Background Flow diversion has been established as an effective treatment in proximal anterior circulation aneurysms. The efficacy in posterior circulation aneurysms remains unclear and may be related to different characteristics of these aneurysms or the presence of perforator rich zones in the basilar artery. We present a case of a pediatric patient with a relatively focal giant mid-basilar aneurysm treated with flow diversion and coils.

Patient This 15 year old male presented with unilateral left sided hearing loss and increasing unsteadiness when trying to play sports at school. He was found to have a giant (40mm) partially thrombosed basilar aneurysm at the level of AICA with significant brainstem mass effect but no sign of hydrocephalus. Multiple treatment options were considered including flow reversal with bilateral vertebral occlusion and bypass, stent-coiling, and flow diversion with or without coils. Consideration was given to pre-procedure ventriculoperitoneal shunting as well. The decision was made to use flow diversion with no shunting. Bilateral vertebral access was obtained and a coiling catheter was placed into the aneurysm from the right vertebral artery and a single 4.25 mm × 25 mm Pipeline embolization device (Covidien Neurovascular: Dublin, Ireland) was placed across the aneurysmal segment from the left, ensuring apposition to the AICA origins. Angioplasty was performed to further ensure complete basilar and AICA apposition distal and proximal to the aneurysm. Target XL coils (Stryker Neurovascular: Fremont, CA) were then deployed through the previously positioned catheter until there was no further filling of the aneurysm. The patient was placed on a course of dexamethasone, which was tapered after 6 weeks, and there was no sign of hydrocephalus. A 6-month angiogram showed some coil compaction and a tiny amount of residual filling at the base. A 9-month angiogram showed complete angiographic exclusion of the aneurysm and continued filling of both AICA vessels, at which point the clopidogrel was discontinued. A one-year follow-up MRI showed decreased size and mass effect on the brainstem and no sign of filling of the aneurysm. The patient remains without hearing on the left, but other symptoms have completely resolved and the patient has returned to normal activity at school.

Conclusion In carefully selected cases, flow diversion offers potential curative reconstruction for otherwise incurable aneurysms, even in pediatric and posterior circulation cases. We hypothesize that the success of this case is related to the relatively focal rather than fusiform location of the aneurysm.

Disclosures A. Carlson: None. C. Taylor: None. A. Coon: 2; C; Covidien, Microvention, Stryker Neurovascular.