Letter to the Editor: Commentary on Pyogenic Andersson Lesion in Patient With Ankylosing Spondylitis (Korean J Neurotrauma 2022;18:139-143).

Dear Editor,

Thank you for the opportunity to review the paper titled “Pyogenic Andersson Lesions in Patients With Ankylosing Spondylitis.” An Andersson lesion (AL) is a localized vertebral body or discovertebral lesion of the spine in ankylosing spondylitis.2) Most studies refer to mechanical stress or inflammation when describing AL; there is still an ongoing debate on its exact etiology.1) Therefore, I would like to comment on this case. The association between AL and infection has been mentioned several times in previous studies; however, the histopathological findings of this lesion have been generally reported as chronic inflammation without any bacterial/tubercular infection.13) In this case, it would be more reasonable to state that as you already described in your article, acute pyogenic spondylitis was accompanied by AL, resulting in acute neurological symptoms. If the term “pyogenic AL” is to be used, it would be necessary to provide evidence and the mechanisms by which AL is caused by an infectious process.