Surgical treatment of giant aneurysms is difficult and surgical results are not satisfactory. The authors reviewed the results of our surgery (aneurysmal clipping) of 26 giant aneurysms (internal cerebral artery: 13, anterior cerebral artery: 6, middle cerebral artery: 5, basilar artery: 1, vertebral artery: 1). The outcome of our cases is as follows: good (17), fair (2), poor (1), dead (6). Presenting several representative cases, the authors also described technical aspects of aneurysmal clipping: (1) systemic heparinization should be done to prevent cerebral embolism, when a temporary trapping procedure is used before neck clipping. (2) when the aneurysmal dome is punctured and the neck is clipped, additional clips should be applied to prevent slip-out of the clip first applied on the neck; (3) The technique of retrograde suction decompression of the aneurysm is useful in giant para-clinoidal aneurysms. This permits reflow of blood without any trouble, when it takes a long time to dissect the aneurysmal wall and clip the neck. This technique can be used repeatedly. (4) In cases of partially thrombosed giant aneurysms, thrombectomy makes neck clipping easier.
In addition, one case of large middle cerebral artery aneurysm, which showed hemorrhagic infarction presumably due to hyperperfusion following aneurysmal clipping, was presented. This phenomenon appeared to be similar to the normal perfusion pressure breakthrough phenomenon, which is well known in patients with large arteriovenous malformations
