Benjamin Brucker: Thanks so much, Alan. I want to thank you and UroToday for inviting me to talk about bulking in women. And here are my disclosures and conflicts of interest.
We know that stress urinary incontinence is very common in women ,accounts for 50% of all incontinence cases. And this is incredibly costly and bothersome to women, with things like obesity and parity, very common risk factors for developing stress incontinence. Before we talk about bulking, I think it's important that we understand the concept of ISD and why ISD and bulking have always paired together. The theories of stress urinary incontinence and why women have continence have changed over the years, starting with things like the anatomic theories. And then, ultimately how we ultimately treat patients based on these theories. Then as we progressed in our understanding, there were differences in how women were continent because of pressure transmission theories. And then, finally, Ed McGuire and Dr. Blaivas proposed sphincteric theories.
When we have all of these different theories and we try to put them together, this is a slide that I think I probably have seen in one of your talks, Alan, where we're trying to understand ISD and its relationship with incontinence, but also hypermobility. Trying to integrate the anatomic and functional factors. And as we looked at this slide we'd say, well, maybe there are two different things. I will call to your attention that all patients that have incontinence have some degree of ISD by definition. But the reason this was really important, was ISD historically had been a prerequisite for bulking. ISD is not so easy for us to define. We all knew what it was. We knew that there were patients that had high volume leaks. We knew that patients with certain treatments did worse, and those were patients that had ISD.
Traditionally, things like retropubic suspensions were in fact done commonly, but didn't work well with women with fixed urethras, and that's what bulking was used for. We used bulking for patients that had failed traditional incontinence surgeries. And bulking compared to something like a midline incision obviously was a lot less morbid, so we'd use bulking in patients that were maybe a little more frail, elderly, and had fixed urethras. But the fact of the matter is there wasn't a lot of evidence that said ISD was necessarily needed for bulking to be successful. Realizing that as time has gone on, we understand that hypermobility and the measures that we use to assess hypermobility don't necessarily correlate or predict the degree of stress incontinence. And measures like UPP don't necessarily predict surgical outcomes, and are definitely unreliable.
However, in insurance reimbursement in the 90s really followed what we were using bulking for. And so, though there was not necessarily a reason, we always had ISD being synonymous with bulking. Introduce the mid-urethral sling many years later, and realizing that the mid-urethral sling would be effective in a patient that had a hypermobile urethra or a fix urethra, so now the designation became a little less important. And knowing that someone had presence of hypermobility didn't necessarily mean they couldn't have a bulking agent done.
Guidelines have followed suit. Where are we in 2025? Realizing now that in the AUA guidelines we see as a surgical option for women with stress incontinence, a bulking agent is offered. We do see there are comments in the special cases of fixed urethra where bulking agents can be used, but now ISD is not a diagnosis that is necessarily needed, at least according to guideline data, to choose urethral bulking agents. And other guidelines that follow suit, the EAU and AUGS really explaining that, hey, bulking can be offered. It's a low-risk procedure. There are some comments they make about informing patients that repeat injections certainly are likely. And they do mention that there's no evidence of one agent being more efficacious than the other, although polyacrylamide hydrogel may have improved safety and durability.
What we use is very varied. There were a lot of agents over the years that we've used for bulking. And then if we look at the things that are available to us in the modern day, Microplastique, Durasphere, Coaptite, and then polyacrylamide or Bulkamid are the agents that we have. Great concept put forth, Chris Chapple and Roger Dmochowski in the reports in Urology explaining that there are homogenous gels, things like Bulkamid or combination product, Microplastique, Durasphere, and Coaptite. And we get a little bit more collagen in growth and stabilization with the homogenous gel versus a little bit more of an immunologic response with giant cells and other inflammatory cells with some of these combination products where there's a little bit of a difference, perhaps contributing to why some of the longevity of the agents may matter.
There are different ways of delivering bulking, there are different number of injection sites. And I don't have an answer for you because there's not a lot of good comparative data to say that three cushions versus four cushions versus two cushions works. In general, though, the modern agents, I think there's been a trend to proprietary delivery systems really to help make these deliveries a little bit more reproducible. And I think that's the key in any surgical procedure. Here you can see some of the different options that we have.
