Hematological inflammatory indices (Table 2) are currently very popular and have diagnostic, prognostic, and predictive, roles in various diseases. Considering their promising roles, we hypothesized that hematological inflammatory indices may have a distinctive value between brucella spondylodiscitis and type 1 Modic Changes (MCs). If the hypothesis is valid, early diagnosis-differential diagnosis-treatment processes may become easier and more successful. Given that hematological inflammatory indices are faster, practical, simpler, inexpensive, and easily accessible indicators, they may be more appropriate tools in differentiation between brucella spondylodiscitis and type 1 MCs.

This is a retrospective comparative study focusing to distinguish between brucella spondylodiscitis and type 1 MCs considering hematological inflammatory indexes. Patients' data were obtained from Hospital Information Systems, between 2020 to 2024. A total of 35 patients with brucella spondylodiscitis and 37 type 1 MCs were enrolled in the study. Diagnoses of brucella spondylodiscitis and type 1 MCs were supported by microbiological, serological, and radiological diagnostic tools. Patients' hematological parameters were recorded, and hematological inflammatory indexes (NLR, MLR, PLR, NLPR, SII, SIRI, AISI) were derived from baseline CBC tests.

Based on the diagnostic tools and criteria1,2,14,21, cases diagnosed with lumbar brucella spondylodiscitis or lumbar type 1 MCs in the past 5 years and who had simultaneously lumbar MRI, Complete Blood Count (CBC) test, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) results, and aged 18-65 years were selected to yield a study population. On the other hand, cases with inadequate data, aged <18 or >64 years, other infectious spondylodiscitis types than brucella, other MCs types than type 1, and other non-infectious conditions such as rheumatic spondylodiscitis (ankylosing spondylitis or Andersson lesion) were excluded from the study. Also, previous or recurrent brucella spondylodiscitis, involved other spinal levels than the lumbar spine were exclusion causes.

The two groups were statistically assessed and compared for baseline features such as age, gender, symptom duration, CRP, ESR, CBC values, and indexes derived from the CBC.

Inclusion Criteria:

• Clinical diagnosis of lumbar brucella spondylodiscitis in the past 5 years
• Clinical diagnosis of or lumbar type 1 Modic Changes (MCs) in the past 5 years
• Having simultaneously lumbar Magnetic Resonance Imaging (MRI), Complete Blood Count (CBC) test, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) results
• Being between the ages of 18-65

Exclusion Criteria:

• Cases with inadequate data
• Being under 18 years of age and over 65 years of age
• Having other infectious spondylodiscitis types than brucella
• Having other MCs types than type 1
• Having other non-infectious conditions such as rheumatic spondylodiscitis (ankylosing spondylitis or Andersson lesion)
• Having previous or recurrent brucella spondylodiscitis, involved other spinal levels than the lumbar spine

A total of 35 (17 female and 18 male) patients with brucella spondylodiscitis and 37 (26 female and 11 male) type 1 Modic Changes (MCs) were enrolled in the study. Diagnoses of brucella spondylodiscitis and type 1 MCs were supported by microbiological, serological, and radiological diagnotic tools. Patients' hematological parameters were recorded, and hematological inflammatory indexes (NLR: neutrophil/lymphocyte; MLR: monocyte/lymphocyte; PLR: platelet/lymphocyte; NLPR: neutrophil/(lymphocyte*platelet); SII (neutrophil*platelet/lymphocyte): systemic inflammatory index; SIRI (neutrophil*monocyte/lymphocyte): systemic inflammatory response index; AISI (neutrophil*platelet*monocyte/lymphocyte): aggregate index of systemic inflammation. ) were derived from baseline CBC tests.