Prediction of thoracic kyphosis using the Debrunner kyphometer.

The Debrunner kyphometer is an accepted tool for detecting and evaluating thoracic kyphosis. This prospective study was conducted to create a mathematical formula that provides, with high approximation, the roentgenographic angle of thoracic kyphosis (T4-T12) using only the kyphometer. Several clinical (kyphometer value, age, and sex) and radiographic (Cobb angle [T4-T12]) parameters from 90 consecutively screened adolescents (44 male and 46 female) were correlated using simple and multiple linear regression analyses. The reliability of measurement using the Debrunner kyphometer was high. The kyphometer value was strongly correlated with the roentgenographically measured thoracic Cobb angle (simple linear regression analysis; probability range, 0.0026 to 0.0002). There was no correlation between age or sex and thoracic kyphosis. The predicted kyphosis angle using the kyphometer and the mathematic formula was 44.66 degrees +/- 2.68 degrees, (range 27 to 62 degrees), and the real roentgenographic kyphosis angle was 47.5 degrees +/- 3.53 degrees, (range, 24 to 70 degrees). The kyphometer and formula were more reliable and accurate when kyphosis less than 50 degrees was measured. In this study, the authors constructed a mathematical formula that accurately provides the roentgenographic T4-T12 kyphosis angle in adolescents using only the Debrunner kyphometer with a deviation of less than 3 degrees. The authors recommend that all physicians engaged in kyphosis screening programs use the kyphometer combined with the recently constructed simple mathematic formula. This method will reduce the cost of school screening programs, overdiagnoses, and unnecessary exposure of adolescents to irradiation.