Clinical, radiological, and hematological correlates of recurrence after surgical evacuation of chronic subdural hematoma: a retrospective cohort study

Background Chronic subdural hematoma (CSDH) is one of the most frequently encountered conditions in neurosurgical practice, particularly among older adults, and its incidence is expected to rise with population aging and increasing antithrombotic medication use. Although surgical evacuation is effective in most patients, recurrence requiring further treatment is a well-recognized complication. This retrospective cohort study aimed to describe the clinical, radiological, hematological, and surgical characteristics of patients surgically treated for CSDH and to examine their association with postoperative recurrence. Results Fifty-seven patients treated surgically for CSDH were included. Recurrence occurred in 13 patients (22.8%); all recurrences were radiologically confirmed on computed tomography (CT), and 7 of 13 (53.8%) were symptomatic. Median time to recurrence was 39 days (interquartile range [IQR] 22–55 days). Six of 13 patients with recurrence (46.2%) underwent reoperation (repeat burr-hole drainage in 3, craniotomy in 3). The cohort had a median age of 78 years (IQR 68–83) and was predominantly male (42/57, 73.7%). Burr-hole craniostomy was the most common surgical technique (42/57, 73.7%), and a subdural or subperiosteal drain was used in 51/57 (89.5%). No continuous variable (age, Glasgow Coma Scale [GCS] score, hematoma thickness, midline shift, hematoma volume, hemoglobin, platelet count, international normalized ratio [INR], number of burr holes, drain duration) differed significantly between patients with and without recurrence (all Mann–Whitney U p > 0.05). Among categorical variables, direct oral anticoagulant (DOAC) use was the only factor significantly associated with recurrence (3 of 4 DOAC users recurred versus 10 of 53 non-users; Fisher’s exact p = 0.034); no other clinical, radiological, or surgical categorical variable showed a statistically significant association with recurrence. Conclusions In this cohort, approximately one in five patients experienced recurrence after surgical evacuation of CSDH. Preoperative DOAC use was associated with a higher rate of recurrence, whereas no other clinical, radiological, hematological, or surgical variable reached statistical significance, likely reflecting the limited statistical power afforded by a small sample and a small number of recurrence events. These findings should be interpreted as hypothesis-generating associations rather than validated predictors and require confirmation in larger, adequately powered cohorts before informing clinical decision-making.