Inclusion Criteria:

1. Age ≥ 18 years.

2. Unilateral chronic subdural hematoma (cSDH) or subacute-to-chronic subdural hematoma, confirmed by CT or MRI.

3. Presence of clinical symptoms attributable to cSDH, such as headache, limb weakness, gait disturbance, cognitive decline, speech disturbance, seizure, or impaired consciousness.

4. Radiological indication for surgery, defined as one of the following:

   Maximum hematoma thickness ≥ 10 mm, and/or Midline shift ≥ 5 mm, or Even if these thresholds are not met, clinically significant symptoms requiring surgery as judged by the treating neurosurgeon.

5. Plan to undergo twist-drill puncture drainage with a closed drainage system.

6. Written informed consent signed by the participant or their legally authorized representative.

Exclusion Criteria:

1. Bilateral cSDH requiring simultaneous bilateral surgery.
2. Acute subdural hematoma, or a condition where the hematoma is predominantly composed of an acute hemorrhagic component.
3. Markedly septated, organized, or calcified hematoma in which minicraniotomy or craniotomy is required preoperatively.
4. Previous surgery on the ipsilateral side for cSDH.
5. Concomitant intracranial conditions requiring specific treatment, including but not limited to: intracranial tumor, brain abscess, vascular malformation, or ruptured aneurysm.
6. Severe coagulation disorder that cannot be corrected before surgery.
7. Life expectancy < 6 months.
8. Pregnancy.
9. Any condition that, in the judgment of the investigator, makes the patient inappropriate for participation in the study.