Experimental animal studies of clip‐induced microvascular trauma

Abstract

This study was designed to evaluate microvascular clip potential for causing changes in vessel-wall tissue and the extent to which this potential is influenced by features of the clip. Light and scanning electron microscopy were used to examine vessel-wall changes after temporary clip occlusion. Vessel patency is shown to be influenced by anastomosis and clip site, changes in occlusion force due to material fatigue are described, and novel clip features to reduce vessel trauma are proposed. Evaluation of mechanical clip properties showed that material fatigue does not lead to relevant loss of precision in alpha-type clips. While the modified clip designed to reduce trauma cannot abolish trauma altogether, it significantly reduces the associated changes and hence the risk of thrombosis. Arteries were more sensitive than veins to clip-induced trauma, with increased occlusion force producing more severe damage than increased clipping time. Maximal changes were seen in the tunica media. These results indicate the paramount importance of applying modest clip pressure commensurate with the requirements of microvascular Surgery.

A half century (1961-2011) of applying microsurgery to experimental liver research

“…Clamps and vascular clips are instruments used for hemostasis and for bringing small vessels closer together without causing too much tissue damage [3] . New vascular clips have been designed to reduce trauma on the vascular wall [4] . Exposure to the surgical field is made up of separation, aspiration and traction.…”

Reversal of intraoperative arterial thrombosis with a fibrinolytic agent when treating large and giant partially thrombosed aneurysms of the middle cerebral artery

“…The possibility cannot be excluded that altered arterial endothelium in the areas where temporary clips are applied 3,9,10 might serve as sites for acute thrombus adhesion.…”

Valoración del daño parietal a nivel vascular, tras la aplicación de métodos extraluminales de oclusión temporal

“…Existen además múltiples estudios realizados con animales (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) que concluyen que el uso de diferentes dispositivos de oclusión conducen a daños en las estructuras vasculares Los clamps vasculares convencionales y los lazos comprimen la pared del vaso más de lo estrictamente necesario y por lo tanto, originan daño tisular. Han sido descritas diversas formas de daño vascular originadas por la oclusión vascular desde el exterior del vaso o extraluminal.…”

“…Se valoró por observación histológica la presencia de neoformación en la capa íntima, considerándose que existía presencia de neoíntima cuando existían más de una capa celular en el endotelio o hiperplasia moderada o severa, y ausencia de neoíntima cuando no se apreciaba reacción en dicha capa vascular. (12)…”

“…También encontramos otros estudios que se preocupan de describir las características ideales de los clamps vasculares u otros sistemas de oclusión (12) , o describen novedosos diseños con el fin de minimizar el daño, como los diseños de Darcin en 2004 (21) , o modifican clamps preexistentes con el fin de minimizar el daño, como los trabajos de Dujovny en 1981 (7) , o incluso mucho antes, en 1966, los diseños de Thomas J. Fogarty (146) También podemos encontrar estudios comparando diferentes tipos de clamp (3,112) .…”