Key Points

• Complications of midline sternotomy could be of noninfectious or infectious origin. Within those categories, the reunited sternum could be stable or unstable. Perioperative instability is termeddehiscence, whereas later separation is known as non-union.
• Instability begets infection and infection begets instability.
• Preexisting conditions such as obesity, diabetes, osteoporosis, and immunocompromised status require thorough preoperative planning to reduce the risk of dehiscence and poststernotomy mediastinitis.
• Preventive interventions such as normalization of glucose levels and hemoglobin concentration, surgical breast reduction, and screening for and prophylactic treatment of methicillin-resistantStaphylococcus aureus, especially in high-risk patients, are to be considered.
• Normal and exaggerated breathing movements of the thorax act against the cohesive force of different sternal closure techniques. Risk factors (modifiable and non-modifiable) relative to sternal instability, such as an impaired sternal blood supply after internal thoracic artery harvesting, asymmetrical sternotomy, and so on, may endanger the healing of the sternum.
• Sternomediastinitis is the most significant complication and is associated with high morbidity and mortality rates.
• Re-entry for bleeding, cardiopulmonary resuscitation, concomitant infections, prolonged mechanical ventilation, and early tracheostomy increases the risk of deep sternal wound infection. If necessary, percutaneous or minitracheostomy with meticulous isolation of the sternal area is recommended.
• Clinical observation with an active search for early signs of sternal infection and instability in conjunction with CT imaging and, if necessary, aggressive surgical treatment, are key elements for success.
• Open treatment of poststernotomy mediastinitis should be kept as brief as possible. Small signal hemorrhages often precede a major bleed, and if they occur, urgent reoperation should be considered.
• Parasternal weaving remains the gold standard technique for the repair and/or prevention of sternal dehiscence.
• Vacuum-assisted closure and muscle flaps are proven methods for the treatment of sternomediastinitis.

In the early years of cardiac surgery, areas of the heart were exposed through conventional anterolateral or posterolateral thoracotomies. As cardiac interventions became more complex, these incisions were often extended across the sternum into the contralateral pleural cavities (so-called clamshell incision). Midline axial sternotomy, first described by Milton in 1887, was popularized by Julian and colleagues in the mid-1950s[1] and offered a more extended exposure of the heart. Although changes in cardiac surgery, such as the off-pump and other types of minimally invasive methods, including port access and robotic surgery, revived some of the old incisions and introduced new ones (Figure 1), midline axial sternotomy still remains a popular technique due to its ultimate exposure, quick and easy performance, minimal blood loss, and little if any functional impairment. Despite its unsurpassed advantages, however, this approach also carries a potential for complications, which may result in significant morbidity and mortality as well as increased costs of treatment.[2]

Figure 1 

Sternotomy incisions used to expose the heart. A, Midline axial sternotomy. B, Lazy S midline sternotomy. C, Modified trap-door incision. D, Clamshell incision. E, Anterior thoracotomy with transverse sternotomy. F, T-shaped lower sternotomy. G, Manubriotomy with transverse sternotomy. H, Transxiphoid exposure.

In this chapter, the complications of sternotomy are discussed in two principal categories: noninfectious and infectious. Within each of these categories, the discussion is subdivided according to whether the sternum is stable or unstable.