Wide variability of the definitions used for native vertebral osteomyelitis: walking the path for a unified diagnostic framework with a meta-epidemiological approach

Background context: Native Vertebral Osteomyelitis (NVO) has seen a rise in incidence, yet clinical outcomes remain poor with high relapse rates and significant long-term sequelae. The 2015 IDSA Clinical Practice Guidelines initiated a surge in scholarly activity on NVO, revealing a patchwork of definitions and numerous synonyms used interchangeably for this syndrome.

Purpose: To systematically summarize these definitions, evaluate their content, distribution over time, and thematic clustering.

Study design/setting: Meta-epidemiological study with a systematic review of definitions.

Patients sample: An extensive search of multiple databases was conducted, targeting trials and cohort studies dating from 2005 to present, providing a definition for NVO and its synonyms.

Outcome measures: Analysis of the diagnostic criteria that composed the definitions and the breaking up of the definitions in the possible combinations of diagnostic criteria.

Methods: We pursued a thematic synthesis of the published definitions with Boolean logic, yielding single or multiple definitions per included study. Using 8 predefined diagnostic criteria, we standardized definitions, focusing on the minimum necessary combinations used. Definition components were visualized using Sankey diagrams.

Results: The literature search identified 8,460 references, leading to 171 studies reporting on 21,963 patients. Of these, 91.2% were retrospective, 7.6% prospective, and 1.2% RCTs. Most definitions originated from authors, with 29.2% referencing sources. We identified 92 unique combinations of diagnostic criteria across the literature. Thirteen main patterns emerged, with the most common being clinical features with imaging, followed by clinical features combined with imaging and microbiology, and lastly, imaging paired with microbiology.

Conclusions: Our findings underscore the need for a collaborative effort to develop standardized diagnostic criteria. We advocate for a future Delphi consensus among experts to establish a unified diagnostic framework for NVO, emphasizing the core components of clinical features and MRI while incorporating microbiological and histopathological insights to improve both patient outcomes and research advancements.