Spondylodiscitis following endovascular abdominal aortic aneurysm repair: imaging perspectives from a single centre's experience.

OBJECTIVE: Very few reports have previously described spondylodiscitis as a potential complication of endovascular aortic aneurysm repair (EVAR). We present to our knowledge the first case series of spondylodiscitis following EVAR based on our institution's experience over an 11-year period. Particular attention is paid to the key imaging features and challenges encountered when performing spinal imaging in this complex patient group. MATERIALS AND METHODS: Of 1,847 patients who underwent EVAR at our institution between January 2006 and January 2017, a total of 9 patients were identified with imaging features of spondylodiscitis (0.5%). All cross-sectional studies before and after EVAR were assessed by a Consultant Musculoskeletal Radiologist and a Musculoskeletal Radiology Fellow to evaluate for features of spondylodiscitis. RESULTS: All 9 patients had single-level spondylodiscitis involving lumbosacral levels adjacent to the aortic/iliac stent graft. Eight out of nine patients had an extensive anterior paravertebral phlegmon/abscess that was contiguous with the infected stent graft and native aneurysm sac ± anterior vertebral body erosion. Epidural disease was present in only 3 out of 9 patients and was a minor feature. MRI was non-diagnostic in 3 out of 9 patients owing to susceptibility artefact. 18F-FDG PET/CT accurately depicted the spinal level involved and adjacent paravertebral disease in patients with non-diagnostic MRI and was adopted as the follow-up modality in 3 out of 5 surviving patients. CONCLUSION: Spondylodiscitis is a rare complication post-EVAR. Imaging features of disproportionate anterior paravertebral disease and anterior vertebral body bony involvement suggest direct spread of infection posteriorly to the adjacent vertebral column. Use of MRI versus 18F-FDG PET/CT as the optimal imaging modality should be directed by the type of stent graft deployed

Development of a standardized histopathology scoring system for intervertebral disc degeneration in rat models: An initiative of the ORS spine section

International audienceBackground:Rats are a widely accepted preclinical model for evaluating inter-vertebral disc (IVD) degeneration and regeneration. IVD morphology is commonlyassessed using histology, which forms the foundation for quantifying the state of IVDdegeneration. IVD degeneration severity is evaluated using different grading systemsthat focus on distinct degenerative features. A standard grading system would facili-tate more accurate comparison across laboratories and more robust comparisons ofdifferent models and interventions.Aims:This study aimed to develop a histology grading system to quantify IVD degen-eration for different rat models. Materials & Methods:This study involved a literature review, a survey of experts inthe field, and a validation study using 25 slides that were scored by 15 graders fromdifferent international institutes to determine inter- and intra-rater reliability.Results:A new IVD degeneration grading system was established and it consists ofeight significant degenerative features, including nucleus pulposus (NP) shape, NParea, NP cell number, NP cell morphology, annulus fibrosus (AF) lamellar organization,AF tears/fissures/disruptions, NP-AF border appearance, as well as endplate disrup-tions/microfractures and osteophyte/ossification. The validation study indicated thissystem was easily adopted, and able to discern different severities of degenerativechanges from different rat IVD degeneration models with high reproducibility forboth experienced and inexperienced graders. In addition, a widely-accepted protocolfor histological preparation of rat IVD samples based on the survey findings includeparaffin embedding, sagittal orientation, section thickness < 10μm, and staining usingH&E and/or SO/FG to facilitate comparison across laboratories.Conclusion:The proposed histological preparation protocol and grading system pro-vide a platform for more precise comparisons and more robust evaluation of rat IVDdegeneration models and interventions across laboratories