Chest Reconstruction, Sternal Dehiscence

n thoracic and trunk reconstruction, plastic surgery plays a major role in addressing wound healing problems, complex defects, and cancer reconstruction. The introduction of the midline sternotomy incision allowed access to mediastinal structures and greatly propelled the field of thoracic surgery. The ability to gain access to the mediastinal organs through this approach allows the safe and effective treatment of cardiothoracic disease today.

History of the Procedure

Early use of the midline sternotomy was fraught with high complication rates. Sternal wound infection occurred in as many as 5% of patients, leading to sternal wound dehiscence, with reported incidence of mediastinitis in 0.4-6.9% of patients. These complications often led to significant morbidity, with reported mortality rates of more than of 50%. Sternal dehiscence initially was treated conservatively with open drainage and debridement with packing. Graft exposure, desiccation of wound margins, osteomyelitis, and, ultimately, sudden death, were grave consequences. This led to closed management with catheter-antibiotic irrigation; however, the mortality rate remained approximately 20%.

The management of infected sternal wounds changed with the principles of wide debridement and muscle and musculocutaneous flap transposition. In 1976, Lee introduced the greater omentum flap. Jurkiewicz et al then demonstrated the effectiveness of pedicled muscle flaps for management of sternal dehiscence and infection. The use of vascularized regional tissue allowed for greater blood flow, obliteration of dead space, and faster healing time because of quicker resolution of infection. Today, the management of sternal dehiscence and infection involves wide debridement of devitalized infected soft tissue and bone, culture-specific antibiotics, and flap closure (eg, muscle, musculocutaneous, omentum) to achieve wound healing. Thus, the mortality rate from sternal wound dehiscence dropped to less than 10%.

Etiology

Factors associated with sternal wound dehiscence

Numerous studies were performed to identify causative factors of sternal wound dehiscence and subsequent infection. Factors identified include hypertension, smoking, diabetes, obesity, the use of an intra-aortic balloon pump, and the use of bilateral internal mammary arteries (IMAs). Females are at greater risk than males. Prolonged postoperative ventilatory support is also implicated.

Clinical

In one study, factors associated with mortality included septicemia, perioperative myocardial infarction, and an intra-aortic balloon pump. Strict aseptic technique; attention to hemostasis; and precise, motionless sternal approximation are advocated to prevent mediastinitis. In the clinical evaluation of suspected mediastinitis or sternal dehiscence, careful examination of the patient is warranted. Findings of erythema, fever, increased leukocyte count, and sternal instability are important. If clinical deterioration of the patient or further signs of breakdown are observed (ie, increased erythema, drainage, separation of incision), obtain wound cultures, administer appropriate antibiotics, and perform swift aggressive debridement followed by early flap coverage. This combination can reduce the incidence of mortality, decrease hospital stay, rapidly propel the patient's recovery from thoracic surgery, and avert the complications of mediastinitis.