Abstract
We report a rare case of oculomotor nerve palsy caused by vertical sandwich-like compression, which is being pinched between the internal carotid-posterior communicating artery (IC-PC) aneurysm and tortuous parent artery. A 76-year-old female with a past history of the aneurysmal coiling against subarachnoid hemorrhage admitted at our hospital because of gradual worsening of her ptosis on the right. Magnetic resonance imaging of the head did not reveal any ischemic stroke on the midbrain, however, a carotid angiogram newly demonstrated an unruptured saccular aneurysm at the origin of the IC-PC junction. During surgical clipping of the aneurysm, it became clear that the tortuous parent artery at the supraclinoid portion of the internal carotid artery (ICA) had been directly compressing right oculomotor nerve, and the IC-PC aneurysm was located below the inferior aspect of the nerve, with resulting upward displacement of the oculomotor nerve. As a result of clipping of the aneurysmal neck, the supraclinoid ICA was just medially displaced and straightened up by the clip-head. Vertical sandwich-like compression of the oculomotor nerve was then released by above procedures. Though newly formed aneurysmal compression at IC-PC junction was typically considered to be the main reason for oculomotor nerve palsy, it was judged that tortuous supraclinoid ICA might contribute to the tendency to manifest as oculomotor nerve palsy under local surrounding background.
