Flow Diversion for the Treatment of Basilar Bifurcation Aneurysm

Flow diversion for basilar apex aneurysms has rarely been reported.

A retrospective review of prospectively maintained databases at 8 academic institutions (St. Michael’s Hospital, Toronto, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.Toronto Western Hospital, University of Alabama at Birmingham, State University of New York at Buffalo, University of Florence, Italy. Toulouse University Hospital, Yale School of Medicine, New Haven), was performed from 2009 to 2016 to identify patients with basilar apex aneurysms treated with flow diversion. Clinical and radiographic data were analyzed.

Sixteen consecutive patients (median age 54.5 yr) underwent 18 procedures to treat 16 basilar apex aneurysms with either the Pipeline Embolization Device (Medtronic) or Flow Redirection Endoluminal Device (Microvention). Five aneurysms (31.3%) were treated in the setting of subarachnoid hemorrhage. Seven aneurysms (43.8%) were treated with flow diversion alone, while 9 (56.2%) underwent flow diversion and adjunctive coiling. At a median follow-up of 6 mo, complete (100%) and near-complete (90%-99%) occlusion was noted in 11 (68.8%) aneurysms. Incomplete occlusion occurred more commonly in patients treated with flow diversion alone compared to those with adjunctive coiling. Patients with partial occlusion were significantly younger. Retreatment with an additional flow diverter and adjunctive coiling occurred in 2 wide necked aneurysms. There was 1 mortality in a patient (6.3%) who experienced posterior cerebral artery and cerebellar strokes as well as subarachnoid hemorrhage after the placement of a flow diverter. Minor complications occurred in 2 patients (12.5%).

Flow diversion for the treatment of basilar apex aneurysms results in acceptable occlusion rates in highly selected cases. Both primary flow diversion and rescue after failed clipping or coiling resulted in a modified Rankin Scale score that was either equal or better than at presentation and the technology represents a viable alternative or adjunctive option 1).

Da Ros et al., retrospectively analyzed data from all consecutive patients treated with flow-diverter stents between January 2011 and January 2015. Patients with large basilar apex aneurysms treated with a flow-diverter stent were included in the study. Clinical presentations, technical details, intra- and perioperative complications, and clinical and angiographic outcomes were recorded, with a midterm follow-up.

Of the 175 aneurysms treated with flow-diverter stents, 5 patients (2 women and 3 men; age range, 44-58 years) received flow-diverter stent for basilar apex aneurysms. The mean follow-up after stent deployment was 21 months (range, 15-24 months). One patient died on day 31 from an early postprocedural midbrain hemorrhage. One patient had a right cerebellar hemispheric ischemic lesion with a transient cerebellar syndrome resolved within 24 hours without neurologic sequelae at the latest follow-up. The mRS was 0 in 4 patients and 6 in 1 patient at last follow-up.

Flow diversion is a feasible technique with an efficacy demonstrated at a midterm follow-up, especially in the case of basilar apex aneurysm recurrences after previous endovascular treatments. Concern about its safety profile still exists 2).

A 73-year-old male was previously treated for an unruptured 11-mm basilar apex aneurysm with stent-assisted coiling using a Neuroform stent. The aneurysm was retreated twice with repeat coiling. After the third recurrence and persistent aneurysm growth into a giant, symptomatic lesion, we decided to proceed with flow diversion. We performed Y-stenting of the basilar bifurcation using three PFEDs, and was recoiled the aneurysm sac. Due to the low porosity of the flow diverters, a side-by-side double-barrel configuration was necessary in the basilar artery. Without the PFED’s resheathable capability, it would not have been possible to perform Y-stenting with flow diverters 3).



Dmytriw AA, Adeeb N, Kumar A, Griessenauer CJ, Phan K, Ogilvy CS, Foreman PM, Shallwani H, Limbucci N, Mangiafico S, Michelozzi C, Krings T, Pereira VM, Matouk CC, Zhang Y, Harrigan MR, Shakir HJ, Siddiqui AH, Levy EI, Renieri L, Cognard C, Thomas AJ, Marotta TR. Flow Diversion for the Treatment of Basilar Apex Aneurysms. Neurosurgery. 2018 Dec 1;83(6):1298-1305. doi: 10.1093/neuros/nyx628. PubMed PMID: 29529233.

Da Ros V, Caroff J, Rouchaud A, Mihalea C, Ikka L, Moret J, Spelle L. Large Basilar Apex Aneurysms Treated with Flow-Diverter Stents. AJNR Am J Neuroradiol. 2017 Jun;38(6):1156-1162. doi: 10.3174/ajnr.A5167. Epub 2017 Apr 27. PubMed PMID: 28450438.

Ding D, Starke RM, McGuinness B, Brew S. Double-barrel Y-configuration Stenting for Flow Diversion of a Giant Recurrent Basilar Apex Aneurysm with the Pipeline Flex Embolization Device. J Neurosci Rural Pract. 2016 Dec;7(Suppl 1):S99-S102. doi: 10.4103/0976-3147.196439. PubMed PMID: 28163518; PubMed Central PMCID: PMC5244076.

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