The Mölnlycke Health Care blog

Pressure ulcer prevention: Pressure alone is not a sufficient measure of possible tissue damage

By : Professor Amit Gefen, November 11 2015Posted in: The Mölnlycke Health Care blog

Professor Amit Gefen, Ph.D., Department of Biomedical Engineering, Tel Aviv University, Israel

Pressure ulcers are a common but preventable hospital-acquired injury. In understanding how to prevent pressure ulcers, both clinical and scientific evidence should be used together to illustrate how and why pressure ulcers form, including understanding that direct pressure alone is not a sufficient predictor of the risk for tissue breakdown in deep tissues, where damage is not visible to the naked eye. By the time a pressure ulcer is visible, considerable damage has already been done. I have discussed biomechanical modelling and its contribution to looking at factors that promote the formation of pressure ulcers in a previous blog post and throughout my research. The scientific evidence has concluded that multilayer dressings used prophylactically can help prevent heel pressure ulcers. My up-to-date research has taken this conclusion further1.

3D model of a heel showing the different components; elastic support, Mepilex Border Heel, skin, fat, soft tissues in volume of interest, Achilles tendon, calcaneus bone

In measuring the biomechanical efficacy of dressings in preventing heel ulcers, we have not only confirmed the clinical evidence showing that multilayer dressings prevent pressure ulcers, but have also determined through finite element modelling, particularly looking at pressure and shear distributions in soft tissues, that the design and material composition of the dressing critically matters in reducing not only the total volume of exposure to mechanical strains in tissues, but also the intensity of the strain exposure.

Heat maps illustrating pressure and shear distribution in soft tissue without dressing and with Mepilex Border Heel. The heat maps indicate that Mepilex Border Heel reduces both total volume of strain and intensity of the strain.2

When examining the pressure and shear distributions, it was clear that not all types of pressure, and indeed, not all tissues, are the same and must be studied and treated uniquely. Our findings indicate that biomechanical efficacy is achieved with certain dressings because of unique design principles and features that address pressure and shear redistributions within the soft tissues, as well as a low friction coefficient at the outer surface of the dressing and skin-dressing interfaces that reduce the risk of skin damage and the frictional stress.

The mechanisms by which pressure ulcers form and tissue damage occurs under the surface of the body are complex. However, with current scientific knowledge and progress, these mechanisms can be studied quantitatively, and also, luckily, prevention is not as complicated.

Join me and my colleagues for Stop Pressure Ulcer Day, 19 November 2015, to learn more about scientifically proven pressure ulcer risk reduction. Register for the "Proof into practice" webinar at (external link, opens in a new window).



  1. Levy, A., Frank, M.B., Gefen, A. The biomechanical efficacy of dressings in preventing heel ulcers. Journal of Tissue Viability 2015.
  2. Reprinted from Journal of Tissue Viability, Volume 24, Issue 1, Ayelet Levy, Mor Ben-Or Frank, Amit Gefen, The biomechanical efficacy of dressings in preventing heel ulcers, Pages 1-11. Copyright 2015 with permission from Elsevier.
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The surgical and wound care environment is always changing. The Mölnlycke Health Care blog addresses topics and trends in surgery and wound care. Among these topics are efficiency, health economy, infection control and patient safety. Read more about this blog and how to comment.

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