Persistent Abducens Nerve Palsy after Successful Endovascular Treatment of a Dural Cavernous Sinus Arteriovenous Fistula

Special Article - Ophthalmology: Clinical Cases and Images

Austin J Clin Ophthalmol. 2016; 3(1): 1063.

Persistent Abducens Nerve Palsy after Successful Endovascular Treatment of a Dural Cavernous Sinus Arteriovenous Fistula

Neil R Miller¹* and James W McManaway²

¹Neuro-Ophthalmology Division, The Wilmer Eye Institute, The Johns Hopkins Hospital, USA

²Neuro-Ophthalmology Division, Hershey Pediatric Ophthalmology Associates, USA

*Corresponding author: Neil R. Miller, The Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287-9204, USA

Received: November 03, 2015; Accepted: May 04, 2016; Published: May 12, 2016

Abstract

Although cranial neuropathies are not uncommon after endovascular occlusion of dural cavernous sinus arteriovenous fistulas (DCAVFs), they almost always resolve or at least improve. We report the case of a healthy 57-year-old woman who developed left proptosis, chemosis and conjunctival injection that led to a diagnosis of a left-sided DCSAVF. The fistula was successfully embolized using a combination of a detachable balloon and platinum coils; however, following treatment the patient developed a left sixth (abducens) nerve paresis that did not resolve and eventually required surgical correction. It is unclear if the sixth nerve palsy resulted from chronic ischemia due to interruption of the vascular supply to the abducens nerve or from direct compression of the nerve. Patients with DCAVFs for whom endovascular treatment is planned should be warned of the potential for both transient and persistent post-procedure diplopia that ultimately may require treatment.

Keywords: Dural arteriovenous fistula; Cavernous sinus; Sixth nerve palsy; Embolization; Superior ophthalmic vein; Endovascular

Introduction

Dural cavernous sinus arteriovenous fistulas (DCSAVFs) are abnormal communications between the meningeal branches of the external and/or internal carotid artery and the cavernous sinus that may require treatment by one of several endovascular techniques [1]. Although the endovascular techniques used to close DCSAVFs are generally safe, complications can occur regardless of the specific approach, the material used to close the fistula, and whether or not the fistula is successfully closed [1,2]. Most often, these consist of dysfunction of the cranial nerves within the cavernous sinus, with the abducens nerve being most frequently affected [2]. Such cranial neuropathies usually are transient, resolving within days to weeks after the embolization [2,3]. Occasionally, however, they persist. We describe a patient who developed an isolated, persistent abducens nerve palsy after successful endovascular closure of a DCSAVF and discuss the potential mechanisms by which this complication may have occurred.

Case Report

A 57-year-old woman with no history of head trauma began to hear a swishing sound in the left occipital region and then developed redness and swelling of her left eye. An examination revealed normal visual acuity, conjunctival chemosis of the left eye, 4 mm of left proptosis, and asymmetric intraocular pressures of 10 mmHg OD and 17 mmHg OS. Auscultation of the left orbit revealed a faint bruit. A diagnosis of probable DCSAVF was made, and the patient underwent magnetic resonance angiography that supported the diagnosis. A catheter angiogram demonstrated a left-sided DCSAVF fed by branches from the right internal and external carotid arteries as well as the left external carotid artery (Figure 1). It was elected to follow the patient in the hope that the fistula would close spontaneously. The patient did not improve over the subsequent 6 months. Accordingly, she underwent closure of the fistula using an inflatable balloon introduced into the cavernous sinus through the ipsilateral superior ophthalmic vein (SOV) in the manner first described by Miller et al. [4]. Prior to this procedure, the patient had visual acuity of 20/25 OU, with normal color vision, normal visual fields, and normally reactive pupils. Extraocular movements were full, and the patient was orthophoric at distance and near. The left eye was injected, with dilated, “arterialized” conjunctival and episcleral vessels (Figure 2). The irides were normal without evidence of rubeosis. Tensions were 6 mmHg on the right, and 15 mmHg on the left. Ocular pulse amplitudes were 1.4 mm on the right and 4.5 mm on the left. Ophthalmoscopy revealed a slightly hyperemic left optic disc and somewhat dilated retinal vessels. There were no retinal hemorrhages or exudates. The right optic fundus was normal in appearance. Exophthalmometry revealed values of 15 mm on the right and 19 mm on the left. Corneal and facial sensation were equal and normal bilaterally. The remainder of the patient’s neurologic examination was normal.