Effect of postural alignment alteration with age on vertebral strength

Area of Science:

• Biomechanical engineering
• Geriatric medicine
• Radiology

Background:

• Age-related changes in posture, including increased thoracic kyphosis and pelvic tilt, are common.
• These postural shifts can alter the biomechanical forces acting on the spine.

Purpose of the Study:

• To investigate the impact of age-related postural alignment changes on vertebral strength.
• To quantify the relationship between the upper body lever arm and L1 vertebral strength.

Main Methods:

• EOS biplane radiographs were used to reconstruct the spine and body envelope in 117 subjects aged 20-83.
• Barycentremetry calculated the upper body center of mass lever arm relative to the L1 vertebra.
• Finite element analysis modeled vertebral strength under personalized lever arm conditions.

Main Results:

• Older subjects exhibited greater forward sagittal alignment and an increased lever arm (average 24 mm forward in the elderly vs. 1 mm backward in the young).
• Vertebral strength decreased significantly with age, from 2527 N in the young group to 1820 N in the elderly group.
• Age-related postural alterations led to a reduced vertebral strength.

Conclusions:

• Age-related modifications in global sagittal alignment significantly decrease vertebral strength.
• Postural alignment is a critical factor in assessing vertebral strength, particularly in elderly populations.
• Findings suggest postural alignment should be considered in the evaluation of osteoporotic patients.