No abstract

Review of literature, level of evidence IV.

IV.

Objectives: The aim was to determine the characteristics of patients who developed Cutibacterium acnes spinal implant-associated infection (SIAI) and the associated risk factors. Methods: We conducted two parallel caseecontrol studies comparing 59 patients with SIAI caused by C. acnes (cases 1) and 93 patients with SIAI caused by other microorganisms (cases 2) diagnosed during 2010e2015 with 302 controls who underwent spinal instrumentation without subsequent infection. Results: Late-onset infections (median time to diagnosis, 843 days versus 23 days; p < 0.001) were more common in cases 1 than in cases 2. However, 20/59 (34%) of cases 1 occurred within the first 3 months after the index surgery. In addition, cases 1 were less likely to have fever (27%, 16/59 versus 58%, 54/93; p 0.001) or wound inflammation (39%, 23/59 versus 72%, 67/93; p < 0.001). Moreover, 24/59 (40%) of cases 1 presented with polymicrobial infections, and staphylococcal pathogens accounted for 22/24 (92%) of the co-infections. By comparing and contrasting the two multivariate risk models (cases 1 versus controls and cases 2 versus controls), the following factors associated with C. acnes SIAI development were identified: age <54 years (adjusted odds ratio (aOR) 2.43, 95% confidence interval (CI) 1.09e5.58, p 0.03), a body mass index <22 kg/m 2 (aOR 2.47, 95% CI 1.17e5.29, p 0.02), and thoracic instrumentation (aOR 16.1, 95% CI 7.57e37.0, p < 0.001). Conclusions: Future therapeutic and prophylactic studies on C. acnes SIAI should focus on young, thin patients who undergo spinal instrumentation procedures involving the thoracic spine.

Cohort observational study level III.