title: Functional compressive mechanics of a PVA/PVP nucleus pulposus replacement.
abstract: Emerging techniques as an alternative to the current treatments of lower back pain include nucleus replacement by an artificial material, which aims to relieve pain and restore the normal spinal motion. The compressive mechanical behavior of the PVA/PVP hydrogel nucleus implant was assessed in the present study. PVA/PVP hydrogels were made with various PVP concentrations. The hydrogels were loaded statically under unconfined and confined conditions. Hydrogels were tested dynamically up to 10 million cycles for a compression fatigue. Also, hydrogel nucleus implants with a line-to-line fit, were implanted in the human cadaveric intervertebral discs (IVD) to determine the compressional behavior of the implanted discs. Hydrogel samples exhibited typical non-linear response under both unconfined and confined compressions. Properties of the confinement ring dictated the observed response. Hydrogel moduli and polymer content were not different pre- and post-fatigues. Slight geometrical changes (mostly recoverable) were observed post-fatigue. In cadavers, hydrogels restored the compressive stiffness of the denucleated disc when compared with equivalent condition of the IVD. The results of this study demonstrate that PVA/PVP hydrogels may be viable as nucleus pulposus implants. Further studies under complex loading conditions are warranted to better assess its potential as a replacement to the degenerated nucleus pulposus.
authors.affiliation: Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA.
authors.forename: Abhijeet
authors.initials: A
authors.lastname: Joshi
authors.forename: Garland
authors.initials: G
authors.lastname: Fussell
authors.forename: Jonathan
authors.initials: J
authors.lastname: Thomas
authors.forename: Andrew
authors.initials: A
authors.lastname: Hsuan
authors.forename: Anthony
authors.initials: A
authors.lastname: Lowman
authors.forename: Andrew
authors.initials: A
authors.lastname: Karduna
authors.forename: Ed
authors.initials: E
authors.lastname: Vresilovic
authors.forename: Michele
authors.initials: M
authors.lastname: Marcolongo
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002102:Cadaver; D019245:Compressive Strength; D006801:Humans; D020100:Hydrogels; D020007:Implants, Experimental; D007403:Intervertebral Disc / Q000033:anatomy & histology*; D008422:Materials Testing; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D011205:Povidone / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D011142:Polyvinyl Alcohol; D011205:Povidone