Fill of the nucleus cavity affects mechanical stability in compression, bending, and torsion of a spine segment, which has undergone nucleus replacement.

Study Design: Axial loading, rotation, and bending were applied to human cadaveric lumbar segments to investigate the changes in disc mechanics with denucleation and incremental delivery of a novel hydrogel nucleus replacement.

Objective: The purpose of this study was to investigate the effect of nucleus implant injection pressure/volume relationships on the quasi-static mechanical behavior of the human cadaveric lumbar intervertebral disc to determine if intact biomechanics could be reproduced with nucleus-implanted discs.

Summary Of Background Data: Previous studies have shown that volumetric filling of the nucleus cavity with a compliant nucleus replacement device will affect compressive stiffness of the implanted intervertebral disc, but data regarding restoration of mechanics through cavity pressurization are lacking.

Functional compressive mechanics of a PVA/PVP nucleus pulposus replacement.

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.