Inclusion Criteria:  Patients undergoing elective spinal surgery; Clinical diagnosis of diabetes (using the diagnostic criteria proposed by the WHO Expert Committee on Diabetes in 1999); Use metformin or sitagliptin; The age ranges from 18 to 90; Sign informed consent.  Exclusion Criteria:  Acute traumatic injury; Patients with cerebral hemorrhage, cerebral infarction, Parkinson's disease, spinal cord transverse syndrome, spinal cord hemiere syndrome, Guillan-Barre syndrome and other neurological diseases affecting patients' somatosensory and motor; Combined with rheumatoid arthritis, ankylosing spondylitis and other rheumatoid arthritis; Patients with long-term use of glucocorticoids; complicated with malignant tumor; Pregnant women; Suffering from schizophrenia, bipolar disorder, hysteria and other mental diseases; The use of two or more than two mechanisms of hypoglycemic drugs; Do not sign informed consent.