The position of the sacrum in the frontal plane - A sonographie study aim of the study

Aim of the study: The position of the sacrum in the frontal plane is import ant for the statics of the spine. The most common method of investigating t he sacrum is its visualisation on an antero-posterior X-ray film. The aim o f this study was to find a method of determining the position of the sacrum in the frontal plane by sonography. Method: Criteria for the correct imagi n of the upper rim of the sacrum are presented and the procedure for measur ing sacral tilt is introduced. The results of the sonographic measurements of 107 patients are compared with the results of X-ray measurements. The in traindividual differences are described and statistically evaluated. Result s: Almost 90% of the patients revealed a difference between the sonographie and the radiologie measurement of less than three millimeters. The overall sensibility was 80%. The specificity was 82%. The results were calculated for different age groups. They turned out to be better in children and adol escents than in adult patients. Obese adults had significantly worse result s than patients with normal body weight. Conclusions: This study suggests t hat the method presented can help to provide reliable information on the po sition of the sacrum, especially in children and adolescents. By using sono graphy we can partly reduce the necessary X-ray exposure, especially in the diagnosis and treatment of leg length discrepancies.