Ergonomic analysis of microlaryngoscopy

Authors

  • Melissa McCarty Statham MD,

    1. University of Pittsburgh Voice Center, Department of Otolaryngology, Pittsburgh, Pennsylvania, U.S.A.
    2. Department of Industrial Hygiene (M.S.R.), University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.
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  • Alison L. Sukits BS,

    1. Department of Bioengineering, Pittsburgh, Pennsylvania, U.S.A.
    2. Department of Industrial Hygiene (M.S.R.), University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.
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  • Mark S. Redfern PhD,

    1. University of Pittsburgh Voice Center, Department of Otolaryngology, Pittsburgh, Pennsylvania, U.S.A.
    2. Department of Bioengineering, Pittsburgh, Pennsylvania, U.S.A.
    3. Department of Industrial Hygiene (M.S.R.), University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.
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  • Libby J. Smith DO,

    1. University of Pittsburgh Voice Center, Department of Otolaryngology, Pittsburgh, Pennsylvania, U.S.A.
    2. Department of Industrial Hygiene (M.S.R.), University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.
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  • John C. Sok MD, PhD,

    1. University of Pittsburgh Voice Center, Department of Otolaryngology, Pittsburgh, Pennsylvania, U.S.A.
    2. Department of Industrial Hygiene (M.S.R.), University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.
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  • Clark A. Rosen MD, FACS

    Corresponding author
    1. University of Pittsburgh Voice Center, Department of Otolaryngology, Pittsburgh, Pennsylvania, U.S.A.
    2. Department of Industrial Hygiene (M.S.R.), University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.
    • 1400 Locust Street, Building B, Suite 11500, Pittsburgh, PA 15219
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Abstract

Objectives/Hypothesis:

To apply ergonomic principles in analysis of three different operative positions used in laryngeal microsurgery.

Study Design:

Prospective case-control study.

Methods:

Laryngologists were studied in three different microlaryngeal operative positions: a supported position in a chair with articulated arm supports, a supported position with arms resting on a Mayo stand, and a position with arms unsupported. Operative positions were uniformly photographed in three dimensions. Full body postural data was collected and analyzed using the validated Rapid Upper Limb Assessment (RULA) tool to calculate a risk score indicative of potential musculoskeletal misuse in each position. Joint forces were calculated for the neck and shoulder, and compression forces were calculated for the L5/S1 disc space.

Results:

Higher-risk postures were obtained with unfavorably adjusted eyepieces and lack of any arm support during microlaryngeal surgery. Support with a Mayo stand led to more neck flexion and strain. Using a chair with articulated arm supports leads to decreased neck strain, less shoulder torque, and decreased compressive forces on the L5/S1 disc space. Ideal postures during microlaryngoscopy place the surgeon with arms and feet supported, with shoulders in an unraised, neutral anatomic position, upper arms neutrally positioned 20° to 45° from torso, lower arms neutrally positioned 60° to 100° from torso, and wrists extended or flexed <15°.

Conclusions:

RULA and biomechanical analyses have identified lower-risk surgeon positioning to be utilized during microlaryngeal surgery. Avoiding the identified high-risk operative postures and repetitive stress injury may lead to reduced occupationally related musculoskeletal pain and may improve microsurgical motor control. Laryngoscope, 2010

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