Tiny aneurysms treated with single coil: morphological comparison between bare platinum coil and matrix coil.

Objective: We analyzed the angiographic results of tiny aneurysms treated with various kinds of single coils including polyglycolic-polylactic acid (PGLA)-coated coils.

Methods: Forty aneurysms with diameters measuring less than 4mm were treated with a single bare platinum, Matrix1, or Matrix2 coil. Most of the aneurysms were treated with a 2 mm diameter coil, except for seven treated with a 3 mm coil, four treated with a 2.5 mm coil, and two treated with a 1.5 mm coil. The mean length of the coils was 3.6 cm.

Results: With mean packing ratios of 21.2%, 19.7%, and 22.8%, we achieved initial complete occlusion rates of 9.5% with the platinum coil, 28.6% with the Matrix1 coil, and 25.0% with the Matrix2 coil. The mean follow-up interval was 23.1 months and the complete occlusion rate improved up to 47.6% for the platinum coil, 57.1% for the Matrix1 coil, and 83.3%for the Matrix2 coil. Compared to the Platinum group, the Matrix2 group showed a greater tendency toward more complete occlusion on the follow-up images. Regardless of coil type, the aneurysms treated with a stent-assisted technique showed better complete occlusion rates (50.0% vs. 90.0%, p=0.03).

Conclusions: The tiny aneurysms treated with a single Matrix2 coil tended to have better follow-up angiographic results than the aneurysms treated with a single platinum coil. Furthermore, the use of a stent-assisted technique and increasing the packing density also positively affected the healing of these tiny aneurysms.