Fenestration of supraclinoid internal carotid artery and associated aneurysm: embryogenesis, recognition, and management.

OBJECTIVE

Fenestration of internal carotid artery (ICA) is extremely rare and may be associated with aneurysms arising from the fenestrated segment. Here we report two cases with successful surgical clipping of associated saccular aneurysms, and we systematically review the 12 previously reported cases.

METHODS

In one case of 39-year-old female patient, the aneurysm and fenestration were found incidentally in the course of a workup for headaches and a thyroid nodule. In the second case, a 32-year-old female patient, the aneurysm was associated with subarachnoid hemorrhage in the setting of suspected postpartum eclampsia. In both instances the fenestration involved the supraclinoid ICA, and the aneurysm arose from the duplicated segment proximal to the origin of the posterior communicating artery. The aneurysms were more proximal than typical posterior communicating artery aneurysms, and fenestration was suspected by rotational three-dimensional angiography, and confirmed at surgery.

RESULTS

In both instances the aneurysm was approached via an extended pterional craniotomy. In one case, partial anterior clinoidectomy was necessary, along with decompression of the optic nerve canal for optimal exposure of the aneurysm neck. Clip reconstruction was successful, obliterating the aneurysm and preserving ICA patency.

CONCLUSIONS

ICA fenestration should be considered when one analyzes ventral supraclinoid ICA aneurysms. In these and other reported cases, aneurysm is generally amenable to surgical clipping despite broad neck incorporating the fenestrated arterial segment.