Abstract
BACKGROUND: Postoperative delirium (POD) is a common complication of total hip arthroplasty (THA), with neuroinflammation playing a critical role in its mechanism. However, the dynamic association between peripheral and central inflammatory markers, as well as their predictive value for POD, remain unclear. This study aims to investigate the perioperative dynamic changes of inflammatory markers in plasma and cerebrospinal fluid (CSF) of THA patients and their relationship with POD. METHODS: A total of 280 THA patients were retrospectively enrolled and divided into a delirium group (n = 71) and a non-delirium group (n = 209) according to the Confusion Assessment Method (CAM) assessment 7 days after surgery. The levels of IL-6, TNF-α, and CRP in plasma and CSF were measured before surgery, 1 day after surgery, and 3 days after surgery. Their correlations with the Preoperative Mini-Mental State Examination (MMSE) score and diagnostic efficacy for POD were analyzed. RESULTS: In the delirium group, the plasma levels of interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) increased continuously after surgery, peaking on the 3rd day postoperatively, with significant differences compared with the non-delirium group (all P < 0.001). The increases in CSF IL-6 and TNF-α were more significant (IL-6 on the 1st day after surgery: P < 0.001), and they were strongly negatively correlated with the MMSE score (r = -0.62). The predictive efficacy of CSF IL-6 and TNF-α for POD (AUC = 0.88 on the 3rd day after surgery) was better than that of plasma indicators (AUC = 0.85). In patients over 65 years old, the central inflammatory response occurred earlier (r = -0.71 on the 1st day after surgery), and the correlation between inflammatory markers and cognitive impairment was stronger in patients under general anesthesia (P < 0.01). CRP in CSF showed no significant predictive value (AUC = 0.60). CONCLUSION: Postoperative delirium after THA is closely associated with a coordinated increase in peripheral and central IL-6 and TNF-α. Cerebrospinal fluid detection provides a more sensitive early warning signal for POD.