Transvenous embolization of dural carotid-cavernous fistulae with transfacial catheterization through the superior ophthalmic vein

Endovascular treatment in bilateral cavernous sinus dural arteriovenous fistulas: a systematic review and meta-analysis

Few studies have discussed the disease nature and treatment outcomes for bilateral cavernous sinus dural arteriovenous fistula (CSDAVF). This study aimed to investigate the clinical features and treatment outcomes of bilateral CSDAVF. Embase, Medline, and Cochrane library were searched for studies that specified the outcomes of bilateral CSDAVF from inception to April 2022. The classification, clinical presentation, angiographic feature, surgical approach, and treatment outcomes were collected. Meta-analysis was performed using the random effects model. Eight studies reporting 97 patients were included. The clinical presentation was mainly orbital (n = 80), cavernous (n = 52) and cerebral (n = 5) symptoms. The most approached surgical route was inferior petrosal sinus (n = 80), followed by superior orbital vein (n = 10), and alternative approach (n = 7). Clinical symptoms of 88% of the patients (95% CI 80-93%, I² = 0%) were cured, and 82% (95% CI 70-90%, I² = 7%) had angiographic complete obliteration of fistulas during follow up. The overall complication rate was 18% (95% CI 11-27%, I² = 0%). Therefore, endovascular treatment is an effective treatment for bilateral CSDAVF regarding clinical or angiographic outcomes. However, detailed evaluation of preoperative images and comprehensive surgical planning of the approach route are mandatory owing to complexity of the lesions.

Cavernous sinus dural arteriovenous fistula treated with transvenous embolization through facial vein: A case report

BACKGROUND

Although the inferior petrosal sinus (IPS) is the most common approach route for transvenous embolization (TVE) of cavernous sinus dural arteriovenous fistulas (CSDAVFs), other routes should be chosen in cases which the IPS is occluded. We report a case in which the superior ophthalmic vein (SOV) approach through the facial vein (FV) was the first choice to achieve radical cure of a hemorrhage-onset CSDAVF.

CASE DESCRIPTION

An 81-year-old female presented with a history of transarterial embolization (TAE) and TVE for the left CSDAVF 27 years ago. She was transported to us with a chief complaint of consciousness disturbance, and head computed tomography (CT) showed subcortical hemorrhage in the right frontal lobe. Cerebral angiography revealed CSDAVF with draining into the right SOV and right superficial middle cerebral vein (SMCV). Angiography, computed tomography venography, and contrast-enhanced magnetic resonance imaging did not show IPS, but the outflow pathways to the SOV, FV, and internal jugular vein were confirmed, so an approach through the FV was selected.

CONCLUSION

The FV was selected through the right femoral vein and thanks to the distal access catheter (DAC) being guided to the SOV, the microcatheter could be easily guided to the SMCV through the cavernous sinus (CS). TVE was performed, complete occlusion was confirmed. When preoperative occlusion of the IPS was confirmed, the FV was useful for the first choice of route, and the use of DAC allowed us to complete the treatment accurately and quickly.

Transfemoral trans-facial vein-superior ophthalmic vein to embolize cavernous sinus dural arteriovenous fistulas

Cavernous sinus dural arteriovenous fistula (CS-DAVF) is an abnormal communication between the CS and dural arteries from the internal carotid artery and external carotid artery. CS-DAVFs are not uncommon. The preferred treatment for most CS-DAVFs is transvenous embolization (TVE), which can achieve a high cure rate with few complications. The trans-inferior petrous sinus (IPS) route from the internal jugular vein to the CS is the favorite and most direct route to perform TVE in the great majority of CS-DAVFs. However, when the trans-IPS route fails and if the facial vein (FV) is patent and dilated, transfemoral trans-FV-superior ophthalmic vein (SOV) embolization of the CS-DAVF can be attempted. However, the transfemoral trans-FV-SOV route to embolize CS-DAVFs is often challenging, and there is insufficient knowledge about it. Therefore, an updated review of the transfemoral trans-FV-SOV route to embolize CS-DAVFs is necessary, and this review includes our experience. The images in this review are from our institute without the dispute of copyright. Issues regarding the transfemoral trans-FV-SOV route to embolize CS-DAV were discussed, including the FV anatomy and variation, various TVE routes to access CS-DAVF, the procedure of the transfemoral trans-FV-SOV route to embolize CS-DAVF, difficulty, and solution of the transfemoral trans-FV-SOV route to embolize CS-DAVF, and complications and prognosis of transfemoral trans-FV-SOV to embolize CS-DAVF. By reviewing the transfemoral trans-FV-SOV route to embolize CS-DAVFs, we found that this route provides a valuable alternative to the other transvenous routes. A good prognosis can be obtained with the transfemoral trans-FV-SOV route to embolize CS-DAVFs in select cases.

What is the most effective method to treat indirect carotid-cavernous fistula?

To review the most relevant treatment options for indirect carotid-cavernous fistulas (iCCF), cohorts of 20 patients or more published after 2000 were analyzed. Clinical and radiological outcomes, as well as embolization techniques and material, had to be clarified in the study to be considered. Statistical analysis was based on calculating the relative percentage of therapeutic methods or embolic material, followed by calculating parametric and nonparametric correlations. Some 22 studies and 1550 patients were included. Transvenous embolization (TVE) was used in 53% of the patients and was strongly associated with coiling (rw = 0.66, p = 0.0.0012; rs = 0.53, p = 0.0138), transarterial embolization (TAE) was preferred in 11% of the patients and was strongly linked to liquid embolics (rw = 0.44, p = 0.0434;rs = 0.64, p = 0.0018). A combination of TAE and TVE treatment was used in 7% and a combination of embolic materials in 13% of the patients. None of the endovascular techniques or embolization materials showed significant superiority over the others in clinical outcome and obliteration rate. Radiosurgery in 22% and mechanical compression in 5% of patients showed a lower obliteration rate (rw =  - 0.48, p = 0.0254; rs =  - 0.45, p = 0.0371). The clinical outcomes were comparable to endovascular treatment (EVT). The remaining 2% of the patients were treated by open surgery or a combination of EVT and radiosurgery. Transvenous coiling is the preferred EVT method for iCCF. However, comparable results may be accomplished with TAE using liquid. Radiosurgery may achieve a lower percentage of fistula occlusion, but the clinical results are equal to EVT.

