Direct access of non-dilated superior ophthalmic vein for embolization of cavernous sinus dural arteriovenous fistula: a systematic review and illustrative case.

PURPOSE: To identify and technically characterize published attempts at direct superior ophthalmic vein (SOV) access for cavernous sinus dural arteriovenous fistula (CCF; indirect carotid-cavernous fistula) when SOV caliber, patency, or angiographic visibility was unfavorable, and to describe a separate institutional illustrative case. METHODS: We performed a PRISMA 2020-compliant systematic review with descriptive technical synthesis. MEDLINE, CINAHL, PsycINFO, EMBASE, the Cochrane Library, and Scopus were searched in April 2026. Eligible reports described direct exposure, puncture, cannulation, or attempted cannulation of the SOV itself and provided sufficient case-level technical detail. Caliber, patency, and angiographic visibility were classified separately. Outcomes were summarized as raw counts. The institutional case was not included in review denominators. RESULTS: Five reports provided eight published access attempts. Numerical SOV diameter was not reported in any literature case. Patency was described as thrombosed in four attempts, occluded in one, stenosed or narrowed in one, without reported obstruction in one, and not reported in one. Angiographic visibility was incompletely characterized. The complete sequence of direct SOV cannulation, target-compartment navigation, and embolization was reported in six attempts. Two attempts failed because a small, stenotic, or fibrotic vein could not be traversed. All six successfully treated cases had immediate angiographic occlusion and clinical improvement. Paired visual acuity improved in the five successfully treated cases with extractable data. No SOV-access complication was reported in those six cases, but adverse-event reporting and follow-up were heterogeneous, and only one had explicitly reported follow-up angiography. The institutional case had complete occlusion at 3 months. CONCLUSIONS: Published case-based experience documents that direct SOV access can be technically feasible despite non-dilation, impaired patency, or poor angiographic visibility. It may be considered a salvage option in experienced centers when conventional venous routes are not feasible. However, the evidence is too small and selected to estimate expected success, safety, or superiority of any access or embolization technique. KEY POINTS: • Non-dilated, stenosed, or angiographically occult superior ophthalmic vein with or without thrombosis may remain surgically identifiable and catheterizable for treatment in selected carotid-cavernous fistulas. • Direct superior ophthalmic vein access may be considered a salvage strategy option in experienced centers after failed or infeasible conventional transvenous access. • The complete sequence of direct SOV cannulation, target-compartment navigation, and embolization was reported in six of eight published access attempts. These counts are not estimates of expected procedural success. • The evidence is limited to five reports with heterogeneous anatomy, incomplete imaging definitions, variable follow-up, and substantial publication and reporting bias.