Optic nerve contact and compression by the carotid artery in asymptomatic patients

Management of patients with a neurovascular conflict involving the optic nerve and a non-diseased intracranial artery: Three cases

Introduction

Determining whether a neurovascular conflict (NVC) involving the anterior visual pathway (AVP) and a non-diseased intracranial artery is amenable for microvascular decompression is challenging. Moreover, it is unclear whether microvascular decompression of the optic nerve is an effective therapy.

Research question

What are the outcomes of different treatment strategies for NVCs involving the AVP and a non-diseased intracranial artery?

Material and methods

Data on patients with symptomatic NVCs involving the AVP and a non-diseased intracranial artery was collected and included treatment and outcome parameters. The case series was drafted in accordance with the CARE guidelines.

Results

Three patients aged 53,53 and 55 visited our out-patient clinic with a suspected symptomatic NVC between the optic nerve and a non-diseased intracranial artery. A conservative treatment was opted for in the first patient aimed at treating her glaucoma, with temporary improvement of symptoms. Microvascular decompression of the optic nerve was performed in two patients. One operated patient developed post-operative complications resulting in posterior circulation perfusion decline, while the other experienced a worse tunnel vision with a decrease in visual acuity.

Discussion and conclusion

The diagnosis of a symptomatic NVC between the AVP and a non-diseased intracranial artery should be considered with caution, i.e. after exclusion of all other causes. Microvascular decompression can be performed but does not necessarily improve symptoms. A better understanding of the pathophysiological mechanisms underlying these NVCs is warranted to determine the benefit of microvascular decompression of the optic nerve.

Optic Disc Cupping Due to Dolichoectatic Internal Carotid Artery Optic Nerve Compression

BACKGROUND

To determine whether significant compression of the optic nerve by the internal carotid artery (ICA) can produce an optic neuropathy with optic disc cupping that resembles glaucoma in patients without elevated intraocular pressure (IOP).

METHODS

This was a retrospective case series of patients referred to neuro-ophthalmology for a possible nonglaucomatous optic neuropathy. Patients were included in the study if they had preserved visual acuity, optic disc-related visual field defects, optic nerve cupping, IOP less than 21 mm Hg, open angles, and unequivocal radiological compression of the ipsilateral optic nerve by an intracranial blood vessel.

RESULTS

Three patients were included with a mean age of 56.3 (range 29-82) years. Patient 1 was a 58-year-old man incidentally noted to have left optic nerve cupping on a routine examination. He had an inferior arcuate defect and the left prechiasmatic optic nerve was elevated and compressed by a tortuous left ICA. Patient 2 was a 29-year-old man with a normal-tension glaucoma (NTG) diagnosis for 7 years in the right eye treated with latanoprost. He had a superior greater than inferior arcuate defect and there was vascular compression of the optic nerve between the supraclinoid ICA and A1 segment of the anterior cerebral artery. Patient 3 was an 82-year-old woman with an NTG diagnosis for 10 years who had progression of her visual field defects despite low IOPs. MRI showed mass effect on the right optic nerve by a dolichoectatic right supraclinoid ICA.

CONCLUSIONS

Significant compression of the optic nerve by a normal, tortuous, or dolichoectatic ICA may result in an optic neuropathy with optic disc cupping that resembles glaucoma.

Optic Neuropathy Due to Compression by an Ectatic Internal Carotid Artery Within the Orbital Apex

ABSTRACT

Neurovascular compression is a rare but potentially treatable cause of optic neuropathy. Although incidental contact of the cisternal optic nerve and internal carotid artery (ICA) is common, compressive optic neuropathy occurring within the orbital apex has not been comprehensively described. We report a case of intra-orbital and intracanalicular optic nerve compression due to an ectatic ICA in a patient with congenital absence of the contralateral ICA. This report describes the complementary roles of advanced neuroimaging and neuro-ophthalmologic examination in rendering the diagnosis.

Optic nerve vascular compression in a patient with a tuberculum sellae meningioma

Background. Optic nerve vascular compression in patients with suprasellar tumor is a known entity but is rarely described in the literature. Case Description. We present a unique, well-documented case of optic nerve strangulation by the A1 segment of the anterior cerebral artery in a patient with a tuberculum sellae meningioma. The patient presented with pronounced progressive visual deterioration. Following surgery, there was immediate resolution of her visual deficit. Conclusion. Vascular strangulation of the optic nerve should be considered when facing progressive and/or severe visual field deterioration in patients with tumors proximal to the optic apparatus.

Surgical decompression for optic neuropathy from carotid artery ectasia: case report with technical considerations

OBJECTIVE

Symptomatic compression of the optic nerve (ON) through its intracranial course or within the orbit may occur at several locations by abnormalities of adjacent soft tissue, bony, or vascular structures. Compressive optic neuropathy secondary to vascular ectasia is a rare phenomenon.

CASE DESCRIPTION

An adult male patient presented with a several month history of monocular visual loss. Imaging demonstrated compression of the ipsilateral ON by an ectatic carotid artery. Magnetic resonance imaging, ophthalmologic examination, and cerebral angiography did not demonstrate an alternative etiology of his visual loss. Conservative management was recommended; however, the patient's vision deteriorated further and pterional craniotomy was offered. Intraoperative examination demonstrated a distal origin of the ophthalmic artery that was bulging into, and pulsating against, the adjacent ON. Anterior clinoidectomy, falciform ligament transection, and sponge padding of the ON were then performed. The patient's visual loss improved rapidly postoperatively and at 1 month follow-up the patient exhibited normal visual fields on ophthalmologic testing.

