Chronic subdural hematoma (CSDH) is a frequent condition in neurosurgery, leading to fluid accumulation between the meninges, brain compression, neurological dysfunction, and potentially herniation. The efficacy of treatments and their long-term outcomes remain uncertain, with no established standard. Notably, neuroendoscopy-assisted hematoma evacuation, in contrast to burr-hole drainage, enables direct visualization and thorough removal of the hematoma, thereby minimizing residue, lowering recurrence rates, and shortening drainage duration. This study will undertake a multicenter trial to compare these two methods and determine the superior treatment approach for CSDH.

Chronic subdural hematoma (CSDH) is a common disease in neurosurgery. It is generally considered to be a closed fluid collection situated between the dura mater and arachnoid mater, formed by blood or blood degradation products. This collection causes a local mass effect, compressing adjacent brain tissue and leading to varying degrees of neurological dysfunction. In severe cases, it can induce brain herniation, endangering the patient's life. In recent years, despite the availability of various pharmacological and surgical treatment options for CSDH, the efficacy and long-term prognosis of these treatment methods and strategies remain not entirely clear, and a standardized treatment approach has yet to be established. Neuroendoscopy-assisted hematoma drainage is one of the treatment methods for CSDH, but its current application is not widespread. The core of this method involves neurosurgeons directly observing the hematoma structure during surgery with the assistance of a neuroendoscope, enabling them to thoroughly irrigate and aspirate the hematoma under direct vision and sever hematoma septations. This approach enhances the hematoma clearance rate, ultimately reducing the amount of postoperative hematoma residue. Compared with conventional burr-hole drainage, neuroendoscopy-assisted burr-hole drainage reduces the recurrence rate of CSDH and shortens the duration of postoperative drainage. This study aims to conduct a multicenter randomized controlled trial comparing neuroendoscopy-assisted hematoma drainage with burr-hole drainage, with the objective of scientifically and rigorously determining the optimal clinical treatment strategy for CSDH.

Inclusion Criteria:

1. Patient (18 years to 90 years) presenting with clinical symptoms and neurological deficits of CSDH.
2. CSDH verified on cranial computed tomography or magnetic resonance imaging.
3. Written informed consent from patients or their next of kin according to the patient's cognitive status.

Exclusion Criteria:

1. No clinical symptoms correlating with chronic subdural hematoma.
2. Lack of mass effect and midline shift < 5 mm on the radiological image, or no need surgery judged clinically by neurosurgeons.
3. Previous surgery for CSDH during the past 6 months.
4. Previous intracranial surgery for any other neurological disorder.
5. Poor medication conditions or the presence of severe comorbidities so that surgery cannot be tolerated, or follow-up cannot be completed.
6. Severe coagulopathy or a high risk of life-threatening bleeding (including any one of the following three criteria: prothrombin time or activated partial thromboplastin time prolonged by more than 10 seconds; international normalized ratio > 3.0; absolute platelet count < 100×109/L).
7. Postoperative compliance is suspected to be insufficient for 3-month follow-up visit.
8. Reproductive-age women without verified negative pregnancy testing.
9. Participating in another research.

This study plans to share de-identified individual participant data (IPD) six months after the publication of its core findings, aiming to enhance transparency and foster scientific collaboration in the field. The shared data will encompass: ① clinical indicators at baseline and follow-up (e.g., demographic characteristics, laboratory tests, outcome events); ② records of experimental interventions (grouping, surgical protocols); and ③ exclusion of identifiable information (names, precise birth dates, addresses, etc.). The data will be stored in an encrypted institutional data repository (or a public repository such as Figshare), and access will be granted only after the signing of a Data Use Agreement (DUA).

Data sharing will be opened 6 months after the completion of the study, with a duration of 5 years.

Access to IPD is available to collaborators within the original research consortium. External researchers may apply via a formal request to the principal investigator (PI), including a rationale for access, proposed analysis plan, and confirmation of compliance with institutional review board (IRB) requirements. All users must sign a data usage agreement prior to receiving data.

The design is open labeled with only the investigators for postoperative follow-up evaluation, the outcome assessors, and data analysts being blinded in all 24 centers. Before outcome assessment begins at every follow-up evaluation, the patients will be reminded not to reveal any information about their group allocation. If details of group allocation can be detected by the investigator during follow-ups, another blinded researcher will replace to evaluate outcome.