Clip ligation of contralateral P1 aneurysm: extending the working depth of microsurgery along the skull base.

Clip ligation of posterior circulation aneurysms can be challenging because of limited operative working space and angles. Certain proximal posterior cerebral (P1) aneurysms are especially challenging because of their locations within the lateral anterior interpeduncular fossa. We present a 52-year-old woman who had previously undergone coil embolization of a ruptured right-sided posterior communicating artery aneurysm. She also had two other small aneurysms (left posterior communicating artery and right P1 aneurysms). She underwent clip ligation of the latter two unruptured aneurysms through a left-sided pterional craniotomy. The microsurgical techniques to clip ligate a contralateral P1 aneurysm are discussed in the video. The video can be found here: http://youtu.be/YBE7FcFGlpQ .