We present 3 cases of ruptured aneurysms with circumferential dilatation of the internal carotid artery (IC). Two of the cases presented repeated hemorrhage following neck clipping of the berry aneurysms arising from the anterior wall of IC. In the second surgery, it was confirmed that the newly formed aneurysm extended circumferentially from the primary aneurysm, which had been obliterated completely in the initial surgery.
Case 1 died of rerupture of the aneurysm following the second fundus-wrapping surgery. In Case 2, the aneurysm was obliterated safely using a fenestrated clip in the second surgery. Case 3 with subarachnoid hemorrhage underwent craniotomy because of progressive dilatation of C2 segment. Intraoperatively multiple blister-like bulging spots were identified on the surface of circumferentially dilated IC. It was repaired by so-called clipping on wrapping method. In the surgery, the clip produced mild narrowing of IC in spite of careful application of the clip to avoid kink. This finding suggested that this type of aneurysm was formed by a special mechanism such as arterial dissection.
We stress the necessity of close postoperative observation even if neck obliteration seems to have been complete in the IC anterior wall aneurysm. Furthermore we recommend extraordinary procedures such as a combination of trapping and bypass surgery or the so-called clipping on wrapping method in this type of aneurysm.