99mTc MDP and 67Gallium Dual Isotope Imaging in the Evaluation of Sternal Osteomyelitis and Wound Dehiscence

Abstract

Sternal infections are a major cause of morbidity and mortality in patients undergoing cardiac surgery. They occur in 1% to 3% of patients who undergo open-heart surgery and carry a moderately high mortality rate. Sternal infections can range from minor, superficial infections to open mediastinitis with invasion of the sternum, heart, and great vessels. Infection can lead to partial or complete separation of bony sternum thus compounding the problem. Identifying osteomyelitis (OM) is a challenge to the surgeons especially in the postoperative setting. Although clinically presence of fever and leukocytosis along with sternal wound dehiscence suggests deep infection. Localization and ascertaining the extent of sternal infection is difficult. Treatment entails surgical debridement with closed irrigation, open-wound packing, or muscle or omental flap procedures, as well as antibiotic therapy. In sternal OM, delineation of sinus tracts into the various planes of anterior mediastinal tissues is essential to achieve proper surgical drainage and antibiotic cover. This is exclusively achieved by Gallium infection imaging and additional use of SPECTCT (Single photon emission computed tomography). Only when the postoperative site is devoid of residual infection, thoracic and trunk reconstruction can be performed to provide stability to sternal dehiscence.