Single-use scopes and suction: How innovation is moving endourology forward

In an interview with Urology Times, Mantu Gupta, MD, discussed advances and challenges in kidney stone surgery, emphasizing safety, efficiency, and innovation in endourology.

Gupta highlights that modern visualization tools have largely eliminated the need for fluoroscopy in most stone procedures. With high-quality digital optics and smaller, more maneuverable scopes, urologists can directly visualize the urinary tract rather than relying on radiation. Fluoroscopy remains necessary in select cases, such as stent placement for obstructing stones, but Gupta’s team has developed training techniques that minimize even that need in most situations.

Managing difficult cases, such as those involving solitary kidneys, obesity, or anatomic anomalies, requires tailored approaches. Although obesity does not significantly alter ureteroscopy outcomes, it complicates percutaneous surgery due to longer access tracts and reduced imaging quality. Anatomic variants such as pelvic or horseshoe kidneys pose unique challenges with tortuous ureters and altered stone clearance.

Gupta notes that innovation in ureteroscopy is being driven primarily by single-use ureteroscopes. Recent disposable models have equaled or surpassed reusable scopes in deflection, image quality, and size, enabling less invasive procedures and stent-free surgery. Although cost remains a barrier for some institutions, Gupta believes disposables will supplant reusable scopes as quality improves and prices drop.

Suction technology is another transformative development. By lowering intrarenal pressure, improving visualization, and enabling evacuation of larger stone fragments, suction systems are expanding the role of ureteroscopy into cases previously reserved for percutaneous nephrolithotomy (PCNL). Gupta emphasizes, however, that adoption requires mastering new fluid pressure dynamics to avoid collapse of the system or pressure-induced renal injury.

Looking ahead, Gupta identifies preventing ureteral damage and managing thermal risks from high-power lasers as key research priorities. He anticipates that advances in suction systems, laser modulation, and scope design will continue to make kidney stone treatment safer, less invasive, and more cost-effective. Gupta is a professor of urology at the Icahn School of Medicine at Mount Sinai, chair of urology at Mount Sinai West and Mount Sinai Morningside Hospitals, director of the Mount Sinai Kidney Stone Center, and director of endourology and stone disease for the Mount Sinai Health System, all in New York, New York, and editor in chief of the journal Videourology.

What are the most effective strategies you use to minimize radiation exposure for both patients and staff during stone surgery, and how do you balance that with procedural efficiency?

Gupta: Basically, fluoroscopy was used for many years because it was a substitute for our ability to directly visualize the urinary tract. Fluoroscopy served as a substitute to see areas we couldn’t see with our eyes. For example, when we are placing a stent for an obstruction, we cannot see where the stent is going, so we use fluoroscopy. If we inject contrast dye, we want to see where the dye is going. Or if we’re treating stones, we want to make sure we are not missing any stones. What’s changed is [that] our ability to visualize has drastically improved from what it was even just a few years ago, and in the past 30 years, a huge improvement [has been seen]. Our scopes are smaller. They can get up the ureter easily. They have much better optics, including digital optics, that allow us to see better, and we can pretty much visualize every little part of the urinary tract better with a camera than we can with an x-ray and can deflect to even hard-to-reach places. And because we have that ability to visualize, there’s really no reason to use fluoroscopy to see anything. The only reason to use it is for our own insecurity, because we are used to using it, have been trained to use it, and it provides a degree of comfort that we are in the right place and doing the right thing. But technically, there’s no good reason to continue using it for the majority of what we do. Sure, we’ll still use it on occasion—for example, when we’re putting a stent in for an obstructing stone, because we’re not directly visualizing that stone. We want to make sure that the wire goes past that stone and we put a stent into the right place, because we don’t have the benefit of vision to do it with, but in procedures where we’re using our vision to do the entire procedure, such as ureteroscopy with laser for a stone, there’s no use for fluoroscopy anymore.

For stent placement at the end of ureteroscopy, we have developed a specific protocol. At the end of surgery, we place the guidewire in the calyx or renal pelvis through the scope, remove the scope, reinsert the scope into the bladder, and then place the appropriately sized stent under direct vision into the bladder and up the ureter, deploying the bottom coil in the bladder. As long as the wire remains stationary, we can be pretty confident the stent ends up in the right place in the top. The bottom we know, because we’re visualizing it. The technique is nuanced in that it requires tactile feedback instead of fluoroscopic. A novice may not have that same tactile feedback and will have to be trained on how to do it. Even someone who’s in practice but not used to doing it would have to be trained on how to do it. But once they’re trained, we find it’s relatively simple. We did a study looking at this, and there was not a single case where we had to change the position of a stent, move a stent, or remove a stent early [when] putting a stent in without using fluoroscopy. In fact, we have not used fluoroscopy for a single ureteroscopic laser lithotripsy procedure in over 2 years.

