Efficacy of goreisan for asymptomatic bilateral and unilateral chronic subdural hematoma

Aim Chronic subdural hematoma (CSDH) is a common neurosurgical clinical entity but the complication rates are not well established. Almost all CSDH patients undergo surgical intervention, but some patients are treated pharmacologically. In this study, we investigated the medical treatment of asymptomatic or mild symptomatic CSDH using only goreisan. Methods Eight patients with unilateral/bilateral CSDH without neurological disorder were given goreisan. Maximum vertical thickness of CSDH slice was measured on neuroradiological imaging. Treatment duration was defined as the period from when goreisan was first prescribed to the last visit, when either resolution of CSDH or neurosurgical intervention were indicated. Results Eight patients with 11 lesions (three patients had bilateral CSDH) were enrolled in this study and treated with only goreisan. The median treatment duration was 10 weeks. Two patients required surgery because of hematoma increase with neurological deterioration. Six of eight patients did not require surgery. Conclusions Medical treatment using goreisan for asymptomatic CSDH was effective. Some studies have demonstrated that aquaporin-4 (AQP4) plays an important role in CSDH. In recent studies, goreisan was found to inhibit AQP4 expressed on the outer membrane of CSDH. In the present patients, goreisan may have inhibited AQP4 on the outer membrane of CSDH, thereby decreasing membrane permeability. Therefore, we speculate that goreisan causes a decrease in CSDH hematoma volume. Furthermore, we speculate that goreisan may be associated with the inflammation process, thereby resolving CSDH.