**5. Comprehensive analyses of Brucellar spondylodiscitis in preclinical models**

Several techniques can be applied for the evaluation of Brucellar spondylodiscitis in animals. To observe the targeted vertebral body and intervertebral disc


#### **Table 2.**

*Magnetic resonance imaging* **(***MRI) classification of Brucellar spondylodiscitis adapted from [14].*

#### **Figure 3.**

*Histological descriptions of the paravertebral soft tissue of Brucellar spondylodiscitis model in rabbits [14]. Hematoxylin and eosin staining features predominant lymphocyte and monocytes infiltration with sparsely distributed epithelioid cells and multinucleated giant cells. Yellow arrows indicate multinucleated giant cells and red arrows specify epithelioid cells. Yellow arrowheads define lymphocytes and red arrowheads display monocytes (magnification: (left) × 40; (right) × 100).*

postoperatively, *in vivo* plain radiography, computed tomography, and magnetic resonance imaging (MRI) analyses should be performed under a general anesthesia. Specifically, the MRI findings were classified into five types, such as discitis type, spondylitis type, paraspinal/psoas abscess type, appendicitis type, and compound type, with a previously reported classification system (**Table 2**) [14]. Histological analysis for samples biopsied from the affected intervertebral disc, upper and lower end-plates, paravertebral soft tissue, psoas, and granulation tissue is highly recommended for identify the pathological pattern of the infection [60]. The pathological characteristics of Brucellar spondylodiscitis in rabbits are the massive inflammatory cell infiltration without evident bony erosions within the biopsied paravertebral structures, including lymphocytes, monocytes, and multinucleated giant cells (**Figure 3**) [61]. Blood test and bacteria culture can be done to further investigate the pathophysiological status of Brucellar spondylodiscitis.
