STUDY DESIGN: A retrospective cohort study. PURPOSE: To investigate the risk factors for postoperative delirium after spine surgery, excluding older age, which has already been established as a strong risk factor. OVERVIEW OF LITERATURE: More than 30 risk factors have been reported for delirium after spine surgery, making it challenging to identify which factors should be prioritized. We hypothesized that risk factors could not be prioritized to date because the factor of older age is very strong and influenced other factors. To eliminate the influence of older age, we performed an age-matched group comparison analysis for the investigation of other risk factors. METHODS: This study involved 532 patients who underwent spine surgery. Two patients of the same age without delirium (delirium negative group) were matched to each patient with delirium (delirium positive group). Differences in suspected risk factors for post-operative delirium between the two groups identified from previous reports were analyzed using univariate analysis. Multivariate analysis was performed for factors that showed a significant difference between the two groups in the univariate analysis. RESULTS: Fifty-nine (11.1%) of 532 patients developed postoperative delirium after spine surgery. Large amounts of intraoperative bleeding, low preoperative concentration of serum Na, high postoperative (day after surgery) serum level of C-reactive protein, low hematocrit level, low concentration of albumin, and high body temperature were detected as significant risk factors in the univariate analysis. Large amounts of intraoperative bleeding remained a risk factor for postoperative delirium in the multivariate analysis. CONCLUSIONS: We should pay attention to and take precautions against the occurrence of postoperative delirium after spine surgery in patients of older age or those who experience severe intraoperative bleeding.
Body Temperature ; C-Reactive Protein ; Cohort Studies ; Delirium ; Hematocrit ; Hemorrhage ; Humans ; Multivariate Analysis ; Retrospective Studies ; Risk Factors ; Spine

Endurance exercises, such as cycling or running, are useful for reducing arterial stiffness. However, individuals with a low physical fitness level, or patients suffering from leg diseases with pain, are unable to perform such moderate-intensity lower-limb exercises for long periods of time. The aim of this study was to evaluate the effects of acute cycling with Electrical muscle stimulation (EMS) on the brachial to ankle pulse wave velocity (ba-PWV). Ten healthy adult men performed 3 sessions, as follows of 20 min: cycling at 50% VO2max (C), cycling at an intensity of 50%VO2max subtracted from VO2 during EMS (LC), and cycling at the intensity of the LC trial while also being combined with EMS (LC+E). The ba-PWV was measured before and after each exercise. In addition, the femoral artery blood flow (BF) was measured in eight healthy adult men before and after exercise using an ultrasound imaging system. In the C and LC+E trials, the ba-PWV significantly decreased immediately after the exercise session, whereas the ba-PWV did not significantly change following the LC trial in any session. Compared with the baseline, the femoral artery BF values significantly increased after all trials. In the C and LC+E trials, the femoral artery BF was significantly greater than that in the LC trial. Acute endurance low-intensity cycling with EMS results in a reduction in the arterial stiffness which is similar to that with moderate-intensity exercise.