Postoperative deep wound infection in posterior spinal fixation surgeries: Does it affect the clinicoradiological outcome? - At a minimum follow-up of 2 years

Abstract

Background: Incidence of postoperative deep wound infection (PODWI) after lumbar surgery varies from 2.1% to 6.7%.Studies looking into the effect of postoperative infection on functional recovery of the patient have thrown conflicting results. The aim of this study is to evaluate 2-year functional and radiological outcome of patients with PODWI. This was a retrospective, matched cohort study. Materials and Methods: A total of 23 patients developing acute PODWI (<3 months) after instrumented posterior spinal fusion (IPSF) from 2005 to 2013 were treated by debridement along with antibiotics for 6 weeks (3 weeks intravenous and 3 weeks oral). Their preoperative and postoperative (6 months and 2 years) functional scores in the form of Oswestry Disability Index (ODI) and visual analog scale (VAS) were queried from the electronic database. Fusion was assessed at 2 years using radiograph and computed tomography scan. A noninfected control group (CG) was identified matching indication, type and number of levels of fusion, ODI, and Charlson Age-matched Comorbidity Index. Unpaired t-test was used for statistical analysis. Results: Out of 23 patients, 21 underwent posterior spinal fusion, and two had additional anterior surgery. Mean lag time before the diagnosis of infection was 4.7 weeks. Most common pathogenic organism was Staphylococcus aureus. All patients except one had documented fusion at 2-year follow-up. Four patients developed discharging sinuses. Implant removal had to be done in three patients. The mean ODI difference at 6 months from baseline was higher in the CG (33) as compared to infected group (19) (P < 0.001). Difference at 2 years was comparable for the two groups (P = 0.4). No significant difference was found in the VAS scores between the two groups. Small sample size and retrospective nature are the potential limitations of this study. Conclusions: Patients with acute PODWI after IPSF treated appropriately have comparable long-term outcome to patient with noninfected surgery; however, initial short-term worsening in functional status was seen in infected patients. Fusion was a predictable outcome.

Keywords

• deep wound infection
• functional outcome
• instrumented posterior spinal fusion