First reported single-surgeon transpalpebral hybrid approach for indirect cavernous carotid fistula: illustrative case

BACKGROUND

Failure to reach the cavernous sinus after multiple transvenous attempts, although rare, can be challenging for neurointerventionists. The authors sought to demonstrate technical considerations and nuances of the independent performance of a novel hybrid surgical and endovascular transpalpebral approach through the superior ophthalmic vein (SOV) for direct coil embolization of an indirect carotid cavernous fistula (CCF), and they review salient literature regarding the transpalpebral approach.

OBSERVATIONS

An illustrative case, including patient history and presentation, was reviewed. PubMed, MEDLINE, and Embase databases were searched for articles published between January 1, 2000, and September 30, 2021, that reported ≥1 patient with a CCF treated endovascularly via the SOV approach. Data extracted included sample size, treatment modality, surgical technique, performing surgeon specialty, and procedure outcome. The authors’ case illustration demonstrates the technique for the hybrid transpalpebral approach. For the review, 273 unique articles were identified; 14 containing 74 treated patients fulfilled the inclusion criteria. Oculoplastic surgery was the most commonly involved specialty (5 of 14 studies), followed by ophthalmology (3 of 14). Coiling alone was the treatment of choice in 12 studies, with adjunctive use of Onyx (Medtronic) in 2.

LESSONS

The authors’ technical case description, video, illustrations, and review provide endovascular neurosurgeons with a systematic guide to conduct the procedure independently.

Combined Transradial and Upper Extremity Transvenous Accesses in the Treatment of Carotid-Cavernous Fistulae: Two Case Reports and a Literature Review

The expansion of indications for neurointerventional procedures, combined with the need to treat a diverse patient population, has driven a need for broader access options. Concurrent arterial and venous access is often necessary for the diagnosis and treatment of various neurovascular diseases. Although complication rates are low, life-threatening severe complications have been reported with these access methods. Moreover, venous access through traditional routes can be challenging in patients with large body habitus. There is a growing trend of utilizing radial artery access for neuroendovascular procedures due to the increased ease of access and similar efficacy. Nevertheless, the use of upper limb veins in neurointerventional procedures is still rare. Upper extremity transvenous access (UETV) has recently emerged as an alternative strategy for neurointerventionalists, but data are limited. This study reports two cases of successful combined upper extremity transvenous access (TVA) and transradial access (TRA) in the treatment of carotid artery-cavernous fistulae. Combined TRA and UETV is a feasible, promising access strategy for patients and may also confer the same safety and patient satisfaction outcomes that have been seen with TRA. Further studies are needed to elucidate the exact impact this strategy has on patient outcomes and satisfaction.

Hybrid Surgical and Endovascular Approach via the Contralateral Superficial Middle Cerebral Vein to Occlude Cavernous Sinus Dural Arteriovenous Fistula in a Hybrid Operating Room: A Case Report

Most cases of cavernous sinus dural arteriovenous fistula (CS-dAVF) are treated via the inferior petrous sinus (IPS) through the transfemoral vein approach, but there are cases where treatment through the superficial middle cerebral vein (SMCV) is required. A hybrid operating room (OR) is useful because it allows for smooth direct surgery and endovascular treatment in a clean surgical field. We herein report a case of simultaneous treatment for CS-dAVF by coil embolization via a contralateral SMCV and middle cerebral artery (MCA) aneurysm by clipping in a hybrid OR. A 68-year-old woman had been suffering from left chemosis and ptosis for 2 months before visiting our hospital. Digital subtraction angiography (DSA) revealed Borden type II and Cognard type II a+b CS dAVF with parenchymal hemorrhaging and an unruptured left M1/M2 junction aneurysm. Since passing through the CS via the femoral vein was unsuccessful, we decided to access the right CS via the left CS through the intercavernous sinus (ICS) via the left SMCV by the pterional approach in a hybrid OR equipped with a multi-axis working system angiography machine. Endovascular treatment via direct cannulation into the contralateral SMCV following craniotomy in a hybrid OR is an optional strategy for treating complicated CS-dAVF.

Endovascular management of cavernous sinus dural arteriovenous fistulas: Overall review and considerations

Cavernous sinus dural arteriovenous fistulas (CSDAVFs) are arteriovenous shunts between small dural branches arising from the external and/or internal carotid arteries and the cavernous sinus (CS). And now a days, endovascular treatment is the treatment of choice in CSDAVF. We review the anatomy and classifications of CSDAVFs, discussing and detailing these considerations in the treatment of CSDAVFs, theoretically and in the light of recent literatures.

Endovascular Treatment of Cavernous Sinus Dural Arteriovenous Fistulas. Institutional Series, Systematic Review and Meta-Analysis

Purpose

Endovascular treatment represents the first-line therapy for cavernous sinus dural arteriovenous fistulas (CS-dAVF); however, different approaches and embolic agents as well as occlusion rates, complications and clinical outcomes are reported among the published series. In this study we performed a comprehensive meta-analysis to investigate clinical and radiological outcomes after endovascular treatment of CS-dAVFs.

Methods

PubMed, Ovid Medline, Ovid EMBASE, Scopus, and Web of Science were screened for a comprehensive literature review from 1990 to 2020 regarding series of patients treated for CS-dAVF with endovascular approaches. We performed a proportion meta-analysis estimating the pooled rates of each outcome also including data of patients treated in our center.

Results

A total of 22 studies reporting 1043 patients and 1066 procedures were included. Chemosis was reported in 559 out of 1043 patients (45.9%), proptosis in 498 (41.5%), and ophthalmoplegia in 344 (23.5%). A transvenous embolization was preferred in 753 cases (63.2%) and coils were used in 712 out of 1066 procedures (57.8%). Overall, 85% (95% confidence interval, CI 69.5–96.1%) of patients had a complete resolution of symptoms, while complications occurred in 7.75% (95% CI 3.82–12.7%) with minimal permanent deficits (0.15%). The mortality rate was 1 out of 1043 patients (< 0.001).

Conclusion

A transvenous coiling is the most common endovascular approach for CS-dAVF, achieving a high percentage of radiological and clinical resolution and low complication rates. Transvenous approaches show less complications than transarterial ones, and coils appear safer than liquid embolic agents.

