CT EVALUATION OF POSTSTERNOTOMY COMPLICATIONS

Complication rates after sternotomy are between 0.5% and 5% [1]. Mortality is high: 27% for mediastinal infection and 50% for diffuse mediastinitis [2]. More recent series report a 10-20% mortality rate if the diagnosis is made early and sternal debridement and antibiotic lavage are performed [3]. Predisposing factors for complication include repeat surgery for hemorrhage or to redo a coronary artery bypass, external cardiac massage, mechanical ventilation, tracheostomy, and error in surgical technique (e.g., off-centered sternal incision or inadequate sternal fixation). Imaging choices include plain film radiography, tomography, CT, scintigraphy, and sinography. CT plays a major role in the assessment of complication, depicting the extent and depth of the abnormality. The scans must be studied for abnormalities in the presternal, sternal, and retrosternal compartments. CT scans that show no abnormalities are useful for reassurance: the presence of preserved mediastinal lat planes rules out infection requiring surgical intervention [4]. Detection of abnormalities on CT scans can be used to guide further evaluation, including the sampling of collections for culture, or may indicate the need for immediate surgery. Imaging and clinical findings should be compared closely.