Endovascular Embolization of Spontaneous Vertebro-Vertebral Arteriovenous Fistula with liquid embolics in a case of Neurofibromatosis Type I

CLINICAL DETAILS

• 30 year old female, postpartum 2nd month now presented to psychiatry department with Mood & Sleep disturbances, repetitive suicidal thoughts, headache and neck pain since 2 months.
• MRI Brain with cervical spine screening was done to rule out organic cause, which revealed incidental Left Vertebral Arteriovenous fistula.

MRI

MRV

TOF MRA

Plain radiograph

Café au lait macules and cutaneous neurofibromas
Positive family history in sibling and father

ENDOVASCULAR INTERVENTION

• Indication for treatment: Compressive myelopathy & steal phenomenon
• Goal: To completely block the fistula and sacrifice the dysplastic left vertebral artery.
• Hardware used:
  • 6F long sheath
  • 6F intermediate guiding catheter
  • DMSO compatible microcatheter
  • 0.014” microwire
  • 3 vials of EVOH (1.5ml vial)
  • 1ml of 50% NBCA-Lipoidal suspension

After complete evoh injection

You do not have permission to view this object.

Embolic cast after glue injection

POST OPERATIVE CARE

• Breast-feeding with-held for 48 hrs.
• Tab Dexamethasone tapered over a period of 3 weeks.
• Analgesics for post-operative pain.
• No post-operative neurological deficits.
• Tab Aspirin 75mg BD for stroke prophylaxis.

 
Vertebro-vertebral arteriovenous fistula is a direct communication between the extracranial vertebral artery or its muscular/radicular branches and epidural venous intervertebral plexus, without intervening capillaries.
Most common cause is penetrating neck injury, blunt cervical trauma, iatrogenic forms of trauma.
Rare causes: Neurofibromatosis type 1, Fibromuscular dysplasia or Ehlers-Danlos syndrome.

REVIEW OF LITERATURE

• NF-1-related vascular abnormalities incidence is relatively higher ~ 0.4 to 6.4%.
• NF-1 can have vascular manifestations including aneurysms, stenosis and arteriovenous malformations.
• NF-1-related spontaneous Vertebro-vertebral AVF is very rare in clinical practice.

EXACT PATHOGENESIS IS UNCLEAR

Riccardi hypothesis: Mutation of the NF-1 gene → Altered expression of neurofibromin in endothelial and smooth muscle cells of blood vessels → Loss of maintenance effect of neurofibromin on blood vessels → Inflexible blood vessels → Smooth cell dysplasia & unopposed proliferation

CLINICAL PRESENTATION AND MANAGEMENT

• Asymptomatic or Symptomatic due to compression on the spinal cord or roots, bleeding, or vascular steal phenomenon.
• Prompt treatment is required as symptoms are progressive either due to compressive myelopathy or due to spinal venous congestion.
• Endovascular treatment is the first line of management.
• Open surgery is usually not preferred
  • Requires laminectomy; may affect the spine stability
  • Risk of haemorrhage (vascular fragility in dysplastic vessels)
  • Thromboembolic complications

ENDOVASCULAR TECHNIQUES – ANTEGRADE ROUTE

1. Constructive techniques
   Occlusion of fistula with preservation of parent vessel
   Indicated in normal parent vessel & Contralateral vertebral artery is hypoplastic with no collateral circulation<
    
2. Destructive techniques
   Occlusion of fistula with parent vessel sacrifice
   Indicated in dysplastic vessel & Contralateral vertebral artery is co-dominant with good collateral circulation

ENDOVASCULAR OPTIONS

Covered stent grafts

• Preferred if vessel is normal with straight course.
• Requires Dual Anti-platelets protection.

Detachable balloons

• Can be inflated and contracted repeatedly before separation for precise placement and optimal occlusion.
• Risk of recurrence of the fistula if the balloon is deflated.

Coil embolisation

• Controlled deployment for precise occlusion
• Preservation of parent vessel is possible

Liquid embolics

• NBCA/ EVOH polymer can be used
• Can flew away from target site in high flow fistulas
• Risk of non-target vessel embolisation
• Always look for anterior spinal artery origin to avoid inadvertent embolisation

Combination of methods can be used.

Which method is best?

REFERENCES

• Chen J, Liang T, Cen J, et al. Extracranial Vertebral Artery-Internal Jugular Vein-Spinal Vein Fistula in Neurofibromatosis Type I: Case Report and Literature Review. Front Neurol. 2022;13:855924. Published 2022 Apr 28. doi:10.3389/fneur.2022.855924
• Sheerin UM, Holmes P; London NF1 Research Group, Childs L, Roy A, Ferner RE. Neurovascular complications in adults with Neurofibromatosis type 1: A national referral center experience. Am J Med Genet A. 2022;188(10):3009-3015. doi:10.1002/ajmg.a.62931
• Gupta A, Murumkar V, Peer S. Endovascular Management of Traumatic Vertebral Artery Pseudoaneurysm Associated with Vertebral Arteriovenous Fistula Using a Covered Stent. Cureus. 2019;11(9):e5716. Published 2019 Sep 21. doi:10.7759/cureus.5716
• Briganti F, Tedeschi E, Leone G, et al. Endovascular treatment of vertebro-vertebral arteriovenous fistula. A report of three cases and literature review. Neuroradiol J. 2013;26(3):339-346. doi:10.1177/197140091302600315