What is the role of external lumbar drainage (ELD) in managing refractory intracranial hypertension following traumatic brain injury (TBI)?

Role of External Lumbar Drainage in Managing Refractory Intracranial Hypertension Following TBI

External lumbar drainage (ELD) is an effective second-tier therapy for managing refractory intracranial hypertension in traumatic brain injury patients when basal cisterns are discernible, with studies showing significant ICP reduction and improved outcomes. We suggest performing external lumbar drainage to treat persisting intracranial hypertension when conventional therapies fail and basal cisterns remain visible on imaging.

Indications and Positioning in Treatment Algorithm

• External ventricular drainage is suggested as a treatment for persisting intracranial hypertension that doesn't respond to sedation and correction of secondary brain insults (Grade 2+ recommendation) 1
• ELD should be considered after failure of first-line treatments for intracranial hypertension, including:
  • Sedation optimization 1
  • Correction of secondary brain insults 1
  • External ventricular drainage (if feasible) 1
• ELD is positioned as a rescue therapy before more invasive third-tier interventions such as decompressive craniectomy or barbiturate coma 2

Safety Considerations and Patient Selection

• Critical safety requirement: Basal cisterns must be discernible on CT imaging before ELD placement to minimize herniation risk 3, 4, 5
• Contraindications include:
  • Obliterated basal cisterns 5, 6
  • Significant midline shift 1
  • Coagulopathy or abnormal hemostasis 2
• The risk of cerebral herniation with lethal outcome is approximately 6% when proper patient selection criteria are applied 5

Efficacy Data

• ELD consistently demonstrates significant ICP reduction:
  • From 30.9 ± 7.9 mm Hg to 14.1 ± 5.9 mm Hg in one study 3
  • From 32.7 ± 10.9 to 13.4 ± 5.9 mm Hg in another larger study 5
  • From 30.6 ± 4.7 mm Hg to 11.5 ± 3.9 mm Hg in a smaller series 6
• ELD significantly reduces the need for additional second and third-tier interventions (60 vs 25 interventions, p<0.001) 2
• Episodes of intracranial hypertension (ICP>20 mmHg) within one day decreased from 10 to 2 after ELD implementation 2

Outcomes and Mortality Benefits

• Good functional outcomes (GOS 4-5) at 6 months were observed in 76% of patients treated with ELD for refractory intracranial hypertension 3
• In-hospital mortality was significantly lower than predicted in patients receiving ELD (16% vs predicted 48%) 2
• Favorable outcomes were better than predicted by prognostic calculations (GOSE 1-4: 49% vs CRASH prediction: 87% vs IMPACT prediction: 51%) 2

Special Considerations

• ELD appears particularly effective in cases of acute traumatic external hydrocephalus, where abnormally enlarged cranial subarachnoid spaces are present following traumatic subarachnoid hemorrhage 4
• Duration of ELD use is typically 5-7 days 2
• Potential complications to monitor include:
  • ICH rebound after ELD removal (reported in 24% of patients) 3
  • Cerebrospinal fluid infection (though rare with proper management) 3

Comparison to Other Second/Third-Tier Therapies

• Decompressive craniectomy, while effective at reducing mortality (26.9% vs 48.9%), may increase the risk of poor neurological outcomes 1
• ELD offers a less invasive alternative to decompressive craniectomy with potentially better functional outcomes in appropriately selected patients 2, 4
• ELD may help avoid the need for barbiturate coma, which carries significant systemic complications including arterial hypotension 1, 2

Implementation Recommendations

• ELD should be implemented with continuous ICP monitoring 3, 2, 5
• CSF drainage should be controlled based on ICP values and neurological status 5, 6
• Close monitoring for signs of herniation or neurological deterioration is essential 5
• ELD should be maintained for approximately 5 days, with vigilance for ICP rebound upon removal 3, 2