Lumbar keyboard protrusion can be divided into three developmental stages: 1, pre-protrusion: this period of the nucleus pulposus due to degeneration, injury can become fragmented masses, the fiber ring can become thin, soft or produce fissures. 2, protrusion phase: when the disc is under increased pressure and imbalance, the degenerated nucleus pulposus can protrude from the weakness or rupture of the fibrous ring, which can appear in five conditions: (1) annular bulging of the fibrous ring: bulging between the posterior edge of adjacent vertebrae, the fibrous ring is intact that Bulging. (2) limited bulging of the fibrous ring: limited bulging of the fibrous ring, but the fibrous ring is intact, which can produce clinical symptoms. (3) Herniated disc: the herniated nucleus pulposus is bounded by a very thin fibrous annulus, which can produce typical symptoms. (4) Prolapsed disc: the herniated nucleus pulposus passes through a completely ruptured fibrous ring and reaches under the posterior longitudinal ligament. The nucleus pulposus may be located above or below the nerve root, or just anterior to the spinal canal. (5) Free disc protrusion: the nucleus pulposus passes through the ruptured annulus fibrosus and posterior longitudinal ligament and is free in the spinal canal or even located in the intradural and subarachnoid space, compressing the cauda equina or nerve root. 3, late protrusion: disc herniation fibrosis or calcification. The intervertebral disc is degenerated, the fibrous ring is wrinkled, the vertebral space is narrowed, the vertebral body is sclerotic, and bone superfluous is formed. Nerve root damage, long-term compression can lead to adhesion, degeneration and atrophy of the nerve root. Hypertrophy of the ligamentum flavum, which is a secondary lesion, can lead to spinal stenosis. Degeneration and hyperplasia of the intervertebral joints, due to narrowing of the intervertebral space and increased compensatory loading of the intervertebral joints, with degenerative spinal stenosis.