Inclusion Criteria:  Diagnosed as spinal disc herniation (prolapse), spinal stenosis, Non-traumatic spinal instability, spondylolisthesis, degenerative scoliosis not caused by congenital spinal deformity. 2. Hospitalized patients under operation. 3. Over 18 yrs. 4. Patients in North China.  Exclusion Criteria:  - Patients diagnosed as Hypertrophy of Posterior Longitudinal Ligament or Hypertrophy of Ligamentum Flavum.