Disco-vertebral destructive lesions (So-called Andersson Lesions) associated with ankylosing spondylitis

Transpedicular wedge resection osteotomy for the treatment of a kyphotic Andersson lesion-complicating ankylosing spondylitis

“…As a result of persistent motion at the fracture site, the healing process stops and the bone fails to unite, which leads to pseudarthrosis [12]. Spinal pseudarthrosiscomplicating AS is currently known as an Andersson lesion (AL) [4,5,7,11]. In addition, an AL may result in a localized progressive painful kyphotic deformity that leads to considerable disturbances of posture and sagittal balance.…”

Complications of the spine in ankylosing spondylitis with a focus on deformity correction

“…47 Andersson lesions are often mistaken for an infectious process, but cultures and histological studies reveal no causative organism. 15,29 Enthesitis, Synovitis, Syndesmophytes, and Enthesophytes Enthesitis, inflammation of the insertion points of ligaments and tendons that are ubiquitous in the spine, is considered the characteristic inflammatory lesion in AS. Andersson and Romanus lesions result from enthesitis.…”

“…3 Biopy specimens of Andersson and Romanus lesions have revealed a similar process. 15,47 Lesions that progress to ankylosis feature fibrous tissue, cartilage, and reactive bone formation. 7 More recent work by François et al 19 has shown that inflammation in the subchondral areas of the bone marrow precedes the findings of enthesitis described earlier.…”

“…15 These lesions are thought to occur in areas of the spine that are still capable of mobility when the rest of it is ankylosed. Thus, the spine becomes over-dependent on these sites for movement.…”

“…In contrast to the inflammatory lesions that ossify in AS, new bone does not form at these pseudarthrosis sites. 15 Histologically, fibrous tissue is abundant and reflects healing at the site of a microfracture.…”