A comparative study in opening and closing pressures of cerebral aneurysm clips.

Modern aneurysm clips with newer metallurgic properties and state-of-the-art designs have evolved through the years. Regretfully, manufacturers are still not required to provide product information regarding clip strength, and when such information is supplied, there is no interbrand consistency to how it is obtained. This experiment compares the closing pressures of 5 commonly used brands of aneurysm clips: Yasargil, Sugita, Sundt-Kees, Vari-Angle McFadden, and Heifetz. Interclip comparison is also made of opening pressures, that is, the arterial pressure required to open an aneurysm clip. Findings show a distinct difference in closing forces among these brands of aneurysm clips. The study of opening forces indicates that the important factors determining clip release or displacement were the failure of the clip to cross the vessel completely and intrinsic characteristics of the vascular wall.