Impact of ultrasound-guided nerve block on postoperative delirium in elderly patients undergoing diabetic foot surgery: a propensity score-matched retrospective study.

BACKGROUND: Postoperative delirium (POD) is a common and serious complication in elderly patients undergoing diabetic foot surgery, often linked to excessive opioid use and systemic neuroinflammation. This study aimed to evaluate whether ultrasound-guided nerve block (NB) reduces the incidence of POD compared to general anesthesia (GA) in this high-risk population. METHODS: We conducted a propensity score-matched (PSM) retrospective cohort study involving 137 patients. The primary outcome was the incidence of POD, while secondary outcomes included intraoperative opioid consumption (sufentanil equivalent) and postoperative interleukin-6 (IL-6) levels. Standardized mean differences (SMDs) were used to assess covariate balance after matching. RESULTS: After PSM, the incidence of POD was significantly lower in the NB group (5.6%) than in the GA group (25.0%, P = 0.046). NB significantly reduced intraoperative sufentanil requirements (P < 0.001) and suppressed the elevation of IL-6 at 24 h postoperatively (P < 0.001). The protective association with NB was directionally consistent across crude, multivariable-adjusted, and matched analyses. No significant differences were observed in postoperative CRP levels or length of hospital stay (P > 0.05). CONCLUSION: Ultrasound-guided NB is associated with a lower POD risk in elderly patients with diabetic foot, consistent with potential mediation through opioid-sparing and anti-inflammatory mechanisms.