Sternal dehiscence is an infrequent but serious complication that is often a precursor to mediastinitis. Median sternotomy, which provides excellent access to the heart and surrounding structures, is the most commonly used incision for open cardiac surgery. Transverse sternotomy in association with bilateral thoracotomy (ie, clamshell incision) is used less often but may be needed to manage large tumors, chest trauma or to perform bilateral lung transplantation. Median sternotomy complications occur in 0.5 to 5 percent of patients with 0.2 to 3 percent of patients developing mediastinitis . For transverse sternotomy, the rate of wound complications appears to be similar [2,3]. The risk of sternal wound complications may be greater in adults undergoing open heart surgery due multiple medical comorbidities compared with other populations (eg, trauma, children).
The use of minimally invasive surgical methods (including robotic surgery), alternative surgical approaches and catheter-based techniques have reduced the incidence of sternal dehiscence and mediastinitis . However, mortality remains high (up to 35 percent) [5-12].
The diagnosis, management, and measure to prevent sternal wound complications will be reviewed here. The diagnosis and medical management of mediastinitis is discussed elsewhere. (See "Postoperative mediastinitis after cardiac surgery".)
RISK FACTORS FOR STERNAL WOUND COMPLICATIONS
The etiology of sternal wound complications is multifactorial [11-16]. Any factor that contributes to poor wound or bone healing (eg, osteopenia, malnutrition), or increases the risk for surgical site infection (eg, diabetes, immunosuppression) may be clinically important, especially if two or more factors are present . Although postoperative sternal wound infection is clearly associated with sternal dehiscence, whether the sternal wound infection has caused the sternal dehiscence or the sternal dehiscence has caused the sternal wound infection is usually not known. Thus, it is essential to follow measures that can help prevent surgical site infection . (See 'Prevention' below.)
Sternal wound healing is impaired if the edges of the sternum are not aligned properly, the sternum is ischemic, or the bone is abnormal. Technical factors that contribute to poor sternal union include the creation of an asymmetric sternotomy incision that is difficult to realign, residual separation of the sternal edges after closure, and bone ischemia due to excessive use of electrocautery or possibly internal thoracic artery harvesting (particularly if bilateral). Perioperative factors that increase the risk for sternal dehiscence include prolonged operative time, the need for chest compressions, postoperative bleeding, transfusion and reoperation . (See 'Sternal closure' below.)