Baseline Characteristics Associated with Improved Outcomes in Patients Undergoing Primary Decompressive Craniectomy for Acute Subdural Hematoma Evacuation—A Retrospective Observational Study

<i>Background and Objective</i>: The study's aim is to identify a subgroup of patients who would benefit from primary decompressive craniectomy (pDC) after acute subdural hematoma (aSDH) evacuation. <i>Materials and Methods</i>: A retrospective analysis of 290 patients undergoing aSDH evacuation between 2016 and 2021 was conducted. Osteoplastic craniotomy (OC) was performed in 213 cases (73.4%), whereas 77 individuals underwent pDC. Preoperative characteristics, such as age, initial GCS score, hematoma thickness, midline shift, and cisternal effacement score (CES), were used to predict outcome at discharge by the Glasgow Outcome Scale (GOS). <i>Results</i>: Older age, lower initial GCS, and higher CES preoperatively were independently associated with lower GOS scores at discharge. Age and degree of cisternal compression remained significant predictors of GOS score in the pDC subgroup. Survivors who underwent pDC were younger in comparison to deceased individuals receiving OC (mean age 55.43 ± 14.58 vs. 72.28 ± 14.63, <i>p</i> < 0.001). Patients who achieved favorable outcomes after pDC were significantly younger compared to those who had poor outcomes after OC (mean age 49.20 ± 12.05 vs. 72.28 ± 14.32, <i>p</i> < 0.001). <i>Conclusions</i>: Younger patients (<55 years old) with initial GCS scores of 4-6, midline shifts of 1 to 2 cm, subdural hematoma thickness of 1 to 2.5 cm, and CES in a range of 7-12 may benefit from pDC as it could potentially improve survival and functional outcomes after aSDH evacuation.