Long-Term Angiographic Findings in Patients Treated With Microsurgical Clipping of Intracranial Aneurysms

Microsurgical clipping remains a durable treatment for intracranial aneurysms. Despite the low rate of re-treatment, recurrence of subarachnoid hemorrhage is 3% within the first 10 years. This may be caused by rupture of a recurrent or residual aneurysm at the clip site or by rupture of another untreated aneurysm. We investigated the natural history of aneurysms treated with microsurgical clipping at our institution over a 10-year period. A secondary objective was to analyze our compliance rate with follow-up angiograms at three and 10 years and to investigate a role for less-invasive imaging modalities to manage microsurgical clipping patients. Ruptured and/or unruptured aneurysm patients treated with microsurgical clipping from 2000–2008 who had angiographic follow-up were included. Data were analyzed with respect to formation of de novo aneurysms, presence of residual aneurysm after clipping, and the rate of recurrence after complete clipping. There were 24 residual aneurysms (13%), two de novo aneurysms (1%) and one recurrent aneurysm (0.5%). The size of the aneurysm was significantly associated with having a residual aneurysm. Patient sex was also significantly associated with having a residual aneurysm. Compliance with angiographic follow-up occurred in 31% of patients treated with the majority only having one study at three years. Microsurgical clipping of aneurysms is durable with a low rate of recurrence and rebleeding. Residuals do not show angiographic progression and rarely require re-treatment. Compliance with angiographic follow-up is poor and this suggests that less invasive and expensive imaging modalities should be evaluated. Categories: Neurosurgery