Is lumbar drainage (lumbar puncture with cerebrospinal fluid drainage) safe in patients with external brain herniation through a craniectomy (surgical removal of a portion of the skull) defect?

Lumbar Drainage in Patients with External Brain Herniation Through Craniectomy Defect

Lumbar drainage is contraindicated in patients with external brain herniation through a craniectomy defect due to the high risk of paradoxical herniation, which can be rapidly fatal. 1

Mechanism of Paradoxical Herniation

Paradoxical herniation occurs when cerebrospinal fluid (CSF) removal from the lumbar space in a patient with a craniectomy defect creates a pressure gradient that causes:

• Downward displacement of brain tissue
• Midline shift away from the craniectomy site
• Compression of vital brainstem structures
• Rapid neurological deterioration

This phenomenon results from the combined effects of:

• Atmospheric pressure on the exposed brain
• Gravity
• Intracranial hypotension from CSF drainage 2

Evidence Against Lumbar Drainage in Craniectomy Patients

Multiple case reports document catastrophic outcomes when lumbar drainage is performed in patients with craniectomy defects:

• Paradoxical transtentorial herniation following lumbar puncture in decompressive craniectomy patients 3
• Sinking skin flap syndrome and paradoxical herniation after lumbar drainage with 11% mortality rate 4
• Brain herniation in the direction opposite to the craniectomy site 2

Alternative CSF Diversion Methods

For patients with craniectomy who require CSF diversion:

• External ventricular drainage (EVD) is the preferred method if hydrocephalus is present 5
• EVD allows for controlled CSF drainage while monitoring intracranial pressure
• Placement of an EVD can be performed using neuronavigation for greater precision 5

Management if Lumbar Drainage is Absolutely Necessary

If lumbar drainage must be performed (which should be rare and only after neurosurgical consultation):

1. Obtain recent CT imaging to confirm patent basal cisterns
2. Establish baseline neurological examination
3. Correct any coagulation abnormalities
4. Position patient flat or in slight Trendelenburg position
5. Use smallest possible needle
6. Remove minimal CSF volume
7. Implement continuous ICP monitoring
8. Perform frequent neurological assessments 1

Emergency Management of Paradoxical Herniation

If paradoxical herniation occurs following lumbar drainage:

1. Place patient in Trendelenburg position immediately
2. Administer rapid intravenous fluid boluses
3. Clamp any drainage catheters
4. Consider emergency cranioplasty as definitive treatment 6, 2

In one documented case, placement of a lumbar epidural blood patch successfully reversed paradoxical herniation 6.

Risk Factors for Complications

The mean daily CSF volume drained is a significant risk factor for developing sinking skin flap syndrome or paradoxical herniation in craniectomy patients with lumbar drainage 4.

Conclusion

The current evidence strongly advises against performing lumbar drainage in patients with external brain herniation through a craniectomy defect. The risk of paradoxical herniation and subsequent neurological deterioration or death outweighs potential benefits. External ventricular drainage should be considered as the preferred alternative for CSF diversion in these patients when necessary.