[Effect of position with respect to gravitational force on the hydrodynamics of an experimental model of saccular aneurysm]. / Influencia de la posición con respecto a la fuerza de gravedad sobre la hidrodinámica de un modelo experimental de aneurisma sacular.

We wish to confirm the hypothesis that the hydrodynamics of brain aneurysms depend partially on their position, with respect to the force of gravitation, and so developed an experimental model of latex aneurysms, which was subjected to a pulsatile flow. Four different registers were made with an injection of ink and radioisotopes. A physical model was designed which allowed a quantitative analysis of the results and which allows a mathematical analysis of the aneurysm's hydrodynamics. The results suggest that when an aneurysm is oriented against the force of gravity, it has a very low risk of thrombosis, and the scarce turbulence of the flow condition a lower risk of growth and rupture, in comparison with other conditions. The greatest flow turbulence against the wall is found in the aneurysm oriented downwards, that is parallel to the force of gravity. Due to its hydrodynamics, the downwards aneurysm has the highest probability of complication, since it has; a) higher risk of rupture due to the impact of the stream upon the wall and to the turbulence this impact produces, b) a higher risk of thrombosis produced by the circulatory stasis which has a dome. This combination of factors (rupture and thrombosis) allows these aneurysms to grow more than others.

Estenosis por acodadura y rizos de la arteria carotida interna extracraneal acompanantes de aneurismas intracraneales ipsolaterales. Presentacion de cinco casos. / Stenosis by bending of the ellow and curling of the extracranial internal carotid artery associated with intracraneal aneurysms.Report of 5 cases

Se evaluo la frecuencia de anomalias de la arteria carotida interna en su porcion cervical en 83 pacientes consecutivos portadores de aneurisma intracraneal, que se compararon como grupo con 100 pacientes sometidos a estudios por enfermedad no vascular. Cinco pacientes (6 por ciento), presentaron alteraciones carotideas extracraneales con estenosis secundaria, ipsolaterales al aneurisma intra craneal.Del grupo testigo solo 3 por ciento presentaron anormalidades carotideas a nivel del cuello. Se ha propuesto que las anomalias carotideas extracraneales tienen una funcion importante en la patogenesis de los aneurismas intracraneales, pero hasta el momento, los casos informados en la literatura son mas frecuentemente contralaterrales al sitio de la lesion, al parecer por aumento del esfuerzo hemodinamico. Se informan cinco casos de aneurismas intracraneales ipsolaterales a la lesion carotidea extracraneal, y lo que constituye una frecuencia dos veces mayor que en la poblacion normal, con la peculiaridad de que todos los casos fueron ipsolaterales a la lesion cervical