Sudden Unilateral Blindness after Intracranial Aneurysm Surgery.

Kang, Sung Dong

Original Article

Journal of Korean Neurosurgical Society 1996;25(12): 2438-2444.

Department of Neurosurgery, College of Medicine, Wonkwang University, Iksan, Korea.

ABSTRACT

The incidence of unilateral blindness and ophthalmoplegia after aneurysm surgery is very rare, but if there is, it is mainly caused by intraoperative nerve injury. We experienced 6 cases of unilateral blindness immediately after surgery for 5 recent years. These patients were classified from Hunt-Hess grade I to II except for one patient with III. All patients complained of visual loss with varying degree of lid edema and ophthalmoplegia ipsilateral to the surgery site. Angiographic examination of these patients revealed that the aneurysm site was located at the internal carotid artery bifurcation in one case and the middle cerebral artery bifurcation in five cases. All of them were relatively far from the optic nerve. The aneurysm was clipped easily with minimal brain retraction via standard pterional craniotomy since the brain was slack in all cases. In all cases, injuring the optic nerve during surgery was remote. All patients showed evidence of retinal ischemia of fundoscopy with or without fluorescein an giography. The pathophysiology of this ischemic event is unknown. In our patients, we could exclude possible etiologic factors such as abnormal systemic and ocular conditions, causing ischemia in intraorbital structures, increased intracranial pressure, intraoperative hypotension, carotid atherosclerosis, and vasculitis. Accordingly we believe that the complications ween in our cases were most likely related to intraorbital ischemia initiated by a collapse of the arterial and venous channels in the orbit and/or to direct or indirect contusion on the intraorbital structures. These situations could be produced by inadvertent pressure placed on the eyeball with a bulky retracted frontal skin flap. Visual acuity in these patients ranged from no light perception to the ability to see objects and detect color. Their conditions were irreversible. Unfortunately a satisfactory treatment is lacking. Neurosurgeons should be aware that this complication may follow intracranial aneurysm surgery and should ensure that the retracted flap is not compressive to the eye-ball, especially in patients with risk factors.

Key Words: Unilateral blindness; Aneurysm surgery; Compression intraorbital ischemia