No tubes, no stents: Investigators explore advanced approach to PCNL

In this interview, Mantu Gupta, MD, discusses an innovative approach to percutaneous nephrolithotomy (PCNL) in which no nephrostomy tube and no stent is left in the patient following the procedure. This was explored in the recent publication, “Is Totally Tubeless Percutaneous Nephrolithotomy a Safe and Efficacious Option for Complex Stone Disease?” for which Gupta served as the senior author.

Mantu Gupta, MD

Gupta is the chair of Urology for Mount Sinai West and Morningside Hospitals, as well as the director of the kidney stone center at Mount Sinai and a professor of urology at the Icahn School of Medicine at Mount Sinai in New York, NY.

This transcription has been edited for clarity.

Could you describe the background/rationale for this study?

The standard for many decades has been to remove larger kidney stones through a tract that's put through the skin into the kidney directly called percutaneous nephrolithotomy. The standard has been, at the end of the procedure, to leave a tube in the kidney so that there's no collection of urine inside the kidney and that the kidney is drained. But the problem with a nephrostomy tube, people quickly find out, is that they're quite painful. Patients are admitted to the hospital and have the tube in for 1 to several days and it has to drain into a bag, so they're very uncomfortable for patients.

About 20 years ago or so, a few investigators started trying to do the procedure without leaving a nephrostomy tube in to drain the kidney, but instead leaving a stent in to drain the kidney. It was found that there was no increase in complications by not leaving in a nephrostomy tube. It was less painful for patients, and patients recovered quicker and were able to be sent home sooner without a nephrostomy tube. That was called tubeless percutaneous nephrolithotomy, or tubeless PCNL. But the stent is still very bothersome to patients. In fact, one study by Arthur D. Smith, MD and his colleagues at Long Island Jewish Medical Center showed that when they looked at how uncomfortable a patient was after PCNL and their quality of life, the patients who had stents in actually had worse quality of life symptoms and outcomes and more discomfort after they were discharged from the hospital than patients who had a temporary nephrostomy tube that was removed before they left the hospital. So maybe temporarily, patients who have nephrostomy tube have more pain, but after they leave the hospital, they have less pain than patients who initially did not have a nephrostomy tube but have a stent. So, stents are very uncomfortable. A lot of patients know about them. Anyone who's had a kidney stone and had a stent knows how that feels. It causes a lot of urgency, frequency, bladder pain, painful urination, bleeding, and other symptoms and complications.

So, some investigators have started looking at whether the procedure can be done without leaving a nephrostomy tube and also without leaving a stent. That's called totally tubeless percutaneous nephrolithotomy. That procedure has been done, but by very few urologists over the years. There are only about 5 comparative studies that compare totally tubeless PCNL to standard, or tubeless PCNL. All those studies have shown that there is an improvement in discomfort and a quicker discharge from the hospital using totally tubeless percutaneous nephrolithotomy.

Could you discuss the current research on this approach?

What we started doing in our center at Mount Sinai about 3 years ago is started sending all of our patients home after surgery instead of admitting them to the hospital. That's called ambulatory PCNL, or same-day discharge PCNL. The advantage of that is that they get to go home to their normal environment and don't have any of the annoyances or discomforts of having to stay in the hospital. Then we said “well, why don't we take this one step further?” What if we can do both? We can do ambulatory PCNL and also totally tubeless PCNL at the same time, sending them all home on the same day of the surgery, after having removed a large kidney stone, with nothing in them: no tube, no catheter, no stent, and no stone. Wouldn't that be wonderful? So, we started doing it.

We found that as we got better and better at doing it, the majority of patients now can go home in this fashion. They can go home the day of the procedure with nothing in them. We found that patients who have this procedure are ecstatic. They can't stop talking about it when they come back for the post-op visit."I can't believe you removed that giant stone out of me through this tiny nick in the skin, and that's all I have. And I hardly had any pain afterwards." So, that's what led to this current review article to look at the current state of matters when it comes to totally tubeless PCNL, where we are now, and what can we do to advance this. We want to have other centers start doing what we are doing.

We're actually doing a prospective, randomized trial that has already started. We already have several patients enrolled, but we're looking to enroll over 200 patients in this trial, comparing totally tubeless PCNL with tubeless PCNL. With tubeless PCNL there's no nephrostomy tube but they get a stent, and with totally tubeless PCNL they get no stent, no nephrostomy tube, and they go home. All the patients are going to go home the same day in the study. We're going to compare outcomes. We're going to look at complication rates, we're going to look at pain –– we're going to be calling them and get pain scores after the surgery –– we're going to be looking at blood loss, and we're going to be looking to get stone-free rates to make sure that we're not compromising the initial purpose of the procedure, which is to get the stone out. We'll make sure we're not compromising on that outcome by doing totally tubeless.

