Neurosurgical management of intracranial aneurysms following unsuccessful or incomplete endovascular therapy.

The publication of the ISAT trial in 2002 has resulted in increasing numbers of patients with aneurysmal subarachnoid haemorrhage undergoing endovascular coiling, as first line treatment for aneurysm occlusion. During the first 2-year period post-ISAT, in which all suitable intracranial aneurysms were coiled first, we had to perform surgery in seven patients out of 54 who underwent initial coiling. The reasons for subsequent surgery were failed coiling, residual or recurrent aneurysm necks and delayed aneurysmal rebleeding despite coiling. We reviewed our surgical experience with the repair of these previously coiled aneurysms to identify unique technical difficulties. In particular, we found that an aneurysm height to neck ratio of less than 2:1 after coiling, and the use of stent-assisted coiling presented formidable challenges to direct clipping.