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Summary
Sonographers are at risk for developing work-related musculoskeletal disorders such as inflammation
of the tendons (tendonitis) or tendon sheaths (tenosynovitis), bursitis, muscle strains, and pathology
of the nerves in the upper extremities, neck, and back. NIOSH recommends appropriate engineering controls,
work practices, hazard communication, and training to prevent these work-related musculoskeletal disorders.
Description of Exposure
Work-related musculoskeletal disorders currently account for one-third of all occupational injuries
and illnesses reported to the Bureau of Labor Statistics (BLS) by employers every year.
The following
are factors that, in combination and over time, lead to musculoskeletal injuries:
- Static and awkward postures and movement resulting from the use of the transducer and positioning of
both patients and equipment
- Persistent and continual pressure for sustained periods of time during exams
- Poor workplace ergonomics in the design of equipment, chairs, tables, and lighting
- Increased exam scheduling
- Sonographer height, age, and gender
Case Study
NIOSH [1999] conducted an investigation at a hospital antenatal unit in which most of the sonographers
had reported neck, shoulder, and arm pain while performing ultrasound. NIOSH investigators interviewed
several workers and assessed the jobs using video analysis. The following findings were noted:
- The main risk factors noted during trans-abdominal ultrasound procedures were awkward postures
(mainly right shoulder flexion and abduction), sustained static forces, and various types of pinch
grips while maneuvering the transducer. Extreme wrist postures varied because of the
way sonographers had to move the transducer to accommodate different patient sizes. Small patient
abdomens mainly led to the use of shoulder movements while large abdomens led to greater wrist flexion
and extension.
- Standard positioning of the equipment resulted in twisting of the neck to view the monitor, flexion
and abduction of the shoulder, and extension of the elbow while operating the controls.
- The shape of the abdominal transducer resulted in several distinct types of grips, ranging from a
pinch grip to a power grip to an intermediate type of grip (the most commonly seen is with the 3rd and
4th fingers on one side and the thumb on another). The power grip—the most comfortable over the
long term was used when the hand could be spread along the wide (3-inch) edge of the transducer.
Controls
NIOSH recommends the following controls to reduce the risk of musculoskeletal injury for sonographers:
Equipment
- Provide adequate work space for personnel, sonography equipment, the patient table, and other equipment.
- Ensure that sonography equipment is fitted with a high-resolution screen that has a high refresh rate
(85 Hertz or higher), a noninterlaced monitor and an easily adjustable “brightness control”
to reduce eye strain. Position the equipment monitor directly in front of the sonographer.
- Position the keyboard to allow the arm to be in a relaxed position with the upper arm close to the
body (minimal flexion and abduction) and the elbow at a 90-degree angle. A laptop computer may enable the
sonographer to achieve a favorable position with respect to the patient. However, be aware that laptops
can present other problems because the keyboard and monitor cannot be positioned separately, which make
them difficult to handle at the bedside.
- Use a posture-enhancing adjustable chair to accommodate the sonographer through adjustable footrests,
seat heights, and lock and release casters. Casters should allow for rolling between patients and the
ultrasound machine when necessary, yet prevent rolling backwards when performing necessary procedures.
- Use motorized adjustable tables (including those equipped with drop-down side rails) to optimize the
positions of the patient and the sonographer. The table should be as narrow as possible (preferably 24 to
27 inches wide) to allow for proximity to the patient and to reduce the amount of shoulder abduction
needed to reach the patient’s far side.
Work Practices
- Decrease the duration of static posturing:
- Vary postures throughout the day.
- Sit or stand, depending on the exam.
- Decrease hand-grip pressure:
- Alternate the scanning hand and vary the grip used.
- Take short breaks.
- Loosen grip on the transducer.
- Minimize awkward and extreme postures.
- Increase tissue tolerances through exercise and adequate rest.
Scheduling
- Schedule different types of exams for each sonographer in a workday to decrease strain on
musculoskeletal tissues specific to one type of exam.
- Limit the number of portable exams to help minimize those tasks with higher number of pinch
grips and increased static or awkward postures.
- Consider a maximum number of scheduled exams for sonographers. Take into account existing
ergonomic conditions and equipment, the type of exams performed, experience of the sonographer,
and the duration of the individual exams. Because of the complexity of each diagnostic situation,
it is difficult to specify an allowable limit to the number of exams per day. Until better information
is obtained, take into account the total examination time per day (more exams of shorter duration or
fewer exams of longer duration).
Training
Periodic training and reassessment regarding the above ergonomic interventions should include the following:
- Setting up the equipment, bed, and chair
- Modifying the equipment positioning during scanning
- Positioning patients
- Using adaptive equipment or devices, such as cushions and wedges and the
patient’s limbs for resting the elbows during scans
- Taking rest breaks during the procedures
- Maintaining good physical fitness and conditioning
- Optimal handling of specialized tests such as trans-vaginal examinations
- Having symptoms promptly evaluated by a licensed health care provider.
Acknowledgments
The principal contributors to this publication were Robin Epp MD, MPH, University of Iowa, Department
of Occupational and Environmental Medicine; Bruce Bernard, MD, MPH and Daniel Habes, National Institute
for Occupational Safety and Health; Ashok Nimgarde, MD, Harvard University; and Joan Baker, Society of
Diagnostic Medical Sonography.
References
NIOSH [1999]. Hazard evaluation and technical assistance report: University of Medicine and Dentistry of
New Jersey, St. Peter’s University Hospital, Piscataway, New Jersey. Cincinnati, OH: U.S. Department
of Health and Human Services, Centers for Disease Control and Prevention, National Institute for
Occupational Safety and Health, NIOSH HETA 99–0093–2749, Health Hazard Evaluation Report
No. 99–0093. Available at: www.cdc.gov/niosh/hhe/.
For More Information
For more information about work-related musculoskeletal disorders in sonographers, see
NIOSH,
Society of Diagnostic Medical Sonography [2003]. Industry Standards for the Prevention of Work-Related
Musculoskeletal Disorders in Sonography. Plano, TX.
To receive documents or other information about
occupational safety and health, contact NIOSH at
NIOSH—Publications Dissemination
4676 Columbia Parkway
Cincinnati, OH 45226–1998
Telephone: 1–800–35–NIOSH (1–800–356–4674)
Fax: 513–533–8573
E-mail: pubstaft@cdc.gov
or visit the NIOSH Web site at www.cdc.gov/niosh
For a monthly update on news at NIOSH, subscribe to NIOSH eNews by visiting
www.cdc.gov/niosh/eNews.
DHHS (NIOSH) Publication No. 2006–148
September 2006
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