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Ask Dr. Schwartz: Using the Resonance® stent

We sat down with Dr. Bradley Schwartz, Chairman of Urology, Southern Illinois University, to discuss his experience with the Resonance® Metallic Ureteral Stent. In the second installment of this three-part series, Dr. Schwartz provides a detailed overview for using the Resonance stent in practice.

Refer back to video one to hear Dr. Schwartz talk about his approach to treating extrinsic ureteral compression.

To schedule a tele-education or Resonance event with Dr. Schwartz, please email:


How long have you been placing the Resonance stent?
I think the Resonance stent has been around for pretty close to 10 years, and we started putting it in pretty shortly after it became available on the market in the United States. I think we’re probably around 7, 8, 9 years that we’ve been using it and that’s been our experience.

What are the advantages of the Resonance stent?
I think some of the things that really come to mind as being true advantages of the stent are that these patients really don’t have to undergo stent changes every three months or every four months. And we, in urology, might think of that as being a pretty benign procedure and not being very intrusive, but when we really think about the whole process, it really is—it’s kind of a pain in the neck for the patient and their families to come in and get these done three or four times a year, four or five times a year. So, again, I think the huge advantage to me is that these patients typically will only undergo one procedure every 10 to 12 months. And you look at the cost figures. Again, we’ve done some—we’ve had at least two publications on economics, and I know there have been some other publications on economics—that the cost to the hospital, the cost to the patient, and the overall cost to the medical system is diminished by use of these stents.

One comment we get not infrequently is, “We don’t want to spend 1,000 bucks for a stent like this.” Well, when you look at the hospital systems and the way they buy products and such, that’s understandable, because that’s money out of their pocket to buy a product. When you talk about OR time, and inpatient time, and anesthesia time, those are all kind of hypothetical and kind of weird costs that these hospitals build in. But when it comes down to it, the hospital really truly does save money over a one-year time period, considering the change of three or four stents in a year. We’ve looked at that, we have two publications on that, and there have been other publications supporting our work, that it is an economical stent when all is said and done. It’s not only cost. It’s not only financial cost. I think patients who have this, and if we can put it in and they remain tolerable and they can remain asymptomatic for that calendar year, it’s just something they can forget about. Their quality of life is enhanced greatly. So, it’s not only measurable economics, but it is a quality-of-life issue that we really need to keep in mind for these patients who, a lot of them already have bad disease and other medical problems. They’re already going to physicians’ offices for appointments and procedures and testing, and if we can just eliminate this from their mind for that year, then they don’t ever have to worry about it for that year, and they can concentrate on the other things that they have to do.

What has been your experience with the tolerability of this stent?
The tolerability studies that we’ve had—our publications, along with a number of others, Dr. [Thomas] Turk, Dr. [Evangelos] Liatsikos—from really around the world, have demonstrated that metal stents are not any differently tolerated than the polymer stents. So, just because a metal stent is in place, they should tolerate it just as well as they did the polymer stents. There should be no difference.

Discuss your technique for exchanging the Resonance stent.
The big major difference of the Resonance stent is the way it’s placed, right? There’s no central lumen, you have to place the stent through a lumen. You know, for a urologist, it’s maybe just thinking backwards, or you know, you have a black-and-white issue, and now it’s a white-and-black issue. You have to just kind of change your way of thinking about it. So, a common question, clearly, is, “Well if I take that metal stent out during a replacement, I’m going to lose continuity because this is a really bad stricture and a bad obstruction.” So, again, my advice, and the way we do it here, is we pass a wire first. If we can get that wire past the stricture and up into the kidney, then we won that battle. So, all we have to do is keep the wire in place, and pull the stent out. I never—never say “never,” never say “always”—it is rare that I just pull a stent out without having some access. Now, if there’s trouble passing the wire, which there clearly can be with some of these strictures, again, you can pass one of the yellow 5 Fr catheters up and help gain a little purchase and a little bit of buttress to help get that wire negotiated up there.

You can also do ureteroscopy. These ureters distal to the stricture are very, very wide and dilated. You can pass a really small, rigid ureteroscope up and even identify and look where you want to pass that wire and just do it under direct vision. I feel strongly enough that I want to get a wire passed before I take the stent out, that I will do ureteroscopy before I take the stent out first. Once you do that, you can then grab the metal stent and pull it out. And you already have control of the kidney.

Another technique I think that is very useful and helpful for urologists is—the graspers that we have in our hospital I think are fairly classic and fairly typical, reusable graspers. They have good tensile strength and they have good closure and good closing capability. The problem is, oftentimes, that if you grab the stent midway in the grasper, it will kind of just squirt out when you try to grab it. So, one of the suggestions that I have, that I find very, very useful is you need to try to grab the tip of the stent, right in the very kind of crux of the grasper, and that way the alligator part, or the corrugated areas of the grasper, will really latch on to that and then you can pull it out. But you might get very, very frustrated urologists if they keep trying to grab it and it just keeps falling out. You can also use a basket to grab these stents and pull them out, if worse comes to worse.

How do you size the stent to ensure you get a good fit?
One of the things that always comes up with any stent placement for urologists is how to find the appropriate size and length. And it can be a struggle. All of us have been confronted with scenarios and cases where we choose the wrong stent, we realize it, we have to open another stent, patient comes back sooner than anticipated. A lot of issues with that. There have been some publications to try to identify the best way to measure a stent and get the best fit. I don’t use any fancy equations or measurements. When I inject contrast into the renal pelvis, if that contrast is right around the 11th or 12th rib, I can almost be assured that a 24 cm stent is going to be about the right size. If there’s a lot of tortuosity—and again, a lot of these metal stents are put in ureters that have been obstructed for a long time. So, you get, you know, you get these ureters that are serpiginous, and if you look at the linear distance of those, it’s longer than a normal ureter. So, you do have to take that into consideration.

I think with the Resonance stent, sometimes there might be a feeling that you have it sized perfectly—and you might use a 24 cm stent—and you put it in and it just feels long, it appears long, the patient might have some more symptoms. Clearly that’s happened to me. There’s no question. When I go back and look at a lot of my patients through the years, what we’ve used, if they come back with a lot of symptoms, and we look back at their op report and we see what size that we used, when we look in the bladder and there’s a fair amount sticking out into the bladder, and the renal pelvis curl is appropriate, we will then go to a shorter stent and hopefully it will provide less symptoms, less tolerability issues, less phone calls to the office, if we can size it properly.

I don’t have a great, Nobel Prize-winning caveat to tell the size. I think every urologist has something in the back of their mind that they like to use. I think if you’re going to err on putting a size stent in for the metal stent, for the Resonance, you might want to err a little bit on the shorter side, just because they do tend to maybe fit a little bit larger.

Dr. Schwartz is a paid consultant of Cook Medical.