Embolization coils occlude a target vessel or aneurysm by promoting thrombosis within a metallic framework. The key distinction between coil types is the release mechanism: pushable coils detach immediately on deployment, while detachable coils remain attached to the delivery wire until the operator confirms position and deliberately releases them.
Why controlled deployment matters
In delicate anatomy — a cerebral aneurysm, a high-flow arteriovenous connection, or a vessel adjacent to critical branches — the ability to reposition or fully retrieve a coil before commitment is a major safety advantage. Detachable systems let the operator assess coil conformation, packing, and stability, and withdraw the coil if position is suboptimal.
Detachment mechanisms
- Mechanical detachment. A physical interlock releases the coil when the operator actuates the delivery handle.
- Electrolytic detachment. A small current dissolves a junction to release the coil in a controlled, predictable way.
- Hydraulic detachment. Pressure through the delivery catheter separates the coil at the designed release point.
Design features that affect performance
Coil softness, primary and secondary shapes (helical, complex, 3D), and stretch resistance determine how a coil frames an aneurysm and fills its volume. Framing coils establish a stable basket, filling coils build packing density, and finishing coils complete occlusion near the neck. Matching coil properties to lesion geometry is central to a durable result.
Clinical applications
Detachable coils are used across cerebral aneurysm treatment, peripheral vessel and visceral aneurysm occlusion, and preoperative or palliative tumor devascularization, often alongside liquid embolics or vascular plugs in a combined strategy.
INVAMED technologies in this space
INVAMED's embolization portfolio includes the Spider detachable coil system, MultiBEAM vascular plugs, and LIBRO liquid embolic; explore the embolization category.
Device availability and approved indications vary by country. This content is prepared for healthcare professionals and does not replace clinical judgment or the instructions for use.