Intervertebral discs are avascular. Oxygen, nutrients and bicarbonate diffuse from capillaries in cartilaginous endplates into discs to feed and maintain disc cells. As we age, calcified layers form at the endplates, blocking and occluding capillaries. Diffusion zones of oxygen and nutrients in disc become shallow. Cells in mid-layer of the disc suffer chronic anaerobic and starving conditions. Lactic acid is produced. Disc cells die from starvation, causing disc degeneration and forming fissures in annulus. Lactic acid leaks from fissures to the outer annulus of the disc to cause irritation, inflammation and persistent pain. Spirals of filament are implanted into the painful and degenerating disc to draw oxygen, nutrients and bicarbonate from the shallow diffusion zones of the cartilaginous endplates into the mid-layer of the degenerating disc. Oxygen inhibits anaerobic production of lactic acid; nutrients feed disc cells to halt disc degeneration; bicarbonate neutralizes lactic acid in the mid-layer to relieve pain.

The present invention relates to a surface modification method for improving the hemocompatibility of biomedical metallic substrate, comprising: fixing a sulfur-containing monomolecular film on the surface of oxide layer of a biomedical metallic substrate by molecular self-assembly. The surface modification will improve the hydrophilicity and hemocompatibility of the biomedical metallic substrate in contact with the blood, and ensure that the biomedical metallic substrate is non-toxic to the endothelial cells.