Reproduction of the Lumbar Lordosis

Andreasen ML et al. Reproduction of the Lumbar Lordosis: A Comparison of Standing Radiographs Versus Supine Magnetic Resonance Imaging Obtained with Straightened Lower Extremities. Journal of Manipulative & Physiological Therapeutics January 2007; 39(1):26-30. 

ABSTRACT: Objective: This study investigates whether it is possible to reproduce the lumbar lordosis in the upright position during magnetic resonance imaging (MRI) by positioning the patient supine with straightened lower extremities and investigates intra-and interexaminer reliability of measurements of the lumbar lordosis on radiographs and MRI. Methods: This was an observational study, which included an intra-and interexaminer reliability study. The lumbar lordosis was measured digitally on radiographs taken from 22 patients in an upright standing position, and 22 MRI scans of the same patients lying supine with straightened lower extremities. These measurements were compared statistically. Intra-and interexaminer reliability was calculated applying the Bland and Altman method. Results: The lumbar lordosis in the standing position was reproduced in the straightened supine position with a median deviation of 3°. Intra- and interexaminer reliability was better for MRI than for radiographs. The mean differences were close to 0, especially for interexaminer reliability during MRI. On radiographs, there was a higher agreement on interexaminer than on intra-examiner reliability. Conclusion: The findings of this study show that lumbar lordosis in the upright position can be reproduced by positioning the patient supine with straightened lower extremities. COMMENTS: It has been observed by many chiropractors who take upright x-rays find that recumbant x-rays often show a significantly different lumbar curve. Gravity is a major factor, but also, the legs are often flexed on recumbant x-rays. In this study, supine MRIs can match the lumbar curve of standing x-rays if the legs are kept straight.