In the craniotomy group, after removing the flap and opening the dura, because of the pressure difference of “distant brain-hematoma-brain tissue around bone window”, some brain tissue bulged out from bone window under the influence of brain tissue pressure and hematoma pressure, significantly decreasing the brain tissue pressure. Thus, in the process of hematoma removal, the pressure difference of "brain-hematoma " hardly forms. The hematoma does not retract and is not easy to remove. The only way for removal is the use of a brain spatula to pull brain tissue and reveal hematoma for clearance, which is also challenging because excessive pulling can easily damage brain tissue.