This study will measure the interface pressure between a patient and his or her support surface in the operating room for prolonged (>2 hour) operative cases. Eligible patients will receive an adhesive padded bandage (similar to Mepilex Gentle Border) that collects interface pressure data. When the patient is being positioned in the operating room, this bandage will be applied to the sacrum. At the completion of the case the bandage will be removed and the status of the skin will be recorded and a photo of the sacrum will be taken for documentation. Skin status will be reassessed at 24 hours, and at the 1 week, 1 month, and 4 month regularly scheduled follow-ups with the surgeon. Pressure ulcer development will then be correlated with interface pressure characteristics during the operative case, using demographic data to check homogeneity between the experimental and control groups. If at interim analysis there is a clear relationship between a pressure threshold and pressure ulcer development, the second portion of the study will not blind healthcare providers to the live data. They would be able to see the pressure measurement and reposition the patient to effectively offload.