What Is a Carotid-Cavernous Fistula?

Carotid-cavernous fistula (CCF) generally refers to the rupture of the arterial wall or branch of the cavernous sinus segment of the internal carotid artery, resulting in abnormal arteriovenous communication with the cavernous sinus. An abnormal communication between the internal carotid artery and / or external carotid artery dura mater and the cavernous sinus is called cavernous sinus dural arteriovenous fistula.

Basic Information

English name: carotid-cavernous fistula, CCF
Visiting department: neurosurgery
Common causes: Fracture of skull base and middle carotid artery wall damage caused by motorcycle accident

Common symptoms: Pulsating exophthalmos, intracranial murmurs, conjunctival congestion and edema, eye movement disorders, headaches, etc.

Carotid cavernous sinus fistula classification

By cause

It is classified as traumatic (more than 75%) and spontaneous (less than 25%).

2. According to the amount of stolen blood

Divided into high-flow fistula (mostly traumatic) and low-flow fistula (mostly spontaneous).

3.Barrow typing (1985)

According to the relationship between carotid arteries and branches and targets in anatomy and angiography, they are divided into 4 types: Type A internal carotid arteries communicate directly with cavernous sinus, accounting for 75% to 84%. They are more common in trauma and rupture of cavernous sinus aneurysms; Type B internal carotid artery branches communicate with cavernous sinus, accounting for 7%; Type C external carotid artery branches communicate with cavernous sinus, accounting for 3% to 10%. It is common in young patients. The common blood supply artery is the middle meningeal artery in the spine. The branch above the hole supplies blood to the cavernous sinus; D-type B + C, both the internal and external carotid arteries communicate with the cavernous sinus through their meningeal branches, and there is often bilateral simultaneous blood supply, accounting for 9% to 21%.

4. According to the needs of pathology and treatment

Divided into direct type (A type), hard film type (B or C or D type) and mixed type (both direct type and hard film type).

Causes of carotid cavernous sinus fistula

Traumatic CCF

It most often occurs in skull base fractures caused by head injuries or head crush injuries caused by motorcycle traffic accidents, especially when the fractures of the temporal bone and sphenoid bone spread to the carotid canal, and the fracture fragments puncture the cavernous sinus neck Arterial wall; Orbital puncture or shrapnel injury, usually a single large breach; Pseudo aneurysm rupture caused by internal carotid artery wall contusion and point bleeding caused by trauma; arterial wall first There are congenital, inflammatory or atherosclerotic lesions that occur due to minor injuries; Branches of the internal carotid artery of the cavernous sinus segment (especially the meningeal pituitary trunk) rupture and cause low-flow CCF; Percutaneous puncture of the trigeminal nerve for half a month Radiofrequency treatment of trigeminal neuralgia, sphenoidotomy for chronic sinusitis, pituitary tumor resection via sphenoid sinus, internal carotid artery thrombectomy with Fogarty catheter, and posterior trigeminal nerve root resection (Frazier operation) ), Etc. can also cause iatrogenic damage.

2. Spontaneous CCF

About 60% of spontaneous direct CCFs have middle carotid artery wall lesions, including cavernous sinus internal carotid aneurysms, fibromuscular dysplasia, Ehlers-Danlos syndrome type IV, Marfan syndrome, neurofibromatosis, late Primary osteogenesis, pseudoxanthomatosis, viral arteritis, and residual primary trigeminal artery.

Traumatic internal carotid artery rupture due to trauma, rupture of internal carotid aneurysm of cavernous sinus segment, iatrogenic internal carotid artery injury, etc. cause high-flow CCF, and rupture of branches of internal carotid artery of cavernous sinus segment mostly cause low-flow CCF.

Clinical manifestations of carotid cavernous sinus fistula

Pulsatile exophthalmos

The degree of protrusion is 4 to 24 mm, with an average of 8 to 10 mm. Pulses that are synchronized with the pulse can be seen. Touching the eyeball can feel the pulsation and "cat asthma" -like tremors, which mostly occur on the same side of the CCF, sometimes bilaterally, and a few have no eyeballs. Outstanding, rarely seen only on the opposite side.

