Outcomes After Standardized Burr-Hole Surgery for Chronic Subdural Hematomas: A Population-Based Consecutive Cohort Study of 2655 Patients

BACKGROUND AND OBJECTIVES: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions. However, current evidence on postoperative outcomes exhibits variability due to small sample sizes, nonstandardized outcome assessment, and variations in surgical techniques. The aim of this study was to overcome these limitations by assessing standardized outcome measures after surgical intervention for CSDH at a high-volume population-based center favoring a uniform burr-hole craniotomy (BHC) approach. METHODS: Adult patients (≥15 years) who underwent surgical treatment of a CSDH at the Karolinska University Hospital from 2006 to 2022 were retrospectively included. Outcome measures included 6-month ipsilateral hematoma reoperation, postoperative complications categorized by the Landriel-Ibanez grading system, neurological function, and mortality. Predictors of outcomes were assessed using multivariable logistic regression models. RESULTS: In total, 2655 patients were included, with 2407 evacuated using BHC and 248 requiring a minicraniotomy. Reoperation for a hematoma recurrence occurred in 11%. Independent predictors of reoperation were male sex, diabetes, preoperative antithrombotic therapy, midline shift, and bilateral surgery. Postoperative complications occurred in 11% of cases, with 3.9% classified as moderate to severe. A complication leading to death was reported in 22 patients (0.8%). The most common postoperative complications were urinary tract infections (1.5%), subdural empyema (1.4%), and seizures (0.7%). Independent predictors of moderate-to-severe complications were higher preoperative Charlson Comorbidity Index and lower Glasgow Coma Scale score. The 1-year postoperative mortality rate was 12%. CONCLUSION: This study provided standardized outcome measures in a large cohort of patients treated for CSDH at a center where BHC was consistently used. Most postoperative complications were mild and either did not require intervention or were managed with pharmacological treatment. The identified predictors of CSDH reoperation and moderate-to-severe postoperative complications offer considerations for clinical management and patient care.