4 Giant Aneurysm of the Subclinoidal (Anterior Genu) ICA Treated with Aneurysm Resection and Reconstruction of ICA with Venous Patch

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Giant Aneurysm of the Subclinoidal (Anterior Genu) ICA Treated with Aneurysm Resection and Reconstruction of ICA with Venous Patch

DAVID G. PIEPGRAS

Diagnosis Giant aneurysm of the subclinoidal ICA

Problems and Tactics This symptomatic giant aneurysm of the anterior genu region of the left internal carotid artery (ICA) was directly approached for direct repair or, if necessary, treatment with trapping and extracranial–intracranial (EC–IC) bypass. In the course of exposure of the aneurysm base, the aneurysm tore with broad disruption of the aneurysm neck. Temporary ICA trapping was performed, the aneurysm was resected off the parent artery, and the broad defect in the arterial wall was reconstructed with a venous patch graft.

Keywords Giant cavernous ICA aneurysm, direct aneurysm repair, ICA reconstruction

Clinical Presentation

A 62-year-old woman presented with a progressive history over several months of left retroorbital pain, diplopia, and facial numbness and paresthesias. Examination revealed complete left sixth nerve palsy and partial third, fourth, and fifth (second division) nerve involvement.

Preoperative Evaluation

Magnetic resonance imaging (MRI) scan and left carotid angiogram had confirmed a giant (3.5 cm diameter) aneurysm of the “cavernous internal carotid artery” (Fig. 4–1). Before proceeding with treatment it was felt advisable to perform trial balloon occlusion (TBO) study and endovascular exploration of the aneurysm neck to define treatment strategies. Endovascular exploration of the aneurysm with a balloon catheter showed a broad aneurysm base off the lateral aspect of the ICA anterior genu, involving the C3 and distal C4 segment of the artery, which could not be occluded with a 10 mm balloon. Temporary balloon occlusion of the ICA was tolerated without symptoms. Baseline cerebral blood flow (CBF) was measured at 35 mL per 100 g per minute; with occlusion, the CBF dropped to 28 as measured by Xe¹³¹ washout. Based on the CBF measurements it was felt that the patient would be at increased risk for acute or delayed stroke with carotid sacrifice, and therefore planned treatment was exploration and clip reconstruction of the aneurysm neck or, if not possible, trapping of the aneurysm with collateral augmentation using EC–IC bypass.

FIGURE 4–1 (A) Anteroposterior and (B) lateral left carotid angiograms demonstrating a giant intracavernous internal carotid artery aneurysm. Enhanced contrast at the anterior genu indicates the site of a broad aneurysm neck.