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The authors developed a simple reproducible technique for aneurysm creation and adapted it to mimic intracranial dissection conditions using glue application as a pseudo-arachnoid type layer. Ten 1-2-month-old healthy domestic swine were employed under general anesthesia. A novel technique for bifurcation aneurysm creation was developed using two arteries and a vein. After aneurysm creation, diluted sulfuric acid was applied on the dome with a micropipette to increase aneurysm fragility in selected zones. The surgical field was then dried and contact glue was applied around the vascular complex in a circular manner so as to emulate arachnoidal connection fibers. Microsurgical dissection of the aneurysm and surrounding vessels was performed by delicately removing the adhesive substance. Diverse aneurysm clipping techniques, emergency rupture situations and vascular reconstruction procedures were trained. Twenty-two aneurysms were created at several vascular sites, one aneurysm dome ruptured during application of sulfuric acid, two aneurysm models were proved to be thrombosed, two aneurysms ruptured during the dissection and no intraoperative deaths occurred. All aneurysms were clipped in an acceptable manner. This bifurcation aneurysm model provides a novel training system to be used not only by neurosurgeons but also by neurovascular interventionists.

Cerebral revascularization is an useful tool in the treatment of giant or complex cerebral aneurysms that can not be clipped directly by different causes. In turn, interventionist endovascular therapy, an emergent technique with very good results in the treatment of cerebral aneurysms during the last five years, is a new complementary tool to cerebral revascularization for the treatment of complex aneurysms. In the present manuscript we emphasize the beneficial effect of revascularization, followed in a short period of time by the endovascular technique in order to either occlude the parent vessel or to exclude the aneurysm from cerebral circulation. Advantages of this form of therapy, as well as the selection of patients and the present revascularization procedures, are commented.

Anterior communicating artery complex accounts for the most frequent site of cerebral aneurysms and it is characterized by its great anatomical variability. The development of aneurysms in this complex has been associated with the asymmetry of its afferent vessels. An anatomical and hemodynamic study of the anterior communicating artery was performed. Twenty brain samples obtained from adult necropsies were studied by means of microsurgical dissection. Additionally; 118 cerebral angiographies from patients with spontaneous subarachnoid hemorrhage were studied. A high number of perforanting vessels originated at the anterior communicating artery complex was a relevant finding. The number, distribution and size of these vessels is reported accurately. Analysis of the angiographies showed the association between the existence of an anterior communicating artery aneurysm and the presence of a blood flow predominance through one of the two proximal anterior cerebral arterias.

Giant serpentine aneurysms (GSAs) are infrequent. We present a 37-year-old patient with a giant serpentine aneurysm of the left middle cerebral artery that was treated with a superficial temporal artery to middle cerebral artery bypass and ligature of the left internal carotid artery. After 2 years, the patient presented new symptoms of neurological deterioration and the computed tomographic scan and arteriography showed regrowth of the aneurysm, which was excised. Enlargement of a giant serpentine aneurysm once it has been treated with ipsilateral carotid ligation and/or bypass anastomosis is rare, and only two cases have been described previously.

A 68-year-old woman with a subarachnoid hemorrhage was operated on for an anterior communicating artery aneurysm demonstrated by angiography. A month later she developed intestinal hemorrhage and a selective angiography showed multiple aneurysmatic dilatations, which were compatible with angiodysplasia, to be the cause of the intestinal bleeding. This association of intracranial and extracranial aneurysms is infrequent.

To study the effect of haemodynamic stress on cerebral aneurysm development, three groups of adult Wistar rats were used: 1) One group with ligation of the right common carotid artery; 2) One with an end-to-side common carotid artery anastomosis and 3) Another group that was sham-operated. Blood flow through the left common carotid artery was measured with an electromagnetic flow transducer (0.85 mm in diameter) in anesthetized animals. Before the experimental intervention, the mean carotid blood flow was 2.8 +/- 0.14 ml/min. Following carotid ligation the blood flow in the patent carotid artery increased 25 +/- 5% after 7 +/- 0.3 days and 37 +/- 18% after 149 +/- 23 days; whereas following carotid anastomosis, carotid blood flow increased 102 +/- 16% after 9.6 +/- 2 days and 103 +/- 35% after 169 +/- 15 days. The sham operation did not significantly affect carotid blood flow. Control values for mean arterial pressure (102 +/- 3 mmHg) and blood gases (PaO2 = 106 +/- 3.4 mmHg, PaCO2 = 38 +/- 1.2 mmHg and pH = 7.32 +/- 0.02) were similar in the three groups of rats and did not change significantly over time after the experimental procedure. Necropsy was carried out 149 +/- 15 days after the experimental intervention. No cerebral aneurysms were found in the rats with carotid ligation or which had been sham-operated, however, three of the eight rats (p less than 0.05) with carotid anastomosis presented single aneurysms in the anterior cerebral-anterior communicating arterial complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Two groups of rats with induced arterial hypertension were studied. One group underwent section of the left common carotid artery with an end-to-side anastomosis of the proximal segment to the right common carotid artery. The second group was subjected to ligation of the left common carotid artery. The number of aneurysms caused by the procedure in the first group was higher, the difference being statistically significant (p less than 0.05, chi-square).