Transvenous Embolization of Cavernous Sinus Dural Arteriovenous Fistula through the Angiographically Occlusive Superior Ophthalmic Vein

Transvenous embolization (TVE) through the superior ophthalmic vein (SOV) is a useful approach for the treatment of cavernous sinus (CS) dural arteriovenous fistulae (DAVFs). This venous route is usually confirmed by angiography. Herein, we present a case of favorable embolization of the CS DAVF through the angiographically occlusive SOV. A 61-year-old man presented with progressive exophthalmos and hypertonia. The patient was diagnosed with a CS DAVF, and TVE was planned. The first approach through the inferior petrosal sinus was infeasible; therefore, we attempted to approach the fistula through the left facial vein. The microcatheter was easily advanced to the shunt point through the angiographically occlusive SOV. We performed coil embolization, and the CS DAVF was completely obstructed.

Middle temporal vein access for transvenous embolization of Cavernous sinus dural arteriovenous fistula: A case report and review of literature

Transvenous endovascular treatment is the first choice for treating most cavernous sinus dural arteriovenous fistulas (CDAVFs). Among several available venous routes, the inferior petrosal sinus is the most commonly used. We report a case of CDAVF treated with endovascular treatment via the middle temporal vein (MTV). A 65-year-old man presented with unilateral chemosis and exophthalmos for approximately two months. Digital subtraction angiography showed a right CDAVF with predominant venous drainage toward the right superior ophthalmic vein. The superior ophthalmic vein primarily drained into the dilated MTV. Both sides of the inferior petrosal sinus were occluded; therefore, transvenous embolization was performed via the MTV route. The fistula was completely obliterated. The patient's symptoms improved and the postoperative course was uneventful. The transfemoral approach via the MTV to treat CDAVF provides a crucial alternative when other venous routes are difficult or impossible to navigate with a catheter.

Clinical improvement in indirect carotid cavernous fistulas treated endovascularly: A patient based review

Patients with indirect carotid cavernous fistulas (CCF) were reviewed to emphasize the importance of diagnosing patients even with trivial findings and to raise awareness. Eighteen patients diagnosed as CCF were included. Neuro-ophthalmological findings before and after treatment, diagnostic investigations, treatment, clinical course was noted. Twelve patients were female (67%), 6 were males (33%) and the mean age at presentation was 54 years (range: 29-70 years). Conjunctival hyperemia was present in all patients. Seventeen (94%) patients had proptosis and diplopia, nine (50%) had orbital pain and/or headache, four (22%) had blurred vision, one (5.5%) had ptosis. On examination, 17 patients (94%) had restricted eye movements, four (22%) had low visual acuity and five patients had (28%) increased intraocular pressure (IOP). One patient had been diagnosed as myasthenia gravis and two as thyroid orbitopathy and had been on treatment accordingly before CCF was diagnosed. In two patients, bilateral findings were present despite unilateral CCF on angiography. Barrow Type B fistula was found in 7 (38%), Barrow Type D in 11 (62%) patients. In three bilateral CCF was detected. All were treated by endovascular intervention. Residual deficits at the sixth month control were, eye movement deficits in seven (39%), decrease in visual acuity in one (5.5%) and elevated IOP in one (5.5%) patient. Indirect CCF patients generally present with mild symptoms and the diagnosis may be overlooked. Mild progressive ophthalmoparesis with conjunctival hyperemia must be warning. Though rare bilateral CCF can be detected as well as unilateral CCF with bilateral findings.

Endovascular Approaches to the Cavernous Sinus in the Setting of Dural Arteriovenous Fistula

Dural arteriovenous fistulas involving the cavernous sinus can lead to orbital pain, vision loss and, in the setting of associated cortical venous reflux, intracranial hemorrhage. The treatment of dural arteriovenous fistulas has primarily become the role of the endovascular surgeon. The venous anatomy surrounding the cavernous sinus and venous sinus thrombosis that is often associated with these fistulas contributes to the complexity of these interventions. The current report gives a detailed description of the alternate endovascular routes to the cavernous sinus based on a single center’s experience as well as a literature review supporting each approach. A comprehensive understanding of the anatomy and approaches to the cavernous sinus available to the endovascular surgeon is vital to the successful treatment of this condition.

Venous Anatomy of the Cavernous Sinus and Relevant Veins

The cavernous sinus (CS) is a dural sinus located on each side of the pituitary fossa. Neoplastic and vascular lesions, such as arteriovenous fistulas, frequently involve the CS. This sinus plays a role as a crossroad receiving venous blood flow from the facial, orbital, meningeal, and neural venous tributaries. The relationship between these surrounding relevant veins and the CS, as well as the CS itself, varies anatomically. For safe and effective surgical and endovascular treatment of lesions involving the CS, knowledge of the anatomy and variations of the CS and the relevant surrounding veins is highly important. In this section, the anatomy and variations of the CS and the relevant surrounding veins are outlined.

Access-route Visualization Using Ultrasonography and CT Angiography to Predict the Feasibility of Transvenous Embolization via the Facial Vein for Cavernous Sinus Dural Arteriovenous Fistulas

Objective

Transvenous embolization (TVE) is an effective treatment for cavernous sinus dural arteriovenous fistulas (CS-DAVFs). The facial vein (FV) can be used as an access route for TVE when a trans-inferior petrosal sinus (IPS) approach is difficult. We evaluated the usefulness of combining ultrasonography (US) with computed tomography angiography (CTA) for confirming that the FV is a suitable access route for treating CS-DAVFs.

Methods

Trans-FV TVE was planned for five CS-DAVF patients in whom the shunt point was located in the posterior compartment of the CS and anterior venous drainage predominantly occurred via the superior ophthalmic vein (SOV). The anterior drainage route was examined with CTA and US. We reviewed the relationships between preoperative CTA/US findings and the accessibility of CS-DAVFs via the FV.

Results

The periorbital and perimandibular drainage pathways were clearly more visible on US than on CTA, and the cervical and thoracic drainage pathways were more visible on CTA than on digital subtraction angiography (DSA). CS-DAVFs were accessible via the FV when (1) the entire drainage pathway could be confirmed on CTA and US, (2) the periorbital and perimandibular pathways were unclear on CTA, but could be confirmed on US, or (3) the FV pathway drained into the internal jugular vein (IJV) or external jugular vein (EJV). On the other hand, TVE was challenging to perform via the FV when (1) the periorbital pathway was unclear on CTA and US, (2) the FV pathway drained into the brachiocephalic vein, or (3) the SOV thrombosed intraoperatively. In all five patients, TVE for CS-DAVFs performed via the FV or IPS was successful.

