[Chronic spondylodiscitis. Clinical aspects and imaging features]

The diagnosis of a chronic inflammatory process involving the vertebral body and disk is often very difficult because patient's history, subjective symptoms and physical findings are often unconclusive. Thus imaging techniques play a decisive role. Radiography, tomography, CT and MR have different capabilities and limitations and provide different findings in spondylodiscitis.

We observed 18 cases of spondylodiscitis in the last three years. The responsible microbe, a Staphylococcus aureus from extraosseous sites, was found in two cases at blood culture. Small cell inflammatory infiltration was confirmed with CT-guided biopsy in one case, while the other cases were diagnosed based on constant chronic back pain, feveret, moderate neutrophile leukocytosis or increased erythrosedimentation speed, plus changes in radiographic patterns following antibiotic therapy.

Plain radiography and tomography are the techniques of choice to detect or suspect the lesion, which is then studied with CT or MRI. Clear-cut irregularities and erosions on opposing vertebral bodies, reactive bone sclerosis and reduced disk space were typical signs in our series; nine patients presented irregular cavitations(s), like bone caries, surrounded by reactive sclerosis in the body near the frontal vertebral plate.

Together with the imaging patterns of all cases, we studied in detail three cases, relative to physical findings and diagnostic techniques. We also compared the changes in chronic spondylodiscitis with those in intraspongious herniation, intervertebral osteochondritis and severe degenerative arthritis. Bone erosions on the anterior cortical surface of the vertebral body were seen in 50% of our cases and may represent a specific sign of chronic spondylodiscitis if the finding is confirmed in further studies.