Gravity Is Our Best Friend Yet Can Also Be Our Worst Enemy: Tissue Deformations and Pressure Ulcer Risk on the Operating Table

At least 1 in 10 patients develop intraoperative pressure ulcers (PUs). The specific rigid (bio)mechanical constraints that apply in the operation room (OR) and which are unique to this clinical environment, including the inability to periodically reposition patients during surgery and the need to use a ‘stable’ support surface with relatively stiff padding materials lead to soft tissue exposure to extreme conditions of sustained tissue deformations and stress concentrations due to bodyweight forces. Accordingly, the risk of intraoperative PUs, which are triggered and driven by a sustained cell and tissue deformation/stress exposure, is especially high on the operating table (OT). Importantly, the basic OT and OT pad designs are simple and have changed very little over at least a century. The available OT pads, in particular, did not evolve despite the well-known and documented risk for PUs among surgical patients. This article reviews the relevant biomechanical studies published by the author and his research group with respect to the extents of tissue deformations expected on the OT at the body regions which are most susceptible to intraoperative PUs, namely the sacral region and the posterior aspects of the heels. These are the body sites which transfer considerable bodyweight forces in a supine position and contain relatively ‘sharp’ bony prominences compressing relatively thin soft tissue structures, as evident by the magnetic resonance imaging (MRI) studies conducted by the author and his team, as reviewed here. The results reported in this article further highlight the roles of OT pad and positioner materials in reducing localized tissue deformations and thereby, in lowering the risk of intraoperative PUs.