Diagnostic, clinical management and outcome of bone flap-related osteomyelitis following cranioplasty

To describe diagnostic, management and outcome of bone flap-related osteomyelitis following cranioplasty.Patients followed-up in our tertiary care hospital for a bone flap-related osteomyelitis after cranioplasty were included in a retrospective cohort (2008-2021). Determinants of treatment failure were assessed using logistic regression and Kaplan-Meier curves analysis.The 144 included patients (81 [56.3%] males; median age 53.4 [IQR, 42.6-62.5] years) mostly presented wound abnormalities (n=115, 79.9%). All infections were documented, the main pathogens being S. aureus (n=64, 44.4%), C. acnes (n=57, 39.6%), Gram-negative bacilli (n=40, 27.8%) and/or non-aureus staphylococci (n=34, 23.6%). Surgery was performed in 140 (97.2%) cases, for bone flap removal (n=102, 72.9%) or debridement with flap retention (n=31, 22.1%), along with 12.7 (IQR, 8.0-14.0) weeks of antimicrobial therapy. After a follow-up of 117.1 (IQR, 62.5-235.5) weeks, 37 (26.1%) failures were observed: 16 (43.2%) infection persistence, 3 (8.1%) relapses, 22 (59.5%) superinfections and/or 2 (1.7%) infection-related deaths. Excluding superinfections, determinants of the 19 (13.4%) specific failures were an index craniectomy for brain tumor (OR=4.038, p=0.033) and curettage of bone edges (OR=0.342, p=0.048).Post-craniectomy bone flap osteomyelitis are difficult-to-treat infections, necessitating prolonged antimicrobial therapy with appropriate surgical debridement, advocating for multidisciplinary management in dedicated reference centers.