Recurrent intracranial aneurysms after successful neck clipping.

BACKGROUND To report the authors' experience with recurrent aneurysms after primarily completely clipped cerebral aneurysms and discuss mechanisms of recurrence and recommended management. METHODS Data were available for 1016 consecutive patients who underwent clipping of ruptured and unruptured aneurysms in a 15-year period from 1993-2007. RESULTS Nine patients were treated for recurrent aneurysms after successful complete clipping of the initial aneurysms; six patients had initial surgery before 1992, and three patients underwent surgery during the study period. Mean elapsed time between the first clipping and the recurrence of aneurysm was 13.3 years ± 7.8. Repeat craniotomy was performed in seven patients, and six patients underwent reclipping of aneurysms with or without removal of the old clips. One patient was treated by construction of an extracranial-intracranial (EC-IC) bypass plus coating of the aneurysm. Endovascular occlusion of the parent artery was performed in one patient. One patient died without any intervention. Recurrent aneurysms could be classified into three types according to the relationship of the new aneurysm neck to the old clip. CONCLUSIONS The incidence of recurrent aneurysms after complete clipping was approximately 0.02% per year; aneurysms recurred after 13.3 years on average with 25 years the longest duration from initial clipping to recurrence. Classification of recurrent aneurysms into three types might be helpful in selecting appropriate surgical management.