The landscape of SUI has also changed, and that's where bulking deserves a little bit of a mention. We know in 2019 there was an FDA warning that said we don't want to manufacture cell meshes for transvaginal prolapse repair. And those slings were not named in that. There was a downturn in number of slings that were done. And around that time, that's when we see bulking agents getting more popular. Obviously, orders of magnitude difference. Slings are still much more commonly performed than bulking, but certainly worth a mention.
The other thing that's modernized is realizing that having a patient be cured or totally dry, which is something that as a physician I may think, hey, that's the most important aspect. But if we look at things like patient satisfaction, you realize that there are a lot of patients that can have, let's say on a visual analog score, a really satisfied great outcome, even though let's say the number of patients that are cured may be a little bit less in something like bulking.
Where does bulking fit in my practice today? Certainly, still used in the frail elderly patient, the ISD patient, the fixed urethra. I also can use it for women that have had slings that are failures. But I do use it now as a primary treatment for stress incontinence. Stress incontinence, sometimes we treat in a little bit more of a stepwise fashion, meaning let's try something that may be a little less invasive. And then, certainly keeping women's busy lives in mind and using an agent for someone that wants to avoid anesthesia or minimize downtime. But I do counsel patients the risk of recurrence is real, and that the idea that they may need future injections would definitely be something I'd discuss with patients. With that, I'd like to wrap my presentation and see if you had any questions, Alan. But thanks for the opportunity to present.
Alan Wein: Terrific. Are there any predictors that you can use urodynamics or otherwise to get an idea of whether bulking is going to be successful or not? Or conversely, whether it's going to fail?
Benjamin Brucker: Yeah. I think probably not. We keep looking for them and we need to keep looking. There are factors that I see on urodynamics that sometimes make me maybe favor bulking over something like a mid-urethral sling. A patient that, let's say, has an underactive bladder or is more of a Valsalva voider, I do worry a little bit more on something like a sling. If they require an abdominal strain to void, maybe a little more obstructive than something like a bulking, which is working in a different factor. But I think parallel to what we see with just straightforward stress incontinence, a woman comes in with stress incontinence, I don't necessarily need to prove that she has a low leak point pressure on urodynamics. If I see stress incontinence on an exam, I think she's a reasonable candidate for bulking.
Alan Wein: Do the secondary injections work as well? In other words, if somebody has a reasonable result the first time around and it wears off, and by the way, how long does it usually take to wear off? And then, does it work again the same way?
Benjamin Brucker: Yeah. I think we see this in a lot of incontinence procedures. People are often wowed when they go from really bad to good. And then when you go from good to a little bit better, maybe the delta's a little less. I think the patient perception is sometimes maybe not as profound. I think there's a lot of expectation setting with patients. And when I do a bulking, I start... Let's say if I'm using polyacrylamide gel, 2 mls is what I'll use, and I won't do more than 2 mls. But I'll tell them that, "Look, if you're not quite where you need to be but you have some improvement, I'm happy to top you off or add a little bit more of a gel agent." Did a lot more of that in the beginning of my practice with polyacrylamide gel, and now I'm just not really needing it as much.
The patients down the road that have, let's say a failure or one of the cushions goes away, you can have a woman that goes back to leaking, you re-bulk her, and she actually does great. Again, it's a little different than the wow of the first time. But I do think, in general, repeating bulking is not unreasonable. And if I can keep the morbidity of bulking pretty low, do it in an office setting, ideally without any anesthesia, then there's not a lot of downtime. So why not try to capture that continence back if a woman has a failure?
Alan Wein: Terrific. Well, thank you so much for your time. Really appreciate it. I'm sure that the watchers on your UroToday will gain a lot from this. Listen, take care, Ben. Thank you again.
Benjamin Brucker: Great. Thanks, Alan. I really appreciate it, and hope everyone enjoyed.