In what clinical situations do you find stone management most challenging—for example, patients with solitary kidneys, morbid obesity, or anatomic anomalies—and how do you adapt your approach?

Gupta: A solitary kidney raises our anxiety, but it doesn’t technically change the way the procedure is done. We’re anxious because we do not want to injure the only good kidney the patient has. That raises our anxiety level a little, and we want to be extra cautious. But technically, the procedure is exactly the same as we would do if they had 2 kidneys.

In terms of morbid obesity, numerous studies have shown that the outcomes are the same whether the patient [has] morbid [obesity] or not, and that’s true whether it’s a ureteroscopic procedure or a percutaneous procedure. However, that doesn’t mean it won’t be more challenging in patients [with] morbid [obesity]. For ureteroscopy, the internal anatomy of the ureter, the kidney, and the bladder is the same regardless of BMI [body mass index]. You could have a patient with a BMI of 50 [kg/m²] or a BMI of 15 [kg/m²], and the internal anatomy is no different, so it doesn’t affect ureteroscopy much in any way. But for percutaneous surgery, it makes the tract longer. To go from the skin to where the urinary system of the kidney is, [it’s] a longer tract, and therefore, we may have to use longer needles. Our visualization may not be as good, whether using ultrasound or fluoroscopy. With fluoroscopy, the x-ray beam has to go through much denser and more tissue to get through the patient, and therefore, the image quality goes down and you may not see as precisely as you would in a thinner patient. In terms of ultrasound, the ultrasound beam has to travel much further to reach the urinary structures, and therefore, it may be more difficult to see the urinary system and be precise with our needle placement. The kidney may be surrounded by more fat and be hypermobile. That’s where it may be more challenging.

In terms of anatomical abnormalities, there are certain anatomical abnormalities that make procedures more challenging. In particular, patients who have anomalous positions of their kidney—whether it’s a pelvic kidney or a horseshoe kidney, when the kidney is not in normal anatomical location—it changes the course of the ureter and changes the anatomy around the kidney such that it may be more difficult. An example would be a pelvic kidney, where a kidney is down in the pelvis, sometimes very close to the bladder. It’s deeper inside the body. It’s not as close to the skin. It may be surrounded by bowel, so there may not be safe percutaneous access. When we’re going ureteroscopically, that ureter tends to be short but tends to be very tortuous. In other words, the ureter goes from the pelvic kidney, which is more anterior than a regular kidney to the posterior part of the bladder. The ureter is making an almost “S” curve. It goes up, down, all around, and it goes back into the bladder. We have to negotiate through that S curve to get up to the pelvic kidney. When we get up to the pelvic kidney, there tends to be more hydronephrosis. The kidney tends to be more dilated and more malrotated. That makes it difficult for us to get our ureteroscope to the places we need to go, to the calyces, and that makes it more challenging. And then in terms of stone removal, even once we fragment a stone, those fragments tend to stay in a dependent location and it may be difficult to get those fragments out compared with a regular kidney. So there are challenges with horseshoe kidneys, pelvic kidneys, patients who have severe scoliosis, where the ureter is much more torturous. Those situations make surgery more difficult.

What role do single-use ureteroscopes currently play in your practice, and in what scenarios do you find them most advantageous compared with reusable scopes?

Gupta: I think most of the advancements in scope technology have now come with the disposable scopes, and that’s because companies are investing their R & D [research and development] into making disposable scopes better and better, because they see that as the future. Even companies that traditionally have made very good quality reusable scopes are focusing now on disposable technology. The advances we’re seeing in optics and in the size of the working channel, durability, deflection, and, in particular, the diameter of the scopes, all these recent advances have come with the disposable ureteroscopes. The reusable scopes have always been there. They’re a standard that can always be relied on. But there are not going to be further improvements in that technology, since everyone’s moving away from them.

