Heart surgery. Image 2 of 9. Surgeon using a circular saw to open a patient's chest during heart surgery. An incision has been made through the skin using a scalpel and a cautery knife. The saw is used to cut through the breast bone. This chest is being opened to perform a repair on an aortic aneurysm near the heart. For a sequence showing the operation, see images M560/461 to M560/469.