Evaluation of the Predictive Impact of Serum S100B and S100B Polymorphisms on Postoperative Cognitive Dysfunction and Delirium

Postoperative cognitive disorders, including postoperative cognitive dysfunction (POCD) and postoperative delirium (POD), are common complications associated with surgery and anesthesia. These conditions affect perception, memory, and learning abilities, and are associated with increased morbidity, prolonged hospital and intensive care unit stays, and higher healthcare costs. Although the exact mechanisms underlying these disorders are not fully understood, perioperative inflammatory processes and neuronal injury are considered key contributing factors.

In recent years, considerable research has focused on identifying reliable biomarkers for the early prediction of postoperative cognitive disorders. Among these, S100B protein has emerged as a promising marker of neuronal injury and blood-brain barrier dysfunction. In addition, single nucleotide polymorphisms (SNPs) in the S100B gene may influence individual susceptibility to cognitive impairment.

The aim of this study is to investigate the relationship between serum S100B levels, S100B gene polymorphisms, and postoperative cognitive disorders.

In this prospective study, preoperative cognitive function will be assessed using standardized cognitive tests. Blood samples will be collected preoperatively and within 30 minutes after surgery for the measurement of serum S100B levels. Cognitive assessment will be performed preoperatively and repeated at 1, 3, and 6 months after surgery. Patients will also be evaluated for postoperative delirium during the first 3 postoperative days.

The incidence of postoperative cognitive dysfunction and postoperative delirium will be recorded, and the association between S100B levels, genetic polymorphisms, and cognitive outcomes will be analyzed. The predictive value of these biomarkers for postoperative cognitive disorders will also be evaluated. Particular emphasis will be placed on the perioperative change in S100B levels (ΔS100B) as a potential predictor of postoperative cognitive outcomes.

Inclusion criteria

• Adult patients (≥18 years) undergoing elective surgery under anesthesia
• Patients able to provide informed consent
• Patients with sufficient cognitive function to complete cognitive assessments
• Patients who agreed to participate in follow-up evaluations

Exclusion criteria

• Patients with a history of neurological or psychiatric disorders affecting cognitive function
• Patients with diagnosed dementia or severe cognitive impairment
• Patients with inability to complete cognitive tests (e.g., severe visual, hearing, or language impairment)
• Patients with alcohol or substance abuse
• Patients undergoing emergency surgery
• Patients with missing baseline cognitive assessment
• Patients who refused participation or were lost to follow-up