Infectious spondylodiscitis: Epidemiology, diagnosis, microbiological findings, clinical features and outcomes in a 14-year retrospective study.

Purpose: To describe the epidemiology, diagnosis, microbiological findings, clinical features, and outcomes of infectious spondylodiscitis (IS).

Methods: Retrospective analysis of 98 IS patients (2010-2023 - Trieste Hospital). Clinical, radiological, and microbiological data analysed, multivariate logistic regression assessed risk factors for poor outcomes.

Results: The incidence of IS was 3 cases per 100,000 inhabitants per year. Pyogenic infections accounted for 54% of cases, tuberculosis for 10%, while 35% remained of unknown etiology. Back pain (79%) and fever (72%) were the most common symptoms. Staphylococcus aureus was the most common pathogen, with 34 cases, representing 64% of pyogenic spondylodiscitis. Blood cultures were positive in 47% of pyogenic cases, 25% of all cases. PET/CT showed higher diagnostic utility (83%) than labeled leukocyte scintigraphy (54%). The lumbar spine was the most affected region (63%), followed by thoracic (25%) and cervical (12%). Neurosurgical biopsy showed a 33.3% positivity rate, while CT-guided biopsy yielded 22%. Cervical (OR 4.76) and thoracic (OR 3.89) involvement were associated with worse outcomes. Major complications included radicular nerve damage (51%), epidural/paravertebral abscesses (45%), endocarditis (14%), and a need for surgical intervention in 8%, with persistent neurological sequelae in 3%. Infection-related mortality rate was 6%.

Conclusion: S. aureus remains the leading pathogen in IS. Blood cultures play a key role, yielding positive in half of pyogenic cases. PET/CT surpassed leukocyte scintigraphy and improved MRI diagnostic accuracy. Lumbar involvement correlates with better outcomes, and open biopsy provides a higher diagnostic yield than percutaneous TC-guided biopsy. Empirical therapy is required in one-third of cases.