Medicosurgical management of deep wound infections after thoracolumbar instrumentation: risk factors of poor outcomes.

BACKGROUND: Surgical site infection (SSI) after thoracolumbar osteosynthesis is a common complication. Its management relies on surgical revision and antibiotic therapy, but treatment failure is not uncommon. The aim of our study was to assess the frequency of SSI management failure and its risk factors. METHODS: A retrospective study of patients hospitalized from 2011 to 2019 at the University Hospital of Caen was carried out. The infection rate and the time to onset of failure were assessed over a minimum follow-up of 1 year. Treatment failure was defined as the occurrence of a new intervention in the spine in the year following the end of antibiotic therapy, the establishment of long-term suppressive antibiotic therapy, or death from any cause within 1 year of the end of antibiotic therapy. We compared the treatment failure group with the treatment success group to determine risk factors for treatment failure. RESULTS: A total of 2881 patients underwent surgery during the study period, and 92 developed an SSI, corresponding to an SSI rate of 3.19%. Thirty-six percent of the patients with an SSI presented treatment failure. The median time to failure was 31 days. On multivariate analysis, diabetes mellitus was identified as a risk factor for treatment failure, whereas prolonged postoperative drainage for 4 to 5 days was a protective factor. CONCLUSIONS: The number of failures was significant, and failure occurred mainly during the early phase. To decrease the risk of treatment failure, prolonged duration of postoperative drainage seems to be helpful. Additionally, as diabetes is a risk factor for treatment failure, good control of glycemia in these patients might impact their outcomes.