Outcomes of Craniotomy vs Burr Hole Evacuation for Chronic Subdural Hematoma: A Retrospective, Multicenter Study

Introduction: Craniotomy and burr hole evacuation are both effective treatments for chronic subdural hematoma (cSDH); studies comparing their outcomes have yielded mixed results. This study compares craniotomy and burr hole evacuation for cSDH across four outcomes: 30-day mortality, 30-day readmission, 6-month retreatment, and length of stay (LOS).

Methods: We performed a retrospective chart review of cSDH patients treated at four level 1 trauma centers (February 2009–August 2021). Patients treated with bilateral surgery or MMA embolization were excluded. Multivariable regression using bidirectional stepwise selection was performed to assess the relationship between surgery type and outcomes. A stratified analysis compared outcomes across three age groups: < 65, 65–74, and ≥75.

Results: We identified 599 patients for analysis, 277 of whom underwent craniotomy (46.2%). Craniotomy and burr hole groups had comparable preoperative characteristics (age, GCS, midline shift, anticoagulation, and cSDH volume). Median volume removed was higher for Craniotomy (63 mL vs 55 mL, p< 0.01). Craniotomy was independently associated with higher odds of mortality (OR 2.66, 95% CI: 1.42–5.16, p< 0.01) and readmission (OR 1.66, 95% CI: 1.14­–2.42, p< 0.01) compared to burr hole. There were no significant differences in retreatment (OR 0.80, 95% CI: 0.47-1.33, p=0.39) or LOS (β= -1.03, 95% CI: -2.98­–0.91, p=0.30). In patients aged < 65 years, there were no significant differences in mortality (7.6% vs. 1.4%, p=0.10) or readmission (26% vs. 30%, p=0.6). In those aged 65–74, craniotomy had higher readmission (33% vs. 14%, p< 0.01), but no difference in mortality (5.3% vs. 3.6%, p=0.7). For patients ≥75 years, craniotomy was associated with higher mortality (17% vs. 7.3%, p< 0.01) and readmission (30% vs. 19%, p=0.04).

Conclusion : Craniotomy was independently associated with higher odds of 30-day mortality and readmission compared to burr hole evacuation, with no differences in retreatment or LOS. Older age modified the associations of craniotomy with higher mortality and readmission.