RESUMO
BACKGROUND: The evaluation of the vertebral, local and segmental kyphosis according to Cobb is usual practice in the determination of traumatic, idiopathic and degenerative spinal deformities. The present study compares the inter- and intraobserver reliability of these 3 angles in the lateral X-rays of thoracic spine fractures with spinal kyphosis. METHODS: From 1999 till 2007 all patients with adequate X-rays, age < 50 years, traumatic, thoracic spine fracture, kyphotic deformity and surgical intervention were included. The vertebral, local and segmental kyphosis were assessed by 3 observers at 2 time-points in the preoperative lateral X-rays. RESULTS: 63 patients, 11 women and 52 men, with a mean age of 34 years could be evaluated. In all cases an adequate trauma had led to the fracture. The most common trauma was an injury with a motorcycle; the 12th thoracic vertebra was most commonly affected. The segmental kyphosis showed 'excellent' results for inter- and intraobserver reliability (Ø-ICC: 0.8189 and Ø-ICC:0.8003). 'Good' results for inter- and intraobserver reliability could be evaluated for the vertebral (Ø-ICC: 0.7797 and Ø-ICC: 0.7797) and local (Ø-ICC: 0.7532 and Ø-ICC: 0.7296) kyphosis. CONCLUSION: Due to excellent and good results for inter- and intraobserver reliability of the segmental,vertebral and local kyphosis in the lateral X-rays of the thoracic spine, these angles could be a helpful tool, indicating a surgical procedure in traumatic thoracic fractures with kyphosis. Further possible interesting applications in the usage of these 3 angles could be the observation of the vertebral sintering in surgically or conservatively treated vertebral fractures. Appropriate studies should be performed before general recommendations can be given.