Still, our hospital happens to be a late adopter of the disposable technology. They still feel that reusable scopes are more economical than the disposable scopes. They don’t really care about the carbon footprint, although that is a concern with the disposable scopes. They’re more concerned about cost to them, to their system, and they feel that reusable scopes are more economical. We point to studies that have been in the literature showing that the cost of reusable scope is about $1000 a use. If you look at multiple different studies, that seems to be right around where it comes out to, and that’s because of the cost of repairs, the cost of acquiring new scopes, and the cost of sterilization. Our hospital looked at it and said, “Our cost of reusable scope per use is only $350.” I said, “How can that be when other studies are saying it’s $1000?” It turns out that I’m very gentle with my ureteroscopes. My ureteroscopes, which no one else is allowed to use, tend to last longer. So I may be getting 50, 60, 70 uses out of a scope, whereas [in] the US, it tends to be around 15 to 20 uses. For me, they’re saying it’s not economical to use disposable scopes. When we use a disposable scope, we have to fill out a form that explains why we’re using a disposable scope. Is this difficult anatomy [where] you’re worried that the scope will get damaged, and that’s why you want to use it? Is it because the patient’s infected and the risk of transmitting infection is going to be lower with a disposable scope that you are using and throwing away compared with a reusable scope, which may get contaminated and not get decontaminated or sterilized as well as you’d like? There have been studies showing that we think we’re sterilizing equipment very well but we may not be doing as good a job as we think. A lot of that literature has come from the GI [gastrointestinal] literature with colonoscopes and so forth, but it’s true also for our reusable cystoscopes and ureteroscopes. We have to justify the use in our center. They don’t put too much pressure on us not to use it, but we have to justify the use. The writing’s on the wall in terms of what’s going to happen in the future. As these disposable scopes become cheaper, there’s more and more competition, [and] they become better quality, I think everyone is going to be switching to using disposable ureteroscopes.

How does the image quality and deflection of the single-use scopes compare with the latest generation of reusable scopes in your experience?

Gupta: Reusable scopes are pretty reliable. Most of them, the newer-
generation ones, have very good deflection abilities. Initially, some of the disposable scopes didn’t meet the same standards in terms of the visual quality and the deflection ability and were also a little more fragile in terms of breaking. But we’ve come a long way, and the newer-generation disposable ureteroscopes have overcome some of those early hindrances, and I think their deflections have gotten better now to the point where they’re surpassing those of reusable scopes, where you can deflect almost 360° in some of these scopes. The deflection doesn’t break as easily as it used to. Sometimes, if you pulled too hard on the deflection mechanism, you’d break a wire, and then it would no longer be able to deflect. That also doesn’t happen as often, and the quality of the image has gotten better. Most of these scopes [utilize] digital imaging using a CMOS [complementary metal oxide semiconductor] or a CCD [charge-coupled device] chip at the tip. They’re not fiber-optic like many of our reusable ureteroscopes are. The quality of the image is getting better. The light diffusion is getting better. Initially, with some of these disposable ureteroscopes, it would be bright in the center and not so bright toward the edges; you’d get a halo effect. They’re getting better at that. They’re having autoadjustment of the light, so it’s balancing it out nicely.

I think one of the biggest advancements has been the size of the ureteroscope. We’ve had the privilege of being able to use a 6.3F ureteroscope made by HugeMed, and that’s revolutionized how we do some of our procedures in the office and in the OR [operating room] because it fits almost every ureter. If you have a pediatric patient or you have a patient with a known tight ureter, that’s our go-to scope for getting up that ureter. I think other companies are going to follow suit and have smaller ureteroscopes, and that’s going to make it less invasive for patients and make it less likely we have to put a stent in. Already, we’re pioneering stent-free surgery with both PCNL and ureteroscopy, but I think the smaller scopes are going to make it even less likely for us to put [in] a stent in the future.

How well do single-use ureteroscopes perform in difficult cases, where high durability and deflection are tested?

Gupta: I have found no issue with the newer-generation disposable ureteroscopes in terms of their performance. Still, there are situations where you will get what’s called a flash artifact: When you fire a laser, there’ll be a flash artifact on the screen that obscures your vision for a second or less than a second until it goes back. That’s quite distracting. But some of the newer ureteroscopes—for example, the HugeMed and the Ambu ureteroscope—have new technology that reduces that artifact. So that’s gotten better.

The other situation where the digital ureteroscope, especially the disposable ones, may be inferior is in bloody cases. When the urine gets bloody in the kidney, you don’t get as good visualization with digital technology [as] you do with fiberoptic. That has something to do with the light being absorbed by the blood and affecting the camera optics. But I think the scopes are getting better at that as well, so I think that’ll be a thing of the past.

Q.In which scenarios do you find suction technology most beneficial—for example, during mini PCNL, ureteroscopy, or managing infected stones?