Conclusion

CTA and US are useful for confirming the anterior access route for trans-FV TVE for CS-DAVFs and predicting the feasibility of such treatment. Our findings suggest that CS-DAVFs can be accessed via the FV if the periorbital drainage pathway can be confirmed on US, even if the pathway is unclear on CTA.

Transvenous embolization through the ipsilateral deep facial vein: A novel approach route for treatment of a cavernous sinus dural arteriovenous fistula

The superior ophthalmic vein (SOV) approach through the facial vein is usually preferred for transvenous embolization of a cavernous sinus dural arteriovenous fistula (CS DAVF) when the ipsilateral inferior petrosal sinus is angiographically occluded. However, navigating the microcatheter can sometimes be difficult because of stenosis or tortuous angulation at the junction between the angular vein and SOV. We present a novel transvenous access route to treat a CS DAVF using the ipsilateral deep facial vein through the SOV to reach the cavernous sinus. A 66-year-old woman presented with left-sided chemosis, exophthalmos, and external ophthalmoplegia. Angiography showed a left CS DAVF associated with a dilated SOV and retrograde cortical venous reflux. A dilated drainage vein, which branched from the SOV, ran through the lateral aspect of the orbit and exited the orbit through the inferior orbital fissure. This vein connected with the ipsilateral deep facial vein draining into the facial and internal jugular veins. We performed transvenous embolization via the SOV approach through the deep facial vein and achieved complete obliteration, by placing 3 platinum coils, without complications. Ophthalmic veins may connect with the cavernous sinus and pterygoid plexus, passing through the superior and inferior orbital fissures, respectively. Our case suggests that the deep facial vein may provide access to the SOV through the inferior orbital fissure without passing the difficult tortuous angle between the angular vein and SOV.

The Superior Ophthalmic Vein: Anatomical Perspective for Transvenous Access to the Cavernous Sinus

The anatomical characteristics of the superior ophthalmic vein (SOV), which is crucial when performing craniofacial surgeries and transvenous access to the cavernous sinus, have not been documented. The present study aimed to explore them using magnetic resonance angiography (MRA). A volumetric, phase-contrast MRA was performed in 74 outpatients not bearing vascular or tumorous pathologies in the face, orbit, and cavernous sinus. The entire course of the SOV was delineated in 46 patients (62%), for 76% on the right side and 83% on the left. These SOVs consistently showed a characteristic morphology with a laterally coursing proximal segment and a medially coursing distal segment. The latter segment was connected to the angular, supraorbital, supratrochlear, facial, and external nasal veins that were inconsistently delineated. The angular vein was tortuous in 51% of the patients on the right and 53% on the left. The morphology of the proximal part of the SOV was also variable and involved a tortuous segment in 11% of the patients on the right and in 7% on the left. Furthermore, in 4 patients (8.7%), a fenestration was found in the right SOVs. Inconsistent tributaries of the SOV, tortuous angular vein, and possible tortuous segment and fenestration of the SOV can make orbital transvenous access to the cavernous sinus difficult.

Impact of transvenous embolization via superior ophthalmic vein on reducing the total number of coils used for patients with cavernous sinus dural arteriovenous fistula

Although transvenous embolization (TVE) via the superior ophthalmic vein (SOV) is adopted in treating cavernous sinus dural arteriovenous fistula (CS DAVF), its effect on the coil volume is rarely understood. The purpose of the study was to investigate if there is a difference in the total number of coils used and in patient safety when comparing two access strategies. We retrospectively reviewed charts for patients with CS DAVF treated with TVE between January 2008 and March 2018. The baseline patient characteristics, details of procedure, placed coils, and clinical results were compared. A total of 42 patients with CS DAVF were treated with the inferior petrosal sinus (IPS) (n = 32) or SOV (n = 10) approach. TVE via SOV showed a high success rate of 100% (10/10) by transfemoral access. The total number (23 versus 11; P < 0.001), length (159 versus 81 cm; P = 0.003), and volume of placed coils (111 versus 46 mm³; P = 0.005) were significantly lower in patients treated via SOV. Patients treated via SOV had significantly higher initial intrasinus pressure (49 versus 59 mmHg; P = 0.022) obtained by microcatheters; however, no adverse events occurred related to elevated sinus pressure between both approaches. Procedural complications and cranial nerve palsy outcomes were not significantly different. In cases with a visualized pathway to the SOV, this approach should be preferred, in all other cases standard approach via the IPS should be used, even if it cannot be visualized.

Bilateral Cavernous Sinus Dural Arteriovenous Fistulae : The Strategies for Endovascular Treatment

PURPOSE

Most cavernous sinus dural arteriovenous fistulas (CSDAVF) are unilateral; however, simultaneous bilateral CSDAVFs occasionally may be found. This article reports on 141 patients and compares the angioarchitecture and outcomes of embolization of bilateral CSDAVFs with those of unilateral CSDAVFs, with reference to limited demographics (sex and age) of the patients.

METHOD

From January 2010 to February 2018 a total of 141 consecutive patients with CSDAVFs were referred for transvenous embolization. Bilateral CSDAVFs were found in 20 patients (14.2%, with a mean age of 62.2 years). The angioarchitecture of the 141 patients with CSDAVFs were evaluated by conventional cerebral angiography. We compared the angioarchitecture and treatment outcomes of 20 bilateral and 121 unilateral CSDAVFs, and in relation to the patients' sex and age.

RESULTS

Female patients significantly dominated the bilateral CSDAVFs (90%, p = 0.043). Bilateral eye symptoms were significantly more common in bilateral CSDAVFs (p = 0.011), with dominant orbital and cavernous symptoms, and showed statistical significance (p = 0.049 and 0.011, respectively). Occlusion of one CSDAVF may significantly decrease the fistula flow of the other untreated side (n = 13, 65%), leading to less coil utilization for embolization in bilateral CSDAVFs (p < 0.001). There was no statistical significance in the occurrence of occlusion of the inferior petrous sinus(s), in pial vein reflux, and treatment outcomes in the unilateral and bilateral CSDAVFs.

CONCLUSION

Bilateral CSDAVFs were more dominant in female patients and frequently presented with orbital and cavernous symptoms. Fewer coils were used per lesion in the bilateral CSDAVFs. There was no statistical significance in bilateral and unilateral CSDAVFs in terms of impact of venous drainage, pial vein reflux and treatment outcomes.

