Blood biomarkers for brain injury in chronic subdural hematomas: postoperative dynamics and relation to long-term outcome

OBJECTIVE The aim of this study was to investigate whether the biomarkers neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and tau (total [t] and brain-derived [BD]) are elevated in plasma preoperatively; if there is a dynamic biomarker response to surgery; and if the biomarker levels are related to long-term outcome in chronic subdural hematomas (CSDHs). METHODS Eighty-five CSDH patients surgically treated between 2022 and 2023 at Uppsala University Hospital, Uppsala, Sweden, were included in this prospective, observational study. NSE, GFAP, NfL, t-tau, and BD-tau were evaluated in plasma pre- and postoperatively (6–24 hours after surgery) and in the CSDH fluid. Health-related quality of life was evaluated using the 5-level EQ-5D (EQ-5D-5L) at 6 months postoperatively. RESULTS GFAP, NfL, and tau levels decreased after CSDH surgery (p < 0.02). NSE and BD-tau levels also decreased, but not significantly. Older age and larger CSDH volume were associated with higher preoperative GFAP, NfL, and BD-tau levels (p < 0.05). Higher preoperative values and greater dynamics (Δ [postoperative value − preoperative value]) of GFAP, NfL, and BD-tau correlated significantly with worse levels of several EQ-5D-5L domains (p < 0.05). A higher preoperative NfL level in plasma was independently associated with a lower EQ-5D-5L visual analog scale score (p < 0.001). CONCLUSIONS Surgical CSDH patients exhibit ongoing central nervous system cellular injury, demonstrated via increased fluid biomarkers for brain injury preoperatively, which immediately improved after surgery and was strongly related to long-term outcome. The extent of preoperative biomarker elevation could aid in the decision-making for surgical indication and urgency.