Inflammation markers and risk factors for recurrence in 35 patients with a posttraumatic chronic subdural hematoma: a prospective study

OBJECT: To evaluate the role of local inflammation in the pathogenesis and postoperative recurrence of chronic subdural hematoma (CSDH), the authors conducted an investigation in a selected group of patients who could clearly recall a traumatic event and who did not have other risk factors for CSDH. Inflammation was analyzed by measuring the concentration of the proinflammatory and inflammatory cytokines interleukin (IL)-6 and IL-8. The authors also investigated the possible relationship between high levels of local inflammation that were measured and recurrence of the CSDH. METHODS: A prospective study was performed between 1999 and 2001. Thirty-five patients who could clearly recall a traumatic event that had occurred at least 3 weeks previously and who did not have risk factors for CSDH were enrolled. All patients were surgically treated by burr hole irrigation plus external drainage. The concentration of inflammatory cytokines was very high in the lesion, whereas it was normal in serum. In five cases in which recurrence occurred, concentrations of both IL-6 and IL-8 were significantly increased (p < 0.01) in comparison with cases without a recurrence. In a layering hematoma, the IL-6 and IL-8 concentrations were significantly higher (p < 0.05). Layering CSDHs were also significantly correlated with recurrence. Trabecular hematoma had the lowest cytokine levels and the longest median interval between trauma and clinical onset. The interval from trauma did not significantly influence recurrence, although it did differ significantly between the trabecular and layering CSDH groups. Concentrations of IL-6 and IL-8 in the CSDHs did not differ significantly in relation to either the age of the hematoma (measured as the interval from trauma) or the age of the patient. CONCLUSIONS: Brain trauma causes the onset of an inflammatory process within the dural border cell layer; high levels of inflammatory cytokines were significantly correlated with recurrence and layering CSDH. A prolonged postoperative antiinflammatory medicine given as prophylaxis may help prevent the recurrence of a CSDH.