MICROSURGICALLY PRODUCED BIFURCATION ANEURYSMS IN A RABBIT MODEL FOR ENDOVASCULAR COIL EMBOLIZATION

The authors present a detailed account of the microsurgical production of bifurcation aneurysms in chinchilla rabbits for basic studies of e ndovascular coil embolization of aneurysms. End-to-side anastomoses of both common carotid arteries (CCAs) were performed, and a venous pouc h was fitted into the newly created bifurcation. These experimental an eurysms closely mimic human cerebral aneurysms in size and hemodynamic features. Sixty-three animals underwent operation. Fifteen animals di ed in the course of the experiment and 15 were excluded because of a C CA occlusion within the carotid bifurcation. Electrical detachable pla tinum coils, also known as Guglielmi detachable coils (GDCs), and tung sten mechanical detachable coils (MDCs) were used for the endovascular occlusion of 26 bifurcation aneurysms (16 rabbits were treated with G DCs and 10 with MDCs). Initially, complete angiographic obliteration ( 95%-100% occlusion of the aneurysm) was achieved in nine rabbits and i ncomplete obliteration (< 95% occlusion) was seen in 17 animals. Final angiography 3 to 6 months later demonstrated complete occlusion in on ly four and partial occlusion in 22 aneurysms. At present, the histopa thological examination of 17 embolized aneurysms has revealed incomple te obliteration of all aneurysms, even in those three cases that were thought to be completely embolized according to angiographic criteria. A general overestimation of the radiological degree of aneurysm oblit eration was found.