The goal of this observational study is to better understand how chronic subdural hematoma (CSDH) progresses and how patients are treated and cared for. The study focuses on three main questions:

1. What are the characteristics of patients with CSDH when they are diagnosed?
2. What treatments do patients with CSDH receive?
3. What are the outcomes for patients with CSDH, including their functional ability, cognitive health, and neurological status?

Participants will receive their usual standard treatment. As part of the study, they will complete a brief telephone interview three months after their treatment.

Rationale:

Chronic subdural hematoma (CSDH) is a common condition encountered by neurologists and neurosurgeons. While guidelines for the management of CSDH have recently been developed, high-quality evidence to inform these recommendations, particularly level I evidence from randomized clinical trials (RCTs), is awaited. Significant variability in the management of CSDH persists at international, national, and inter-hospital levels. To further refine and implement evidence-based guidelines, a detailed understanding of current clinical practices and their associated outcomes is essential.

Objective:

To describe the baseline characteristics, treatment strategies, and outcomes of patients diagnosed with chronic subdural hematoma.

Study design:

A prospective, observational multicenter cohort study.

Study population:

All adult patients diagnosed with chronic subdural hematoma.

Main study parameters/endpoints:

The primary endpoint is functional outcome, measured by the modified Rankin Scale (mRS) at 3 months. Secondary endpoints, also assessed at 3 months, include recurrence, mortality, complications, hospital length of stay, Markwalder Grading Scale (MGS), modified National Institutes of Health Stroke Scale (mNIHSS), and Telephone Interview for Cognitive Status (TICS).

Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

Patients will be treated in accordance with standard clinical practice. Study participation imposes minimal additional burden, consisting of a single telephone interview at three months, estimated to take approximately 10 minutes. The findings from this registry are expected to benefit future CSDH patients by informing evidence-based guidelines and improving care practices.

Inclusion Criteria:

• Patients diagnosed with CSDH
• 18 years or older

Exclusion Criteria:

• Patients who do not consent to participate in the registry

Patients diagnosed with CSDH will be recruited from participating centers.

De-identified research data may be shared with third parties to enhance its scientific value. Requests for data must be submitted to the principal investigators, accompanied by a detailed description of the study's objectives and methods. Data will be available for sharing beginning in January 2028. Sharing will be permitted for scientific purposes, such as individual patient meta-analyses. Additionally, explicit consent will be required for sharing de-identified data outside the European Union.

Data will be available for sharing beginning in January 2028.

Written proposals will be reviewed by the registry's principal investigators to evaluate their suitability for data use. Before any data is shared, a data-sharing agreement compliant with Dutch regulations will be established.