Methods Patient Population

ChroniC subdural hematoma is a common condition after head trauma. It is often successfully treated surgically by inserting a bur hole and draining the liquefied hematoma. However, to the best of our knowl-edge, for nonemergency cases not requiring surgery, no reports have indicated the best approach for preventing hematoma enlargement or resolving it completely. To date, conservative treatments have not been established. The resolution of CSDH after treatment with simple ob-servation has been reported as a relatively rare phenom-enon.5,7 Several studies have shown that hyperfibrinolytic ac-tivities play a major role in the liquefaction and enlarge-ment of CSDH.4,6 We hypothesized that tranexamic acid, an antifibrinolytic agent that has fewer side effects than other agents and is widely used for hemostasis,2 would inhibit the hyperfibrinolytic activity of CSDH. Therefore, we assessed the effects of tranexamic acid on CSDH vol-ume