Ergonomics in the Dark Room: Creating a Healthy Work Environment ...
Ergonomics in the Dark Room: Creating a Healthy Work Environment for the Radiologist Patel S, MD Reich S, MD Yadavalli S MD, PhD Beaumont Health System and Oakland University William Beaumont School of Medicine, Royal Oak MI INTRODUCTION The occupational hazards of being a radiologist are often equated to radiation exposure and, rightly so, resident education emphasizes this aspect in extensive detail. However, very little attention is paid to occupational hazards encountered at the reading station, where, assuming average work hours, a radiologist can spend 40 hours a week, 1600 hours a year, and 40,000 hours over the course of his or her career. This presentation will address common occupational hazards and ways they can be mitigated without compromising productivity.
EYE STRAIN Caused by fatigue of ciliary and extraocular muscles due to prolonged accommodation and vergence required for near vision work. Eye dryness is also implicated as there is a decreased blink rate during mental concentration. Can hinder productivity and diagnostic interpretation by causing perceptual errors, performance errors, and decrease in reaction time.
OPTIMIZING IMAGE DISPLAYS
CUBITAL TUNNEL SYNDROME
LOW BACK PAIN
Resolution of display should match matrix of image data to limit interpolation artifacts.
Sustained elbow flexion may cause ulnar nerve compression between the medial epicondyle, the olecranon, and overlying cubital tunnel retinaculum.
The sitting position causes the pelvis to rotate posteriorly which results in a decrease in physiologic lumbar lordosis and increased axial force at the disc spaces, thus aggravating discogenic low back pain.
Smallest perceivable difference in an image is a function of luminescence of display, which is best at low luminescence levels according to the Barten Model of the human visual system. Maximal luminescence of a display should be avoided as the stability and uniformity of a display decreases over time due to use. Fine details are best processed by foveal region of the retina, which only spans about 5° in diameter.
CARPAL TUNNEL SYNDROME Positive tilt of the desk surface or elevated desk height results in flexion of the elbow < 90° (red arrow) and sustained dorsiflexion (blue arrow) of the wrist.
Can be prevented by:
a b
a) Top of monitor at or just below eye level b) Monitor should be arms length away from body
Persistent dorsiflexion results in elevated carpal tunnel pressure and median nerve compression. Pressure changes on the median nerve occur when dorsiflexion of the hand is > 15° from horizontal. Negative tilt surface of the desktop can enable extension of the elbows at an angle slightly > 90° with elimination of dorsiflexion at the wrist.
Assuring the pixel response time of LCD displays is between 25-30ms to decrease screen flicker while reviewing a stack of gray scale images. Avoiding moving closer to the display to see fine details and instead use zoom and pan functions. Limiting time spent reviewing high image volume screening studies (lung cancer screening and CT colonography).
Exacerbated by elevated desk height which causes elbow flexion at an angle < 90°.
Adjustable table heights can reduce the amount of time sitting at the workstation. a) Wrist and elbow relationships should not change b) Eyes remain at or just above top of the monitor c) Good posture maintained
Optimum seated position:
Commonly occurs with use of hand-held dictation microphones and telephone receivers. Leaning on hard surfaces can exacerbate symptoms by direct compression of the ulnar nerve.
d
e
c
Use of headsets and remote microphones can help limit elbow flexion while dictating reports.
b a
a) Feet firmly planted, ankle neutral b) Knee flexed at roughly 90° c) Hips flexed at 90-120° d) Elbows close to body and angled at 90-120° e) Forearm at level of desk surface. No significant wrist flexion
b a
b c
a
c
Seats with added low lumbar support can help restore normal lumbar lordosis. Chair optimization:
Having adjustable light in the room so that light coming off the viewing monitor is equal to the light coming of the wall (20-40 lux). Positioning the viewing monitor 25 in (60 cm) away from the eyes with gaze directed slightly below horizontal plane.
ACTIVITY AT THE WORKSTATION
a c
a
b
a) Adjustable chair height and incline b) Gap between chair front and back of knees c) Lumbar support that accentuates normal spinal curvature
Redistributing seating pressure off the ischial tuberosities can decrease axial loading on the lumbar spine via forward tilting seats, tilting down the back part of the seat, or balance ball chairs. Seats that promote periodically adjusting positions help relive tension on low back muscles.
Modification of the desk surface may be necessary to keep the mouse from sliding forward. A mouse with extra weighting or possibly a joystick can be considered when scrolling through many images is necessary for interpretation.
Foot rests can be used if desk height cannot be appropriately adjusted and is too high.
CONCLUSION Behaviors learned during training are likely to set in and become permanent. This poster emphasizes the importance of early awareness and adoption of healthy habits in the everyday reading room for encouraging long-term health and optimized function.
REFERENCES 1) Vertinsky T, Forster B. “Prevalence of Eye Strain Among Radiologists: Influence of Viewing Variables on Symptoms.” AJR 2005 Feb; 184(2): 681-686. 2) Kagadis GC et al. “Medical Imaging Displays and Their Use in Image Interpretation.” Radiographics 2013 Jan-Feb ; 33(1): 275-290. 3) Ruess L et al. “Carpal Tunnel Syndrome and Cubital Tunnel Syndrome: Workrelated Musculoskeletal Disorders in four Symptomatic Radiologists.” AJR 2003 July; 181(1): 37-42. 4) Makhsous et al. “Biomechanical Effects of Sitting with Adjustable Ischial and Lumbar Support on Occupational Low Back Pain: Evaluation of Sitting Load and Back Muscle Activity.” BMC Musculoskeletal Disorders 2009 Feb; 10(17). 5) Goyal N et at. “Ergonomics in Radiology.” Clinical Radiology 2009 Feb; 64(2): 119/126.
