The first published account of ergonomic concerns in sonography was termed “sonographer’s shoulder” by Marveen Craig in 1985.3 A subsequent study in 1997 by the Health Care Benefit Trust utilized data collected from almost 1,000 sonographers practicing in the United States. Results showed 84% experienced musculoskeletal pain related to scanning, with neck, shoulder, wrist, hands/fingers, and back as the most commonly affected sites.4 The Industry Standards for the Prevention of Work-Related Musculoskeletal Disorders in Sonography were first published in 2003, and since then, there have been significant ergonomic improvements in the design of sonographic workstation equipment.5 Today, almost all ultrasound systems have some degree of adjustability and sonography exam tables are now designed specifically for various ultrasound applications. Despite these improvements, a 2009 study indicated 90% of clinical sonographers experienced symptoms of WRMSDs, an increase of 9% from the 1997 study.6
The reason for an increase in symptoms of work related musculoskeletal discomfort among sonographers is multi-factorial. While there have been significant improvements in the design of ultrasound systems and workstation equipment for sonographers, not all sites have a full complement of state-of-the-art equipment. Additionally, exams are increasingly completed at the patient’s bedside or in other departments, where the sonographer does not have access to ergonomically designed workstation equipment and has the added burden of transporting equipment. Moreover, technological changes in workflow have resulted in increased interaction with computers, which increases the sonographer’s exposure to ergonomic hazards that have mechanical risk factors similar to scanning. Staff shortages due to injuries and increasing referrals for sonography have resulted in insufficient rest periods, further increasing the duration of the sonographer’s exposure to risk.
Although there are a growing number of workplace factors contributing to symptoms in sonographers, a primary driver of WRMSDs is due to an accumulation of repeated exposure to physical risk factors, many of which are related to sonographer scanning techniques. Many sonographers are utilizing the same scanning techniques from 30 years ago, despite the improved design and technological advances of workstation equipment. Individual movements and activities associated with musculoskeletal disorders are not necessarily harmful in and of themselves, but frequent repetition or prolonged duration of exposure, along with a pace that lacks sufficient time for recovery can be risk producing. In sonography, the primary physical risks include:
- Force is the exertion of physical effort applied by a body part to perform a task. Higher forces and/or longer durations of force can increase the risk. Examples of force include: Pushing/pulling, lifting, gripping, and pinching. In sonography, force is often associated with downward pressure applied with the transducer to obtain an image and grip force to hold the transducer.7
- Repetition is performing the same or similar tasks repetitively, either continually or frequently for an extended period of time without adequate recovery time. The severity of the risk increases with higher repetition of motions, particularly with other ergonomic risk factors such as force and/or awkward posture. Sonographers who perform the same type(s) of exams repeatedly, or exams using similar muscle activity have an increased exposure to risk factors associated with repetition.7
- Awkward or sustained postures occur when body parts are positioned away from their neutral position. These postures can put stress on the joint and its associated muscles. The potential for risk increases the further from neutral and the longer the awkward posture is sustained. Examples include: flexion/extension of the wrist, excess abduction of the shoulders, forward flexion of the shoulders (reaching), bending/twisting at the waist, and bending or rotating the neck. Sonographers often exhibit awkward postures during scanning in an effort to access the region of interest or as a result of insufficient adjustability of equipment.7
- Contact pressure is sustained contact between a body part and an external object. In sonography, examples include resting the hip or forearm against the exam table while scanning.7
A simplified explanation of how injuries occur is when the load placed on a tissue exceeds the capacity of that tissue. Muscular activity increases in proportion to the load exerted upon it. When a muscle is unable to meet the demands of a task, there is additional strain placed on the tendons associated with that particular muscle resulting in tendonitis, tenosynovitis or bursitis.7 Inflammation of muscles, tendons, or ligaments surrounding nerves can cause pressure against the nerves and result in muscle weakness, numbness, and tingling.7 Repeated exposure to these loads, or risk factors, interferes with the ability of the body to recover and results in the accumulation of trauma to the muscles and tendons, which often ends in chronic conditions identified as musculoskeletal disorders. Awkward postures of the trunk, neck, and upper extremities, as well as excess gripping and downward force applied with the transducer, contribute to sonographers’ symptoms of discomfort and risk for injury. For sonographers, the mechanism of injury to the shoulder is felt to correspond to frequent abduction of the scanning arm combined with static loading of the muscles related to pressure applied with the transducer. This results in mechanical compression of portions of the rotator cuff against the bony structures the shoulder girdle, decreased perfusion of blood to the muscles and tendons, and micro trauma to the muscle fibers.8 Back and neck pain have been found to be associated with repeated episodes of twisting of the neck and trunk, particularly when combined with abduction of the arm. Risk factors for the hand/wrist and elbow have been associated with awkward postures, repetition and sustained or forceful gripping.8,10
Excerpt from the Work Related Musculoskeletal Disorders in Sonography white paper.
3. Craig M. Sonography: An Occupational Hazard. Journal of Diagnostic Medical Sonography 1985;1(3):121-126.
4. Pike I, Russo A, Berkowitz J, Baker J, Lessoway V. The Prevalence of Musculoskeletal Disorders Among Diagnostic Medical Sonographers. Journal of Diagnostic Medical Sonography 1997;13(5):219-227.
5. Industry Standards for the Prevention of Work Related Musculoskeletal Disorders in Sonography. Society of Diagnostic Medical Sonography. Available at: http://www.sdms. org/?ID=19. Accessed August 1, 2017.
6. Evans K, Roll S, Baker J. Work-Related Musculoskeletal Disorders (WRMSD) Among Registered Diagnostic Medical Sonographers and Vascular Technologists: A Representative Sample. Journal of Diagnostic Medical Sonography 2009;25(6):287-299.
7. CCOHS(WRMSD): Canadian Centre for Occupational Health and Safety; Work-related Musculoskeletal Disorders https://www.ccohs.ca/oshanswers/diseases/rmirsi.html. Accessed August 8, 2016.
8. Village J & Trask C. Ergonomic analysis of postural and muscular loads to diagnostic sonographers. International Journal of Industrial Ergonomics. 2007;37:781-789.
10. Bertoloni E, Fenaroli M, Marciano F. Sonographers’ workplace improvement: ergonomics evaluation using modelling and simulation software. Proceedings of the 2012 International Conference on Industrial Engineering and Operations Management, Istanbul, Turkey, July 3–6, 2012.