the most common form of transportation for persons with spinal cord injury (SCI) in the United States. Up to 80% of persons with SCI have described shoulder pain since beginning wheelchair use and 40-67% have reported currently having pain. The research group from the University of Minnesota recently fabricated a novel ergonomic wheelchair, which allows for independent positioning of the push rims and drive wheels, with a chain to link their rotations. This model determined that an anterior placed push rim provided better functional biomechanics. The preliminary studies have yielded promising results with one subject commenting that he had "absolutely no pain" and the ergonomic wheelchair took "all pressure off his shoulders". However, whether the novel ergonomic wheelchair has the potential to improve rotator cuff health has not yet been assessed in persons with SCI.Aim: To determine whether manual wheelchair users with SCI have reduced subacromial rotator cuff compression using the theorized optimal push rim position compared to the standard wheelchair push rim position. Methods: Our approach will be to simulate wheelchair propulsion while assessing kinematics using bi-plane fluoroscopy, and 2D/3D shape matching. We will recruit 10 persons with SCI to assess subacromial compression for the ergonomic and standard wheelchair push rim positions using patient-specific arthrokinematics driven rigid body models. This is a technique developed in a previous study developed by the University of Minnesota research group for assessing subacromial rotator cuff compression using exact bone kinematics.Innovative elements of the project: The innovative elements of this proposal are using biplane fluoroscopy and 2D/3D shape matching to directly determine the rotator cuff compression during both hand-rim positions. This will provide direct quantitative measures of rotator cuff compression, which have never previously been done. We will also get direct user feedback for both hand rim positions to help with better wheelchair design.Impact on treatments and rehabilitative efforts for functional improvement of people with SCI or traumatic brain injuries: This proposal has the potential to benefit millions of persons with SCI over the long term by preventing and/or reducing the progression of shoulder pain and subacromial rotator cuff compression in persons with SCI, through reducing specific stresses to the rotator cuff during manual wheelchair propulsion.