Relationship between spinal structural damage on radiography and bone fragility on CT in ankylosing spondylitis patients

Marine Fauny (1, 2) , Frank Verhoeven (3) , Edem Allado (1, 4) , Eliane Albuisson (5, 6, 7) , Astrid Pinzano (8, 1) , Caroline Morizot (1) , Isabelle Chary-Valckenaere (1, 8) , Damien Loeuille (1, 8)

1 Service de Rhumatologie [CHRU Nancy]
2 Saint Charles Hospital, 54200 Toul, France
3 Service de Rhumatologie
4 DevAH - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité
5 InSciDens [Nancy]
6 IECL - Institut Élie Cartan de Lorraine
7 DRCI - Délégation à la Recherche Clinique et à l'Innovation [CHRU Nancy]
8 IMoPA - Ingénierie Moléculaire et Physiopathologie Articulaire

Abstract To evaluate whether the risk of bone fragility on computed tomography (CT) (scanographic bone attenuation coefficient of the first lumbar vertebra (SBAC-L1)) is associated with the severity of spine structural involvement (mSASSS) in patients with ankylosing spondylitis (AS). This retrospective study included AS patients, followed from 2009 to 2017, who fulfilled the New York criteria and who underwent thoraco-abdomino-pelvic CT and radiography (spine, pelvis). The structural involvement was retained for mSASSS ≥ 2. The SBAC-L1 was measured in Hounsfield units (HU). A SBAC-L1 ≤ 145 HU was used to define patients at risk of vertebral fracture (VF). A total of 73 AS patients were included (mean age: 60.3 (± 10.7) years, 8 women (11%), mean disease duration: 24.6 years (± 13.9)). Sixty patients (82.2%) had a mSASSS ≥ 2 (mean score 20.7 (± 21.2)). The mean SBAC-L1 was 141.1 HU (± 45), 138.1 HU (± 44.8) and 154.8 HU (± 44.9) in the total, mSASSS ≥ 2 and mSASSS < 2 populations, respectively. Patients with bone bridges had lower SBAC-L1 than mSASSS ≥ 2 patients without ankylosis ( p = 0.02) and more often SBAC-L1 ≤ 145 HU (73% vs 41.9%, p = 0.006). A SBAC-L1 ≤ 145 HU was not associated with structural spine involvement, but patients with bone bridges had significantly decreased SBAC-L1 and an increased probability of being under the fracture threshold.

Domaines: Imagerie

Marine Fauny, Frank Verhoeven, Edem Allado, Eliane Albuisson, Astrid Pinzano, et al.. Relationship between spinal structural damage on radiography and bone fragility on CT in ankylosing spondylitis patients. Scientific Reports, 2021, 11, pp.9342. ⟨10.1038/s41598-021-88838-9⟩. ⟨hal-03401291⟩