Abstract
Background and purpose: Selection of the appropriate first coil in cerebral aneurysm embolization is essential to establishing a stable coil frame and thereby to providing recurrence-free treatment. However, the criteria for selecting the first coil have not been established. The aim of this study is to experimentally evaluate the coil-loaded mechanical force on the aneurysmal wall and to provide a reference for the rational selection of first coils.
Methods: Two experiments were performed using two coil systems (the Guglielmi Detachable coil [GDC] and Electro Detach coil [ED]). First, counterforces created by step-wise compression on the coils were measured. The diameter of the coils, ranging from 3.0 mm to 16.0 mm, was set to an uniform value of 3.0 mm before compression. Second, each coil was inserted into a silicon aneurysm model of 4 mm in diameter and then counterforces from the coil-filled silicon aneurysm were measured.
Results: Step-wise compression of a coil led to an almost linear increase in counterforce values. The diameter differences had little effect on these values as long as the stock-wire diameter and primary diameter of the coils were constant. Stock-wire diameter seemed to be the primary determinant of the value. In the experiment using the silicon aneurysm model, the counterforce was not dependent on coil diameter, but seemed to be determined by stock-wire diameter and length of the coils.
Conclusion: The force on the aneurysm wall caused by insertion of the coil into the aneurysm depends primarily on diameter of the stock-wire and not on the size of the coil.
