RESUMO
OBJECTIVE: The purpose of this study was to assess the efficacy of diode laser combined with intradiscal vancomycin for iatrogenic discitis (ID) infected with Staphylococcus aureus. BACKGROUND DATA: In vivo and in vitro studies have reported that diode laser has a potential bactericidal effect on S. aureus. METHODS: The rabbit ID model was induced by injecting S. aureus into the intervertebral discs (IVDs). The animals were classified into the following groups: Group M, model; Group N, non-treatment; Group O, operation; Group V, vancomycin; Group L, laser; and Group C, laser with vancomycin. The rabbits were killed when paraplegia occurred and target IVD regions were removed for histopathological examination. RESULTS: In Group M, MRI findings revealed narrowing of the disc space, with changed T1 and T2 signals. In Group N, pathological examination showed a narrowed disc space, inflammatory changes in disc tissue, extensive erosion and hyperostosis of bony end plates, and an epidural abscess. Narrowed disc space and bone fusion were observed in Group O. In Group V, narrowed disc spaces, focal inflammatory changes of the disc tissue, and focal erosion and hyperostosis of bony end plates were seen. In Groups L and C, cavitation, inflammatory lesions, focal erosion, and hyperostosis of bony endplates were observed. However, in Group C, fibrosis was found in the nucleus region, with a smaller area of cavitation and better preservation of IVD structure than in Group L. The ID score was lowest in Group O, at 9.7 ± 0.95. The ID scores in Groups V and L were 12.2 ± 1.32 and 12.6 ± 0.97, respectively, significantly less than in Group N. The Group C ID score of 10.9 ± 0.99 was significantly less than that of Groups N, V, and L. CONCLUSIONS: High power diode laser combined with intradiscal vancomycin contained the pathological process of ID in this rabbit model.