Mechanical characterization of a simple gel in a prototype device that models a degenerative intervertebral disc /
A large part of low-back pain occurrences are due to disc herniation or prolapse of the nucleus pulposus. An alternative technique to existing treatments of low back pain includes nucleus pulposus replacement by an artificial material to relieve pain and restore normal function. To date, there has been a deficiency in testing new materials in a physiologically accurate model of a degenerative intervertebral disc. The goals of this study were to use a simple gel system in a simple geometry simulating the disc space to identify how the extrudability of the gel changed as its characteristics were altered and compare those to the native tissue as well as determining the experimental reproducibility and relationship to measurable rheological properties. A prototype device modeling a degenerative intervertebral disc was constructed in PlexiglasTM, which consisted of a circular disc shape with a lateral channel to simulate an annular tear. Agarose gels of varying weight percent were made and samples were tested in compression in the degenerative disc device. The rheological properties of the gels were measured in a parallel-plate dynamic oscillatory shear experiment. The compressive moduli and rheological properties were compared with those of the native tissue. The elastic and viscous moduli of the agarose gel did not completely match those of nucleus pulposus, but the static compressive modulus was similar in the two materials. The compression experiments conducted showed reproducible results and a correlation to rheological properties of the simple polymer gel system. Since a test protocol was established, the extrudability of more complex polymer gel systems can be tested on the degenerative disc device and related to its measurable rheological properties.
School:Oregon State University
School Location:USA - Oregon
Source Type:Master's Thesis
Keywords:polymer colloids in medicine
Date of Publication: