Management of Large Subdural Hematoma
Immediate surgical evacuation via craniotomy is indicated for large subdural hematomas, particularly when patients demonstrate deteriorating neurological status, decreased level of consciousness, or significant mass effect with midline shift. 1
Indications for Urgent Surgical Intervention
The 2022 AHA/ASA guidelines strongly recommend immediate surgical removal of the hematoma for patients who are deteriorating neurologically, have brainstem compression, or have significant hematoma volume. 1
Specific criteria requiring urgent surgery include:
- Decreased level of consciousness (GCS ≤7/15) 1
- Progressive neurological deterioration 1
- Significant midline shift or mass effect on imaging 1
- Brainstem compression 1
Timing is critical—delaying surgical intervention in patients with decreased consciousness leads to irreversible neurological damage and increased mortality. 1, 2
Surgical Approach Selection
Acute Subdural Hematoma
- Craniotomy is the standard surgical approach for acute subdural hematomas to achieve adequate evacuation of coagulated blood 1
- Mini-craniotomy with endoscopic assistance can be considered when standard craniotomy is limited by anatomical constraints 3
- In hyperacute cases (first few hours) with mixed-density components on CT suggesting uncoagulated blood, temporizing subdural evacuation port system (SEPS) placement may be used as a bridge to definitive craniotomy 4
Chronic Subdural Hematoma
- Burr hole drainage is the preferred first-line surgical treatment for symptomatic chronic subdural hematomas presenting with altered consciousness 2
- Craniotomy should be reserved for acute-on-chronic subdural hematomas with solid components 2
- Middle meningeal artery embolization (MMAE) is an emerging treatment showing efficacy in promoting hematoma resorption and reducing recurrence rates 5
Medical Management of Intracranial Pressure
While awaiting or alongside surgical intervention:
Mannitol 0.25 to 2 g/kg body weight as a 15% to 25% solution administered intravenously over 30 to 60 minutes is indicated for reduction of intracranial pressure and brain mass 6
Additional ICP management measures:
- Elevate head of bed 20-30 degrees to facilitate venous drainage 7
- Avoid hypo-osmolar fluids that worsen cerebral edema 7
- Treat exacerbating factors: hypoxia, hypercarbia, hyperthermia 7
Post-Operative Management
- Monitor in ICU with consideration for ICP monitoring to maintain cerebral perfusion pressure between 50-70 mmHg 1
- Consider subdural drain placement during surgery to reduce recurrence rates 2
- Maintain euvolemia; avoid both hypovolemia and hypervolemia 2
- Monitor for complications: rebleeding, seizures (occur in up to 23% of patients), and infection 7, 1
Critical Caveats and Pitfalls
Evaluate and reverse coagulopathies or anticoagulant/antiplatelet therapy prior to surgery to minimize bleeding complications 1, 2
Avoid nephrotoxic drugs or other diuretics when administering mannitol, as concomitant use increases risk of renal failure 6
Monitor cardiovascular status and electrolyte levels during mannitol administration, as excessive loss of water and electrolytes may lead to serious imbalances including hypernatremia or hyponatremia 6
Risk factors predicting hematoma expansion that warrant closer monitoring include:
- Initial SDH size >8.5 mm (best threshold for predicting need for surgery) 8
- Concurrent subarachnoid hemorrhage 8
- Hypertension 8
- Convexity location 8
- Initial midline shift 8
Note: No patient with initial SDH ≤3 mm required surgery in recent studies, though 11% enlarged to maximum 10 mm 8