In vivo measurements of nutrient transport into herniated intervertebral discs

INTRODUCTION: A loss of nutrient supply has long been thought to be a major factor leading to disc degeneration and recent in vivo measurements have supported this hypothesis. Solute transport from the blood vessels through the endplate into the disc, measured by following gadolinium [1] or nitrous oxide [2] transport, has found that effective endplate permeability falls significantly in degenerate and scoliotic discs [2]. Computations support the importance of loss of nutrient supply by showing that once endplate permeability falls below a critical level, disc cell viability is compromised [3]. Here we give additional information on transport into pathological human discs in vivo. We measured solute transport into herniated human discs during routine surgical procedures. These measurements were then used as a basis for calculations of critical glucose concentrations and hence cell survival in order to determine which discs could be good candidates for cellular repair strategies.