The word“broad neck”had been used vaguely up to this time and no definition decided in aneurysm surgery. Therefore, intraoperative management of the broad neck aneurysm was not discussed in detail formerly. On this report we measured the diameter of the parent artery and the aneurysmal neck and decided on the definition of the broad neck aneurysm on the angiographic films from our consecutive 55 cases. The definition of the broad neck aneurysm is that the diameter of the aneurysmal neck is wider than the diameter of the parent artery within 1 cm proximal to the aneurysm. The results are as follows. ICPC, IC anterior choroidal artery aneurysm: The average diameter of the parent artery is 4.5mm. The average diameter of the neck is 4.0mm. The percentage of the broad neck is 23.5%.
IC-bifurcation aneurysm: The average diameter of the parent artery is 3.2mm. The average diameter of the neck is 4.3mm. The percentage of the broad neck is 75.0%.
Middle cerebral artery aneurysm: The average diameter of the parent artery is 3.3mm. The average diameter of the neck is 4.2mm. The percentage of the broad neck is 87.5%.
Acom aneurysm: The average diameter of the parent artery is 2.9mm. The average diameter of the neck is 3.0mm. The percentage of the broad neck is 25.0%.
Distal anterior cerebral artery aneurysm: The average diameter of the parent artery is 1.9mm. The average diameter of the neck is 3.4mm. The percentage of the broad neck is 75.0%.
Basilar artery aneurysm: The average diameter of the parent artery is 3.6mm. The average diameter of the neck is 5.9mm. The percentage of the broad neck is 83.3%.
There were a few discrepancy between the radiological measurement and the actual intraoperative measurement. When we operate the broad neck aneurysm, the most cautions point is not to make stenosis or kinking of the parent artery and the distal artery, but clipping of the broad neck aneurysm is not always easy. We are forming the new surgical neck to these aneurysms. The concrete method of the formation of the new surgical neck is that we pinch the aneurysmal dome at just distal to the essential neck with bipolar forceps and weak current is on intermittently at several times. After this technique we can apply the aneurysmal clip easily with safety not to make stenosis or kinking of the parent artery and the distal artery. We recommend this method.