CONCLUSIONS

We present a patient with severe monocular visual loss and significant anatomic displacement of the ON by an ectatic internal carotid artery-ophthalmic artery complex with dramatic and rapid visual improvement after surgical decompression. Complete untethering of the nerve and total cessation of transmitted pulsatility may not be necessary for symptomatic improvement. Optic nerve contact or displacement by the ipsilateral carotid artery is common in asymptomatic patients, therefore ruling out other etiologies of monocular visual loss before surgical decompression is paramount.

Optociliary Shunt Vessels in Compressive Optic Neuropathy by the Intracranial Internal Carotid Artery

Purpose

To report a clinical case of optic nerve compression by supraclinoidal internal carotid artery associated with optociliary shunt vessels.

Methods

A 78-year-old woman with the clinical triad of left visual loss, ipsilateral optic disc pallor, and retinochoroidal (optociliary) shunt vessels is reported. She complained of loss of vision in the left eye of 2 years' duration.

Results

A diffuse depression of the visual field was found in the affected eye. Magnetic resonance imaging revealed left optic nerve compression by the supraclinoidal internal carotid artery.

Conclusions

The occurrence of optociliary shunt vessels, visual loss, and optic atrophy is a non-specific sign of chronic optic nerve compression and in some instances may be falsely localized.

Optic nerve compression by normal carotid artery in patients with normal tension glaucoma

AIM

To determine whether compression of the optic nerve by the intracranial carotid artery (ICA) can be a causative factor of normal tension glaucoma (NTG).

METHODS

The medical records of 103 eyes of 54 Japanese patients with NTG and 104 eyes of 52 age matched control patients were reviewed. The neuroradiological findings of magnetic resonance images (MRI) were evaluated to determine the relation between the optic nerve and ICA. The clinical characteristics and general medical conditions, such as diabetes and systemic hypertension, were also compared between the two groups.

RESULTS

The prevalence of optic nerve compression by the ICA in patients with NTG was 49.5%, which was significantly higher than that in control group with 34.6% (p = 0.035). Bilateral compression of the optic nerve was detected in 22 patients with NTG (40.7%), and this was also significantly higher (p = 0.029) than that in the control group (11 patients, 21.2%). In the NTG group, eyes with cup/disc ratio (C/D ratio) > or =0.7 showed a higher percentage of compression (52.6%) compared with eyes with C/D ratio of <0.7 (12.5%; p = 0. 042). The presence of diabetes and hypertension did not affect the incidence of optic nerve compression by ICA significantly.

CONCLUSIONS

The significantly higher percentage of NTG patients who had optic nerve compression by the ICA suggests that compression of the optic nerve by ICA may be a possible causative factor or a risk factor for optic nerve damage in some patients with NTG.

Carotid artery ectasia coexistent with primary open angle glaucoma

A 60-year-old smoker presented with high intraocular pressure in the right eye with a right afferent pupil defect and visual field suggestive of primary open angle glaucoma in the right eye only, when an examination 2 years earlier had revealed no hint of ocular pathology. Radiological investigations demonstrated prominent ectasia of the internal carotid arteries extending into the proximal middle cerebral arteries. The changes in the carotids extended throughout the cavernous sinus regions, encroached on the under surface of the optic chiasm and were closely related to the internal aspects of both optic canals. In primary open angle glaucoma management, neural imaging is not normally recommended; however, neural imaging investigations should be considered if the presentation is not typical of a chronic bilateral optic neuropathy

New onset of crossed eyes in an adult

A 77-year-old woman presents with a seven-year history of an isolated slowly progressive esotropia with bilateral abduction defects. The only potential cause discovered was dolichoectasia of the intracavernous carotid arteries.

Symptomatic compression of the optic nerve by the carotid artery: clinical profile of 18 patients with 24 affected eyes identified by magnetic resonance imaging

OBJECTIVE

To characterize the clinical features and course of patients with magnetic resonance imaging (MRI)-defined optic nerve compression by the supraclinoid carotid artery.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Eighteen patients with 24 affected eyes were identified by reviewing case records from the author's referral-based neuro-ophthalmology practice. Predetermined inclusion and exclusion criteria were applied to potential participants.

MAIN OUTCOME MEASURES

The following variables were abstracted from the medical record: age, gender, presenting symptoms, past medical problems, visual acuity, color vision, visual field, pupillary reactions, optic disc appearance, other neurologic signs, and previously documented and follow-up examinations.

RESULTS

There were eight women and ten men ranging in age from 28 to 86 years (median age, 72 years) at the time of diagnosis. Ten (56%) of 18 patients had hypertension. Twelve patients had unilateral optic neuropathy, whereas 6 patients had bilateral optic neuropathy. One patient presented with subacute superior orbital fissure syndrome due to mass effect of a dolichoectatic carotid artery. Another patient had oculomotor nerve palsy with signs of aberrant regeneration due to intracavernous mass effect of a dolichoectatic carotid artery. One patient had a bitemporal hemianopia associated with bilateral compression of the immediate prechiasmatic optic nerves by dolichoectatic carotid arteries. The predominant pattern of visual field loss in most patients reflected nerve fiber bundle injury. A central scotoma or absolute central visual field loss was noted in only 6 (25%) of 24 affected eyes. Most patients demonstrated saucerlike excavation of the optic disc. Progression of visual acuity loss occurred at a relatively slow rate.

CONCLUSIONS

Although uncommon, intracranial compression of the optic nerve by the carotid artery should be considered in a patient with unexplained or progressive unilateral or bilateral optic neuropathy. This entity can be diagnosed using clinical skills to exclude more common causes of optic nerve injury and coronal-oriented MRI to confirm anatomic compression of the symptomatic optic nerve. Although many affected patients have excavation of the optic disc and nerve fiber bundle visual field defects, most have additional signs atypical for glaucoma, minimizing the potential for diagnostic confusion between the two disorders.