Optic Nerve Sheath Fenestration—Indications and Techniques

Abstract

The optic nerve is a white matter tract of the brain and its sheath is composed of pia mater, arachnoid mater, and dura mater. The subarachnoid space (SAS) of the optic nerve sheath, which contains cerebrospinal fluid, is contiguous with the SAS of the brain. Elevated intracranial pressure is transmitted to the optic nerve head through the SAS resulting in papilledema. Optic nerve sheath fenestration (ONSF) can be an effective surgical technique to preserve vision in patients with progressive optic neuropathy due to papilledema caused by idiopathic intracranial hypertension (IIH); however, a dreaded complication of ONSF is visual loss. This article will discuss the rationale, indications, and complications of ONSF. A variety of surgical techniques can be employed to perform an ONSF. In particular, the medial transconjuctival approach will be highlighted.