Inclusion Criteria:  A. Written informed consent obtained from the patient or his/her legally acceptable representative B. Acute ischemic stroke within middle cerebral artery or internal carotid artery occlusion  Regardless of anterior cerebral artery (ACA) or posterior cerebral artery (PCA) involvement C. Patients of both sexes aged ≥ 19 years and ≤ 82 years D. NIHSS score ≥ 15 points, NIHSS loss of consciousness 1a score ≥ 1 point E. Patients with proximal cerebral arterial occlusion (such as middle cerebral or internal carotid artery) F. Unilateral ischemic lesion of at least 2/3 of the middle cerebral artery (MCA) territory involving basal ganglia confirmed by computed tomography (CT) or magnetic resonance imaging (MRI) Decided to perform decompressive hemicraniectomy within 48 hours after symptom onset - Onset time was defined as the time when patients were lastly seen normal  Exclusion Criteria:  A. Premorbid modified Rankin Scale (mRS) score ≥ 2 B. Presence of other type of brain lesions including traumatic brain injury, contralateral or infratentorial infarct.  C. Absence of bilateral pupillary reflex D. Known bleeding disorder or coagulopathy E. Sepsis F. End stage malignant disease G. Pregnancy or during breast feeding H. Life expectancy less than 3 year