The clinical characteristics of patients who presented in poor clinical grade due to ruptured middle cerebral artery aneurysms (MCAAs) associated with large sylvian hematomas (SylH) were analyzed and an ingenious designed prophylactic hinged craniectomy was introduced. Twenty-eight patients were graded into Hunt-Hess grades IV-V and emergency standard micro-neurosurgeries (aneurysm clipping, hematoma evacuation and prophylactic hinged craniectomy) were performed, and their clinical data were retrospectively analyzed. 46.43% of the patients reached encouraged favorable outcomes on discharge. The favorable outcome group and the poor outcome group significantly differed in terms of patients' anisocoria, Hunt-Hess grade before surgery, extent of the midline shift and time to the surgery after bleeding (P<0.05). There were no significant differences in age, sex, volume and location of the hematoma, size of aneurysm between the favorable and poor groups (P>0.05). However, ingenious designed prophylactic hinged craniectomy efficiently reduced the patients' intracranial pressure (ICP) after surgery. It was suggested that preoperative conditions such as Hunt-Hess grading, extent of the midline shift and the occurrence of cerebral hernia affect the prognosis of patients, but time to the surgery after bleeding and prophylactic hinged craniectomy are of significant importance for optimizing the prognosis of MCAA patients presenting with large SylH.