Mechanical age-related differences in the human cadaveric annulus fibrosus

Area of Science:

• Biomedical Engineering
• Orthopedic Research
• Gerontology

Background:

• Human intervertebral disc degeneration is a common age-related condition.
• The annulus fibrosus (AF) is crucial for spinal structural integrity.
• Understanding age-related changes in the AF is vital for treating spinal disorders.

Purpose of the Study:

• To investigate age-related mechanical property variations in the human annulus fibrosus.
• To analyze differences in intralamellar and interlamellar matrix properties with aging.

Main Methods:

• Mechanical testing of human cadaveric discs (ages 53-90).
• Tensile testing of single-layer and bilayer AF samples.
• 180° peel testing of multilayer AF samples to assess interlamellar matrix.

Main Results:

• Increasing age significantly decreased AF stiffness and strength (failure stress, stress at 15% strain).
• Age did not significantly impact interlamellar matrix properties (peel test results).

Conclusions:

• The annulus fibrosus becomes weaker and more compliant with age.
• Age does not appear to affect the adhesive properties of the interlamellar matrix within the AF.