Letter. "Corrosion" of tungsten spirals. A disturbing finding.

SUMMARY: Very long-term (more than 30 months after treatment) skull plain films of patients treated with Mechanical Detachable Spirals "MDS" (tungsten) for intracranial aneurysm or dural fistula by venous approach, showed a decreasing level of radiopacity of the spirals suggesting that this material was resorbing with time. To date, all the aneurysms selectively treated with "MDS" which were followed-up by angiography more than 30 months after treatment (three cases) showed recanalization. The recanalization was proportional to degree of the "corrosion".