Multimodality Therapy for Primary Sternal Osteomyelitis

Abstract

To the Editors: Primary sternal osteomyelitis (PSO) accounts for 0.3% of cases osteomyelitis.1 It is defined by the absence of a cause of infection, such as thoracic surgery, illicit drug use, blunt chest trauma, immunosuppression, or spread of infection from contiguous foci. The most common causative organism in the pediatric population is methicillin resistant Staphlycoccus aureus (MRSA) followed by Salmonella in patients with sickle cell disease.2 Uncomplicated cases of PSO have been managed with antibiotic therapy alone, reserving surgical debridement for complex cases ie, with abscess formation or sternal instability. Our center recently treated a 14-year-old male with complex primary sternal osteomyelitis associated with a chest wall abscess. Percutaneous sampling of the abscess fluid revealed MRSA. The patient was taken to the operating room where complete drainage of the abscess was ensured and all nonvital tissue was debrided including the anterior table of the upper left sternum, the left first and second costocartilages, and the medial margin of the pectoralis major muscle. After complete debridement, methylmetacrylate beads impregnated with vancomycin were placed in the surgical site before closure (Fig. 1). A “second look” operation was done 48 hours later. At that time, the methylmetacrylate beads were removed, and there was no evidence of infection. The wound was closed with pectoralis muscle flaps. The patient was maintained on parenteral antibiotics in the perioperative period and treated for a total of 6 weeks.FIGURE 1.: Methylmetacrylate beads impregnated with vancomycin placed in the surgical site after initial sternal debridement.Because PSO is less virulent than secondary osteomyelitis of the sternum, Lin et al3 recommend limited surgical debridement of the sternum preserving the posterior periosteum. Some authors have combined surgical debridement with postoperative antibiotic therapy for 6 weeks.4 Most cases of primary sternal osteomyelitis in the pediatric population have been managed with antibiotics alone. In fact, only 4 reported pediatric cases have been treated with surgical debridement.2 In 2005, Upadhyaya et al5 reported 4 cases of pediatric PSO. All patients in that series were treated with antibiotics alone; none of the patients presented with an abscess. Long-term outcome of isolated antibiotic therapy for PSO is unknown, particularly as it relates to development of indolent osteomyelitis. We believe the morbidity associated with indolent osteomyelitis and mediastinitis warrants an aggressive approach to the treatment of complex PSO. In our 14-year-old patient, the presence of an abscess was the deciding factor in proceeding with surgical debridement. We believe preservation of the posterior periosteum of the sternum, a “second look” procedure for possible further debridement, muscle flap closure of the surgical site, and antibiotic therapy for a total of 6 weeks should be the fundamental components of therapy in patients with complex PSO. In this case, we elected to use a novel delivery mechanism for local antibiotics, vancomycin impregnated methylmetacrylate beads placed in the surgical site. This delivery system provides the surgeon with a useful adjunct for locally treating a potentially morbid infection. Therefore, we recommend consideration of this multimodality therapy for treating complicated primary sternal osteomyelitis in children. Roosevelt Bryant III, MD David L.S. Morales, MD Department of Congenital Heart Surgery Texas Children's Hospital Houston, TX Baylor College of Medicine Houston, TX Kanchan Phalak, BA Baylor College of Medicine Houston, TX