EVALUATION OF RISK FACTORS FOR WORK-RELATED MUSCOLOSKELETAL DISORDERS IN MEDICAL SONOGRAPHERS David R. Burnett, M.S.1, Naira H. Campbell-Kyureghyan, Ph.D.1, Peter M. Quesada, Ph.D.1 1
University of Louisville, Louisville, KY, USA Email:
[email protected]
INTRODUCTION Since the introduction of medical ultrasound, the health care community has been greatly reliant on this technique as a means for diagnosis. However, the improvements in ultrasound technology have also led to an increase in both the number of sonograms performed and the duration of each procedure [1,2], and prior research has shown that medical sonographers have an increased risk of developing musculoskeletal disorders (MSDs), particularly in the low back, neck, and upper extremities. Although the prevalence of work-related injuries in medical sonographers is well known, there has been limited quantifiable evidence relating to the potential biomechanical causes. The specific aim of this study is to identify and quantify possible risk factors for the development of work-related MSDs in medical sonographers through biomechanical analysis methods. METHODS A biomechanical evaluation of work-related risk factors was performed on seven full-time sonographers at the University of Louisville Hospital Diagnostic Imaging Facility. All research and subject consent was in accordance with the approved protocol from the University of Louisville’s IRB. Customized Nordic questionnaires were used to determine the prevalence of MSDs and the existence of perceived risk factors for injury. Electrogoniometers were used to evaluate the average and maximum joint angles of the wrist, elbow, and shoulder, and surface electromyography (sEMG) was used to analyze right and left middle deltoid and upper trapezius muscle activity during five typical scanning procedures: right abdominal (RA), left abdominal (LA), right deep venous thrombosis (RDVT), left deep venous thrombosis (LDVT), and thyroid (TH). Comparison of muscle
activity between scans was based on average root mean squared (RMS) values, and the possibility of muscle fatigue was determined through changes in median frequency (MDF). RESULTS AND DISCUSSION 6 out of 7 (86%) sonographers reported musculoskeletal pain in at least one upper extremity joint. Shoulder pain was reported by 71% of subjects, and sustained shoulder abduction and scanning large patients was perceived as a risk factor for injury by 100% of the sonographers. TH, LA, and LDVT scans resulted in large average shoulder abduction and elbow flexion angles, therefore producing a large moment arm about the shoulder joint. During bilateral scanning procedures, sEMG average RMS amplitude values for left sided scans were consistently larger than for right sided scans for both the left and right deltoid muscles. TH, LA, and LDVT scans were associated with significant differences (p < 0.05) between the initial and minimum MDF values for all muscle groups. Pain in the hands/wrists was reported by 43% of subjects and may be attributed to sustained transducer usage and nonneutral wrist angles ranging from 64° of flexion to 50° of extension and 26° of radial deviation to 27° of ulnar deviation. This study has shown that biomechanical analysis methods can be used to identify and quantify work-related risk factors such as awkward postures and muscle fatigue, and it appears that solutions could be proposed to reduce the risk of MSDs in sonographers. REFERENCES [1] Schoenfeld, A et al., 1999, European Journal of Ultrasound, 10, 41 – 45. [2] Vanderpool, HE et al., 1993, Journal of Occupational Medicine, 35(6), 604 – 610. ACKNOWLEDGEMENTS This project was funded by the University of Louisville Hospital.
