Lumbar lordosis measurement: A new method versus Cobb technique

Study Design. A historic cross-sectional study of lumbar lordosis in 199 healthy individuals aged 1-30 years. Objective. To evaluate the magnitude and rate of the development of the normal lumbar lordotic curve with age using two methods of measurement. Summary of Background Data. There is no agreement among spine physicians on the range of the normal lumbar lordotic curve. In certain conditions, such as a tethered spinal cord, a change in lordotic curve may indicate or even precede the onset of neurologic symptoms. Reliable measurements of the lumbar lordotic curve may aid in the early diagnosis and management of these conditions, before irreversible neurologic change ensues. Methods. The lumbar lordotic curve was measured by the traditional Cobb technique and by a newly designed method, tangential radiologic assessment of lumbar lordosis. The data were subjected to the Morgan-Pitman test for correlated variances to observe which of the two methods was more reliable in measuring the magnitude and rate of change in the lumbar lordotic curve. Results and Conclusions. The rate of development of the lumbar lordotic curve appears to be nonlinear, increases during first year of life and during puberty, and reaches a plateau of approximately 50 degrees at maturity. The tangential radiologic assessment of lumbar lordosis method is more reproducible and more reliable in the lumbar lordotic curve, providing a smaller range of normal values (8 degrees-16 degrees less) than the Cobb method.