INTRODUCTION

This presentation will outline the technique that we use in treating selected patients with distensible venous vascular malformations (DVVMs) of the orbit (orbital varices).

CLASSIFICATION OF ORBITAL VASCULAR

LESIONS

An exhaustive discussion of this classification is beyond the scope of this presentation but is discussed in detail elsewhere (2,3). The overall concept distinguishes ‘‘new growth’’ from ‘‘malformation’’ and emphasizes the difference between an acquired arteriovenous shunt or fistula (i.e., carotid-cavernous fistula) and other vascular malformations. Vascular malformations can then be subdivided based at least in part on flow into noflow, venous flow, and arterial flow lesions. A lymphatic vascular malformation would typify the no-flow lesion, and arteriovenous malformation the arterial flow lesion. Venous flow lesions include distensible venous, nondistensible venous, and combined nondistensible venous–lymphatic vascular malformations. It is the DVVMs that enlarge with Valsalva maneuver or bending for which the combined technique of direct puncture embolization followed by surgical excision has been used.

DVVMs may be superficial, deep (posterior to the globe), or a combination of these. Their involvement may extend beyond the boundaries of the orbit to include the face, paranasal sinuses, or intracranially; these are called complex venous malformations (Fig. 1).

ANATOMY OF ORBITAL REGION VENOUS

STRUCTURES AND RELATIONSHIP WITH

DVVMs

The orbital venous system has a significant outflow connection via the superior and inferior orbital veins to the cavernous sinus, venous plexus of the pterygopalatine fossa, and supratrochlear and angular veins of the face.

The relationship of DVVMs to normal veins of the orbit and its neighboring structures is variable but at least in part

Figure 1 Coronal CT (A) and MR (B) imaging and lateral (C) and frontal (D) views from a direct injection show a complex DVVM extending from superficial to deep in the orbit and also intracranially through a bony defect in the roof of the orbit. (Borrowed with permission from Ref. 2.)

predictable by the location of the malformation. The distensibility of these lesions indicates relatively large functioning connections with the normal venous system. When the pressure in the venous system is elevated, it is reflected back stream into the malformation, which distends. Depending on venous connections, these DVVMs can on occasion be visualized by indirect orbital venographic techniques. Those connected to the superior ophthalmic vein may be seen this way (Fig. 2). However, the best means to delineate specific

Figure 2 Direct venogram demonstrates a venous orbital malformation. This is characterized by an ectatic venous outflow channel that is part of the superior ophthalmic vein. (Borrowed with permission from Ref. 3.)

features of a DVVM and its connections is by direct intralesional injection. The DVVMs can be relatively simple ectatic areas that merge with adjacent normal orbital veins (Fig. 3B), or more complex malformations with multiple channels and saccular areas that flow into dysplastic venous networks to the pterygopalatine fossa or the superior or inferior ophthalmic venous systems (Figs. 3 and 4).

CLINICAL MANIFESTATIONS OF DVVMs

Generally, DVVMs do not warrant treatment. Superficial lesions might be seen as dark, tortuous epibulbar varices or as subcutaneous lid masses (Fig. 5). Deep lesions will be less