What are the indications for an emergency burr hole in the setting of a subacute hematoma?

Emergency Burr Hole Indications for Subacute Subdural Hematoma

Emergency burr hole drainage is indicated for subacute subdural hematomas when patients present with altered consciousness, neurological deterioration, or significant mass effect with midline shift, as this represents a life-saving intervention that can rapidly reduce intracranial pressure and prevent irreversible brain damage. 1, 2

Primary Indications for Emergency Burr Hole

Neurological Status Criteria

• Glasgow Coma Scale ≤8 or rapidly deteriorating consciousness level requires immediate burr hole evacuation 1, 2
• Progressive neurological deterioration with signs of cerebral herniation (pupillary changes, posturing, brainstem compression) mandates emergent intervention 3, 4
• Patients presenting with altered consciousness, vomiting, and tiredness from symptomatic chronic/subacute subdural hematoma should undergo burr hole drainage as first-line treatment 1

Radiographic Criteria

• Hematoma thickness >5 mm with midline shift >5 mm indicates need for surgical evacuation 3
• Significant mass effect causing brainstem compression or fourth ventricle obliteration requires immediate decompression 3
• Evidence of acute-on-chronic components may necessitate craniotomy rather than simple burr hole, but burr hole can serve as temporizing measure 1, 4

Clinical Decision Algorithm

Step 1: Immediate Assessment

• Obtain Glasgow Coma Scale score and perform pupillary examination 3, 2
• Assess for signs of increased intracranial pressure (altered consciousness, vomiting, headache) 3, 1
• Emergency CT scan to confirm diagnosis, assess hematoma size, location, and mass effect 3, 2

Step 2: Determine Urgency

• If GCS ≤8 or deteriorating: Proceed immediately to burr hole evacuation, even before transfer to operating room if herniation imminent 4, 5
• If GCS 9-12 with symptoms: Urgent burr hole drainage within hours 1, 2
• If GCS ≥13 but symptomatic: Expedited burr hole drainage as first-line treatment 1

Step 3: Surgical Approach Selection

• Burr hole drainage is preferred first-line treatment for subacute/chronic subdural hematomas presenting with altered consciousness 1
• Reserve craniotomy for acute-on-chronic hematomas with solid components that cannot be evacuated through burr hole 1
• Consider emergent single burr hole as temporizing measure followed by definitive craniotomy if inadequate decompression 4, 6

Critical Time-Sensitive Considerations

The most important pitfall is delaying surgical intervention while attempting "stabilization"—this leads to irreversible neurological damage and increased mortality. 2, 5

• In patients with impending herniation, burr hole can be performed in emergency department before CT or transfer to prevent further brain damage 5
• Emergent single burr hole evacuation followed by decompressive craniectomy shows significantly better outcomes (higher GCS scores at 1 and 6 months, better Glasgow Outcome Scale scores) compared to medical management alone in herniation cases 4
• Time from presentation to decompression directly correlates with outcome—earlier intervention associated with better neurological recovery 2, 4

Pre-Procedural Management

Coagulopathy Reversal

• Evaluate for anticoagulant or antiplatelet therapy and reverse prior to intervention when possible 1, 2
• Check platelet count, PT, aPTT, and INR before proceeding 3
• In coagulopathic patients with liquefied subacute hematomas, burr hole drainage may be safer than craniotomy 7

Hemodynamic Optimization

• Maintain systolic blood pressure >110 mmHg using vasopressors if needed 8
• Avoid hypotensive episodes (SBP <90 mmHg) as single episode worsens neurological outcome 8
• Secure airway with endotracheal intubation if GCS ≤8 or inability to protect airway 3, 8

Post-Procedural Management

• Place subdural drain during surgery to reduce recurrence rates 1
• Maintain euvolemia—avoid both hypovolemia and hypervolemia 3, 1
• Monitor for complications including rebleeding, seizures, and infection 1, 2
• Consider ICP monitoring if GCS ≤8 or unable to perform reliable neurological examination 8, 2
• Maintain cerebral perfusion pressure 50-70 mmHg (or ≥60 mmHg per some guidelines) 8, 2

Important Caveats

Never delay neurosurgical consultation or transfer to a neurosurgical facility—immediate transfer is essential even if it means performing burr hole at non-neurosurgical center first. 8, 5

• In spontaneous intracranial hypotension with subdural hematoma, burr hole drainage can paradoxically worsen herniation—consider Trendelenburg position and epidural blood patch instead 9
• Multiple traumatic subdural hematomas may require combination of burr hole evacuation and craniotomy, with burr hole serving as initial temporizing measure 6
• Burr hole evacuation works best for liquefied subacute hematomas; acute clotted blood may require craniotomy 1, 7