Gupta: Suctioning technology for mini PCNL is an improvement on relying on passive outflow. It can decrease the dust that’s in the view, especially if you’re using a laser, because it’s continuously evacuating that dust, so your field of view is clearer. It maintains lower intrarenal pressures, so it’s less likely for bacteria or endotoxins to get absorbed into the bloodstream and cause sepsis. In general, you can evacuate bigger pieces with use of suction and evacuate them faster than you can if you’re relying on the vortex effect to wash out the fragments with mini PCNL. There are distinct advantages to suction with mini PCNL.

In terms of ureteroscopy, what it allows us to do is to challenge ourselves and tackle bigger stones, stones that we wouldn’t have tackled in the past, because we’re creating so many fragments, we don’t know how to get rid of them. With suctioning technology, we can tackle bigger stones and evacuate that dust continuously as we’re doing the laser procedure or at the end, evacuating fragments through the suctioning sheath. Or, in the case of the CVAC [central venous access catheter] technology, [we can remove] good-sized particles that, [with] traditional ureteroscopy, we couldn’t remove. We can remove them directly through the scope by suctioning them out. The suction technologies are here to stay. They’re going to allow us to tackle bigger stones. Is it going to supplant PCNL totally? No. There are big stones, staghorn stones, infected stones, where PCNL is the better option for patients. I don’t see suctioning technology completely supplanting PCNL, but I think it will supplant the middle-of-the-road case, one that used to be a borderline case [that] you could do retrograde with ureteroscopy or a PCNL. With the advancements with suctioning technology, it allows us to tackle those retrograde. That’s less invasive for the patient, because there’s less risk of bleeding or injury to other organs around the kidney with ureteroscopy than there is with PCNL.

What technical challenges or learning curve considerations should urologists be aware of when adopting suction technology into their workflow?

Gupta:We need to modify how we do surgery, especially if you’re not using an access sheath. Most of the time, we don’t use an access sheath. If you’re used to doing things without an access sheath, then you’re not using very high pressure in the kidney. You tend to keep the pressure low, because without an access sheath, the pressure will build up and cause possible injury to the kidney or cause increased intrarenal pressure and pain afterward from the intrarenal pressure. So we tend to not use high pressures in the kidney when we’re not using an access sheath. With suctioning technology, however, you need the high pressure because you’re collapsing the urinary system with the suction. You cannot work in an environment where the pressure in the kidney is negative, because the mucosa of the kidney will be touching itself. There’ll be no fluid distending it. You need an optimal amount of distension in order to visualize structures and stones and treat them properly. That right amount of pressure in the kidney is probably somewhere between 10 and 30 mm Hg of water. Too low a pressure in the kidney from suction will collapse the system. Too high a pressure could cause sepsis or damage to the kidney. When you’re using a suctioning sheath, because you’re collapsing the system, you need to have high pressure in the kidney. You have to have a system that generates the pressure. Obviously, an autoregulating system that will optimally control the suction and the irrigation simultaneously is ideal, and many companies are working to create a fluid management system that will do that automatically so the urologist doesn’t have to think about it. They set the pressure to what they want it to be, and the automatic system regulates the suction and the irrigation to make that happen.

Looking ahead, what clinical or research questions do you feel remain most pressing in optimizing safety, efficacy, and cost-effectiveness in the treatment of kidney stones?

Gupta: One concern has been temperature damage to the kidney from high-power lasers. These high-wattage lasers are able to generate a good amount of temperature increase in the irrigation fluid, but that’s going to be mitigated by using suctioning technology and increasing the inflow. With that continuous flow of irrigation, temperature increases won’t be a problem anymore, so that’ll be a concern of the past. At the same time, intrarenal pressure, which was a very big concern over the past several years, will no longer be much of a concern because of these systems that will automatically regulate the pressure in the kidney.

The main concern is, are we causing damage to the ureter by putting up these suctioning sheaths and other devices—for example, the CVAC, which is a relatively large ureteroscope? Putting that up the ureter, is that going to lead to an increased risk of damage to the ureter? One other concern is, with these high-power lasers, are we causing damage to the ureter when we’re lasering a stone in the ureter? The stone is touching the wall of the ureter, we’re heating up the stone with our laser, and that can lead to strictures. How can we prevent that from happening? A lot of laser companies are now working on that. I think some of the settings that they had initially promoted were high settings, and we have discovered that we don’t need those high settings. High settings, especially high-frequency settings, can damage the ureter by causing increased temperature in the ureter. I think we’re getting away from those high settings. As the laser technology improves with pulse modulation and improved peak power that more effectively treat stones, I think that will become less of a concern.