A Study for the Reproducibility of Detachable Coil used in Cerebral Aneurysm Coil Embolization

Background/Objectives: In this study, the outer diameter of the detachable coil used for cerebral aneurysm coil embolization was evaluated objectively through quantitative analysis. Methods/Statistical Analysis: Out of the helical shape coils from three companies that had failed coil embolization from January 2012 to May 2015, the outer diameter of 120 coils (20 from each company) with the diameter of 1.5 mm, and 2.0 mm were measured with an optical microscope and compared with the outer diameter of the coil before insertion. Findings: For the coils from all three companies, there were not any significant changes for the outer diameter after keeping the coils in a water bath at 37℃ for 10 and 20 minutes, respectively. For the 1.5 mm sized coils, the average outer diameters before insertion were 1,860μm for coils from company S, 1,530μm for C and 1,554μm for M. Similarly, for the 2.0 mm sized coils, the averages were 2,372μm for company S, 2,038μm for C, and 2,056μm for M, which were larger than the sizes proposed by the companies. After failure, the average changes in outer diameter were 2,074μm for company S, 1,535μm for C and 1,558μm for M measured for the 1.5 mm sized coils, and 2,581μm for company S, 2,043μm for C, and 2,062μm for M among the 2.0 mm sized size coils. The change in the average was the largest for coils from company S, which showed a statistical significance (p<0.05). Also, the shorter the length of a given coil, the smaller the changes seen in the diameter. Application/Improvements: The coils from companies C and M maintained reproducibility; that is, they maintained the original shape after the insertion failure, and did not show significant changes in the outer diameter.