Transarterial and transvenous access for neurointerventional surgery: report of the SNIS Standards and Guidelines Committee

The purpose of this publication is to provide a comprehensive review on the techniques and tools used for vascular access in neurointerventional procedures. Using published literature, we reviewed data on access methods, sites, tools, and techniques for neurointerventions. Recommendations are provided based on quality of data/levels of evidence and, where appropriate, expert consensus. While tools and techniques continue to be developed, current literature and experience supports certain principles regarding vascular access for neurointerventional procedures.

Treatment Outcomes of Cavernous Sinus Dural Arteriovenous Fistulas: Comparison of Radiosurgery and Endovascular Embolisation

BACKGROUND AND PURPOSE

Endovascular treatment (EVT) and stereotaxic gamma-knife radiosurgery (GKRS) can both effectively treat cavernous sinus dural arteriovenous fistulas (CSDAVF). This study compared the prognostic factors and treatment effectiveness of GKRS and EVT for different CSDAVF types.

METHODS

The charts of 200 patients undergoing GKRS and 105 patients undergoing EVT were reviewed for data on symptoms (e.g. orbital, cavernous, ocular, and cerebral). The CSDAVFs were classified into proliferative, restrictive, and late restrictive types. The prognostic factors for complete obliteration (CO) were evaluated in both the GKRS and EVT groups and the latent period to CO was measured. For statistical analysis χ²-tests were used to compare final CO rates for EVT and GKRS across the three CSDAVF types.

RESULTS

The EVT and cavernous symptoms were significant independent predictors of CO. The CO rate after EVT (97.9%) was significantly higher than that after GKRS (63.5%) for restrictive CSDAVFs (P < 0.001) but not for proliferative or late restrictive types. In the GKRS group, cavernous symptoms (hazard ratio, HR: 0.557) and target volume (HR: 0.853) predicted CO, but only target volume remained significant in multivariate analysis. In the EVT group, the latent period to CO was shortest for restrictive CSDAVFs (3.2 ± 1.6 months, P = 0.05).

CONCLUSION

Angioarchitecture did not affect treatment outcomes. Cavernous symptoms were strongly associated with lower complete obliteration rates in the GKRS but not the EVT group. The EVT method remains the treatment of choice, especially for restrictive CSDAVFs; however, compared to EVT, GKRS had lower complication rates and similar therapeutic effects for proliferative type fistulas.

Endovascular treatment of carotid-cavernous sinus fistulas: ophthalmic and visual outcomes

Purpose: The main objective was to report the epidemiology, clinical manifestations, angiography features, treatment modality and post-treatment outcomes in patients diagnosed with carotid cavernous fistulas (CCF). Methods: A retrospective review of the medical imaging database in conjunction with medical records from 2004 to 2017 at the Royal Brisbane and Women's Hospital (RBWH) was conducted.We identified 39 patients with CCF (16 direct, 23 indirect). A total of 37 diagnoses were confirmed by direct catheter angiography. The remaining two cases were diagnosed using magnetic resonance imaging/magnetic resonance angiography. Results: Coils were deployed in 100% of direct and 83% of treated indirect fistulas that were treated. Other embolic agents were deployed alone or in combination with coils. Successful angiographic closure was achieved in 93% of direct and 92% of indirect fistulas. Multiple treatments were required in 33% of direct and 16% of indirect fistulas. Visual acuity improved in patients with direct fistulae(p = 0.02) and was preserved in those with indirect fistulae. Post-treatment diplopia persisted in six patients with direct fistulas and three patients with indirect fistulas. Four patients with indirect fistulas experienced persistent ocular hypertension post-treatment compared to two patients with direct fistulas. Conclusions: Endovascular coils are the most commonly deployed treatment for CCF. Both indirect and direct fistulas achieved high rates of closure; however, indirect fistulas were less likely to require multiple treatments. Good post-procedural vision was achieved for both groups.

Focus on the target: Angiographic features of the fistulous point and prognosis of transvenous embolization of cavernous sinus dural arteriovenous fistula

Background and purpose Transvenous embolization (TVE) is widely utilized as an effective and safe treatment option for cavernous sinus dural arteriovenous fistula (CS-dAVF); however, detecting the exact location of the fistula is challenging. The present study identified the angiographic features of the fistulous point and evaluated the match with the microcatheter tip and fistulous point. Materials and methods An analysis cohort of 45 consecutive patients with CS-dAVF treated by TVE was analyzed retrospectively. The patients were divided into two groups, 22 matches and 23 mismatches, according to whether the fistulous point and the microcatheter tip were in the same compartment of the cavernous sinus (CS). The angiographic findings, the location of the fistulas, the position of the microcatheter tips, the volume of embolic materials, complications, and outcomes were assessed. Results Several angiographic features defined the fistulous points, such as the early opacified area, jellyfish-like sign, changes in the density of the contrast medium, the juncture of different arterial supply, enlarged feeders, and hand-injection angiograms. The fistulas were primarily in the posterosuperior portion of the CS (80%) and medial side (73.3%) according to the internal carotid artery. Both groups achieved effective TVE; the matched group required less embolic material than the mismatched group ( p = 0.024). The patients with cranial nerve dysfunction (CND) required more embolic materials than others ( p = 0.032). Conclusion The fistulous point in most of the CS-dAVFs could be isolated by careful analysis of the angiography images. The matching of the microcatheter tip and fistulous point in the same compartment of CS can reduce the dosage of embolic materials, and a low volume of embolic materials might cause fewer CND complications.

Single-Session Hematoma Removal and Transcranial Coil Embolization for a Cavernous Sinus Dural Arteriovenous Fistula: A Technical Case Report

BACKGROUND

Patients with cavernous sinus dural arteriovenous fistulas (CS dAVFs) with cortical venous varix are indicated for aggressive treatment because of the associated risk for intracranial hemorrhage.

CASE DESCRIPTION

We present a case of surgical transvenous embolization in an 84-year-old woman with CS dAVF who presented with massive intracerebral hematoma. Cerebral angiograms revealed the dural AVF drained only into the superficial middle cerebral vein. Because an emergent mass reduction and prevention of rebleeding were necessary, single-session hematoma removal and transcranial embolization of a CS dAVF were performed in the neurosurgical operating room, using a mobile C-arm fluoroscopy. After the right frontotemporal craniotomy, intracerebral hematoma was removed and coil packing of the affected cavernous sinus was successfully performed via the dilated superficial middle cerebral vein.

