Cerebrospinal fluid leakage into the subdural space: possible influence on the pathogenesis and recurrence frequency of chronic subdural hematoma and subdural hygroma

Abstract

Object The purpose of this study was to clarify whether cerebrospinal fluid (CSF) leakage into the subdural space is involved in the genesis of chronic subdural hematoma (CSDH) and subdural hygroma (SH) and to clarify whether this leakage of CSF into the subdural space influences the postoperative recurrence rate of CSDH and SH. Methods In this prospective observational study, 75 cases involving patients treated surgically for CSDH (67 patients) or SH (8 patients) were evaluated with respect to clinical and radiological findings at presentation, the content of β -trace protein (β TP) in the subdural fluid (βTPSF) and serum (βTPSER), and the CSDH/SH recurrence rate. The βTPSF was considered to indicate an admixture of CSF to the subdural fluid if βTPSF/βTPSER > 2. Results The median β TPSF level for the whole patient group was 4.29 mg/L (range 0.33–51 mg/L). Cerebrospinal fluid leakage, as indicated by βTPSF/βTPSER > 2, was found to be present in 93% of the patients with CSDH and in 100% of the patients with SH (p = 0.724). In patients who later had to undergo repeated surgery for recurrence of CSDH/SH, the βTPSF concentrations (median 6.69 mg/L, range 0.59–51 mg/L) were significantly higher (p = 0.04) than in patients not requiring reoperation (median 4.12 mg/L, range 0.33–26.8 mg/L). Conclusions As indicated by the presence of βTP in the subdural fluid, CSF leakage into the subdural space is present in the vast majority of patients with CSDH and SH. This leakage could be involved in the pathogenesis of CSDH and SH. Patients who experience recurrences of CSDH and SH have significantly higher concentrations of βTPSF at initial presentation than patients not requiring reoperation for recurrence. These findings are presented in the literature for the first time and have to be confirmed and expanded upon by further studies.