Ergonomic Interventions for an Ultrasound Transducer

Details

• Personal Author:
  Meador KA
• Description:
  Sonographers face a number of occupational risk factors for musculoskeletal disorders (MSDs) when performing ultrasound procedures. Over 80% of sonographers experience work-related musculoskeletal symptoms. These musculoskeletal symptoms and injuries have been attributed to activities such as static shoulder abduction, constant applied pressure with the ultrasound transducer, awkward wrist postures, and repetitive twisting of the neck and trunk. The gripping of the transducer, particularly with a pinch grip, has been linked to hand and wrist pain and symptoms of carpal tunnel syndrome and other MSDs. The objective of this study was to design and fabricate ultrasound transducer interventions and evaluate their effectiveness in reducing the risk of upper extremity musculoskeletal disorders. The interventions were designed with the intent of reducing the pinch grip force. It was hypothesized that the transducer interventions would reduce the activity of the muscles of the upper extremity, primarily those of the hand and forearm as they are most engaged in the pinch grip. The three transducer interventions and the control transducer were evaluated using electromyography (EMG) to determine their effect on the muscle activity of the upper extremity while the subject was engaged in a simulated ultrasound scanning task. The subject applied a given static pressure to an abdomen-like surface for 5 seconds per trial. Because sonographers manipulate the transducer at varying angles, the ultrasound task was performed at two different angles. As patient size plays a major role in the gripping and force application of the transducer, the experiment was performed in two parts under different conditions to simulate a scan on a normal-sized patient and on an obese patient. Subjects completed a survey providing subjective feedback about each of the transducers. Both independent variables, INTERVENTION and ANGLE, were significant in the normal and obese patient experiments, and there was no interaction effect. As hypothesized, the interventions significantly reduced the activity of several of the sampled muscles. Most notably, each intervention dramatically reduced muscle activity of the first dorsal interosseous (FDI), which provides much of the force in the pinch grip. The transducer harness, transducer cover, and wide grip transducer decreased FDI activity by 74%, 64%, and 50%, respectively, as compared to the control transducer, in the obese patient experiment. This indicates that the interventions effectively reduced the pinch grip force requirement as intended. The same trend was repeated in the survey results, which ranked the interventions ahead of the control in this order. Subjects also reported that the control caused the greatest pain and discomfort in the hand. While each of the interventions showed improvement over the control transducer, the harness may have performed the best, as its use significantly reduced the activity for the FDI (74%), flexor (10%), extensor (3.0%), deltoid (3.1%), and trapezius (3.5%) muscles in the obese patient experiment. However, the harness also resulted in the highest thenar muscle activity and its design has some limitations. Reducing FDI and extensor activity by 64% and 44% in the obese patient trials, the cover performed the best behind the harness. With each intervention having its own strengths and weaknesses, the best transducer design approach may be to integrate different aspects of the three interventions into a new design. This research has demonstrated that ultrasound transducer interventions can effectively reduce upper extremity muscle activity and, thus, reduce the risk of work-related MSDs, when the intervention design decreases the need to utilize a pinch grip. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Ergonomics Health Personnel Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Biomechanics Carpal Tunnel Syndrome CTS Equipment Design Harnesses Injuries Medical Personnel MSD Muscle Function Musculoskeletal Disorders Posture Ultrasound Upper Extremities

  More +
• Publisher:
  North Carolina State University
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Thesis
• Place as Subject:
  North Carolina ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-76
• NIOSHTIC Number:
  nn:20054219
• Citation:
  Raleigh, NC: North Carolina State University, 2007 Jun; :1-76
• Federal Fiscal Year:
  2007
• Performing Organization:
  University of North Carolina, Chapel Hill
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  Effects of time of day and warm-up on lifting kinematics
• End Date:
  20270630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:12dbe4b03169a2eda03c9228228753e4fb050744a5f2b53b2d2174e5d96eeb4488ed871d888b475beb013c9e9b57673667a0880eb45ac2fdb14929e7d1fa4ccd
• Download URL:
  https://stacks.cdc.gov/view/cdc/216830/cdc_216830_DS1.pdf
• File Type:
  [PDF - 740.86 KB ]