The vascular lesion and its cast are then surgically excised in a relatively blood-free field (Fig. 3).

RESULTS AND COMPLICATIONS OF

TREATMENT

We have published the results of this treatment technique in a select group of six patients out of a larger series of 30 patients with DVVMs of the orbit (2). Four additional patients, of 23 seen since the study series, have been treated successfully but not formally reported. All patients have done well except two. One patient had a superficial lesion treated by glue injection from a direct percutaneous access point without surgical exposure. It was decided not to resect the casted lesion at that time, as it was reasonably flat in contour and no longer distending with ventilator-induced Valsalva maneuver. However, a foreign body reaction developed with localized swelling and tenderness, requiring subsequent surgical excision of the lesion. The other patient with a complication was our first on whom this technique was tried. She was suffering from severe pain and proptosis, and at the outset was accepting the possibility of visual loss if it meant her pain would be gone. Analysis of her treatment indicates that her malformation was not completely excised after embolization. Understanding the hemodynamics and venous outflow is important for success and complication avoidance. Occlusion of the drainage pathway of a lesion or lesions with glue might lead to enlargement or stasis within remaining portions if these are not completely excised. This situation may also lead to thrombosis or hemorrhage with potential risk to vision from pressure effect, which we believe was the mechanism that caused partial visual loss in this patient. The thrombosed portion of her lesion regressed and she was left completely free from pain and without proptosis.

FUTURE CONSIDERATIONS

Other embolic agents besides glue have been used to devascularize lesions in areas of the body outside the orbit. Among

these are polyvinyl alcohol particles, microfibrillar collagen, and ethanol (7). These agents could be directly injected into DVVMs to produce thrombosis but this may be complicated by acute and significant swelling (particularly with ethanol), leading to more profound secondary effects such as visual loss. There is also concern that lesions treated with such agents can overtime recanalize and therefore recur. Because of this, such agents are not likely to be very useful.

The goal will be to find an agent that can be injected directly into these lesions to bring about closure and permanent regression, precluding the need for intraoperative maneuvers with wide exposures and resection.

CONCLUSION

We have reviewed the features of DVVMs of the orbit and provide a look at a new technique for treating these lesions using the combined expertise of interventional neuroradiology and orbital surgery.

REFERENCES

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