The Source for Neurovascular News and Education

August 11, 2020

Most bifurcation aneurysms can be treated using a straightforward, single-stent technique, according to research published online June 22, 2017, ahead of print in Neurosurgery.

The authors propose a simple scoring system that interventionalists can use to help identify those few aneurysms likely to require a more complex treatment approach.

To Neurovascular Exchange, lead author Ajith J. Thomas, MD (Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA), said that stenting is a common, time-tested treatment modality for aneurysms but that bifurcation aneurysms pose a special challenge.

“There are two arms, and putting in a stent may not cover both the arms,” he explained. As a result, “a plethora of devices have come onto the market for bifurcation aneurysms, but none are really superior [to a stent]. The reason why a lot of devices have evolved is there is no real solution [yet].”

Thomas led a multicenter retrospective analysis of 74 bifurcation aneurysms treated with a single stent-assisted coiling technique between 2007 and 2015. After a median follow-up period of 15.2 months, complete occlusion or remnant neck was achieved in 90.6% of these aneurysms.

Aneurysm location, maximal diameter, neck size, and alpha angle were all identified as predictors of occlusion at last follow-up. Thomas et al developed a scoring system based on these predictive factors to help identify which aneurysms can be treated effectively with single stent-assisted coiling and which might require other approaches.

Proposed Scoring System






OR (95% CI)

P Value


Internal Carotid & Basilar

Middle Cerebral & Anterior Communicating

7 (1.9-28.7)


Maximum Diameter

> 9.0 mm

≤ 9.0 mm

4 (1.2-12.2)


Neck Size

> 7.0 mm

≤ 7.0 mm

9 (2.4-36.1)


Alpha Angle

> 165°

≤ 165°

4 (1.2-12.5)



Aneurysms with a score of 0 would be considered Class I. In this series, 14% of Class I aneurysms achieved complete occlusions. Aneurysms with a score of 1-2 were Class II, with 55% of these achieving complete occlusion. Finally, Class III aneurysms had a score of 3-4, and 92% of these achieved complete occlusion. Complete occlusion rates were significantly higher in Class III aneurysms than those in Class I or II.

The goal of the study, explained Thomas, was simply to demonstrate that, in the vast majority of cases, bifurcation aneurysms can indeed be effectively treated with single stent coiling, with no need for more complicated techniques or exotic devices. The scoring system is designed to help interventionalists identify the minority of patients most likely to benefit from different tactics.

“The single stent is easy [to use], and the Y stent is a little more challenging,” he said. “If you can’t use a single stent, then you could go onto a Y stent or other devices. . . . You may have a slightly higher rate of recanalization [with a single stent], but you can retreat it with a Y stent. But after you’ve done this once, you may not be able to use the newer devices, like the PulseRider [Pulsar Vascular].”

Adeeb N, Griessenauer CJ, Patel AS, et al. The use of single stent-assisted coiling in treatment of bifurcation aneurysms: a multicenter cohort study with proposal of a scoring system to predict complete occlusion. Neurosurgery. 2017; Epub ahead of print.


Thomas reports being on the data safety monitoring committee for a trial sponsored by Stryker.

Related Stories: