Current aetiological research points to sustained exposure to tissue deformations as the primary cause of pressure ulcers, either superficial or deep. The chronic exposure to tissue deformations has multifactorial influence on tissue and cell viability, including damage to cell structures (e.g. plasma membrane and cytoskeleton) as well as obstruction of the vascular and lymphatics. Different model systems, including cell culture, animals, tissue engineering and medical imaging indicated together that the keys for prevention are: (1) Minimizing the exposure to sustained tissue deformations, which allow cells to be structurally and functionally viable, enables perfusion and facilitates clearance of metabolic byproducts. (2) Ensuring that the above said minimization of tissue deformations spans across the entire layered structure of tissues, from superficial to deep, which would protect against superficial, but also, importantly, against deep tissue injuries. There are different approaches in achieving minimal exposure to tissue deformations, which can be taken separately on in combination, for example: (a) Lowering the coefficient of friction at the body-support interface e.g. using special low-friction materials at this interface, which reduces the exposure to shear deformations at the surface of the body and internally. (b) Employing specific equipment or devices designed to alleviate tissue deformations such as multi-layered alternating-stiffness prophylactic dressings that cushion tissues and absorb external shear. (c) Maximizing the immersion and envelopment of the body by the supporting surface, again using special equipment or devices that mold or conform to the body contours, such as shape-memory positioners. Depending on the scenarios of intended use and target patient population, taking each of these technological directions or a combination of them should also involve testing of how the deformation absorption efficacy is affected by the environment of patients, e.g. whether a material that facilitates low interface friction maintains its function when the interface is moist or wet.
Amit Gefen, PhD, Faculty of Engineering, Tel Aviv University Israel, E-mail: email@example.com