Isolated septic facet joints: an underdiagnosed distinct clinical entity

Imaging of Spondylodiscitis: A Comprehensive Updated Review—Multimodality Imaging Findings, Differential Diagnosis, and Specific Microorganisms Detection

“…Virtually all studies have found well-defined paraspinal abnormal signal intensity with intraosseous, epidural, and paraspinal abscesses more frequently in TbS [49][50][51][52][53][54][55][56]. Thin and smooth enhancement of the abscess wall is one of the most reliable MRI findings of TbS (with possible calcifications), whereas ill-defined paraspinal abnormal signal and thick and irregular enhancement of the wall abscess are suggestive of PyS [50][51][52][53].…”

“…They can be infected either hematogenously, through direct inoculation, or via the diffusion of an epiduritis via the retrodural space [50]. The facet joint infections are mostly due to S. aureus and are likely to be underdiagnosed [51]. They can be single or multiple levels, uni-or bilateral, and associated with infectious spondylitis.…”

“…They can be single or multiple levels, uni-or bilateral, and associated with infectious spondylitis. The best imaging modality is CE MRI, which can demonstrate non-specific findings such as fluid in the joint capsule with a contrast enhancement of the synovial, bone marrow edema of the subchondral bone of the facet, bony erosions and edema, pyomyositis, and abscesses in the adjacent soft tissues [51].…”

“…The chronic course, the relative late phase of TbS and the very minimal inflammation of these types of abscesses (named 'cold abscesses') are probably associated with this typical appearance of the abscess wall. Thus, contrast-enhanced infusion is necessary to differentiate these two kinds of spondylodiscitis [51][52][53][54].…”

“…The relative preservation of the intervertebral disc is probably due to the lack of proteolytic enzymes of the Mycobacterium, while organisms involved in PyS (Staphylococcus aureus, Enterobacter, and Salmonella) can produce hyaluronidase, resulting in intervertebral disclysis [43,55]. In some studies, disk space narrowing was similar in both types of spondylitis, possibly because a longer interval existed from presentation to MRI in the cases of TbS considered [49][50][51][52][53][54][55][56][57][58][59][60][61].…”