Inclusion Criteria:  (1) Age: 18~70 years. (2) Diagnosed as CSM or OPLL. (3) Going to receive C3-C7 open-door laminoplasty. (4) Agree to join this study and sign the informed consent.  Exclusion Criteria:  (1) Anterior and posterior combined surgery. (2) Posterior laminoplasty combined fusion. (3) Severe osteoporosis. (4) Morbid obesity. (5) patients with mental disorder. (6) patients with previous history of cervical spine surgery. (7) Abnormal laboratory report of liver function, kidney function and hematologic system.(8) Poor compliance. (9) Patients with other surgical contraindications. (10) Patients with intemperance or taking drugs. (11) Patients who joined other study within the last 3 months.