Objective: Total aneurysm occlusion is crucial for the prevention of rebleeding of a ruptured aneurysm or to avoid rupture of an unruptured lesion. Both surgical and endovascular embolization fail to achieve complete aneurysm occlusion in all the cases. The objective of the study was to establish the safety and efficacy of endovascular treatment for previously clipped residual or recurrent aneurysms. Methods: This was an observational, retrospective study of patients harboring incompletely occluded intracranial aneurysms after clipping who underwent endovascular treatment. Patients were treated using 4 different techniques: (1) simple coiling, (2) balloon remodeling, (3) stent-assisted coiling, and (4) flow diversion. Analyses were performed to identify predictors of total aneurysm occlusion, recanalization and complications. Results: Between May 2010 and September 2018, 70 patients harboring incompletely occluded intracranial aneurysms after clipping met the inclusion criteria in 5 centers. The mean residual aneurysm size was 7.5 mm. Fifty-nine aneurysms were unruptured. Total aneurysm occlusion was achieved in 75.3% of the aneurysms after 1 year. All aneurysms treated with flow diversion revealed complete occlusion according to control angiography. Recanalization was observed in 14.5%. Permanent morbidity and mortality occurred in 2.9% and 1.4% of the patients, respectively. Conclusions Endovascular treatment of recurrent or residual aneurysms after surgical clipping was safe and efficacious. Flow diversion seems to be associated with better anatomical results. A more rigid study, a larger group of patients, and longterm follow-up are required to provide stronger conclusions about the best approach for residual clipped aneurysms.

Objective: Total aneurysm occlusion is crucial for the prevention of rebleeding of a ruptured aneurysm or to avoid rupture of an unruptured lesion. Both surgical and endovascular embolization fail to achieve complete aneurysm occlusion in all the cases. The objective of the study was to establish the safety and efficacy of endovascular treatment for previously clipped residual or recurrent aneurysms. Methods: This was an observational, retrospective study of patients harboring incompletely occluded intracranial aneurysms after clipping who underwent endovascular treatment. Patients were treated using 4 different techniques: (1) simple coiling, (2) balloon remodeling, (3) stent-assisted coiling, and (4) flow diversion. Analyses were performed to identify predictors of total aneurysm occlusion, recanalization and complications. Results: Between May 2010 and September 2018, 70 patients harboring incompletely occluded intracranial aneurysms after clipping met the inclusion criteria in 5 centers. The mean residual aneurysm size was 7.5 mm. Fifty-nine aneurysms were unruptured. Total aneurysm occlusion was achieved in 75.3% of the aneurysms after 1 year. All aneurysms treated with flow diversion revealed complete occlusion according to control angiography. Recanalization was observed in 14.5%. Permanent morbidity and mortality occurred in 2.9% and 1.4% of the patients, respectively. Conclusions Endovascular treatment of recurrent or residual aneurysms after surgical clipping was safe and efficacious. Flow diversion seems to be associated with better anatomical results. A more rigid study, a larger group of patients, and longterm follow-up are required to provide stronger conclusions about the best approach for residual clipped aneurysms.