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

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.