thol 196:374-9. Greenberg MS. 2001. Handbook of neurosurgery. 5th ed. Lakeland (FL): Greenberg Graphics. Kang JD, Stafanovic-Racic M. McIntyre LA. Georgescu HI. Evans CFI. 1997. Toward a biochemical understanding of human intervertebral disc degeneration and herniation. Spine 22:1065-73. Karppinen.I.