EYE STRAIN Caused by fatigue of ciliary and extraocular muscles due to prolonged accommodation and vergence required for near vision work. Eye dryness is also implicated as there is a decreased blink rate during mental concentration. Can hinder productivity and diagnostic interpretation by causing perceptual errors, performance errors, and decrease in reaction time.
OPTIMIZING IMAGE DISPLAYS
CUBITAL TUNNEL SYNDROME
LOW BACK PAIN
Resolution of display should match matrix of image data to limit interpolation artifacts.
Sustained elbow flexion may cause ulnar nerve compression between the medial epicondyle, the olecranon, and overlying cubital tunnel retinaculum.
The sitting position causes the pelvis to rotate posteriorly which results in a decrease in physiologic lumbar lordosis and increased axial force at the disc spaces, thus aggravating discogenic low back pain.
Smallest perceivable difference in an image is a function of luminescence of display, which is best at low luminescence levels according to the Barten Model of the human visual system. Maximal luminescence of a display should be avoided as the stability and uniformity of a display decreases over time due to use. Fine details are best processed by foveal region of the retina, which only spans about 5° in diameter.
CARPAL TUNNEL SYNDROME Positive tilt of the desk surface or elevated desk height results in flexion of the elbow < 90° (red arrow) and sustained dorsiflexion (blue arrow) of the wrist.
Can be prevented by:
a b
a) Top of monitor at or just below eye level b) Monitor should be arms length away from body
Persistent dorsiflexion results in elevated carpal tunnel pressure and median nerve compression. Pressure changes on the median nerve occur when dorsiflexion of the hand is > 15° from horizontal. Negative tilt surface of the desktop can enable extension of the elbows at an angle slightly > 90° with elimination of dorsiflexion at the wrist.
Assuring the pixel response time of LCD displays is between 25-30ms to decrease screen flicker while reviewing a stack of gray scale images. Avoiding moving closer to the display to see fine details and instead use zoom and pan functions. Limiting time spent reviewing high image volume screening studies (lung cancer screening and CT colonography).
Exacerbated by elevated desk height which causes elbow flexion at an angle < 90°.
Adjustable table heights can reduce the amount of time sitting at the workstation. a) Wrist and elbow relationships should not change b) Eyes remain at or just above top of the monitor c) Good posture maintained
Optimum seated position:
Commonly occurs with use of hand-held dictation microphones and telephone receivers. Leaning on hard surfaces can exacerbate symptoms by direct compression of the ulnar nerve.
d
e
c
Use of headsets and remote microphones can help limit elbow flexion while dictating reports.
b a
a) Feet firmly planted, ankle neutral b) Knee flexed at roughly 90° c) Hips flexed at 90-120° d) Elbows close to body and angled at 90-120° e) Forearm at level of desk surface. No significant wrist flexion
b a
b c
a
c
Seats with added low lumbar support can help restore normal lumbar lordosis. Chair optimization:
Having adjustable light in the room so that light coming off the viewing monitor is equal to the light coming of the wall (20-40 lux). Positioning the viewing monitor 25 in (60 cm) away from the eyes with gaze directed slightly below horizontal plane.
ACTIVITY AT THE WORKSTATION
a c
a
b
a) Adjustable chair height and incline b) Gap between chair front and back of knees c) Lumbar support that accentuates normal spinal curvature
Redistributing seating pressure off the ischial tuberosities can decrease axial loading on the lumbar spine via forward tilting seats, tilting down the back part of the seat, or balance ball chairs. Seats that promote periodically adjusting positions help relive tension on low back muscles.
Modification of the desk surface may be necessary to keep the mouse from sliding forward. A mouse with extra weighting or possibly a joystick can be considered when scrolling through many images is necessary for interpretation.
Foot rests can be used if desk height cannot be appropriately adjusted and is too high.
CONCLUSION Behaviors learned during training are likely to set in and become permanent. This poster emphasizes the importance of early awareness and adoption of healthy habits in the everyday reading room for encouraging long-term health and optimized function.
REFERENCES 1) Vertinsky T, Forster B. “Prevalence of Eye Strain Among Radiologists: Influence of Viewing Variables on Symptoms.” AJR 2005 Feb; 184(2): 681-686. 2) Kagadis GC et al. “Medical Imaging Displays and Their Use in Image Interpretation.” Radiographics 2013 Jan-Feb ; 33(1): 275-290. 3) Ruess L et al. “Carpal Tunnel Syndrome and Cubital Tunnel Syndrome: Workrelated Musculoskeletal Disorders in four Symptomatic Radiologists.” AJR 2003 July; 181(1): 37-42. 4) Makhsous et al. “Biomechanical Effects of Sitting with Adjustable Ischial and Lumbar Support on Occupational Low Back Pain: Evaluation of Sitting Load and Back Muscle Activity.” BMC Musculoskeletal Disorders 2009 Feb; 10(17). 5) Goyal N et at. “Ergonomics in Radiology.” Clinical Radiology 2009 Feb; 64(2): 119/126.
