Abstract: To explore the causes of high risk for the delirium of the elderly after spinal operation. Methods: In the study, 116 cases of delirium were retrospectively analyzed from 1 216 patients aged more than 70 years who underwent spinal operation in general anesthesia from April 2007 to April 2011. Of the 116 patients, 62 were male and 54 female, with an average age of 75.3 years, ranging from 70 to 92 years; 36 underwent anterior cervical surgery,41 were treated by posterior cervical decompression surgery, and 39 had posterior lumbar decompression operation. Clinical features, such as gender, operation duration time, blood loss, analgesics drugs, the dosage of methylprednisolone, the leakage of cerebrospinal fluid, saturation of arterial oxygen and bed room periods were observed and the data were analyzed with the single factor risk analysis at first then multiple factors analysis performed by binary Logistic regression. Results: The single factor risk analysis showed that there are significant differences between delirium and nondelirium in operation duration (P=0.032), blood loss (P=0.013), hypoxemia (P=0.002) and fever (P=0.001) after operation. While multiple factors Logistic regression analysis indicated that the dosage of methylprednisolone (P=0.002) and morphine (P=0.005) after operation, the leakage of cerebrospinal fluid (P=0.020), and hypoxemia (P=0.005) were the risk factors of delirium status after operation. Conclusion: The incidence of delirium status after spinal operation could be decreased by application of less dosage of morphine or methylprednisolone and to avoid hypoxemia and the leakage of cerebrospinal fluid during operation.

Key words: Risk factors, Spine, Surgical procedures, operative