2. Intracranial vascular noise

It is the most common and first symptom. It is usually heard after a sudden headache and continuous machine roar-like murmurs, which have a consistent increase in pulse. It can be applied to the orbit, mastoid, temporal, forehead, neck and even the entire head during auscultation. Hearing continuous whistle-like blood vessel murmur, pressing the ipsilateral carotid artery can make the noise disappear or weaken.

3. Conjunctival hyperemia and edema

It can be seen that venous irritation, conjunctival congestion and even bleeding occur in the orbital, medial condyle, eye and conjunctiva, retina and even the face and forehead, which can cause exposed keratitis.

4. Eye movement disorders

The third and fifth cerebral nerves are stretched and compressed by the dilated cavernous sinus and cause ischemia due to dilated vision. The abductor nerve is the most common; the corneal and facial sensations may occur due to the compression of the first and second trigeminal nerves. obstacle.

5. Progressive visual impairment

80% of CCF patients have vision loss, about half have severe vision loss or even blindness, the main cause is eyeball ischemia; if the intraocular pressure exceeds 40mmHg, emergency surgery should be considered to occlude the fistula to prevent permanent blindness, if emergency surgery is not possible, Adjuvant measures such as excision of the epiphysis, oral -adrenergic blockers (acetazolamide), or static mannitol are used to protect vision.

6. headache

It is common in the early stage of the disease, and is mostly limited to the orbit and the temporal region. It is related to the extreme expansion of local and meningeal blood vessels or the first and second trigeminal nerves being stretched by the expanded cavernous sinus.

7. Intracranial and nosebleeds

A small amount of nosebleeds is mostly caused by vasodilatation and rupture of the nasal mucosa, a large number of nosebleeds are mostly caused by sphenoid sinus wall fractures, spongy sinus internal carotid artery formation of pseudoaneurysms and rupture into the sinuses, and urgent operation is required to close the fistula Excessive intracranial venous pressure can cause subdural, subarachnoid, and / or intra parenchymal hemorrhage, which requires emergency surgery.

8. Neurological Dysfunction

Internal carotid blood stealing and intracranial venous congestion can cause increased intracranial pressure, mental disorders, epilepsy, hemiplegia, aphasia, etc. A small number of people who drain to the spinal canal can also cause spinal cord dysfunction.

Imaging examination of carotid cavernous sinus fistula

1. CT scan of head or orbit

It can be seen that the eyeballs are prominent, the eye veins are thickened, the intraorbital muscle group is diffusely thickened, the edge of the eyeball is blurred, the eyelids are swollen, and the bulbar conjunctiva is edema.

2. Head-enhanced CT

It can be seen that the cavernous sinus area and the dilated eye veins are significantly enhanced, and the lateral fissure and frontal area have high density shadows with low density edema of the surrounding brain tissue relative ischemia. It can also be found that skull base fractures compress the internal carotid artery and optic nerve canal.

3.MRI, MRA (magnetic resonance angiography)

Visible expansion of the cavernous sinus, supraocular vein and other drainage veins, MRI can also find cerebral ischemia caused by sneak flow.

4. Cerebral angiography (DSA)

It can be clarified: the location, size and number of fistulas ; understanding of cerebral blood supply status ; cross circulation test to understand the risk of cerebral hemisphere ischemia caused by occlusion of internal carotid artery; Arterial blood supply mainly comes from the middle meningeal artery, accessory meningeal artery, and ascending pharyngeal artery. The venous drainage is most common in the forward drainage, with prominent ocular symptoms; the murmurs behind the ears are obvious in those who drain backward, with dysfunction of cranial nerves in groups III, IV, VI, and the posterior group; those who drain upward can cause subarachnoid hemorrhage Or subdural hematomas; those who drain downward tend to cause nasal mucosal hemorrhage; those who drain inward can show increased intracranial pressure; those who drain to the opposite can produce contralateral eye symptoms; multi-channel drainage is the most common symptom, The purpose of treatment is to occlude the fistula, such as cavernous sinus dural arteriovenous tumor, too many fistulas can occlude the cavernous sinus.

