What are the operative criteria for surgical evacuation of chronic subdural hematoma (SDH) in elderly patients?

Operative Criteria for Chronic Subdural Hematoma

Symptomatic chronic subdural hematomas require surgical evacuation, while asymptomatic patients can be managed with observation alone. 1

Indications for Surgery

Absolute Indications

• Presence of neurological symptoms including headache, confusion, hemiparesis, or aphasia warrants surgical intervention 1
• Neurological deterioration in a previously stable patient is an indication for immediate surgical treatment 1
• Midline shift >5 mm combined with hematoma thickness >10 mm requires surgical evacuation 2

Observation is Appropriate When:

• Asymptomatic patients with incidentally discovered chronic subdural hematomas can be monitored with watchful waiting 1
• Subdural collections of only a few millimeters, particularly in elderly patients with brain atrophy, are relatively common incidental findings that do not require intervention 1

Surgical Approach Selection

First-Line Treatment

Burr hole evacuation under local anesthesia is the preferred initial approach for symptomatic chronic subdural hematomas 1, 3

• This technique is simple, well-tolerated, and particularly advantageous in elderly polymorbid patients 1
• Local anesthesia is associated with decreased risk of complications (p < 0.001), shorter surgery duration (p < 0.001), and shorter hospital stay (p < 0.001) compared to general anesthesia 3
• Postoperative closed-system drainage after burr hole evacuation reduces recurrence rates (risk ratio 0.48,95% CI 0.34-0.66, p < 0.00001) with no increase in complications 4

Alternative Approaches

• Twist drill craniostomy is equivalent to burr hole evacuation in terms of neurologic outcomes, but has significantly higher 30-day recurrence rates (37.3% vs. 2.9%, p < 0.001) 5
• Thick membranes are a relative contraindication for twist drill craniostomy due to high 30-day recurrence 5

Escalation to Craniotomy

Standard craniotomy is indicated for:

• Symptomatic patients with multilobulated hematomas that recur after burr hole evacuation 1
• Patients with recurrent chronic subdural hematoma after initial burr hole treatment 1

Important caveat: In patients >80 years old, standard craniotomy carries higher risk of stroke and increased length of stay compared to less invasive options 5

Management of Recurrence

• First recurrence: Reoperation using either the same burr hole or a new one is indicated 1
• Persistent recurrence after burr hole: Schedule for craniotomy 1
• High-risk patients for recurrence: Consider irrigation of subdural space with thrombin solution 4

Referral Patterns

All patients with chronic subdural hematoma should be referred to a neurosurgical department, preferably a certified level 1 trauma center with experience in neurotrauma care 1

Common Pitfalls to Avoid

• Do not perform twist drill craniostomy in patients with thick membranes due to unacceptably high recurrence rates 5
• Do not omit postoperative drainage after burr hole evacuation, as this significantly increases recurrence risk 4
• Do not delay surgical intervention in symptomatic patients, as neurological deterioration may progress rapidly 1