Recurrence of a large intracranial fusiform aneurysm treated with overlapping Pipeline embolization devices: illustrative case

Abstract

Background: Flow diversion, specifically with the Pipeline embolization device (PED), represents a paradigm shift in the treatment of intracranial aneurysms. Several studies have demonstrated its efficacy and at times superiority to conventional treatment modalities for aneurysms with a fusiform morphology, giant size, or wide neck. However, there may be a nonsignificant risk of recurrence after flow diversion of these historically difficult-to-treat aneurysms, relative to aneurysms with a more favorable morphology and size (i.e., saccular, narrow necked). To date, only three papers in the literature have demonstrated the recurrence of a completely occluded aneurysm on follow-up.

Observations: The authors describe a patient with a giant middle cerebral artery fusiform aneurysm treated with multiple telescoping PEDs. On the 3-month follow-up angiogram, there was complete occlusion of the aneurysm. The patient was lost to follow-up and presented 4 years later with a recurrence of the aneurysm between PED segments, requiring retreatment. The patient represented 3 years posttreatment with the need for repeat treatment of the fusiform aneurysm due to separation of the existing PEDs along with stent reconstruction. At the 20-month follow-up after the third treatment, the initial aneurysm target was found to be occluded.

Lessons: This case illustrates the need for long-term follow-up, specifically for patients with giant wide-necked or fusiform aneurysms treated with overlapping PEDs.

Keywords: aneurysm; endovascular; flow diversion; outcomes.

FIG. 1

A: Initial computed tomography scan demonstrating a well-circumscribed, round lesion involving the MCA. B and C: Anteroposterior (AP) and lateral digital subtraction angiography (DSA) demonstrating a 3.5 × 2.7 × 2.5 cm fusiform aneurysm involving the proximal 38 mm of the M1 segment of the left MCA. There is a 4.5-mm diameter fusiform dilation of the distal M1 and subtle dilation of the proximal M2 branches. D and E: Unsubtracted lateral and oblique angiograms obtained following embolization, showing stasis of flow in the aneurysm well into the venous phase.

FIG. 2

AP (A) and lateral (B) DSA demonstrating no filling of the left MCA aneurysm at the 3-month follow-up.

FIG. 3

A: Three-dimensional (3D) reconstruction CTA demonstrating separation of the PED and recurrence of the aneurysm between PED segments at the 4-year follow-up. B: DSA performed prior to retreatment, demonstrating a recurrent aneurysm between the PEDs. C: DSA performed after the placement of two additional PEDs between separated segments, demonstrating a decreased size of recurrent aneurysms. D: 3D reconstruction of follow-up CTA at 3 months after retreatment showing complete occlusion of the aneurysm. E: 3D reconstruction of CTA showing recurrence of aneurysm between flow diverters at the 3-year follow-up (red arrow). F: DSA at 20 months after retreatment, demonstrating occlusion of the initial aneurysm and dilation of MCA past the stent construction.