RESUMEN
INTRODUCTION: Measurement of the vertebral, local and segmental kyphosis according to Cobb is a standard procedure in the assessment of traumatic, idiopathic and degenerative spinal deformities. The purpose of this study was to evaluate the inter- and intra-observer reliability of these three radiological angles on the basis of lateral X-rays in lumbar spine fractures with spinal kyphosis. PATIENTS AND METHODS: A consecutive series of 88 patients with traumatic lumbar spine fractures with kyphotic deformities were included in the study. All patients were younger that 50 years of age and had an adequate trauma leading to the fracture. Three independent observers with different levels of clinical training measured the vertebral, segmental and local kyphosis of these patients on the basis of lateral X-rays. The readings were repeated 4 weeks later to assess intra-observer reliability. RESULTS: The most common injury mechanism was a fall from a height of more than 3 m. The first lumbar vertebra was the most commonly affected. Mean inter- and intra-observer reliabilities were good for the vertebral (mean ICC: 0.6607; mean ICC: 0.6979) and local (mean ICC: 0.7778; mean ICC: 0.7642) kyphosis and excellent (mean ICC: 0.8129; mean ICC: 0.8103) for the segmental kyphosis. CONCLUSION: In this study, the segmental-, vertebral-, and local kyphosis angle according to Cobb showed sufficient inter- and intra-observer reliability for the use in daily practice and scientific studies.
Asunto(s)
Cifosis/diagnóstico por imagen , Vértebras Lumbares/lesiones , Fracturas de la Columna Vertebral/complicaciones , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , RadiografíaRESUMEN
Evaluation of the kyphosis angle in thoracic and lumbar burst fractures is often used to indicate surgical procedures. The kyphosis angle could be measured as vertebral, segmental and local kyphosis according to the method of Cobb. The vertebral, segmental and local kyphosis according to the method of Cobb were measured at 120 lateral X-rays and sagittal computed tomographies of 60 thoracic and 60 lumbar burst fractures by 3 independent observers on 2 separate occasions. Osteoporotic fractures were excluded. The intra- and interobserver reliability of these angles in X-ray and computed tomogram, using the intra class correlation coefficient (ICC) were evaluated. Highest reproducibility showed the segmental kyphosis followed by the vertebral kyphosis. For thoracic fractures segmental kyphosis shows in X-ray "excellent" inter- and intraobserver reliabilities (ICC 0.826, 0.802) and for lumbar fractures "good" to "excellent" inter- and intraobserver reliabilities (ICC = 0.790, 0.803). In computed tomography, the segmental kyphosis showed "excellent" inter- and intraobserver reliabilities (ICC = 0.824, 0.801) for thoracic and "excellent" inter- and intraobserver reliabilities (ICC = 0.874, 0.835) for the lumbar fractures. Regarding both diagnostic work ups (X-ray and computed tomography), significant differences were evaluated in interobserver reliabilities for vertebral kyphosis measured in lumbar fracture X-rays (p = 0.035) and interobserver reliabilities for local kyphosis, measured in thoracic fracture X-rays (p = 0.010). Regarding both fracture localizations (thoracic and lumbar fractures), significant differences could only be evaluated in interobserver reliabilities for the local kyphosis measured in computed tomographies (p = 0.045) and in intraobserver reliabilities for the vertebral kyphosis measured in X-rays (p = 0.024). "Good" to "excellent" inter- and intraobserver reliabilities for vertebral, segmental and local kyphosis in X-ray make these angles to a helpful tool, indicating surgical procedures. For the practical use in lateral X-ray, we emphasize the determination of the segmental kyphosis, because of the highest reproducibility of this angle. "Good" to "excellent" inter- and intraobserver reliabilities for these three angles could also be evaluated in computed tomographies. Therefore, also in computed tomography, the use of these three angles seems to be generally possible. For a direct correlation of the results in lateral X-ray and in computed tomography, further studies should be needed.