High prevalence of thoracic vertebral deformities and discal wedging in ankylosing spondylitis patients with hyperkyphosis

• Published in: Journal of rheumatology 2001-08, Vol.28 (8), p.1856-1861
• Main Authors: GEUSENS, Piet, VOSSE, Debby, VAN DER HEIJDE, Desiree, VANHOOF, Johan, VAN TUBERGEN, Astrid, RAUS, Jef, VAN DER LINDEN, Sjef
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Diseases of the osteoarticular system; Female; Humans; Hyperostosis, Diffuse Idiopathic Skeletal - epidemiology; Hyperostosis, Diffuse Idiopathic Skeletal - pathology; Inflammatory joint diseases; Intervertebral Disc - pathology; Kyphosis - epidemiology; Kyphosis - pathology; Lumbar Vertebrae - pathology; Male; Medical sciences; Middle Aged; Osteoporosis - epidemiology; Osteoporosis - pathology; Prevalence; Regression Analysis; Thoracic Vertebrae - pathology
• ISSN: 0315-162X; 1499-2752

OBJECTIVE: To study the prevalence of deformities of vertebrae and intervertebral discs in patients with ankylosing spondylitis (AS) in relation to fixed hyperkyphosis of the spine. METHODS: Altogether 50 patients (15 women, 35 men) with AS were studied. Hyperkyphosis was measured by the occiput to wall distance (OWD). Anterior (Ha), mid- (Hm), and posterior height (Hp) of the vertebrae and intervertebral discs were measured on lateral radiographs of the thoracic (Th5-Th12) and lumbar spine (L1-L5). Vertebral shapes were analyzed according to McCloskey, et al. Wedging of discs was calculated as Ha/Hp. Hyperkyphosis was defined as OWD > 1 cm. RESULTS: In the thoracic spine, the prevalence of vertebral deformities was higher in patients with hyperkyphosis (n = 38) compared to patients without hyperkyphosis (n = 12) (45% vs 8%; p = 0.01). The prevalence of thoracic vertebral deformities in patients with hyperkyphosis differed little between men and women (39% vs 58%; p > 0.10) and among patients above and below the age of 45 years (50% vs 33%; p > 0.10). Patients with one or more deformed thoracic vertebrae had a higher mean OWD than patients without deformed vertebrae (12 +/- 7 vs 7 +/- 6 cm; p < 0.01). The total sum of deformities of the thoracic vertebrae and discs explained 43% of the variance of the age adjusted OWD (p < 0.001). Deformities of lumbar vertebrae and discs did not contribute to hyperkyphosis. CONCLUSION: In patients with AS and hyperkyphosis, deformities of the thoracic vertebrae occur frequently and, together with wedging of the thoracic discs, contribute significantly to fixed hyperkyphosis of the spine.