Next generation Medina coil system shows improvements in early human experience

2015

In early use of the Medina coil system, researchers have found the device to be a next generation coil that combines the familiar procedural safety and technique associated with conventional coils, with improved circumferential aneurysm filling, which, they say, it is thought will lead to improved long-term outcomes.

Aquilla S Turk et al discuss in the Journal of Neurointerventional Surgery their experience with the periprocedural safety and performance of the initial human experience with the Medina coil system, a layered three-dimensional coil made from a radiopaque, shade set core wire, and shape memory alloy outer coil filaments.


The authors describe the use of the Medina coil stating: “When deployed, the Medina coil begins a linear configuration and then deforms to fill space within the aneurysm. In its constrained state, the device retains a linear form with the petals unfolding into a wave form pattern. But, as the device is introduced into an aneurysm, it bends on itself and deforms to both cover the aneurysm ostium as well as to create a stable structure while still allowing contrast flow for visualisation. The three dimensional petals that constitute the coil surrounding filaments form broader ‘loops’ rather than thinner wires, as with conventional coils, which allows for stable anchoring of the coil within the aneurysm sac. Mechanically, these broad petals broadly distribute the forces exerted on the aneurysm wall. The Medina coil line constitutes both framing and filler coils. The framing coils provide support and complex into an outer basket. The filler coils are softer, and are designed to fill the internal space within the framing coils.”


In this single centre, operator adjudicated study, the researchers treated nine aneurysms in five patients, ranging from 5 to 17mm in size in various locations. All aneurysms were wide necked with a neck to dome ratio >2:1. All cases were performed without any technical or procedural complications. No periprocedural or postprocedure related clinical complications, such as stroke or aneurysm bleeding, were encountered.

 

The authors write: “Wide necked medium and large sized aneurysms remain a common but challenging group in which to effect successful endovascular treatment. Adjunctive devices such as balloons and stents are often required to achieve acceptable endovascular results, but these techniques have been reported to carry a higher risk. Our early human experience with the Medina coil demonstrates the familiar coil ease of use methods and periprocedural safety. Additionally, we experienced relatively short procedure times while utilising few adjunctive technologies.”

In their experience, they found that the Medina coil, when deployed, takes advantage of its surrounding filament design to provide improved volumetric filling of the aneurysm, which will hopefully result in better long-term occlusion rates.

They add that at this early stage, the long-term implications of the device remain unclear, but the early use is “extremely encouraging”. Of the nine aneurysms treated in this experience, three have undergone follow-up angiography, demonstrating >95% aneurysm occlusion.

Turk et al conclude that “as more delayed angiographic data become available, and larger numbers of aneurysms receive treatment with the Medina coil, it is possible that this technology will represent a major step forward in endovascular coil embolisation in cerebral aneurysms”.