CONCLUSION

The transcortical vein approach enables occlusion of CS dAVF with isolated cortical venous drainage and may be a valuable alternative approach for some cases needed emergency craniotomy.

Cavernous sinus dural arteriovenous fistula treated by facial vein direct puncture: Case report and review of the literature

Introduction In case of cavernous sinus dural arteriovenous fistula (CSDAVF), transvenous embolization (TVE) of the cavernous sinus (CS) via the inferior petrosal sinus (IPS) is generally performed. However, various approach routes have been reported when the accessibility of the IPS is challenging. We herein report a case of CSDAVF treated by TVE with direct puncture of the facial vein. Case report A 70-year-old woman who suffered from tinnitus, chemosis, diplopia and bruit was referred to our hospital. Digital subtraction angiography (DSA) demonstrated CSDAVF. We initially attempted to perform TVE via the IPS route; however, we could not guide a catheter to the CS because of an anatomical difficulty. Then, we performed percutaneous direct puncture of the dilated facial vein, and successfully treated the patient. Conclusion When navigating microcatheter to the CS is difficult because of an anatomical difficulty of the IPS, direct puncture of the facial vein is a feasible route.

Surgical and Nonsurgical Treatment of Vascular Skull Base Trauma

Vascular trauma is associated with blunt skull base fractures and penetrating injuries. We review the contemporary management of cranial vascular trauma, including blunt and penetrating cerebrovascular injury as well as refractory epistaxis from facial trauma.

Endovascular Modalities for the Treatment of Cavernous Sinus Arteriovenous Fistulas: A Single-Center Experience

BACKGROUND

Cavernous sinus (CS) fistulas are classified into traumatic and spontaneous. Traumatic carotid-cavernous fistulas (CCFs) are usually direct internal carotid artery (ICA) high-flow fistulas; whereas spontaneous CCFs are usually dural, low-flow fistulas and generally possess less severe symptoms than direct carotid-cavernous fistulas.

METHODS

This study involved 34 patients who were classified into 2 groups: Group A included 26 patients with direct carotid-cavernous fistula; and Group B included 8 patients with indirect dural cavernous fistula. All patients had ocular manifestations. One patient had subarachnoid hemorrhage. Coils were used alone in 19 cases of direct fistula and in 1 case of dural fistulas. Coils and Onyx (Covidien, Mansfield, MA, USA) were used in 7 cases of direct fistula and in 2 cases of dural fistulas. Onyx alone was used to treat 5 cases with dural fistulas but none of the cases with direct fistulas. Covered stents and coils were used in 2 cases of direct fistulas.

RESULTS

All patients in both groups showed full recovery of their clinical signs and symptoms. Only 1 procedure-related complication was observed (3%) in which a patient had an embolic event and trigeminal dysesthesia as a result of Onyx reflux through external carotid artery-ICA anastomosis.

CONCLUSION

Coils are superior solid embolic agents used for the treatment of direct high-flow fistulas, while Onyx is more valuable in dural low-flow CCF. Onyx shortens the procedure time and decreases procedure cost. Onyx injection inside the CS proper through the transarterial or transvenous route may be safer than Onyx injected inside dural arteries supplying the CS. However, more cases are needed to determine this.

Endovascular treatment with transvenous approach for embolization of carotid cavernous fistula

The aim of endovascular treatment in carotid cavernous fistula is to close the tear side at cavernous sinus part. It can be dealt either by transvenous or transarterial approach. The option is influenced by type of fistula and angioarchitectural findings. We described two different transvenous routes emphasizing on anatomical consideration and its technical aspect.

Difficult indirect carotid-cavernous fistulas--alternative techniques to gaining access for treatment

AIMS

Carotid-cavernous fistulas (CCFs) are abnormal communications between the carotid arterial system and the cavernous sinus that occur mainly in elderly. Occasionally, treatment of indirect CCFs with conventional endovascular approach through large veins or the inferior petrosal sinus may not be possible. In these cases, a direct surgical cut down on to the superior ophthalmic vein (SOV) is necessary. We describe three such cases of embolization of CCFs through SOV, and their results.

METHODS

A retrospective case notes review of treated patients over the past 10 years in one tertiary center constituted our methodology.

RESULTS

The fistulas in two cases were successfully coiled with complete obviation of symptoms and signs. The third case was complicated due to difficulty in canulating a deeply seated vein and so had to be abandoned and catheterized through contralateral superior petrosal sinus and treated with liquid embolic material Onyx(®) successfully.

CONCLUSION

In cases where conventional access to the cavernous sinus may not be possible due to local variations of anatomy, multidisciplinary surgical approaches via the SOV provide an alternative route to successfully and safely close a CCF. However, unexpected anatomical variations could also be encountered within the SOV for which the surgeon should be prepared.

The superior ophthalmic vein: delineation with high-resolution magnetic resonance imaging

OBJECTIVE

To delineate the superior ophthalmic vein (SOV) with high-resolution magnetic resonance (MR) imaging.

METHODS

This retrospective study enrolled 302 consecutive outpatients, 101 patients, 51 males and 50 females, who underwent coronal T2-weighted imaging and 201 patients, 99 males and 102 females, who underwent three-dimensional (3D) phase-contrast (PC) MR angiography.

RESULTS

Coronal T2-weighted imaging clearly delineated the intraorbital course of SOV on serial images in all 101 subjects. The SOV could be topographically divided into three segments in relation to the superior rectus muscle. The SOV crossed over the optic nerve at the level of the anterior ethmoidal foramina in 87% of right orbits and 71% of left orbits. The mean outer diameter of the SOV at the crossing point was 1.7 mm on both sides, but the SOVs were asymmetric in the same individual in 75% of the subjects. 3D PC MR angiography showed that the bilateral SOVs were symmetrical in 16% of subjects, larger in the right orbit in 18%, and larger in the left orbit in 13%, and were unidentified in 52%. The SOV showed a consistent lateral course to the ophthalmic artery.

CONCLUSIONS

The SOV consistently courses lateral to the ophthalmic artery, but tends to show bilateral asymmetry in the outer diameter. The superior rectus muscle, anterior ethmoidal foramen, and anterior ethmoidal artery are valuable landmarks to identify the SOV during transcranial orbital surgery. Combination of high-resolution MR imaging and 3D PC MR angiography is useful for delineating the SOV.

