Fig. 4

Gross pathology and histopathological assessment of the soft tissues in surgical sites. A Representative soft tissue of the lumbar spine appearance in surgical sites after post-surgical days 14 in each treatment group, after overlying skin was removed. B The gross tissue pathology scores based on the criteria of modified Rissing scale on post-surgical days 14 in each treatment group. n = 13. C Representative pathological H&E staining of the soft tissues in surgical sites on postoperative days 14 in each treatment group. D Mean soft tissue histological scores based on the criteria of modified Petty’s scale on postoperative days 14 in each treatment group. n = 5. CON: control (no antibiotics); SV: system vancomycin (88 mg/kg, intraperitoneal injection, half an hour pre-surgery); VP 0.5: intra-wound vancomycin powder, 44 mg/kg, once before the closure of incision intraoperatively; VP 1.0: intra-wound vancomycin powder, 88 mg/kg; VP 2.0: intra-wound vancomycin powder, 176 mg/kg. Data were compared by analysis of variance (ANOVA) test. **P < 0.01 (compared with CON group), ^#P < 0.05, ^##P < 0.01 (compared with SV group), ^ΔΔP < 0.01 (compared with VP0.5 group). ^□P < 0.05, ^□□P < 0.01 (compared with VP1.0 group)