Early postoperative serum S100β levels predict ongoing brain damage after meningioma surgery: a prospective observational study

INTRODUCTION Elevated serum levels of S100beta, an astrocyte-derived protein, correlate with unfavourable neurological outcomes following cardiac surgery, neurotrauma, and resuscitation. This study evaluated whether pre-/postoperative serum S100beta levels correlate with unfavourable clinical and radiological findings in patients undergoing elective meningioma resection. METHODS In 52 consecutive patients admitted for meningioma surgery, serum S100beta levels were determined upon admission and immediately, 24 hours, and 48 hours after surgery. All patients underwent complete pre- and postoperative neurological examination and mini-mental state examination. Radiological evaluation included preoperative magnetic resonance imaging (MRI) and postoperative computed tomography. Tumour volume, brain edema, and bleeding volume were calculated using BrainSCAN software. RESULTS Preoperative S100beta levels did not correlate with the tumour characteristics demonstrated by preoperative MRI (for example, tumour volume, edema volume, ventricular asymmetry, and/or midline shift). Preoperative serum S100beta levels (0.065 +/- 0.040 microg/l) were significantly lower than the levels measured immediately (0.138 +/- 0.081 microg/l), 24 hours (0.142 +/- 0.084 microg/l), and 48 hours (0.155 +/- 0.119 microg/l) postoperatively (p < 0.0001). Significantly greater postcraniotomy S100beta levels were observed with prolonged surgery (p = 0.039), deterioration in the mini-mental state examination (p = 0.005, 0.011, and 0.036 for pre versus immediate, 24 hours, and 48 hours postsurgery, respectively), and with postoperative brain computed tomography evidence of brain injury; bleeding was associated with higher serum S100beta levels at 24 and 48 hours after surgery (p = 0.046, 95% confidence interval [CI] -0.095 to -0.001 and p = 0.034, 95% CI -0.142 to -0.006, respectively) as was the presence of midline shift (p = 0.005, 95% CI -0.136 to -0.025 and p = 0.006, 95% CI -0.186 to -0.032, respectively). Edema was associated with higher serum S100beta levels immediately (p = 0.022, 95% CI -0.092 to -0.007) and at 48 hours after surgery (p = 0.017, 95% CI -0.142 to -0.026). The degree of elevation in S100beta levels at 24 and 48 hours after surgery also correlated with the severity of midline shift and edema. CONCLUSION In patients with meningioma, serum S100beta levels perform poorly as an indicator of tumour characteristics but may suggest ongoing postcraniotomy injury. Serum S100beta levels may serve as a potentially useful early marker of postcraniotomy brain damage in patients undergoing elective meningioma resection.