Indications for Subarachnoid Drain
Subarachnoid (lumbar) drainage is indicated for management of elevated intracranial pressure refractory to medical management and ventricular drainage, particularly in aneurysmal subarachnoid hemorrhage (aSAH) patients, as it improves neurological outcomes and reduces secondary infarctions. 1
Primary Indications for Subarachnoid Drain
1. Management of Hydrocephalus in aSAH
- Acute symptomatic hydrocephalus associated with aSAH should be managed by cerebrospinal fluid (CSF) diversion through either external ventricular drainage (EVD) or lumbar drainage, depending on the clinical scenario 2
- Lumbar drainage is particularly beneficial when hydrocephalus persists despite EVD placement
- Helps prevent development of chronic shunt-dependent hydrocephalus
2. Refractory Intracranial Hypertension
- When intracranial pressure (ICP) remains elevated (>20 mmHg) despite:
- Optimal medical management (sedation, mild hyperventilation with pCO2 30-35 mmHg)
- Hyperosmolar therapy (sodium 150-155 mEq/L)
- Ventricular drainage 3
- Controlled lumbar drainage has been shown to reduce ICP from a mean of 27 mmHg to 9 mmHg in patients with refractory intracranial hypertension 3
3. Prevention of Delayed Cerebral Ischemia (DCI)
- Prophylactic lumbar drainage after aneurysm treatment improves neurological outcomes 1
- Higher lumbar drainage volumes are associated with:
- Fewer secondary infarctions (p=0.009)
- More favorable neurological outcomes (odds ratio 0.61 per 100 mL, p=0.03) 1
- Accelerates clearance of subarachnoid blood, which may reduce risk of vasospasm 2
4. Spinal Cord Protection During Thoracic Aortic Surgery
- CSF drainage is beneficial in reducing the risk of spinal cord injury during thoracic aortic aneurysm repair 2
- Maintains adequate spinal cord perfusion pressure by reducing CSF pressure
- Should be combined with maintenance of adequate distal arterial pressure (minimum 60 mmHg) 2
Contraindications and Precautions
Absolute Contraindications
- Mass lesions with significant midline shift
- Uncorrected coagulopathy
- Local infection at insertion site
Relative Contraindications
- Elevated ICP without prior ventricular drainage (risk of herniation)
- Always place ventriculostomy before utilizing lumbar drains to minimize risk of cerebral herniation 3
Management Considerations
Drainage Protocol
- Maintain CSF pressure between 10-15 mmHg
- Controlled drainage is essential to prevent overdrainage and potential complications
- Monitor ICP continuously when draining CSF
Potential Complications
- Headache
- Spinal or epidural hematoma
- Meningitis
- Persistent CSF leaks
- Subdural hematoma
- Abducens nerve palsy (rare)
- Catheter-related issues (retention, breakage) 2
Evidence Quality Assessment
The evidence supporting lumbar drainage in aSAH comes from several high-quality sources:
- Recent randomized controlled trials (Earlydrain) demonstrate improved outcomes with prophylactic lumbar drainage 1
- AHA/ASA guidelines recommend CSF diversion for aSAH-associated hydrocephalus (Class I, Level of Evidence B) 2
- Prospective studies show significant ICP reduction with controlled lumbar drainage in refractory cases 3
The most recent and highest quality evidence (2024) demonstrates that higher amounts and higher proportions of lumbar drainage volumes are associated with better outcomes in aSAH patients, suggesting a quantity-dependent protective effect 1.