The normal adult human disk is virtually avascular. Nutrients, principally glucose and
oxygen, necessary for survival and activity of disk cells are transported from blood vessels at
its margins to the cells deep within the disk matrix, mainly by diffusion; products of
metabolism, principally lactic acid, are removed by the reverse route. Loss of adequate
nutrient supply has long been associated with the development and progression of disk
degeneration because it adversely affects activity and even the viability of disk cells …