Axial skeletal lesions and disease duration in SAPHO syndrome: A retrospective review of computed tomography findings in 81 patients.

Aims: To explore the relevance of disease duration with axial skeletal lesions in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome based on computed tomography (CT).

Methods: Patients who had undergone whole-spine CT were included from a previously reported single-center cohort of SAPHO syndrome. Patients with previous treatments of bisphosphates, biological agents or surgeries were excluded. Sites of axial skeletal involvement were reviewed including the spine, sacroiliac joints, and anterior chest wall. Duration of osteoarticular involvement was defined as the interval between the onset of osteoarticular symptoms and the CT evaluation.

Results: Eighty-one patients (54 female and 27 male) were included in the study. The mean disease duration was 26.9 ± 34.9 months. Fifty (63.0%) patients showed spinal lesions on CT. The average numbers of involved vertebral segments for corner and endplate lesions were 3.16 ± 3.51 and 0.73 ± 1.85 respectively. Sixty-eight (84.0%) patients exhibited abnormalities in the anterior chest wall. The number of involved vertebral segments showed poor correlation with disease duration for both corner lesions (r  = 0.051, P = 0.043) and endplate lesions (r  = 0.137, P = 0.001). Patients with costoclavicular involvement showed remarkably longer disease duration than those without (49.3 ± 47.7 months vs 18.0 ± 23.5 months, P = 0.006), while no significant difference was detected regarding other structures in the anterior chest wall.

Conclusion: Costoclavicular involvement is a hallmark of long disease duration in SAPHO syndrome. Corner and endplate lesions in the vertebrae and sacroiliac involvement may not relate to disease course.