“…Craniostomy is the main method of surgical treatment, 23) and is performed by twist drill craniostomy (diameter less than 5 mm), 6,7,13,19,23) one burr-hole craniostomy (8-15 mm), 5,7,18,20) and two burr-hole craniostomy. 15,21) Twist drill craniostomy was introduced as a less invasive method for the treatment of CSDH, and is used worldwide. 13,19) The two burr-hole method is also widely used, 15,21) and was introduced to achieve sufficient irrigation, which could reduce the rate of recurrence of CSDH.…”