Sternal wound infection revisited

Abstract

Sternal wound infections (SWIs) can be subdivided into two types, superficial or deep, that require different treatments. The clinical diagnosis of superficial SWI is normally easy to perform, whereas the involvement of deep tissues is frequently difficult to detect. Therefore, there is a need for an imaging study that permits the assessment of SWIs and is able to distinguish between superficial and deep SWI. The present work was a prospective study aiming to evaluate the role of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leucocyte scan in SWI management. Twenty-eight patients with suspected SWIs were included in the study. On the basis of clinical examination they were subdivided into three groups: patients with signs of superficial SWI (group 1), patients with signs of superficial SWI and suspected deep infection (group 2) and patients with suspected deep SWI without superficial involvement (group 3). Ten patients previously submitted to median sternotomy, but without suspected SWI, were also included in the study as a control group (group 4). All patients with suspected SWI had bacteriological examinations of wound secretion, if present. In addition 99mTc-HMPAO labelled leucocyte scan was performed in all patients. The patients of groups 1, 2 and 3 were treated on the basis of the clinical signs and microbiological findings, independently of the scintigraphic results. The patients of group 4 did not receive treatment. The final assessment of infection was based on histological and microbiological findings or on long-term clinical follow-up. Sensitivity, specificity, accuracy and positive and negative predictive values for scintigraphic and non-scintigraphic results were calculated. In the diagnosis of superficial and deep SWI, clinical and microbiological examination (combined) yielded, respectively, a sensitivity of 68.7% and 100%, a specificity of 77.3% and 80.8%, an accuracy of 73.7% and 86.8%, a positive predictive value of 68.7% and 70.6% and a negative predictive value of 77.3% and 100%. The scintigraphic results obtained in superficial SWI yielded a sensitivity of 56.2%, a specificity of 90.9%, an accuracy of 76.3%, a positive predictive value of 81.8% and a negative predictive value of 74.1%, while, by contrast, in deep SWI all of these values were 100%. Therefore, one can conclude that 99mTc-HMPAO labelled leucocyte scan permits accurate diagnosis of deep SWI, solving the main clinical problem in this field. In the present study the categorisation of patients without taking into account 99mTc-HMPAO labelled leucocyte planar scan findings caused a non-negligible number of cases of superficial SWI to be treated as though they were deep SWI. This "overestimation" led to unnecessary surgery, increased and prolonged use of antibiotics with more (higher) toxicity and additional expense.

Operative results after xiphoidectomy in patients with xiphodynia

“…Scintigraphy can however be useful in the diagnosis of sternal fractures during the early period after thorax trauma (Erhan et al) or for diagnosis of deep sternal infections after sternotomy for cardiac illnesses (Liberatore et al). [16][17][18] We stress the importance of excluding any life-threatening diseases first, before diagnosing a patient with xiphodynia.…”

Prevention, Diagnosis and Management of Post-Surgical Mediastinitis in Adults Consensus Guidelines of the Spanish Society of Cardiovascular Infections (SEICAV), the Spanish Society of Thoracic and Cardiovascular Surgery (SECTCV) and the Biomedical Research Centre Network for Respiratory Diseases (CIBERES)

“…Nuclear medicine studies with Tc-99 m HMPAO-labelled leukocytes [ 133 , 135 , 136 , 137 , 138 , 139 , 140 ], Ga-67 [ 134 , 137 , 141 ], indium 111-WBC [ 128 , 138 , 139 ], combined Tc-99 MDP and In-111 WBC [ 132 , 142 , 143 ] (combined Tc-99 MDP and In-111 WBC [ 144 ], 99mtc-labeled monoclonal granulocyte antibody scintigraphy [ 145 ] and, more recently, 99m Tc-UBI 29-41 [ 146 ], have been used in the study of post-sternotomy infection and post-sternotomy osteomyelitis [ 126 , 127 , 131 , 133 , 144 ]. Rouzet et al [ 135 ] showed the usefulness of serial studies with planar scintigraphy in cases of suspected PSM relapse.…”

Imaging Appearances of the Sternum and Sternoclavicular Joints

“…CT may provide better depiction of features such as bone erosion, periosteal reaction, sharply demarcated areas of sclerosis, and soft-tissue swelling (Fig 13) (53,54). When the CT appearance is nonspecific, nuclear medicine studies with radiolabeled leukocytes may provide additional information (54,55).…”