Intracranial post-embolization residual or recurrent aneurysms: Current management using surgical clipping

Post-embolization residual or recurrent aneurysms (PERRAs) are not rare in patients with intracranial aneurysms treated by embolization. Their occurrence is mainly associated with an increased amount of interventional therapy. Repeated interventional embolization can be applied in some patients with PERRAs, whereas surgical clipping is preferred in other cases that are not suitable for repeated interventional embolization due to the difficulties inherent to this operation. The surgical clipping of PERRAs is very complicated and difficult to perform, and relevant reports are rare. This study offers a review of PERRA treatment using surgical clipping. Retrospective studies have shown that PERRAs are common aneurysms of the anterior and posterior communicating arteries. According to the recurrent characteristics of PERRAs, it is reasonable to categorize PERRAs into three types: type I—coils are compressed, and no embolic material fills the neck of the aneurysm; type II—coils are migrated, and very few coils fill the neck of the aneurysm or the parent artery; and type III—coils are migrated, and multiple coils fill the neck of the aneurysm or the parent artery. Direct clipping can be applied to types I and II PERRAs, whereas trapping, wrapping, or auxiliary revascularization is required in type III PERRAs. Most coils do not require removal unless they interfere with clipping. However, it is necessary to avoid damaging the surrounding adhesive tissue during coil removal. Satisfactory therapeutic outcomes can be achieved by selecting appropriate PERRA cases in which to perform surgical clipping.