Endovascular treatment of carotid-cavernous fistulas

Endovascular management has become the treatment of choice for carotid-cavernous fistulas regardless of the fistula type. The endovascular method offers numerous options that render it capable of treating each fistula type by choosing an adequate technique. This advantage along with the advancement in the field has led to fewer complications with higher success rate.

Endovascular treatment of carotid cavernous sinus fistula: A systematic review

Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, hemodynamic features, or the angiographic arterial architecture. Increased pressure within the cavernous sinus appears to be the main factor in pathophysiology. The clinical features are related to size, exact location, and duration of the fistula, adequacy and route of venous drainage and the presence of arterial/venous collaterals. Noninvasive imaging (computed tomography, magnetic resonance, computed tomography angiography, magnetic resonance angiography, Doppler) is often used in the initial work-up of a possible carotid cavernous sinus fistulas. Cerebral angiography is the gold standard for the definitive diagnosis, classification, and planning of treatment for these lesions. The endovascular approach has evolved as the mainstay therapy for definitive treatment in situations including clinical emergencies. Conservative treatment, surgery and radiosurgery constitute other management options for these lesions.

[Superior ophthalmic vein catheterization: treatment of a dural fistula]

We report the case of a 68-year-old woman with a chronic unilateral red eye for 3 months. The ophthalmologic exam showed engorged episcleral vessels, proptosis and chemosis. Motility, visual acuity and fundus examination were normal. Neurological examination was also unremarkable. Given the subacute nature of the proptosis in association with engorged episcleral vessels, brain MRI and MRA were performed, demonstrating a right dural-cavernous sinus fistula. After two attempts via the femoral and facial veins, the dural fistula was accessed and treated via the right superior ophthalmic vein. The fistula was occluded and the symptoms regressed in 48 hours. Arteriography at 3 months confirmed a complete cure.

The superior ophthalmic vein approach for the treatment of carotid-cavernous fistulas: a novel technique using Onyx

Object

Endovascular therapy is the primary treatment option for carotid-cavernous fistulas (CCFs). Operative cannulation of the superior ophthalmic vein (SOV) provides a reasonable alternative route to the cavernous sinus when all transvenous and transarterial approaches have been unsuccessful. The role of the liquid embolic agent Onyx in the management of CCFs has not been well documented, especially when using an SOV approach. The purpose of this study is to assess the safety and efficacy of Onyx embolization of CCFs through a surgical cannulation of the SOV.

Methods

The authors retrospectively reviewed all patients with CCFs who were treated with Onyx through an SOV approach between April 2009 and April 2011. Traditional endovascular approaches had failed in all patients.

Results

A total of 10 patients were identified, 1 with a Type A CCF, 5 with a Type B CCF, and 4 with a Type D CCF. All fistulas were embolized in 1 session. Onyx was the sole embolic agent used in 7 cases and was combined with coils in 3 other cases. Complete obliteration was achieved in 8 patients and a significant reduction in fistulous flow was achieved in 2 patients, which later progressed to near-complete occlusion on angiographic follow-up. All patients experienced a complete clinical recovery with excellent cosmetic results and were free from recurrence at their latest clinical follow-up evaluations.

Conclusions

Onyx embolization is an excellent therapy for CCFs in general, and through an SOV approach in particular. Direct operative cannulation of the SOV followed by Onyx embolization may be the best treatment option in patients with CCFs when all other endovascular approaches have been exhausted.

Combined surgical and endovascular access of the superficial middle cerebral vein to occlude a high-grade cavernous dural arteriovenous fistula: case report

BACKGROUND AND IMPORTANCE

High-grade cavernous sinus (CS) dural arteriovenous fistulae with cortical venous drainage often have a malignant presentation requiring urgent treatment. In the absence of a venous access to the lesion, transarterial embolization can potentially cure these lesions; however, the high concentration of eloquent arterial territories adjacent to the fistula creates a precarious risk of arterial-arterial reflux. In such cases, a combined surgical and endovascular approach may provide the least invasive option.

CLINICAL PRESENTATION

We describe a patient presenting with a venous hemorrhagic infarct caused by a high-grade CS dural arteriovenous fistula (Barrow type D caroticocavernous fistula) with isolated drainage via the superficial middle cerebral vein into engorged perisylvian cortical veins. No transfemoral or ophthalmic strategy was angiographically apparent, and the posterior location of the involved CS compartment mitigated a direct puncture. The patient underwent direct puncture of the superficial middle cerebral vein via an orbitozygomatic craniotomy and the CS was catheterized under fluoroscopic guidance. The CS was coil-embolized back into the distal superficial middle cerebral vein with complete obliteration of the fistula. The patient did well with no new deficits and made an uneventful recovery.

CONCLUSION

This novel combined open surgical and endovascular approach enables obliteration of a CS dural arteriovenous fistula with isolated cortical venous drainage and avoids the additional manipulation with direct dissection and puncture of the CS itself.

Transcortical Venous Approach for Direct Embolization of a Cavernous Sinus Dural Arteriovenous Fistula: Technical Case Report

BACKGROUND AND IMPORTANCE:

Dural arteriovenous fistulas (dAVFs) represent 10% to 15% of all intracranial arteriovenous malformations. Most often, embolization is accomplished with transfemoral catheter techniques. We present a case in which embolization of a cavernous sinus dAVF was made possible through transcranial cannulation of a cortical draining vein.

CLINICAL PRESENTATION:

An 82-year-old woman presented with diplopia, left sixth cranial nerve palsy, intraocular hypertension, and bilateral chemosis. Angiography revealed a complex cavernous dAVF with cortical venous reflux, supplied by both external carotid arteries and the left meningohypophyseal trunk. Percutaneous transvenous access failed, and only partial occlusion was achieved by transarterial embolization. A frontotemporal craniotomy was performed to access the superficial middle cerebral vein in the left sylvian fissure. Under fluoroscopic guidance, a microcatheter was advanced through this vein to the floor of the middle cranial fossa and into the dAVF, permitting coil occlusion.

CONCLUSION:

This transcranial vein technique may be a useful adjunct in dAVF therapy when percutaneous transarterial or transvenous approaches fail or are not possible.

Transorbital endovascular embolization of dural carotid-cavernous fistula: access to cavernous sinus through direct puncture: case examples and technical report

OBJECTIVE

We present 2 cases of carotid-cavernous fistulas that failed multiple attempts at transarterial and transvenous embolization. Direct transorbital puncture for embolization was successful in curing the fistulas. The relevant anatomy and technique are reviewed.

