Development of Endovascular Therapy for Intracranial Aneurysms

Subarachnoid hemorrhage due to the rupture of intracranial aneurysms is one of the causes of life-threatening strokes. The incidence is about 20 per 100,000 among the Japanese population. An intracranial aneurysm is a bulging, weakened area in the wall of an artery in the brain, resulting in abnormal widening or ballooning. Because the aneurysm has a weakened spot, there is a risk of rupture. Although surgical clipping has been the standard treatment for intracranial aneurysms, the procedure is extremely invasive. Coiling is another recent endovascular therapy that has become an important alternative to clipping because it is considerably less invasive. The procedure uses a catheter percutaneously inserted into an artery under fluoroscopic imaging. When the microcatheter has been inserted into the aneurysm, platinum coils are inserted to occupy the aneurysm cavity, which prevents blood flow into the aneurysm. The simple technique, requiring only one microcatheter, without other assisting devices, is standard. When this simple technique cannot achieve satisfactory occlusion, adjunctive techniques using a balloon or stent are used. Coiling is more advantageous than surgical clipping because it does not involve opening the skull, and hospitalization and recovery times are often shorter than with surgical clipping. In the near future, the introduction of flow diverters may dramatically change the treatment outcome of large, fusiform or complex aneurysms.