Carotid-cavernous fistula was one of the first intracranial vascular lesions to be recognized.
The paper of Lang et al. focuses on the historical progression of our understanding of the condition and its symptomatology-from the initial hypothesis of ophthalmic artery aneurysm as the cause of pulsating exophthalmos to the recognition and acceptance of fistulas between the carotid arterial system and cavernous sinus as the true etiology. The authors also discuss the advancements in treatment from Benjamin Travers' early common carotid ligation and wooden compression methods to today's endovascular approaches 1).
Over the years, numerous classification systems have been applied to CCFs. The simplest classification divides CCFs into direct and indirect fistulae.
see Direct carotid-cavernous fistula (High flow).
see Indirect carotid cavernous fistula (Low flow).
Angioarchiecture of the arterial side of the fistula determines the Classification of spontaneous carotid cavernous fistulas after Barrow, the most widely adopted system to classify CCFs.
However, the Barrow classification is not very practical from clinical and therapeutic standpoints, as symptomatology and current treatment approach are influenced largely by venous drainage. In addition, most CCFs are indirect fistulae and fall under Barrow type D because there is always some supply from meningeal branches of both the ICA and external carotid artery 14).
Motor vehicle accidents, falls and other crush injuries contribute to the incidence of basilar skull fractures and the formation of some of the CCFs.
In the setting of a carotid cavernous fistula, flow often reverses into the superior ophthalmic vein, thereby producing evidence of orbital congestion as well as secondary increased intraocular pressure (related to the problems with ocular venous outflow). This flow reversal results in the myriad ophthalmic manifestations of a carotid cavernous fistula.
CCFs present with symptomatology resulting from venous congestion, hypertension, thrombosis, hemorrhage, neural compression, and/or ischemia from vascular steal.
With anterior venous drainage, increased venous pressure results in an increase in intraocular pressure leading to loss of vision, ocular pain, glaucoma, and retinal hemorrhage. Manifestations in the orbit include chemosis, exophthalmos, periorbital pain, and blepharedema. With posterior venous drainage, increased pressure in the cavernous sinus and vascular steal can result in cranial nerve deficits manifesting as ophthalmoplegia, diplopia, ptosis, or anisocoria. Most daunting is cortical symptomatology such as hemorrhage and seizures resulting from retrograde drainage into the superficial middle cerebral vein or the posterior fossa via the petrosal vein.
Enlarged superior ophthalmic veins
Extraocular muscles may be enlarged
May show SAH/ICH from a ruptured cortical vein
Rapid shunting from ICA to CS
Enlarged draining veins
Retrograde flow from CS, most commonly into the ophthalmic veins
see Heuber maneuver
Subarachnoid hemorrhage is low. Major risk is to vision.
50 % spontaneous thrombosis in low flow carotid cavernous fistula.
Ten out of a total of 31 direct carotid cavernous fistulas (DCCFs) were treated with Willis covered stents (WCSs) (Microport, Shanghai China) at West China Hospital from January 2015 to December 2016. The indications for treatment, perioperative findings, and postoperative and follow-up results were collected and analyzed.
All ten patients had successful deployment of WCSs. Complete exclusion of the fistula was achieved in 6 patients immediately after deploying one stent. Endoleak was observed in 4 patients (cases 2, 4, 5 and 9); thus, redilation of the stent with higher pressure was performed, which resolved the endoleak in 2 patients (cases 2 and 9). The other two patients' endoleak persisted after redilation of the balloon; hence, a second stent was deployed in these 2 patients (cases 4 and 5), which eliminated the endoleak in one patient (case 4), and the other patient (case 5) continued to have minimal endoleak. Nine patients had fistulas that were successfully occluded by WCSs during follow-up. One patient had recurrence of a DCCF at the 10-day follow-up; we chose coil embolization to address this DCCF. No stenosis of the internal carotid artery (ICA) or DCCF recurrence, except that in the abovementioned patient, was observed.
WCS was proven to be an alternative treatment method for complex DCCFs through reconstruction and preservation of the ICA. The study also confirmed the safety, efficacy, and midterm durability of WCSs for complex DCCFs without any serious delayed complications 15).
A total of 55 patients with 56 tCCFs (1 bilateral tCCF) were included. Thirty-nine patients (40 tCCFs) were treated successfully in single session of a procedure, while 16 patients (16 tCCFs) experienced a recurrence of tCCF. In multivariate analysis, Lin et al. found that the involvement of C2 or C4 segments (Debrun classification) of intra-cavernous internal carotid artery is an independent risk factor (HR: 2.95, 95% CI: 1.34 - 6.52; p < 0.01) for the recurrence of tCCFs. Endovascular coil embolization demonstrated superior efficacy in successful interventions of tCCFs when compared with detachable balloons (HR: 2.63, 95% CI: 1.06 - 6.57; p < 0.05) and other modalities (HR: 3.06, 95% CI: 1.27 - 7.37; p < 0.05).
A detachable coil is a favorable approach in the management of tCCFs when considering the rate of recurrence. In addition, the involvement of C2 or C4 segments (Debrun classification) served as an independent risk factor of the recurrence of tCCFs. 16).