Sternal resection is necessitated most commonly by primary or secondary malignancy, infection, or radiation osteonecrosis. Primary benign tumors of the sternum are rare. The resulting chest wall defect, which involves loss of skeleton and often overlying soft tissues, depends on tumor extent and type and severity of infection or radiation necrosis.
Sternal tumors are classified as primary tumors (i.e., benign or malignant), adjacent tumors with local invasion (e.g., lung, breast, or pleura), metastases (i.e., sarcomas, carcinomas, and lymphomas), and nonneoplastic lesions (e.g., inflammatory masses or cysts). More than half of all sternal tumors are malignant and more commonly represent a metastasis or direct invasion by adjacent tumor. The most common malignant primary is chondrosarcoma. The most common benign tumor is osteochondroma.1–4
Infections of the sternum occur most frequently after cardiac surgery. Irrespective of procedure, median sternotomy always carries a high risk of infection, particularly in patients with diabetes, obesity, emphysema, prolonged mechanical ventilation, compromised immune system, or bilateral internal thoracic (mammary) artery harvest. Sternal infection associated with wound infection occurs in 1–2% of patients undergoing median sternotomy for cardiac surgery. Primary osteomyelitis of the intact sternum is a far more rare condition but can be seen in cases of Ludwig's angina, sickle cell anemia, active tuberculosis, or fungal infection.5,6
Radiation can cause obliterative endarteritis and ischemic fibrosis, resulting in secondary tissue necrosis and ischemia. Poorly vascularized tissues such as bone and cartilage are especially susceptible to radiation injury. Sternal infection associated with mediastinitis is less common. Once affected by a radiation-induced ischemic process, the sternum then becomes susceptible to secondary infection. This necrosis and secondary infection, although dose-dependent, may occur years after radiotherapy, yet the incidence of radionecrosis is decreasing as improvements are made in the more precise (less toxic) delivery of radiotherapy2 (Table 116-1).
Table 116-1. Blood Supply of Autogenous Tissue Available for Sternal Reconstruction |Favorite Table|Download (.pdf)
Table 116-1. Blood Supply of Autogenous Tissue Available for Sternal Reconstruction
Primary: Thoracoacromial artery (enters laterally)
Secondary: Perforators from internal mammary artery (enter medially)
Superior epigastric artery (extension of internal mammary artery)
Inferior epigastric artery (cannot use a graft based on this artery for chest wall reconstruction)
Long thoracic artery
Serratus branch of thoracodorsal artery
Thoracic intercostal arteries
Dorsal scapular artery
Isolated clavicular resection is rare, but clavicular resection in association with sternal or chest wall resection may be required for tumors, infection, or radionecrosis. As is the case with sternal tumors, most clavicular tumors are malignant. The most common tumor of the clavicle is of metastatic origin. Primary bony tumors of the clavicle are rare. Most are likely to be plasmacytomas.6 In addition, clavicular resection is often used during ...