Technical problems associated with new designs of Guglielmi detachable coils.

Background And Purpose: Recently, we experienced several technical problems that were directly related to new designs of Guglielmi detachable coils (GDCs). We herein present cases involving those problems and propose probable causes.

Methods: We reviewed the clinical and angiographic data of 269 consecutive patients with intracranial aneurysms who had been treated with GDCs between May 1996 and October 2001. We focused on newly encountered technical problems: spontaneous premature coil detachment, backward slipping of the coil into the microcatheter lumen after detachment, and undesirable detachment of the coils at the parent artery. The occurrence and clinical consequences of the problems were investigated before and after the introduction of a new GDC (SynerG) design. Additionally, to confirm the potential causal relationship, in vitro observations and simulation tests were performed.

Results: Of the 269 patients, 69 underwent embolization between March and October of 2001. Among those, we encountered technical problems in 10 (14.5%) cases. The overall number of events was 12, including spontaneous detachment (n = 5), backward slipping of the coil into the microcatheter lumen after detachment (n = 4), and undesirable coil detachment with a segment of the coil remaining at the parent artery (n = 3). No similar problems occurred among the 200 patients treated during the period between May 1996 and February 2001, when the new design coil had not yet been introduced. In vitro observations suggested that the long and stiff segment of the SynerG coil, especially the SR type, was a highly probable cause of these technical problems.

Conclusion: Our clinical experience showed a high incidence of technical problems, and in vitro observations suggested that the new GDC designs could be responsible for them. For safe aneurysm treatment, details of embolization techniques should be modified.