TNF and intervertebral disk degenerative disorder: There is certain evidence in the literature that in a subgroup of patients, painful disc degeneration is characterized by increased levels of proinflammatory cytokines, e.g. interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8) and tumor necrosis factor α (TNF-α)[6,8-11].