Pyogenic spondylodiscitis : The quest towards a clinical-radiological classification.

BACKGROUND: Pyogenic spondylodiscitis (PS) is a debilitating condition laden with orthopedic and neurological complications. The choice of the best step in management is often delayed due to the controversy encompassing its multiple facets. Several classification systems were proposed in the literature to define optimal management; however, consensus was not achieved.
OBJECTIVE: The aim of this study was to review the literature and critically appraise the classification systems of PS and the rationale behind the classification criteria.
METHODS: A literature search was conducted in PubMed. Titles and abstracts of articles were searched using different synonyms of spondylodiscitis and its classification. No restrictions regarding language of publication or date of publication were applied.
RESULTS: A total of 43 papers with 5 encompassing 3 main classifications were found in the literature. These classifications were overlapping but different. They encompassed neurologic deficits, abscess formation and segmental instability, laboratory parameters and morphological changes in magnetic resonance imaging (MRI) as the most important factors used to classify PS, assess the severity and guide treatment.
CONCLUSION: The current classification schemes overlap and encompass the most clinically relevant factors; however, some could be too complex for interdisciplinary clinical practice and do not adequately address unique entities, such as PS of the cervical spine, anterolisthesis and retrolisthesis. Most importantly, some criteria must be utilized in concert with recently published guidelines and should be re-assessed for validity and reliability. A uniform orthopedic parlance is required to optimize the management of this debilitating and life-threatening condition.