Orbital venous malformations are low-flow lesions resulting from vascular dysgenesis during development. Patients may present with vision loss, proptosis accentuated by Valsalva, and/or painful spontaneous thrombosis. The preferred treatment for symptomatic lesions is embolization combined with excision. A 34-year-old male presented to our institution from an outside emergency department with a diagnosis of presumed idiopathic orbital inflammation. For the prior month, he had been experiencing left orbital pressure, subjective eye bulging, and both diplopia and blurry vision when in peripheral gaze or when bending over. Despite initial improvement with steroids, his symptoms recurred with tapering. Visual acuity was reduced to 20/25, but pupils and motility remained normal. Biopsy demonstrated a vascular lesion characterized by fibroadipose tissue with histologically unremarkable blood vessels, and cerebral arteriography showed no high-flow components. A diagnosis of orbital venous malformation was made. He then underwent intraoperative angiography and Onyx embolization followed by excision via a transcaruncular approach. Two prior reports have described the use of Onyx in venolymphatic malformations. This report highlights a detailed approach to defining flow characteristics pre- and intraoperatively and expands upon our understanding of the use of Onyx for such cases.

© 2023 The Author(s). Published by S. Karger AG, Basel

Venous malformations of the orbit are categorized as low-flow malformations according to the International Society for the Study of Vascular Anomalies (ISSVA) classifications of nonorbital vascular malformations. These lesions are a result of vascular dysgenesis during development and can be further categorized as distensible or nondistensible lesions. Clinically, these lesions can present with vision loss, proptosis accentuated with Valsalva, enophthalmos with rest, and painful spontaneous thrombosis [1, 2].

Treatment of these lesions is variable and depends on symptoms as asymptomatic lesions can reasonably be observed. Typical treatments include excision, embolization, sclerosis, or a combination of these approaches. Combined embolization with excision is a well-accepted practice and the preferred approach for many surgeons [3]. To date, there have been two reports describing embolization of orbital venolymphatic lesions with Onyx (ethylene vinyl alcohol copolymer, Medtronic, Minneapolis) followed by surgical excision [4, 5]. Herein, we report a case in which an orbital venous lesion was surgically excised via a transcaruncular approach after successful embolization with Onyx. This case study was conducted in compliance with the Health Insurance Portability and Accountability Act guidelines. Written informed consent for publication was obtained from the patient, and no personal identifying information was reported.

A 34-year-old male with no significant past medical history presented to our institution 1 month after the gradual onset of pressure type pain in the left eye and associated subjective eye bulging. He also reported intermediate diplopia and blurred vision when bending down or looking in any direction. The patient had initially presented to an outside ED 1 week prior to our evaluation, where a noncontrast CT scan showed a bilobed retrobulbar mass causing proptosis, optic nerve impingement, and extraocular muscle impingement (Fig. 1). This information was obtained from a radiology report as the imaging was unavailable at the time of evaluation. The patient was started on 60 mg oral prednisone for presumed idiopathic orbital inflammation, with plans to taper.

Coronal (a) and axial (b) CT scan of the head and orbits, soft tissue window, showing a well-circumscribed intraconal lesion with slight hypodensity of the inferior aspect of the lesion.

One week later, the patient presented to our oculoplastics clinic for follow-up. He reported initial improvement in pain and subjective proptosis while on steroids, but he did note that his symptoms began to return once he tapered to 20 mg oral prednisone. This prompted him to resume his initial 60 mg dose. Exam revealed mild left-sided proptosis, visual acuity of 20/25 in both eyes, normal pupillary reaction, full extraocular motility, and normal slit lamp and funduscopic findings. MRI of the brain and orbits with and without contrast revealed a well-demarcated, multi-lobulated 2.5 cm left-sided intraconal orbital mass with T1 and T2 hyperintensity superiorly and hypointensity inferiorly (Fig. 2). The decision was made to obtain a biopsy.

T1-weighted MRI with contrast, coronal cut (a) and T2-weighted MRI with contrast, axial cut (b) and showing heterogeneous enhancement of a well-circumscribed intraconal lesion.

During the biopsy, the lesion appeared consistent with a vascular malformation. Relatively brisk bleeding prevented excision. A small sample was able to be sent for permanent section, and pathology showed fibroadipose tissue with histologically unremarkable blood vessels. Given the nature of the bleed during the procedure, there was some concern for a high-flow lesion.

Referral was made to interventional radiology for cerebral arteriogram, which did not show any arteriovenous shunting or evidence of a high-flow lesion. At this point, the diagnosis of venous malformation was made. Given that arteriography could not visualize the lesion, it was felt that another procedure with intraoperative direct puncture angiography could better characterize the lesion. No intracranial venous drainage or high-flow components of the malformation were noted.

