Metallurgical analysis of aneurysm and microvascular clips

Abstract

✓ The design of an aneurysm clip and the choice of its component materials require complex considerations of corrosion resistance, biocompatibility, desired performance, and manufacturing practicalities. This study analyzed 10 different types of aneurysm and microvascular clips for chemical composition and metallurgical characteristics. The opening force of each clip was determined with a spring gauge. All components of four multicomponent clips (three aneurysm clips and one microvascular clip) were manufactured from 17-7PH stainless steel, a strong precipitation-hardening grade of good general corrosion resistance. Two multicomponent clips (one aneurysm clip and one microvascular clip) each contained three components manufactured from different alloys. In an implanted clip, an increased rate of corrosion may result from electrolytic reaction between components composed of different alloys. This study demonstrated that 17-7PH stainless steel is a popular alloy for use in vascular clips, but it has several drawbacks. The authors suggest that manufacturers explore the use of PH15-7Mo instead. PH15-7Mo is another precipitation-hardening stainless steel, but contains molybdenum, which renders it potentially more resistant to corrosion than 17-7PH.