ACUTE ROTATOR CUFF TENDON CHANGES ASSOCIATED WITH WHEELCHAIR PROPULSION

Principle Investigator: Michael Boninger, MD

Co-Investigator: Rory Cooper, PhD

2007-2009

Due to lower limb paralysis, individuals with spinal cord injury (SCI) rely extensively on their upper limbs for mobility and activities of daily living (ADL). Thus, any loss of upper limb function significantly affects mobility and independence. Unfortunately upper limb pain is very common in manual wheelchair users, with shoulder pain present in between 30% and 73% of manual wheelchair users (MWUs). Ultrasound is a non-invasive, convenient method that has been used to examine soft tissue structures of the shoulder. Symptoms of pathology of the rotator cuff detected by ultrasound include hypoechoic (due to increased fluid) tendon appearance, hypertrophy of the long biceps tendon, and an increased biceps-supraspinatus/infraspinatus tendon diameter ratio.

The purpose of this study is to measure acute changes in the soft tissue of the shoulder occurring as a result of a wheelchair propulsion task. We will collect baseline images of nerves and tendons of the upper extremity. Subjects will then propel their wheelchair while kinetic and kinematic data are collected. Post-propulsion ultrasound images will be collected using special techniques to maximize repeatability and consistency of the ultrasound readings. A marker that was designed at the center will be place on the skin that is visible on the ultrasound image during the baseline ultrasound exam. Baseline and post-propulsion ultrasound exams will use this marker as a reference point in order to ensure the same ultrasound probe position, tilt, and orientation for both imaging sessions. We will measure changes in the nerves and tendons of upper extremity and related these changes to biomechanical measures, and baseline soft tissue characteristics. We believe that the acute changes in tendons are part of the pathologic process that leads to chronic changes and pain. We aim to determine how acute changes in soft tissue as a result of wheelchair propulsion relate to specific biomechanics as well as to chronic soft tissue pathology. Understanding these relationships will provide insight into the biomechanics of repetitive strain injury at the shoulder and will provide an opportunity to test interventions. We have collect data on a total of 70 wheelchair users. Of the 70 wheelchair users, we have a limited biomechanics dataset on 48 participants as described in A Comparison of the Upper Limb of Manual Wheelchair Users and Crutch Users Before & After an Intense Physical Activity and a full data set on 22 participants. Using ultrasound techniques may help identify the best interventions to reduce an individual’s risk of developing upper limb pathology.