The effect of a liner on the dispersion of backboard interface sacral skin pressures

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Principal Investigator Name
Gregory Nemunaitis, M.D.
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Healthy Volunteers
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Objective: To determine the effects of standard spinal immobilization on healthy volunteers with respect to interface pressures and pain scores on a backboard with and without a gel pressure dispersion liner (PDL). Design: Prospective Study Participants/Methods: Forty volunteers between the ages of 18 and 60 who had no acute pain or illness, were not pregnant, and had no history of back problems were evaluated. An FSA pressure mapping system (Vista Medical, Canada) was used to monitor sacral interface pressures in volunteers lying on a standard backboard and on a PDL placed over the backboard. Measurements were carried out on both surfaces for all volunteers, on different days. Volunteers wore street clothes and were secured to the backboard with soft head-blocks and straps. Pressures were recorded every minute over a 40 minute period. Volunteers were asked to identify the location(s) of any pain and to indicate the corresponding severity using the numeric rating scale (NRS) at the beginning and end of the assessment. Results: The highest pressure generation was found at the sacral prominence of each subject with little variation over the assessment period. Peak interface pressures were higher on the backboard alone than with the PDL (mean 260mmHg vs. 188mmHg). Paired Student T-test showed this difference w\as highly significant (p<0.001). The subjects systematically described more pain on the backboard alone than with the PDL (mean NRS 4.9 vs. 2.4) (p<0.001). Pain scores increased over the assessment period both with and without the PDL.