The Resonance stent has been available in the US for about nine months, and we have been using it with some frequency. It is constructed from a coil of a chromium, titanium, and molybdenum alloy, and it is designed to be very resistant to compression. Its primary use is for malignant obstruction of the ureter and we have used it fairly extensively in this regard. European reports have documented limited encrustation, and the stent is supposed to be safe for up to one year.

To date, our results have been generally good with the stent. We have used around twenty of them, and many patients (although certainly not all) who have failed even double stenting have remained patent with the resonance stent. It is a bit unpredicatable, but it seems that patients with bulky pelvic disease tend to be the ones that fail with the Resonance stent. We will need more experience before definitive statements can be made.

Regarding encrustation, our experience is more limited, but today I removed a Resonance stent that had been deployed for six months. We removed the stent because the patient had responded somewhat to chemotherapy, and we wanted to see if she could remain unobstructed with out the stent. There were two remarkable findings. First, there was almost no edema around the trigone. Second, the stent came out easily, but there was some encrustation around the proximal and the distal coils. Both of these findings can been seen in these two pictures.