Hydrogel Composites for Spinal Disc Replacement Who Cares? A 2002 National Health Survey reported that 34 million Americans over 18 have lower back pain. 80% of people will have some form of back pain in their lives, many of them with extruded discs. People with lower back pain are often less productive and have large medical expenses. Disc or nucleus pulposus replacement attempts to remove debilitating pain and restore functionality. Current “ Solutions ” Composite Perspective Lumbar Decompression Laminectomy – Relieves pressure on nerve root Discectomy – Removal of the nucleus pulposus to relieve pressure on spinal chord Lumbar Spinal Fusion Immobilization of spinal bones via screws to reduce movement related pain This can hasten the degeneration of adjacent intevertebral discs and reduce daily mobility posterior_fusion_x_ray.jpg Replaces only the central cushion and restores disc height However, this requires a fully functional annulus fibrosus Nucleus Pulposus Replacement The Problem Total Disc Replacement An invasive surgery that eliminates all damaged disc tissue It restores function, but without properly imitating the actual function ents/neurological_surgery/clinical/spina/artdis c.html Objective To evaluate the effects of micro-crystalline cellulose filler in a hydrogel matrix as a potentially injectable nucleus pulposus replacement. Properties Analysis Mechanical Testing Rheological Testing Acknowledgements A Special Thanks to: Dr. Skip Rochefort Melissa Taylor Dr. Phil Harding William Beattie Dr. Brian Bay Valerie Cannon Dr. John Simonson Janey-Rae Collins The spine allows for a highly utilized and diverse range of movements. A spinal disc has two essential parts: the annulus fibrosus, which acts as a container for the inner cushion, the nucleus pulposus. Disc herniation is when the annulus fibrosus ruptures and the nucleus pulposus extrudes out. Annulus Fibrosus Nucleus Pulposus Herniation can be caused by a single intense strain/injury or a minor strain/twisting movement if the disc has degenerated over time. China Lim, Paul Cary and Greg Newbloom Chemical, Biological and Environmental Engineering, Oregon State University The study of the flow of matter G’ = Storage (Elastic) Modulus G’’ = Loss (Viscous) Modulus Parallel Plate Geometry with “non-slip” surface Compression Modulus, K where F = applied force A = initial cross-sectional area ∆h = change in height h o = initial height Initial Peak: Breaking Point At Rest Breathing Walking Driving BIO-BASED NANOCOMPOSITES : CHALLENGES AND OPPORTUNITIES - John Simonsen, OSU Wood Science and Engineering Agarose Micro-crystalline Cellulose (MCC) A polymer extracted from red algae Forms a gel network in water when heated and then cooled Is inexpensive and biocompatible Structural component in the cell wall of green plants Is non-soluble in water and highly hydrophilic Synthesis Procedure Methods Agarose is dissolved in water. Microcrystalline cellulose is added and sonicated to disrupt aggregates. The mixture is heated by microwave, and quickly poured into chilled molds to prevent filler settling. The compressive and rheological properties of a native disc may be achieved by varying the matrix and filler to water ratios. The MCC has a tensile strength of 7.5 GPa and was used to increase the “toughness” of the gel. 1% Agarose-gel composites were created in 0.00, 0.04, 0.08, and 0.30 ratios of microcrystalline cellulose to water. Trends were analyzed to predict the effect of cellulose filler on gel strength.