Detached Coil Migration that Assisted Stent Migration, during Stent Assisted Coiling of a Recurrent Aneurysm

Abstract

This is a pictorial case report of previously unreported intra-procedural complication of an intra-procedural migrated stent-coil complex. It shows fluoroscopic detail of the migration of a stent with the help of a migrated coil with subsequent retrieval of coil and deployment of a second stent proximally. It also briefly covers postulated mechanisms for this in the discussion. In our clinical practice we experienced an unusual case during stent assisted coiling of a right Posterior Communicating Artery Aneurysm (PCOM) where a coil migrated through a deployed stent into the parent artery and become ensnared into a distal stent strut. This caused stent migration distally. Studies have shown that stent assisted coiling of cerebral aneurysms is an effective treatment that lowers the risk of recurrence. There are several complications associated with both coiling and stent deployment. Multiple cases of individual coil migration and stent misplacement have been described in the literature, such as coil protrusion through a stent with open cell designs and a single case of delayed coil migration through a deployed stent. Various aetiologies are described for these, which we cover, and we postulate on the factors relevant to our case and suggest the biggest contributing factor was an open side stent design. We believe this is a rare documented acute case of a migrated coil that has assisted stent migration. We suggest caution particularly when small coils need to be deployed alongside open cell and side design stents.