Mar 13 2007
Decubitus, the much-feared bedsores that occur in extended rehabilitation, is a significant challenge for hospitals and rehab centres. At the European Congress of Radiology (ECR) 2007 in Vienna, radiologists from Frankfurt are now presenting special materials meant to prevent pressure ulcers from forming.
Medically speaking, decubitus is a problem that originates in connective tissue. If the pressure exerted on the body exceeds a certain level, the capillaries are pinched off and the tissue receives no nourishment. At the same time, the lymph flow, the body’s method of waste disposal, is blocked. Left untreated, decubitus can cause tissue to die completely and even cause the disintegration of underlying bones.
“If we want to develop materials that stop the formation of pressure ulcers or at least delay them as much as possible, we face a big problem. Our body does not consist of a single homogeneous layer, but rather of many different ones,” Professor Dr. Thomas J. Vogl explained. Dr. Vogl holds the chair for Radiological Diagnostics and Intervention at the University of Frankfurt and is the co-founder of the Center for Biomedical Engineering. “Connective tissue, the muscle system and bones all lie one above the other and respond to exerted pressure in completely different ways. They also vary in thickness at the different zones at risk of ulcer formation. As a result, it is extremely difficult to predict what effect a certain load might have on connective tissue.”
High resolution magnetic resonance images indicate how tissue layers respond to pressure
Professor Vogl was able to present the solution to this problem at the European Congress of Radiology (ECR 2007), an event held in Vienna (at Austria Center Vienna) from March 9 to 13, 2007, and attended by some 16,000 participants from 92 countries. The success of his approach is based on an ingenious combination of ultra-modern high-tech methods. Using a device specially built for the purpose, the tissue in the heels and buttocks of test subjects was exposed to precisely defined levels of indentation pressure. High-resolution magnetic resonance images were assembled with suitable software to create a 3-D model of the region, which showed how the various tissue layers reacted to this pressure.
The results were fed into a Finite Element Model (FEM). This computation method is also used in crash tests in the car industry and allows you to calculate the behaviour of materials consisting of several layers with different mechanical properties. “This calculation showed us how a certain layer of tissue responded to a certain level of pressure, especially over time,” Professor Vogl explained.
High-tech supports as a preventive measure
This data now had to be applied to the properties of the widest variety of supports used underneath bedridden patients. The astounding findings: “The results were virtually all the same for materials that display the same deformation on all sides, i.e. elastic materials,” Professor Vogl noted. “However, substantially better results were achieved with viscoelastic materials, i.e. materials that can expand to varying degrees in different directions.”
The results of these efforts are high-tech supports that help to prevent pressure ulcers for a substantially longer period of time than conventional mattresses, and research projects are already aiming at the next objectives. Professor Vogl revealed, “The University of Frankfurt and the Center for Biomedical Engineering are already applying our findings to office chairs, car seats and other items that exert major pressure on our bodies. We also want to find out whether the level of objectively measurable pressure exerted corresponds to the pain people feel when subjected to strains of this kind. That would be plausible, but has not yet been researched.”