Carotid cavernous sinus fistula diagnosis

Patients with the above-mentioned typical symptoms are not difficult to diagnose, but patients with low-flow CCF due to coma or orbital trauma, or ophthalmology are easily misdiagnosed.

Differential diagnosis of carotid cavernous sinus fistula

Congenital orbital plate defect

As a manifestation of congenital mottling hamartomatosis, the patient's skin may have coffee pigmentation spots and multiple neurofibromatosis, may have eyeball protrusion and pulsation, no intracranial murmur, and no orbital and conjunctival expansion and hyperplasia. X-ray showed the orbital parietal bone defect, the sphenoid ridge and the temporal line disappeared, and the affected orbital was enlarged.

Cavernous sinus thrombosis

There may be exophthalmos and conjunctival congestion and edema, but no eye pulsation, no murmur, and paranasal sinus or facial purulent infection.

3. Posterior tumors and sphenoid ridge meningiomas

Unilateral eyeball prolapse often accompanied by , , cerebral insufficiency paralysis and trigeminal nerve branch distribution of superficial sensation.

4. Intraorbital aneurysm or intraorbital arteriovenous malformation

May have pulsatile exophthalmos and intracranial murmurs, but rarely ophthalmic vein congestion and edema.

5. Intracranial venous sinus thrombosis

Exophthalmos and conjunctival congestion may occur, but no pulsation and noise.

Carotid cavernous sinus fistula treatment

Purpose of treatment

Protect eyesight, eliminate noise, retract exophthalmos, prevent cerebral hemorrhage and cerebral ischemia.

2. Principles of treatment

Occlude the fistula, strive for the best treatment effect with one operation, and protect the internal carotid artery.

3. Therapy

(1) The direct type of CCF is best treated with an arterial detachable balloon (cure rate 89% -98%) or electrolytic detachable coil embolization; generally, the intracranial murmur disappears immediately after the balloon is in place, and the conjunctiva is formed after a few hours Congestion and edema improved significantly, and exophthalmos returned to normal in about a week.

(2) Ehlers-Danlos syndrome type IV should be cautious or avoid using arterial intubation angiography or treatment. MRA can be diagnosed and treated by ocular vein intubation and embolization. Complications of arterial intubation balloon embolization of CCF may include brain. Infarction, pseudoaneurysm, and exacerbation of symptoms (traumatic CCF should not be treated early).

(3) Transcatheter arterial coil embolization of CCF caused by internal carotid artery cavernous sinus segment aneurysm or rupture of the original trigeminal artery may have a small fistula or difficult balloon access. It can be delivered into the fistula with guide wires and catheters. GDC embolism.

(4) Transcatheter embolization via the supraocular vein approach. When arterial approach is difficult, dangerous, or treatment failure, consider embolization via the supraocular vein approach. Intraocular vein cannulation for the indications for CCF uses the supraocular vein as the main drainage vein, and the supraocular vein has a significant dilation; various types of CCF are difficult, dangerous, failing to treat or the internal carotid artery is occluded by the arterial route, and CCF recurs. Carotid-cavernous sinus fistula, the arterial supply is complex, the supply arteries are thin, and the arterial approach is used to occlude the cavernous sinus fistula with little chance of success.

(5) Radiotherapy. Stereotactic -knife is recommended for the treatment of epidural CCF. The radiation dose is 30 to 40 Gy. The fistula can be closed 2 to 20 months after surgery. The cure rate is 90% and there are no adverse reactions. The treatment is effective. The length of time is related to the length of the preoperative course; generally, CCF for meningeal branch blood supply of internal carotid artery is better than those for external carotid artery blood supply. For type D CCF, the external carotid artery branch of the external carotid artery is often used for embolization before radiotherapy; radiotherapy The effect on direct CCF is poor.