Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jun;34(6):2165-2175.
doi: 10.1007/s00586-025-08750-y. Epub 2025 Mar 3.

Posterior fixation without debridement for pyogenic spondylodiscitis can promote infection control: initial evaluation of a pyogenic spondylodiscitis posterior fixation rat model

Hisanori Gamada  1 , Toru Funayama  2 , Yusuke Setojima  1 , Yosuke Ogata  1 , Takahiro Sunami  1 , Kotaro Sakashita  1 , Shun Okuwaki  1 , Kousei Miura  1 , Hiroshi Noguchi  1 , Hiroshi Takahashi  1 , Masashi Yamazaki  1 , Masao Koda  1
Affiliations

Posterior fixation without debridement for pyogenic spondylodiscitis can promote infection control: initial evaluation of a pyogenic spondylodiscitis posterior fixation rat model

Hisanori Gamada et al. Eur Spine J. 2025 Jun.

Abstract

Purpose: Pyogenic spondylodiscitis is a significant health concern, particularly in older individuals. Minimally invasive surgical techniques, such as posterior fixation, are promising for infection control; however, their mechanisms remain unclear. This study aimed to clarify how posterior fixation promotes infection control in an animal model.

Methods: Thirty female Wistar rats were used to create a pyogenic spondylodiscitis model by injecting methicillin-sensitive Staphylococcus aureus into the intervertebral space between the 6th and 7th coccygeal vertebrae. Three days post-injection, rats were divided into fixation and control groups. The fixation group underwent posterior fixation with an external fixator, whereas the control group underwent screw insertion alone. Bone destruction was assessed via microcomputed tomography on postoperative days (POD) 7, 14, and 21. Immunohistochemistry for cathepsin K and receptor activator of nuclear factor-kappa B ligand (RANKL) was performed on POD 7 samples to assess osteoclast activity.

Results: The fixation group showed less bone destruction than the control group at POD 14 (35% vs. 56%, p = 0.0007) and POD 21 (30% vs. 52%, p < 0.0001). The cathepsin K-positive area was significantly reduced in the fixation group (p = 0.027). RANKL expression was localized within the intervertebral disc in the fixation group, whereas RANKL was strongly expressed on the bone surface adjacent to the disc in control. The RANKL-positive area was also reduced in the fixation group (p = 0.041).

Conclusions: Our combined model of pyogenic spondylodiscitis and posterior fixation supports the theory that posterior fixation stability suppresses RANKL and osteoclast expression, promoting infection control.

Keywords: Animal experiment; Bone destruction; Infection; Posterior fixation; Pyogenic spondylodiscitis; Rat.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethical approval: The Institutional Animal Care and Use Committee of the University of Tsukuba (Protocol Code No. 22–098, approved on June 1, 2022) approved all procedures for this study. Competing interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Toru Funayama received research grant from TEIJIN Nakashima Medical (2022-A19, 2023-A11) (Paid directly to institution/employer).

References

    1. Thavarajasingam SG, Subbiah Ponniah H, Philipps R, Neuhoff J, Kramer A, Demetriades AK et al (2023) Increasing incidence of spondylodiscitis in England: an analysis of the national health service (NHS) hospital episode statistics from 2012 to 2021. Brain Spine 3:101733. https://doi.org/10.1016/j.bas.2023.101733 - DOI - PubMed - PMC
    1. Nickerson EK, Sinha R (2016) Vertebral osteomyelitis in adults: an update. Br Med Bull 117:121–138. https://doi.org/10.1093/bmb/ldw003 - DOI - PubMed
    1. Yoon SH, Chung SK, Kim KJ, Kim HJ, Jin YJ, Kim HB (2010) Pyogenic vertebral osteomyelitis: identification of microorganism and laboratory markers used to predict clinical outcome. Eur Spine J 19:575–582. https://doi.org/10.1007/s00586-009-1216-1 - DOI - PubMed
    1. Ito M, Abumi K, Kotani Y, Kadoya K, Minami A (2007) Clinical outcome of posterolateral endoscopic surgery for pyogenic spondylodiscitis: results of 15 patients with serious comorbid conditions. Spine 32:200–206. https://doi.org/10.1097/01.brs.0000251645.58076.96 - DOI - PubMed
    1. Tong YJ, Liu JH, Fan SW, Zhao FD (2019) One-stage debridement via oblique lateral interbody fusion corridor combined with posterior pedicle screw fixation in treating spontaneous lumbar infectious spondylodiscitis: a case series. Orthop Surg 11:1109–1119. https://doi.org/10.1111/os.12562 - DOI - PubMed - PMC

LinkOut - more resources