Lateral Compression Manipulation: A Simple Approach for Sizing Taller-Than-Wide Intracranial Aneurysms with the Woven EndoBridge Device

Diagram depicting the proposed sizing strategy for aneurysms with a high height-to-dome ratio. The appropriate WEB size is determined by strategically swapping the height and width dimensions of the aneurysm. For an aneurysm measuring w × h, it is advisable to use a h × w WEB. When fully deployed, the device undergoes significant lateral compression, leading to a substantial increase in its vertical extension, which helps to achieve an optimal fit for the aneurysm.

An elective embolization was performed on a right cylindrical MCA aneurysm, with measurements indicating a maximum width of 3.82 mm and a height of 8 mm. An 8 × 4 mm WEB SL device was successfully deployed without impeding the adjacent temporal branch. As a result of intense lateral compression, the base of the SL device assumed a cup-shaped configuration, leaving a small “dog ear” at the neck of the aneurysm. At the 6-month follow-up, the aneurysm continued to show satisfactory results (red arrow).

When one deals with aneurysms of noncylindrical shapes, interobserver discrepancies in image interpretation and aneurysm measurement can result in inconsistent results. Aneurysms with noncylindrical shapes generally have smaller actual volumes than their cylindrical counterparts with the same maximum width and height. To ensure an adequate fit within the aneurysms, one must downsize the WEB device by reducing the device height. In this visual representation, all 3 aneurysms share the same maximum width and height dimensions of 5 × 8 mm, suggesting that they should be treated with an 8 × 5 mm WEB device according to the recommended sizing method. However, the actual volumes of the 2 noncylindrical aneurysms are smaller and would not provide sufficient room for an 8 × 5 mm device. The WEB device can be downsized by reducing the height by 1 mm, making an 8 × 4 mm device a more appropriate choice for these aneurysms to address this issue.

WEB embolization of an acute anterior communicating artery aneurysm, characterized by a maximum width of 5.4 mm and a height of 8.5 mm. A strategic downsizing was performed due to the noncylindrical shape of the aneurysm. Instead of using an 8 × 5 mm device, an 8 × 4 mm WEB SL was selected for the procedure. A follow-up at 6 months showed that the aneurysm remained fully occluded (red arrow).