Not the usual suspect

Intraorbital Arteriovenous Fistulas: Case Series and Systematic Review

BACKGROUND AND OBJECTIVES

Intraorbital arteriovenous fistulas (AVFs) are an extremely rare subtype of intracranial fistula with ophthalmic symptoms similar to cavernous sinus dural AVFs or carotid cavernous fistulas but worse visual outcomes. Here, we present a case series and thorough systematic review on intraorbital AVFs to demonstrate treatment modalities and address this rare type of AVF.

METHODS

We conducted a retrospective study at a single center, in which we identified all cases of intraorbital AVFs that occurred between 2002 and 2022. We collected and analyzed data on demographics, fistula characteristics, treatment methods, clinical outcomes, and fistula closure. In addition, we conducted a systematic review of intraorbital AVFs.

RESULTS

Seven cases in our center and 41 cases of intraorbital AVFs reported in the 35 articles were identified. At our center, transarterial embolization (TAE) (42.9%) alone resulted in immediate complete occlusion in 3 cases. Transvenous embolization (14.3%) resulted in one case of immediate complete occlusion. In 2 cases, surgery (28.6%) resulted in immediate complete occlusion. In one case, conservative treatment (14.3%) was used, and the fistula was eventually spontaneously occluded. Immediate complete occlusion rate was 85.7%. One blindness occurred (14.3%). In the literature reported, 3 cases (60%) of retinal artery occlusion were reported when performing TAE via the ophthalmic artery. Two fistulas recurred as reported. In 33 (80.5%) patients, the fistula was finally completely occluded.

CONCLUSION

TAE via the ophthalmic artery carries a high risk of blindness and a low cure rate. Transvenous techniques such as conventional transvenous routes, surgical exposure, or direct puncture of the drainage vein have been used as the first line of treatment for intraorbital AVFs.

Orbital Arteriovenous Fistula Causing Only Visual Impairment due to Compression of the Optic Nerve by the Dilated Superior Ophthalmic Vein

Orbital arteriovenous fistula (AVF) is a rare disease, and its standard therapeutic strategy has not been established. A 70-year-old male consulted an ophthalmologist due to a visual field defect in his left eye. Neurological findings showed visual impairment but no symptoms such as exophthalmos, conjunctival congestion, or diplopia. Magnetic resonance imaging showed marked dilation of the left superior ophthalmic vein (SOV). Cerebral angiography revealed an AVF that was limited to the left orbit. The feeder was a branch of the ophthalmic artery that originated from the first portion, and the drainer was the SOV, which was meandering and significantly dilated. Since the only symptom was visual impairment, the etiology was considered to be compression of the optic nerve due to a dilated SOV rather than increased venous pressure. Transvenous embolization via the facial vein was performed, and a visual field examination 1 week after the operation revealed marked improvement. Orbital AVF that develops only with visual impairment is extremely rare. As demonstrated with this case, coil embolization for proper position and reduction of the venous pressure, which relieves compression on the optic nerve, may be useful in improving the visual impairment.

[Differential diagnosis of intraorbital masses - a narrative review]

OBJECTIVE

Intraorbital masses represent a condition that is frequently threatening for the visual system. A rigorous differential diagnosis is essential to promptly initiate appropriate therapy and optimize prognosis.

MATERIALS/METHODS

Narrative review of current literature and expert recommendations. For further illustration we describe the case of a 71-year-old male admitted to our department three months after sinus surgery. Postoperative intraorbital hematoma of the right orbit had been treated conservatively with antibiotics/corticosteroids, leading to a near-complete unilateral visual loss. The immediate surgical intervention aimed at decompression of the orbit and the optical nerve. Due to the delay, the intervention could not prevent formation of a lipogranuloma. Inflammatory phases associated with the lipogranuloma are successfully managed by conservative treatment based on multidisciplinary recommendations.

RESULTS

In the case reported, delay of surgical therapy acted as a cause of intraorbital lipogranuloma formation. Literature supports our recommendation of immediate surgical intervention in case of acute retrobulbar hematoma. Besides acute conditions, intraorbital masses can be a sign of systemic disease. In every case, a multidisciplinary therapeutic approach is required for adequate management.

CONCLUSIONS

Intraorbital masses can occur as a complication of trauma or e.g. sinus surgery. On the other hand they can be a sign of systemic disease. Timely diagnosis and treatment prevents from visual loss. That is why rigorous differential diagnosis is essential for every discipline managing intraorbital lesions.