Focal stenosis of the sigmoid sinus causing intracranial venous hypertension: Case report, endovascular management, and review of the literature

Abstract

Regardless of the underlying pathology, elevated intracranial pressure is the endpoint of any impairment in either cerebrospinal fluid (CSF) absorption (including arachnoid villi) or intracranial venous drainage. In all age groups, the predominant final common pathway for CSF drainage is the dural venous sinus system. Intracranial venous hypertension (ICVH) is an important vascular cause of intracranial hypertension (and its subsequent sequelae), which has often been ignored due to excessive attention to the arterial system and, specifically, arteriovenous shunts. Various anatomical and pathological entities have been described to cause ICVH. For the second time, we present a unique case of severe focal stenosis in the distal sigmoid sinus associated with concurrent hypoplasia of the contralateral transverse sinus causing a significant pressure gradient and intracranial hypertension, which was treated with endovascular stent placement and angioplasty.

Keywords: Intracranial venous hypertension; endovascular angioplasty/stenting; intracranial venous outflow obstruction; sigmoid sinus focal stenosis.

Figure 1.

Ophthalmoscopic fundus examination (a) demonstrates extensive edema and swelling around the optic disc associated with inappreciable cup-to-disc ratio with blurring of the disc margins suggestive for chronic papilledema. Magnetic resonance (MR) studies ((b)–(h)) and 3D reconstruction time-of-flight MR venography (i) demonstrates ventriculomegaly, increased ICP, irregular appearance of the straight sinus, and markedly diminutive right transverse/sigmoid venous system associated with severe focal stenosis at the left sigmoid/jugular confluence (arrow).

Figure 2.

Digital subtraction angiography (DSA) demonstrates hypoplastic right transverse and sigmoid sinuses extending into a small right internal jugular vein (arrowhead), as well as a focal severe stenosis at distal of the dominant left sigmoid sinus and proximal to the jugular bulb (arrow; (a)–(d)). Direct venous pressure measurements prior to stent placement ((e) and (f)) demonstrates a 20 mmHg pressure gradient across the stenosis: proximal left internal jugular vein = 12 mmHg versus distal sigmoid sinus = 32 mmHg. (g)–(j) Precise 10 mm × 30 mm self-expanding Nitinol stent placement across the stenosis using over-the-wire technique and sequential overlapping balloon angioplasty results in immediate improvement in the appearance of the stenosis with a mild residual stenosis. The pressure gradient is dramatically reduced to normal: proximal left internal jugular vein = 17 mmHg, distal left sigmoid sinus = 20 mmHg, mid-sigmoid sinus = 20 mmHg, distal left transverse sinus = 19 mmHg.

Figure 3.

Three-month follow-up DynaCT venography (a) demonstrates complete patency of the stent within the left sigmoid sinus. One-year follow-up DSA with direct pressure measurements ((b)–(e)) and 3D DynaCT venography (f) demonstrate patent stent within the left sigmoid sinus with significant improvement of pressure gradient across the stent and the pressure gradient between the intracranial dural venous sinuses and the cervical left internal jugular vein (4 mmHg). One-year follow-up fundoscopy (g) confirms significant improvement in papilledema and resolved disc edema with remaining optic nerve atrophy due to previous long-standing intracranial hypertension.

Figure 4.

Severe focal stenosis of the right sigmoid sinus (arrow), with permission from the Journal of Neurosurgery Publishing Group.