Abstract: A method and device for producing an artificial retro-sternal tunnel or space at the conclusion of a sternotomy, for precluding cutting the heart when the sternum is severed during a subsequent or re-do sternotomy involving the same patient. During closure of the longitudinally severed sternum, an implantable elongate member having a length approximately the length of the sternum is disposed longitudinally along the severed sternum and opposing the sternum's posterior surface, and the disposed member is secured to the sternum during closure. In the event a subsequent sternotomy is required for the same patient, the surgeon positions a sternum cutting device at one end of the sternum overlying the implanted member, and longitudinally severs the sternum with the implanted member, which may include a hard elongated inner member, providing a pathway and/or shielding the patient's heart from being unintentionally cut by the cutting device.