Acute frame coil migration during filling coil retrieval in a cerebral aneurysm embolization case: A possible result of a venturi effect?

Coil migration is a known complication of endovascular coiling of cerebral aneurysms. We report an acute coil migration occurring during coiling of an unruptured anterior choroidal aneurysm, while a separate coil was retrieved into the microcatheter concomitantly without direct contact between the coils. The "pulling" of a previously deployed stable coil is presented as an adverse effect that should be noted. This case exemplifies that not only direct entanglement or erroneous malposition can generate acute migration, but possibly, also alteration of physical forces during coil retrieval. A potential mechanism, similar to a venturi effect, caused by a quick suction within the microcatheter at its distal end, is suggested, and the clinical relevance of the case is discussed.