Effects of Esketamine Combined with Dexmedetomidine on Early Postoperative Cognitive Function in Elderly Patients Undergoing Lumbar Spinal Surgery: A Double-Blind Randomized Controlled Clinical Trial

Background: Postoperative cognitive dysfunction (POCD) is a common complication after surgery in elderly patients, and its prevalence can be up to 25.6% at one week after noncardiac surgery. This study mainly evaluates the combined effects of esketamine and dexmedetomidine on the incidence of POCD in elderly patients undergoing lumbar spine surgery and explores the underlying mechanisms. Methods: A total of 162 elderly patients undergoing lumbar spine surgery were randomized into three groups: esketamine combined with dexmedetomidine group (ED group), esketamine group (E group), and dexmedetomidine group (D group). Primary outcome measures included the incidence of POCD on the first postoperative day. Secondary outcomes included the incidence of POCD on the third postoperative day, first postoperative day serum levels of neuron-specific enolase (NSE) and calcium-binding protein beta (S100 beta), patient visual analog scale (VAS) scores at 2, 24, and 48 hours postoperatively, and the incidence of adverse events. Results: The incidence of POCD on the first postoperative day was significantly lower in the ED group compared to the E group (P = 0.017), with no significant differences when compared to the D group (P = 0.064). The levels of serum NSE in patients in the ED group on the first postoperative day were significantly lower than those in E group and D group (ED group vs E group, P = 0.028; ED group vs D group, P = 0.048). The results for the S100 beta were similar to those for the NSE (ED group vs E group, P = 0.005; ED group vs D group, P = 0.011). Conclusion: The combination of esketamine and dexmedetomidine effectively reduces the incidence of POCD on the first postoperative day in elderly patients undergoing lumbar spine surgery.