The entirety of the chest is clipped and aseptically prepared for surgery. For an intercostal thoracotomy the patient lies on their side. The surgeon plans where to make the incision using preoperative imaging, and then counts the number of ribs to find the correct space. A long skin incision is made between two ribs, from the spine down to the sternum. The sheet of muscle overlying the ribs is incised, and then further muscles are cut to gain access to the chest cavity. The ribs are held apart using retractors, so as to allow good visualization. A chest drain is placed and then the ribs closed and bound together with strong suture material.
For a median thoracotomy the patient lies on their back. A skin incision is made and then an oscillating saw is used to cut through the cartilage of the sternum. Again, a chest drain is placed prior to closure, and the sternum held together with wire sutures.
The skin incision is closed and the patient woken.