Case 4 from the drainage group. The patient operated on for the IIIrd ventricle anaplastic haemangiopericytoma developed left temporal-occipital EDH. Epidural drainage with the vacuum system was performed. The drainage was removed 2 days later, with no further complications. A: Pre-op. MR of patient 4 (saggital, enhanced T1-weighted), showing tumor in the IIIrd ventricle, with heterogeneous prominent enhancement. The patient has accompanying hydrocephalus. The tumor was confirmed as anaplastic haemangiopericytoma by postoperative pathological examination. B &C: Intraoperative BUS identifying left temporal-occipital EDH after tumor resection. The patient was operated on through right POPPEN approach. D: Post-op. CT scan a couple of hours after the operation. Left epidural hyperintensive signal and the draining cathether could be seen. There was also another catheter draining the residual cavity left by tumor resection. E: Post-op. CT scan before epidural drainage removal 2 days later. The epidural hyperintensive signal reduced prominently. F: CT scan of the patient after discharging. There was no abnormal signal of the epidural space. G &H: The vacuum drainage system. The vacuum was formed through the strength of the springs, and the volume capacity is 400 ml.