Abstract
Seventeen cases of dorsal internal carotid artery aneurysms were surgically treated, and their operative and angiographic features were reviewed. There were 4 males and 13 females ranging in age from 34 to 61 (average: 47 years). Five cases had multiple aneurysms. All patients presented subarachnoid hemorrhage, caused by rupture of the dorsal internal carotid artery aneurysm in 15 cases and of an associated aneurysm in 2 cases.
Preoperative angiograms were classified into three types according to the operative findings. (1) Ten aneurysms, which projected superiorly in the lateral view and superiorly, slight-medially, or slight-laterally in the anteroposterior view, were found at surgery to be adhered to the basal surface of the frontal lobe, except for one very small aneurysm. (2) Three aneurysms, which were superimposed with the internal carotid artery in the lateral view and projected laterally in the anteroposterior view, were found to be adhered to the medial surface of the temporal lobe. (3) Four aneurysms, which were not seen on the angiogram, had no adhesion. Two of these four aneurysms were incidentally found during approach to an associated ruptured aneurysm. The other two were operated for because the CT scan had shown hematoma in the basal cistern, suggesting rupture of an internal carotid artery aneurysm.
The operative procedures were as follows: clipping in 10 cases, clipping and wrapping in 4, wrapping in 2, and trapping and bypass in 1. Intraoperative rupture occurred in 5 cases, during dissection of the Sylvian fissure in 1 case, just before complete closure of the clip blades in 3, and by slipping-off of the clip in 1.
The above angiographic classification should be useful for preventing premature rupture when retracting the brain and dissecting an aneurysm. As for surgical procedure, the clip should best be placed on the neck parallel to the parent artery, including the neck and part of the parent artery within the clip blades. Complete wrapping with cotton sheet is recommended when clipping is impossible or imcomplete.
