Study Finds, Effect of Postural Alignment Alteration with Ag
EOS biplane radiographs were analyzed to compute the upper body lever arm over the L1 vertebra and its impact on vertebral strength. Postural sagittal alignment alteration was observed with age and resulted in a greater lever arm causing vertebral strength to decrease. A Study was conducted to analyze the impact of postural alignment changes with age on vertebral strength using finite element analysis and barycentremetry.

A total of 117 subjects were divided in three age groups: young, intermediate, and elderly. EOS biplane radiographs were acquired, allowing 3D reconstruction of the spine and body envelope as well as spinal, pelvic, and sagittal alignment parameter measurements. A barycentremetry method allowed the estimation of the mass and center of mass (CoM) position of the upper body above L1, relatively to the center of the L1 vertebra (lever arm).

--A combination of an increase in thoracic kyphosis, cervical lordosis, and pelvic tilt with a loss of lumbar lordosis was observed between the young and the older groups.

--Sagittal alignment parameters indicated a more forward position as age increased.

--The lever arm of the CoM above L1 varied from an average of 1 mm backward for the young group, to averages of 10 and 24 mm forward, respectively, for the intermediate and elderly group.

--As a result, vertebral strength decreased from 2527 N for the young group to 1820 N for the elderly group.

Conclusively, the changes in global sagittal alignment found with age were consistent with previous research. In this simplified loading model, postural changes with aging drastically lowered vertebral strength. In the examination of osteoporotic patients, postural alignment appears to be critical.