Objective:It is relatively rare that chronic subdural hematoma (CSDH) occurs in young people. The aim of this study was to investigate how often an arachnoid cyst (AC) is associated with CSDH in young patients by collecting and analyzing cases of CSDH in young people. In addition, we would discuss the association between the AC and CSDH, which is supposed to help in the diagnosis and treatment of patients with AC.Methods and Materials:This study collected 45 consecutive patient cases with head injury in our hospital from February 2009 to December 2011. Five of 45 patients were diagnosed as CSDH associated with AC by performing either a computed tomography scan of the head or a magnetic resonance imaging. During their treatment in our hospital, we performed burr hole irrigation to evacuate hematoma, leaving AC intact.Results:For young people, our study showed that among patients of CSDH, 11.1% were associated with AC, which were all located in the middle cranial fossa. Those 5 patients with ACs had mild trauma history, and they were admitted to our hospital with complaints of headache, vomit, and/or dizziness. After the evacuation of hematoma by burr hole irrigation, all of the 5 patients were cured.Conclusions:Among all young patients with CSDH, many of them are associated with AC, which indicates that AC is a risk factor for CSDH. Most young patients with CSDH presented with symptoms of increased intracranial pressure, and they were all cured by burr hole irrigation, without fenestration of the AC so as to reduce the surgical injury and risk.