The relationship between facial anatomical features and contact pressure for prone support pillow designs: A combined analytical and experimental approach.

Surgery performed in the prone position requires the patient's face to be supported by padded devices where several pressure-related complications associated with facial support can occur. The objectives: 1) Compare measurements of face pressure between three designs of pillows using a spinal surgery table. 2) Identify relationships between face shape and pillow contact pressure using experimental contact pressure measurements with an analytical model of face-pillow contact. 36 subjects assumed a prone position with their face supported by three pillow designs (GentleTouch® (GT), GentleTouch® 3D (GT3D), ProneView® (PV)). Each pillow was lined with pressure sensing films, enabling contact pressure measurements. Subjects underwent high-resolution face scans to quantify facial geometry. Analytical contact area and volume were predicted using overclosure calculations of the face and pillow geometries. The GT pillow resulted in more than 3 times greater total contact areas above the 2.0 kPa threshold compared to the GT3D pillow (mean difference = 271.4 mm2, p = 0.0036) and the PV pillow (mean difference = 386.7 mm2, p < 0.001). Using analytical predictions, strong positive correlations were observed between the superior-inferior length of the face metric and the contact area (0.61 to 0.95) for all three pillow designs that all reduced with variation in alignment. The curved GT3D is intended to provide greater contact areas at lower pressures, with little contact pressure detected in the cheek and lower eye regions, which was confirmed by these results. The analytical tool developed here, along with the population of facial scans, can be instrumental in designing future pillows.