Clinical outcome of postoperative surgical site infections in patients with posterior thoracolumbar and lumbar instrumentation

Objectives: Postoperative surgical site infection (SSI) is associated with high rates of disability, especially following instrumented spinal surgeries. The management of implant-associated SSI is challenging. This study analysed data from hospital databases to assess the incidence and characteristics related to postoperative SSI after posterior thoracolumbar and lumbar instrumentation.

Methods: Patient demographics, infection characteristics, details of treatment and perioperative factors were reviewed (January 2010-December 2020). Oswestry Disability Index (ODI), Patient Health Questionnaire-9 (PHQ-9) and Visual Analogue Scale (VAS) scores for back and leg pain were analysed preoperatively and postoperatively until final follow-up.

Results: Of the 27,881 procedures collected from the databases, 521 (1.8%) patients were diagnosed with SSI. Of these, 191 (36.7%) patients underwent at least one revision surgery for SSI. The infection rate was significantly higher in patients with lumbar spinal stenosis than in patients with scoliosis or kyphosis (P<0.01). The most commonly isolated pathogen was meticillin-susceptible Staphylococcus aureus (43.4%). The rate of complications secondary to antibiotic treatment was 7.8%, and long-term antibiotic suppression was reported in 15.2% of patients. Instrumentation was retained in 175 (91.6%) patients, and all SSIs were controlled without recurrence during follow-up.

Conclusion: Analysis of 27,881 patients showed an average SSI rate of 1.8%. Patients with deep wound SSI can be treated successfully in most cases with retention of instrumentation. Early diagnosis, positive revision surgery with strict irrigation, thorough debridement and a long-term course of antibiotics are critical to eradicate infection, retain implants, decrease morbidity and achieve wound healing.