In a multi-national population-based cohort, the investigators want to compare the clinical course and clinical outcome of elderly patients (≥70 y/o) compared with younger patients (< 70 y/o) with acute subdural hematoma treated surgically. An improved understanding of the clinical outcome and the prognostic factors of acute subdural hematomas would allow physicians to make better decisions about treatment options in traumatic ASDH in the elderly population.

Primary endpoint:

In a population based study to evaluate 30-day mortality (perioperative death) in younger versus elderly (≥70 years) patients with ASDH.

Secondary endpoint(s):

1. Describe pattern of care in younger versus the elderly

2. Clinical outcome (Glasgow outcome scale at 6-months (range, 3-12) follow-up in younger versus elderly (≥70 years) patients with ASDH:

   • Good outcome predefined as GOS 4-5
   • Unfavourable outcome predefined as GOS 1-3

3. 30-day morbidity (according to the Ibanez classification) in younger versus elderly (≥70 years) patients with ASDH.

4. To assess the effect of age as an independent prognostic factor in traumatic ASDH for outcome (GOS) in the elderly (≥70 years) using a three-step approach

   1. Match elderly (cases) with younger (controls) patients with respect to

      1. GCS at admission to treating hospital according to severity - mild (GCS 14-15), moderate (GCS 9-13), severe (GCS 3-8)
      2. Midline-shift (with a cut off of > 10 mm)
      3. Dilated pupil(s) (yes/no)

   2. Using a multivariable approach with all patients including age (continuous model) to identify independent predictors of an unfavourable outcome (GOS 1-3)

   3. Using a multivariable approach including age as a continuous variable within the elderly population (≥70 years) to identify independent predictors of an unfavourable outcome among the oldest (GOS 1-3)

Inclusion Criteria:

• Surgically treated ASDH patients

Exclusion Criteria:

• Post-operative ASDH (i.e. inclusion criteria post-traumatic)
• Intracranial surgery within 6 months prior to trauma
• Permanent intracranial device (i.e DBS electode, VP shunt etc.)

Surgically treated patients with acute subdural hematoma