Neurosurgery notes/CSF/Intracranial hypotension/CSF fistula/Spinal CSF fistula

Spinal CSF fistula

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CSF fistula

General

  • AKA spontaneous spinal venous fistula

Presentation

  • Early
    • Postural headache
    • Neck stiffness and tenderness
    • Hearing loss
  • Late
    • Cognitive decline
      • Present like frontotemporal dementia

Presumed pathophysiology (Mr Payal)

  • Type 3 leaks
    • The radicular dural membrane Is thin and there are many periradicular large dilated veins that can ruptured (not sure why ? Increase pressure in vein) and form abnormal connection. Due to the low pressure in veins CSF leaks into the venous system.
    • Blood can enter the CSF causing siderosis

CSF venous fistula

  • First described in 2014
  • Heavily underdiagnosed
  • Perhaps account for 1/4ᵗʰ of all SIH cases
  • Can be multiple
  • Often thoracic, but can be anywhere in the spine
  • How many Chiaris are actually CSF VF?
  • No UK series published yet
  • Neurologists and Neuroradiologists are the key
  • MRI Brain can be normal and often is
  • Vast majority settle with conservative measures or blood patches

Types

  • Type 1 CSF leaks
    • Are caused by a dural tear located ventral to the spinal cord (type 1a) or (postero-) lateral to the spinal cord (type 1b).
  • Type 2 CSF leaks
      • Are associated with simple (type 2a) or complex (type 2b [dural ectasial]) meningeal diverticula.
      • Abnormal outpouchings of the common dural sac, the spinal arachnoid, or the nerve root sheath
      notion image
  • Type 3 CSF leaks
      • CSF-venous fistulas
      notion image
  • Type 4 CSF leaks
    • Are of indeterminate origin.

Investigation

  • MRI brain and spine
    • Look for chiari 1
      • Low pressure chiari
        • Sloping brainstem
        • Full sella
        • Leptomeningeal enchacement
      • High pressure chiari
        • ICP bolt studies
        • Opthalmology review for papilloedema
        • Optic nerve sheath dilatation and tortuosity
      • Deformed
    • SWI
      • Look for siderosis of the cerebellum
  • CT myelogram in lateral positioning
    • Look for contrast leakage
    • Can have multiple leakage

Treatment

  • Blood patch done at least twice
  • Endovascular venous gluing of CSF venous fistula
  • Surgically disconnection of CSF venous fistula via a wilsie approach
  • Surgically closing ventral or dorsal dural tears type 2
    • Ventral
      • More complex require intradural closure via mobilising spinal cord using the dentate ligament
      • Closure can be done using clips or suture.
      • Use a small dural patch + fibrin glue
    • Dorsal
      • More straightforward closure.