Abstract

FONTANA, Horacio; BELZITI, Héctor  and  BURATTI, Sebastián. La circulación cerebral en condiciones normales y patológicas V: El aneurisma, aspectos dinámicos. Rev. argent. neurocir. [online]. 2008, vol.22, n.2. ISSN 1850-1532.

There are four types of aneurysm model: 1) "in vitro". They allow to study qualy and cuantitatively cases of complex circulation. 2) "in vivo". The creation of different models in experimental animals allowed a better knowledge of the circulatory features of aneurysms and to hypothesize about their origin. 3) Post mortem "in vitro" replicas of real human aneurysms on elastic material, allow to analyze the circulation under different conditions in "aneurysms" morphologically similar to human's. 4) Computerized simulation of circulation in virtual 3D replicas of human aneurysms, obtained from different image studies. It is the last developement in the field, and has been achieved through recent advances in the performance of computers and new software. In respect to the relationship between the sack and parent vessels, aneurysms had been classified as: 1) lateral, 2) at the origin of a colateral vessel, 3) terminal in the same axis of the parent vessel, 4) terminal forming angle with the parent vessel. In simplified terms, the flow remains the same for all types of aneurysm. The inflow enters as a jet at the distal portion of the neck and strikes the distal wall of the sack in variable extension (impact zone), after its relation with the parent vessel and, in the terminal type, after the geometric assimetry of the system, specially for those in the axis of the parent vessel. Major diameter of the neck increase the flow and makes it more similar to the basic description. Narrowness of the neck make the flow sluggish and atypical in the sack. The rupture of the aneurysm could be ascribed to the tensión in the wall, be it dynamic in the high flow ones (broad neck, favorable geometry) or static, in those of low flow (narrow neck, unfavorable geometry). As it was to be assumed, each model has advantages and desadvantages and even if the advancemets are remarkable, details of the flow in the sackc as well as the parent vessels remain inaccessible.

Keywords : Cerebral aneurysms; Flow; Models.

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