It may sound unbelievable, but some tools that physicians use to perform invasive surgery were originally developed in the 1930s and have gone through minimal updating since. Most often, these tools have been efficient enough to do the job, even if patients took a long time to heal. This is especially true when a surgeon has to enter the chest cavity for heart or lung operations. To date, there are two primary methods used to open a space large enough for a doctor to work inside the chest: a thoracotomy or a sternotomy.