1991 Volume 19 Issue 1 Pages 135-138
The internal carotid posterior communicating (IC-PC) aneurysm is one of the easiest aneurysms to approach and clip. But, in some cases neck clipping is highly difficult for several reasons. In this report, cause of difficulties of neck clipping and operative complications were analyzed in 54 (34.8%) out of 155 IC-PC aneurysms. The frequent causes of difficulty were 1) large aneurysm, 15 (9.7%), 2) anterior clinoid process covering the proximal side of the neck, 15 (9.7%), 3) posterior communicating artery (P com) arising from the aneurysm itself, 12 (7.7%). Intraoperative troubles were 1) rupture of aneurysm, 18 (11.6%), 2) incomplete clipping with single standard clip requiring multiple or fenestrated clips, 14 (9.0%), 3) removal of the anterior clinoid process required, 13 (8.4%) and 4) slippage of the clip, 5 (3.2%). The distance between the anterior clinoid process and the proximal side of the neck was measured on the lateral view of the preoperative angiogram. This distance was from -3.4mm to +2.0mm, average -0.4mm, in 13 cases of which the anterior clinoid process was removed for clipping, while in 142 cases without clinoid removal the distance averaged +4.8mm. This result suggests that if the proximal side of the neck is located whithin 2mm from the anterior clinoid process, removal of the clinoid would be indicated during surgery. Among 22 patients whose P com was occluded during surgery, 7 (32%) developed some neurological dificits while 15 (68%) remained asymptomatic. Of these seven patients, four developed temporary motor weakness and 3 suffered permanent motor weakness. Mental disturbance such as recent memory disturbance or disorientation was noted in two cases, one temporary, one permanent. Identification of the P com on angiogram was possible in only 6 out of 22 cases with P com occlusion. And, none of the P com was visualized on preoperative angiograms in the symptomatic cases. Although, this study failed to reveal the cases in which P com occlusion was safe. Occlusion of small P com runs the risk of inducing some infarction of the thalamus and other cerebral structures.
