Viscoelastic Shear Responses of the Cadaver and Hybrid III Lumbar Spine 942205

Due to the sparsity of cadaver lumbar shear stiffness data, tests on functional lumbar spinal units and a complete lumbar section (T12-L5) were done in both the anterior and posterior directions. Similar tests were performed on the Hybrid III lumbar spine for comparison.
Sixteen lumber motion segments were tested quasi-statically for their viscoelastic properties in a multi-directional (5-axis) spine machine. A hydraulic testing machine was used to carry out dynamic tests including cyclic tests at several rates of deformation (0.5 - 50 mm/sec) and relaxation tests (300 sec) to determine the associated viscoelastic properties in constrained and unconstrained modes. The specimens were then loaded to sufficient displacement to cause hard or soft tissue failures.
In the quasi-static tests the shear response was linear and the anterior stiffness (155 ± 90 N/mm) was found to be higher than posterior stiffness (104 ± 38 N/mm). In the relaxation tests the load decreased to approximately 60% of its peak value after 30 seconds. Moderate non-linearity was observed in cyclic loading with shear stiffness up to 750 N/mm, depending on the loading rate. Soft tissue only failures occurred in the unconstrained tests at 1290 N (0.5 mm/sec) and 1770 N (50 mm/sec) for anterior loading. Anterior constrained testing failures involved hard tissue at 2800 N and were not rate dependent. The Hybrid III spine elicited higher initial stiffness than cadaver specimens, but was comparable at shear loads greater than 500 N. It also had considerably greater hysteresis than cadaver specimens.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Relationships Between Passenger Car Seat Back Strength and Occupant Injury Severity in Rear End Collisions: Field and Laboratory Studies


View Details


MADYMO Model to Assess Lumbar Spine Loading during Activities of Daily Living


View Details


Biomechanical Experimental Studies of the Lumbar Spine Under Static and Dynamic Loading Conditions


View Details