Roughly 6 weeks later, the patient was brought back to the operating room. A transcaruncular approach permitted access to the lesion, at which point angiography with a 19-gauge spinal needle appeared consistent with the previous MRI. The lesion was filled with Onyx under fluoroscopic guidance, and the lesion and Onyx were then removed without complication (Fig. 3). A small remnant of the lesion and Onyx remained at the conclusion of the procedure and was left in the orbit due to its posterior location. The patient did not attend his postoperative appointments and left town shortly after the surgery. By phone 5 weeks later, he reported he had recovered well, the proptosis had resolved, and there was no recurrence of symptoms.

Intraoperative fluoroscopic angiography again showed no opacification of the malformation to indicate arterial involvement (a). The lesion underwent direct catheterization (b) and injection of Onyx (c), with only a small remnant of Onyx remaining after surgical excision (d).

One of the most critical steps in evaluating a suspected vascular lesion is to characterize its flow characteristics. In addition to a detailed history, several exam techniques may be useful including palpation, auscultation, and observation with and without Valsalva. Pulsations from high-flow lesions may be detected by palpation and even by careful auscultation if they are superficial enough. Distensible, low-flow malformations with significant outflow communication with the systemic venous system may show rapid proptosis with Valsalva and resolution with release of Valsalva. Low-flow malformations with few and/or small outflow pathways may be less dynamic. Imaging modalities such as cerebral angiography and dynamic MRA can also be useful when exam alone cannot fully characterize the lesion, as with our patient [2].

This flow rate distinction significantly impacts treatment strategy. In high-flow lesions such as arteriovenous malformations, the goal of treatment is to eradicate both the nidus of the malformation and the diseased outflow venous endothelium. There is also higher risk of complications from intraoperative hemorrhage. Low-flow malformations can be treated with excision, embolization, or sclerosis. Complete excision can be difficult, and thrombosing agents such as Tisseel (Baxter) or Evicel (Ethicon) can be used to assist. Sclerosing agents (alcohol, sodium tetradecyl sulfate 3%, sodium morrhuate 5%, bleomycin A5, and doxycycline) are less commonly used in venous malformations due to the risk of leakage into the vascular supply of the eye and/or cavernous sinus. Many surgeons today prefer the combination of embolization with excision as an effective treatment modality [3].

Onyx (ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide) is a liquid embolic agent originally approved by the Food and Drug Administration for endovascular embolization of brain arteriovenous malformations. When used preoperatively in a percutaneous or transarterial manner, it has been reported to reduce hemorrhagic complications of surgery in multiple different head and neck surgeries [6–8]. Case reports have discussed its use in embolizing orbital tumors including orbital meningiomas that are supplied by the ophthalmic artery [9–11]. Dantas and Lv detailed Onyx embolization of high-flow arteriovenous lesions [12, 13]. In 2021, reports by El-Namaani et al. and Magan et al. [4, 5] described successful preoperative use of Onyx for venolymphatic lesions.

Onyx has lava-like flow characteristics which are believed to allow for a more controlled injection. It is nonadhesive in nature with a low precipitation rate, which allows for deep penetration into lesions before solidification [11]. As an embolizing agent rather than a sclerosing agent, it is thought to pose lower risk of downstream vascular complications and is generally well tolerated in the head and neck [4, 7]. A review of 105 pediatric spinal and cranial tumors embolized with Onyx demonstrated a 24% complication rate including ischemic infarct, nontarget occlusion, hemorrhage, cerebral edema, retained catheter, pulmonary edema from dimethyl sulfoxide, and bronchospasm from contrast [14]. Minor, transient local inflammation has been observed in facial arteriovenous malformations [8].

While orbital and cavernous sinus lesions are typically embolized transcutaneously under ultrasonic or fluoroscopic guidance followed by delayed excision, our team opted for open surgical direct puncture embolization followed immediately by excision due to the degree of proptosis and risk of optic neuropathy [4, 5, 12, 13] That said, adjacent tissue damage may argue for more prompt removal of Onyx, as was demonstrated by cranial and sympathetic nerve injuries in the case of delayed excision of a carotid body tumor [15]. Permanently retained Onyx in the orbit has not been described, but it is recommended to excise the hard cast given the risk of globe or optic nerve impingement [4].

To our knowledge, this is the fifth report of its use to treat an orbital vascular lesion and the third report pertaining to a low-flow lesion [4, 5, 12, 13]. Location within the orbit dictates surgical approach, and this is the first case describing transcaruncular incision for direct, intraoperative puncture angiography and excision of a lesion. Its favorable properties in combination with growing evidence of its efficacy support the use of Onyx as an embolizing agent in the multi-disciplinary treatment of low-flow orbital vascular malformations.

This research publication complies with the Declaration of Helsinki. Ethics Committee and IRB approval were not required in accordance with the policies of University of Colorado Health (https://www.uchealth.org/wp-content/uploads/2019/12/UCHealth-IRB-SOP-Nov-2019.pdf). Written informed consent to publish case history and images was obtained from the patient.

The authors have no conflicts of interest to declare.

No funding sources.

Garrison P. Wier and Ryan D. Larochelle participated in the care of this patient, manuscript drafting, and manuscript revision. Joshua Seinfeld and Eric M. Hink participated in the care of this patient and manuscript revision.

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.

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