Modelling an adult human head on a donut-shaped gel head support for pressure ulcer prevention.

Patients who are stationary endure prolonged pressures and shear loads at contact areas between their body and the support surface, which over time may cause pressure ulcers (PUs). Donut-shaped gel head supports are commonly used to protect the occiput, which is among the most common anatomical sites for PUs; however, the biomechanical efficacy of these devices is unclear. To investigate their effects on scalp tissues, we have used our three-dimensional anatomically realistic finite element model of an adult head, to which we have added a donut-shaped gel head support. We then compared the occipital scalp tissue loads' occurrence while the donut-shaped gel head support is in use with those associated with a fluidised head positioner and a standard medical foam. The donut-shaped gel head support inflicted the greatest exposure to tissue mechanical stresses, particularly to the high (and therefore dangerous) stress domain, when compared to the other positioners. We concluded that while the donut-shaped gel head support is designed to avert tissue loads away from the occiput and disperse them to the surroundings, in practice, it fails to do so. In fact, the donut-shaped gel head support imposes the head-weight forces to transfer through a relatively narrow ring of scalp tissues, hence increasing the risk of developing occipital PUs. KEY MESSAGES: a donut-shaped gel head support is meant to reduce the occurrence of pressure ulcers in scalp tissues to investigate the effects of donut-shaped gel head support on scalp tissues, we have used our anatomically realistic computational model of an adult head the donut-shaped gel head support imposes the head-weight forces to transfer through a relatively narrow ring of scalp tissues the highly distorted and deformed tissues at that ring are at a high risk for injury.