Evaluation of intraoperative neuronal damage using S100beta, GFAP and NSE biomarkers in patients undergoing robotic-assisted laparoscopic surgery

Introduction: Certain robotic surgical procedures require prolonged steep trendelenburg positioning, which may disrupt cerebral autoregulation and lead to potential injury. This study aims to assess the occurrence of neuronal injury in patients undergoing robotic surgery in steep trendelenburg position through cognitive dysfunction tests and the biomarkers S100 beta protein, GFAP (Glial Fibrillary Acidic Protein), and Neuron-Specific Enolase (NSE). Materials and Methods: The study included 59 patients aged 18–70 years, with an American Society of Anesthesiologists (ASA) physical status score of 1–3, scheduled for elective RALS at the Department of Anesthesiology and Reanimation, Akdeniz University Faculty of Medicine, between March 2022 and March 2024. Data collected included age, body mass index (BMI), comorbidities, medications, alcohol consumption, and ASA classification. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) tests were administered one day before surgery and at postoperative hours 6, 24, and 96. Routine intraoperative monitoring as recommended by ASA guidelines was employed. Levels of S100 beta, GFAP, and NSE were measured preoperatively and at postoperative hours 1, 24, and 96. Data were analyzed using IBM SPSS Statistics 25 (SPSS Inc., Chicago, IL, USA) and GraphPad Prism 9.00. Statistical significance was set at p < 0.05. Results: In the early postoperative period, the incidence of postoperative cognitive dysfunction (POCD) in patients undergoing robotic-assisted laparoscopic prostatectomy in the steep Trendelenburg position was found to be comparable to that of patients undergoing minor surgical procedures. No significant changes were observed in the levels of the biomarkers S100 beta and GFAP, which were used to evaluate neuronal injury. Although NSE levels showed a significant increase, this rise was not correlated with POCD. Consistent with the literature, the development of POCD was associated with patient age, a BMI exceeding 27.3, elevated preoperative neutrophil-to-lymphocyte ratio, low preoperative hemoglobin levels, and an ASA score of 3. There was no observed difference in POCD rates between the use of sevoflurane and propofol. Conclusion: The incidence of cognitive dysfunction observed after robotic surgery was comparable to that seen following minor surgical procedures. Among the biochemical markers of neuronal injury, no significant changes were noted in S100 beta or GFAP levels. However, NSE levels were significantly elevated at postoperative hour 24 compared to preoperative values and levels at postoperative hours 1 and 96. Similarly, preoperative NSE levels were significantly lower than levels at all postoperative time points. Despite these findings, correlation analysis did not reveal a relationship between NSE levels and cognitive dysfunction, suggesting that steep Trendelenburg positioning during robotic-assisted laparoscopic surgery does not conclusively increase neuronal injury. We believe our findings warrant further investigation in larger patient series. Key Words: Robotic Surgery, Neuronal Damage, Postoperative Cognitive Dysfunction, Montreal Cognitive Assessment Scale, Mini-Mental State Examination, Biochemical Markers, S100 beta, Neuron-Specific Enolase, Glial Fibrillary Acidic Protein