CLINICAL PRESENTATION

The first case is a 39-year-old man who presented with a 2-month history of worsening right-sided chemosis, proptosis, double vision, and progressive right eye vision loss. The second case is a 79-year-old woman with a 5-month history of right-sided chemosis and a 1-month history of complete left ophthalmoplegia. Cerebral angiography revealed an indirect carotid-cavernous fistula (CCF) in both patients, supplied by meningeal branches of the internal and/or external carotid arteries.

INTERVENTION

After multiple unsuccessful attempts at transarterial and transvenous embolization, the CCFs were accessed via direct percutaneous transorbital puncture of the inferior and superior ophthalmic veins, respectively. The fistulas were then successfully occluded with a combination of Onyx and detachable coils.

CONCLUSION

In rare cases in which more conventional transvenous and transarterial routes to a CCF have been exhausted, direct percutaneous transorbital puncture represents a viable means of achieving catheterization of the fistulous connection. In most cases, where a prominent arterialized superior ophthalmic vein is present, direct puncture represents a reasonable alternative to ophthalmologic cut-down procedures. Transorbital puncture of the inferior ophthalmic vein provides a direct route to the cavernous sinus in cases where the superior ophthalmic vein is atretic and inaccessible by direct surgical cut-down procedures.

Microsurgery can cure most intracranial dural arteriovenous fistulae of the sinus and non-sinus type

There is consensus that intracranial dural arteriovenous fistulae (dAVF) with direct (non-sinus-type) or indirect (sinus-type) retrograde filling of a leptomeningeal vein should be treated due to the high risk of neurological deficits and hemorrhage. No consensus exists on treatment modality (surgery and/or embolization) and, if surgery is performed, on the best surgical strategy. This series aims to evaluate the role of surgery in the management of aggressive dAVFs. Forty-two patients underwent surgery. Opening and packing the sinus with thrombogenic material was performed in 9 of the 12 sinus-type dAVFs. In two sinus-type fistulae of the cavernous sinus and 1 of the torcular, microsurgery was used as prerequisite for subsequent embolization by providing access to the sinus. In the 30 non-sinus-type dAVFs, surgery consisted of interruption of the draining vein at the intradural entry point. In 41 patients undergoing 43 operations, elimination of the dAVF was achieved (97.6%). In one case, a minimal venous drainage persisted after surgery. The transient surgical morbidity was 11.9% (n = 5) and the permanent surgical morbidity 7.1% (n = 3). Our surgical strategy was to focus on the arterialized leptomeningeal vein in the non-sinus-type and on the arterialized sinus segment in the sinus-type dAVFs allowing us to obliterate all but one dAVF with a low morbidity rate. We therefore propose that microsurgery should be considered early in the treatment of both types of aggressive dAVFs. In selected cases of cavernous sinus dAVFs, the role of microsurgery is reduced to that of an adjunct to endovascular therapy.

Surgical cannulation of a cortical draining vein for endovascular treatment of a dural arteriovenous fistula of the cavernous sinus

Dural arteriovenous fistulas (DAVF) of the cavernous sinus most commonly present with ocular symptoms and can be observed or treated with endovascular approaches, surgery, or radiosurgery. Combined surgical-endovascular approaches have been used for fistulas that are not amenable to standard endovascular approaches. A 40-year-old man presented with ocular symptoms from a cavernous sinus DAVF. Multiple previous transarterial and transvenous embolization attempts had failed. The patient underwent craniotomy for surgical exposure and cannulation of an arterialized sylvian vein. Subsequently he underwent coiling and onyx embolization of the DAVF. The intervention resulted in effective obliteration of the fistula. If a cavernous sinus DAVF is refractory to treatment, surgical exposure and cannulation of a cortical draining vein can facilitate transvenous endovascular treatments.

Triple coaxial catheter technique for transfacial superior ophthalmic vein approach for embolization of dural carotid-cavernous fistula

We report a triple coaxial catheter technique to facilitate the venous access to the superior ophthalmic vein during transvenous embolization of dural carotid-cavernous fistula (DCCF) via the transfacial venous route. Two patients with transvenous embolization of DCCFs by coils were treated with transfacial superior ophthalmic vein (SOV) approach by the triple coaxial catheter technique. The triple coaxial catheter system consisted of a 6F guiding catheter as the outer catheter and a 4F guiding catheter as the middle catheter and a microcatheter as the inner catheter to help navigation and manipulation. The DCCFs were completely obliterated in both cases. There were no complications associated with the procedure. The ophthalmic symptoms of the patients had totally resolved at two-month follow-up. The triple coaxial catheter technique can be used with the transfacial SOV approach in embolization of DCCF. This technique has two advantages over the double coaxial catheter technique because it offers additional length and support for the distal navigation of microcatheter into the SOV.

Superficial temporal vein: route to embolization of cavernous dural arteriovenous fistula

Superficial temporal vein catheterization was used to embolize a dural arteriovenous malformation of the cavernous sinus in a 44-year-old woman. The pertinent venous anatomy is discussed. This route may provide crucial access to the cavernous sinus when conventional approaches such as the Inferior petrosal sinus catheterization are difficult.

Etiology of carotid cavernous fistula in Japanese

BACKGROUND

A carotid cavernous fistula (CCF) develops spontaneously or after trauma, and older publications suggest that the majority of CCF cases are caused by trauma. However, more recent reports question the prevalence of CCFs caused by trauma.

METHODS

The clinical records of 37 consecutive patients diagnosed with a CCF were reviewed. The disease etiology, patient demographics, anatomical classification, and clinical course were investigated.

RESULTS

The CCF was spontaneous in 30 patients, and was related to head or neck trauma in seven patients. The mean age of all patients was 65.8 +/- 10.5 years, and 30 (81.1%) were women. Eight had diabetes and 14 had hypertension. The major signs and symptoms were congestion (86.4%), diplopia (81.1%), bruit (59.5%), and headaches/orbital pain (62.2%). Exophthalmos (67.6%) and elevated intraocular pressure (40.5%) were also frequently noted. In the Barrow classification, seven patients were classified as type A, four as type B, three as type C, and 20 as type D. The classification could not be established in three patients who did not undergo angiography. Of note, almost all patients had consulted an ophthalmologist before the diagnosis.

CONCLUSION

Spontaneous/low-flow CCF is more prevalent than previously reported. The role of ophthalmologists is important because the majority of patients initially consult ophthalmologists, and the signs of low-flow CCF are subtle and may be overlooked.