Abstract: Objective To explore the correlation between intraoperative parameters of somatic tissue oxygen saturation (SstO₂) and cerebral tissue oxygen saturation (SctO₂) and postoperative cognitive dysfunction (POCD) among patients undergoing spinal surgery in the prone position.Methods Clinical data of 126 patients who underwent prone-position open thoracic or lumbar spine surgery in our hospital from January 2021 to December 2024 were retrospectively analyzed.Patients were classified into POCD group and normal group according to the decrease in scores of the mini-mental state examination (MMSE) before and after surgery.Perioperative clinical data and intraoperative SctO₂ and SstO₂ parameters of the two groups were analyzed and compared.Pearson correlation was used to analyze the correlation between intraoperative SstO₂ and SctO₂ parameters and MMSE scores,and Logistic regression was performed to analyze whether intraoperative oxygenation parameters were risk factors for POCD.Results A total of 34 patients developed POCD and 92 patients had no POCD,the incidence of POCD was 26.98%.The absolute reduction value, relative reduction value, and the proportion of cases with the average value < 90% of the baseline value of Sst02 during the operation in the POCD group were (4.95 ± 1.16)%, (7.42 ± 2.03)% and 11 cases (32.35%), which were significantly higher than those in the normal group, which were (3.97 ± 1.21)%, (5.96 ± 1.38)% and 6 cases (6.52%), with statistically significant(P<0.05).Pearson correlation analysis showed that the intraoperative SctO₂ parameters was not correlated with the decrease of MMSE scores after surgery,and the absolute decrease value and relative decrease value of intraoperative SstO₂ were positively correlated with the decrease of MMSE scores after surgery (r=0.564 and 0.627,P<0.05).Logistic regression analysis showed that the absolute decrease,relative decrease,and mean value of <90% baseline of intraoperative SstO₂ were risk factors for the occurrence of POCD (P<0.05).Conclusion The SstO₂ parameter was superior to the SctO₂ parameter in predicting POCD during spinal surgery in the prone position.Monitoring of SstO₂ parameters may be considered during these surgery to prevent POCD.

Key words: spinal surgical procedures, cognitive dysfunction, somatic tissue oxygen saturation, cerebral tissue oxygen saturation