Freehand Ultrasound to Evaluate Scapular Kinematics in Paraplegic Persons

Shoulder pain is a very common problem impacting quality of life in people with spinal cord injury (SCI), reported approximately 60% to 83% among individuals with paraplegia since using a chair. Persons with high-level paraplegia have even higher prevalence of shoulder pain and injury than those with low-level paraplegia. One of the biomechanical factors related to shoulder pain has been linked to alterations of scapular kinematics. To elucidate the mechanism of the shoulder pain and injury during functional activities, comprehensive understanding of three-dimensional scapular kinematics is required. We recently developed a measurement tool, freehand ultrasound (FUS) technology, combining ultrasound with motion capture system, to determine the spatial locations of the scapula. Our preliminary results found that the scapular kinematics measured by FUS at rest and during arm elevation showed excellent repeatability and low standard error in able-bodied population. The purpose of this study is to compare both FUS and a widely evaluated skin-based markers method against a bi-planar radiologic based gold standard in people with paraplegia (Aim 1), and to elucidate the relationship among scapular movement and shoulder pain and pathology (Aim 2). This study will also provide insight into the lesion level on scapular behavior during functional activities (Aim 3). Ten subjects will be recruited for all aims, and additional 30 subjects will be recruited for Aim 2 and 3. Individuals with SCI (below T2) between the ages of 18 and 65 without neurologic deficit in the arm will be included. Three-dimensional scapular kinematics will be measured while subjects perform arm elevation and weight relief raise tasks. We will evaluate shoulder pain using Wheelchair Users Shoulder Pain Index (WUSPI) and pathology using a standardized physical examination (PE) and ultrasound shoulder pathology rating scale (USPRS). We will analyze the standard error of measurement, minimum detectable difference, intra-session repeatability, and assess the agreement of those modalities using Bland and Altman plot. Linear regression models will be used to evaluate the relationship between the scapular kinematics and pain (WUSPI total score) and pathology (USPRS and PE total score). Comparisons will be made between the groups for high-level (at T7 and above) and low-level injury (below T7) using a between-subject analysis of covariance to characterize the scapular behavior. Findings of this study will evaluate the efficacy of FUS to measure scapular kinematics in individuals with SCI. Further understanding of the scapular kinematics associated with shoulder pain and pathology and how the lesion level affecting the altered scapular behavior will contribute to the understanding of normal and pathological scapular kinematics in SCI population. (CHN: SCIRTS chn:wdg)