Novel Associating Hydrogels for Nucleus Pulposus Replacement

Jonathan Thomas, Michele Marcolongo, Andrew Karduna, and Anthony Lowman
Drexel University
203 N. 34th St.  Box 631
Philadelphia, PA  19104
jthomas@drexel.edu
(215) 571-3073
 

Chronic lower back pain is the number one cause of lost work days in the United States, making it one of the most expensive health care issues today.  While the causes of lower back pain remain unclear, it is believed that 75% of the cases are associated with degenerative disc disease, where the intervertebral disc of the spine suffers reduced mechanical functionality due to dehydration of the nucleus pulposus. Current treatment options range from conservative bed rest to highly invasive surgical interventions, such as spinal fusion and discectomy, aimed at reducing pain, but not at restoring disc function.

We propose a replacement of the nucleus with a novel, biocompatible, copolymer gel of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP).   These new gels will be more stable in physiological fluid due to hydrogen bonding between the PVA and PVP chains.  Increased in vitro stability and improved mechanical properties of the copolymers may be attributed to the interpolymer associations between PVA and PVP.  These hydrogen bonds will serve as secondary, physical crosslinks and will provide the networks with additional stability in the event that PVA crystallites melt out of the gel.  The new PVA/PVP gels have potential to serve as an implant material for non-invasive replacement of the nucleus pulposus for degenerative disc disease.