Deep tissue loads in the seated buttocks on an off ‐loading wheelchair cushion versus air‐cell‐based and foam cushions: finite element studies

Abstract For wheelchair users, a common injury is a sitting‐acquired pressure ulcer (PU) which typically onsets near the interface between the ischial tuberosity (IT) and the overlying soft tissues. The risk of developing PUs can be reduced considerably if an adequate cushion is placed on the wheelchair in order to protect tissues from PUs by minimising interface mechanical loads between the body and cushion and also, exposure to internal soft tissue loads. In this work, we studied the biomechanical performances of an off‐loading (OL) cushion with limited adjustability, in comparison to a standard foam cushion and a fully adjustable air‐cell‐based (ACB) cushion. These different cushion design approaches were methodologically and quantitatively analysed and compared here using a finite element (FE) modelling framework. We determined the internal mechanical deformations, strains and stresses in soft tissues of the seated buttocks during symmetric sitting, in a specific anatomy of a person with a spinal cord injury that was acquired during sitting in an open, magnetic resonance imaging configuration. Our results have shown that strains and stresses in muscle, fat and skin tissues are orders of magnitude lower for the ACB cushion with respect to the standard foam and OL cushions. The OL cushion design has taken the approach of protecting at‐risk sites of the buttocks by transferring local internal tissue loads away from the ITs and towards the greater trochanters, at th...
Source: International Wound Journal - Category: Surgery Authors: Tags: ORIGINAL ARTICLE Source Type: research