The patient, with a past medical history of ischemic cardiomyopathy, presented a few months post heart transplant with a two week history of productive cough and complaints of increased sternal mobility. Radiographs showed fractures of his sternal cerclage wire, concerning for sternal dehiscence, which was confirmed with CT. CT also showed a fluid collection between the two halves of the sternum. He was taken to the OR and found to have complete dehiscence of the sternum with a large, simple appearing fluid collection. The sternal wound was debrided and fluid collection drained, followed by plate and screw fixation of the sternum. 

Learning Points:

• sternal nonunion can lead to dehiscence when there is increased intrathoracic pressure, such as coughing
• malalignment of sternal wires or fractures with displacement of wire fragments are specific for sternotomy dehiscence
• associated retrosternal complications include mediastinitis, pericardial effusions, hematomas, loculated effusions, and empyemas ¹
• within the two weeks postoperative period, many of the image findings suggestive of mediastinitis overlap with normal postoperative edema and air. After two weeks, these findings are more indicative of mediastinitis ².

Additional Contributors: Dr. Leanne Lin (https://radiopaedia.org/users/yuanci89?lang=us)