This study will take a couple of years to accomplish, because our goal is to have 200 patients to show the benefit of the procedure. Hopefully with that, we'll be able to promote this procedure and prove to other centers that it's feasible. Because these patients are being randomized, they don't have a choice on whether they get a stent or not. It's a closed envelope design, meaning an envelope's being opened up at the end of the procedure in the operating room, and the envelope's going to say that they're getting the stent or not getting a stent. And that's what we're going to do. That way we can show that if we can randomize it in this way, it's feasible for almost all patients. Of course, patients who we deem need a stent because their ureter's obstructed, or they have inflammation in the ureter, or they have infection in the kidney that needs to be drained, of course, those patients are going to get a stent and they're not going to be included in the study, because safety comes first when it comes to this. We don't want to be compromising patient safety just to prove a point.

Could you expand on which patients may not be well-suited for this approach?

There are some patients who actually know what a stent is and they come in with preconceived notions about a stent. They say, "I really don't want a stent." And obviously, for those patients, a totally tubeless approach is better, but it's not always possible. Like I explained, there are certain circumstances where we say a stent is necessary in order for a safe outcome of the procedure. In those patients, we can convince them that a stent is important by trying to put the appropriate stent for them to minimize their symptoms afterwards. We tend to use silicone stents. I started doing that several years ago, and I found that silicone stents compared to plastic stents, which is the most common stent being placed after the procedure, is much more comfortable because it's softer, it molds to body temperature, and it doesn't cause the same degree of urgency frequency and pain that plastic stents do. So, we tell them, we're going to put a silicone stent that's appropriately sized for you –– it's not too long, not too short –– so the comfort level will be there. Those types of patients need some convincing, but I think by having that tiered approach and explaining what a stent is and why it's important in certain situations, we can overcome their fears.

There are patients who have more extensive stone disease. Let's say they have a complete staghorn stone. A staghorn stone is a stone that branches inside the kidney. It can fill the entire inside of the kidney, such that every part of the kidney is filled with stone: the upper part, the middle part, and the lower part. Some of those patients require multiple access points. In other words, 1 tract into the kidney is not sufficient to remove the stone. You might have to do 2, 3, 4, 5, or sometimes even more access tracts. Every time you do an access tract, that increases the potential complications of the procedure, because you're creating more and more holes in the kidney, so there's more chance for bleeding. In those patients, doing this procedure may not be safe. But sometimes it is, so it depends on the individual patient. But the bigger the stone, the more tracts that are necessary, and the less likely we are to do totally tubeless procedures on them.

The third type of patient where this may not be appropriate is a patient who has an infection stone, a stone that has bacteria in it. In those patients, it's crucial to have good drainage after the surgery. We must, in those patients, put a stent in to make sure that any residual bacteria, puss, debris, stone fragments, blood clots are evacuated out of the kidney. In those patients it is crucial to put a stent, so they are not going to be included in our study and shouldn't in most circumstances get a totally tubeless PCNL.

Could you perform a totally tubeless procedure with tract sizes that are bigger?

There are many different tract sizes that are used for PCNL. Originally, the tract size was about 1 centimeter, which is 30 French. About 15 years ago, I pioneered using a 24 French tract size, which is much smaller than 30 French. Even though it sounds like a small difference, it actually makes a big difference in patient outcomes. We found that there was less bleeding, and patients did much better with the 24 French tract. Now, people have moved to using even smaller tracts: 18 French, 16 French, 14 French, 11 French, and even smaller than 11 French in some circumstances. Those procedures are called mini PCNL or ultra mini PCNL.

Some people who are doing ultra mini and mini PCNLs find it easier not to leave a stent or nephrostomy tube in after the surgery because the tract is smaller and they're less concerned about bleeding. We just completed a study comparing 24 French with mini PCNL, and we really found no difference in bleeding or complications between the 2. So actually, we've moved more and more away from mini PCNL and are doing 24 French tracts more often. We're finding that we can do totally tubeless PCNL with 24 French tracts. The advantage of a 24 French tract is that it's a quicker procedure for the patient. We also found that the intrarenal pressure during the procedure is actually lower than with mini PCNL, where the pressures can go high. So, there's less chance of sepsis and other complications. For those who think that totally tubeless PCNL can only be done with mini PCNL, we have found that that's not absolutely true, and that you can do totally tubeless PCNL even with standard tracts sizes such as 24 French.

What advice do you have for urologists looking to implement this approach?

I think key take-home messages are that in order to get to the level where you can do totally tubeless procedures, you should start with a graded approach. I would first start with using ultrasound guidance for PCNL, because I think ultrasound guidance gives you a more accurate way of getting into the kidney compared with using fluoroscopy. We found our transfusion rates and our hospital stays dramatically dropped after we started using ultrasound. I believe that ultrasound is what allowed us to go to outpatient surgery instead of inpatient surgery with PCNL. On top of that, start with leaving no nephrostomy tube first, because it is still common practice in the United States and elsewhere in the world to leave a tube in at the end of surgery, even though it's been shown to be safe not to leave it. I think that would be the first step, to learn how to do the procedure without a nephrostomy tube. Then, once they get comfortable with that, then proceed to not leaving a nephrostomy tube or a stent.