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BackTable / Urology / Podcast / Transcript #9

Podcast Transcript: Tips & Tricks for Percutaneous Nephrolithotomy (PCNL)

with Dr. Margaret Pearle and Dr. Aditya Bagrodia

Dr. Margaret Pearle, the Vice Chair of Urology at UT Southwestern Medical Center, joins us to discuss percutaneous nephrolithotomy (PCNL). Dr. Pearle shares advice on pre-operative urine culture analysis, CT scans, percutaneous access, and placing a ureteral stent vs. a nephrostomy tube You can read the full transcript below and listen to this episode here on

Table of Contents

(1) PCNL Preoperative Considerations: CT Imaging, Stone Size & Stone Density

(2) Special Considerations for Infectious Stones Cases: Intrarenal Pressure and Infection

(3) Complex PCNL Patients: Obesity, Cerebral Palsy, Spina Bifida

(4) PCNL Pre-operative Workup: Urine Culture Analysis, Antibiotics & Drainage

(5) Continuation of Aspirin & Anticoagulants in Cardiac Patients

(6) Gaining Percutaneous Access: Independent Access vs. Collaboration with Interventional Radiology

(7) PCNL Procedure Techniques

(8) Post-Operative PCNL Care: Nephrostomy Tubes, Ureteral Stents, Chest Imaging & Antegrade Nephrostogram

(9) Dealing with Early and Delayed Postoperative Bleeds: Interventional Radiology Involvement, CTAs, & Arteriograms

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Tips & Tricks for Percutaneous Nephrolithotomy (PCNL) with Dr. Margaret Pearle and Dr. Aditya Bagrodia on the BackTable Urology Podcast)
Ep 9 Tips & Tricks for Percutaneous Nephrolithotomy (PCNL) with Dr. Margaret Pearle and Dr. Aditya Bagrodia
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[Dr. Aditya Bagrodia]
Hello, everyone, and welcome back to the BackTable Urology Podcast, your source for all things urology. You can find all previous episodes for our podcast on iTunes, Spotify, and at My name is Aditya Bagrodia, and along with Jose Silva, we are serving as your hosts.

And I couldn't be happier to introduce our guest today, Peggy Pearle, who is the vice chair of the Department of Urology at UT Southwestern, along with a full professor. I can't say enough about Peggy. I've known her for almost 13 years now. We could spend the entire 45 minutes talking about her. But she is an incredibly comprehensive, deliberate and thoughtful clinician. She is a truly gifted surgeon. Her contributions to education, to research and just general advancement of our specialty has been without comparison.

Personally, she inspired my career in academic urology and I'll forever be grateful. So, thank you, thank you. Thank you for being with us today. How's your day going?

[Dr. Margaret Pearle]
Great, Aditya. Thanks so much. And thanks for the kind introduction. The fact is a lot of my productivity is thanks to you because you worked with me when you were a medical student and a resident, and you've been a phenomenal partner and colleague. So, thank you for inviting me to do this. I'm really happy to be here.

(1) PCNL Preoperative Considerations: CT Imaging, Stone Size & Stone Density

[Dr. Aditya Bagrodia]
All right, great, great. So, a lot of wisdom is coming our way regarding percutaneous renal surgery. And let's just jump on into it, Peggy. So, criteria for performing PCNL, what are your kind of absolute indications for PCNL?

[Dr. Margaret Pearle]
I think absolute indications at least historically have basically been large and complex stones. So, historically greater than two centimeters or whenever there's unusual anatomy that might be difficult to access in a retrograde fashion ureteroscopically or to treat with shock wave lithotripsy.

But I think the indications are definitely moving. As the procedure itself has become less invasive, I think more and more, we're treating smaller and smaller stones because it's a really effective way of treating stones. So, if we can make the procedure more effective, then we can apply it to stones that historically stretched the limits of ureteroscopy or shock wave lithotripsy because of the lower morbidity for the patient.

So, stones down to 15 millimeters or even less, depending on the type of percutaneous procedure, that are being treated now via PCNL. And certainly, anatomic issues. Anytime there's distal obstruction that's not going to allow passage of fragments after the procedure or that doesn't allow retrograde access to the kidney, regardless of the size of the stone would be treated percutaneously.

[Dr. Aditya Bagrodia]
Okay, okay. What is the preferred Imaging for both anatomy delineation and collecting system delineation that you like to go with?

[Dr. Margaret Pearle]
I mean, in our guidelines, we recommend that anyone who's undergoing a percutaneous procedure have CT imaging beforehand. And it's sort of left to the discretion of the practitioner, whether that's done with or without contrast. The fact is, most of the time, we don't have contrast with our CT imaging. So, there can be surprises with anatomy.

So, when I'm in doubt, I like to see a CT urogram and I like to see the collecting system anatomy delineated. A CT without contrast is good for basically establishing the stone burden. And it's good for the relational anatomy of the kidney. So, it's good for showing where the pleural space is, where the liver or spleen is. If there's a malrotation of the kidney, it's good for that. But it doesn't show intrarenal anatomy very well.

So, I think if in doubt, if anything looks funny, it's really helpful to have a CT urogram. If you can't discern whether a stone is in a calyceal diverticulum, then having contrast can be really helpful and it prevents you from having surprises. So, although it's certainly not mandatory, in the past, I used to always insist on having an IVP along with a CT because it did give me that anatomy and I try to avoid the extra radiation associated with a CT urogram. Now, it's sort of difficult to get IVPs altogether, so CT urogram is helpful.

But sometimes it's helpful to just see it more 3-dimensionally even than just looking at axial or coronal imaging. So, it's nice to have contrast, not mandatory, but it does help prevent surprises.

[Dr. Jose Silva]
And Peggy, do you use Hounsfield units as an indication to determine what type of procedure will you go through?

[Dr. Margaret Pearle]
Right, so it's a good question. So, Hounsfield units help us determine the density of the stone and it's most useful for determining whether a stone is amenable to shock wave lithotripsy. So, relatively lower Hounsfield units (Hounsfield units less than 1000) would be considered something amenable to shock wave lithotripsy, provided size and anatomy are also favorable.

For percutaneous approach, less important. But if you're trying to determine what's the best treatment approach, whether it's shock wave lithotripsy ureteroscopy or PCNL, Hounsfield units would be helpful for ruling in or ruling out shock wave lithotripsy as a possibility.

But from the standpoint of PCNL, really, the density of the stone is sort of less important. Just it'll affect how long it might take you to fragment the stone. But in terms of treatment selection, probably not so important.

(2) Special Considerations for Infectious Stones Cases: Intrarenal Pressure and Infection

[Dr. Aditya Bagrodia]
And maybe when we're thinking about stone characteristics, the Hounsfield units, the size of the stone, whether or not potentially you're concerned about it being an infectious stone, I feel like there are so many options now. Of course, there's ureteroscopy. We have standard PCNL. We have many percs, we have micro-percs, we have ultramini-percs. I think we could have an entire conversation about that. But is this a part of your armamentarium, as you think about treating these stones?

[Dr. Margaret Pearle]
Yeah, so that's a great question. So, I freely admit, I'm not fully adept at mini-PCNL or ultra mini-PCNL, and I've done several, but it's not a standard part of my armamentarium. I think from a standpoint of infection stones, I think you want the lowest pressure system, the lowest intrarenal pressure that you can achieve. And there's no question that with mini- and ultra mini-PCNL, the intrarenal pressures are a bit higher.

And there has been at least some data suggesting that the potential for infection may be higher. I'm not sure clinically that's actually been realized. The larger the sheath, the lower the intrarenal pressure, and the less risk there's going to be potentially infectious complications just from pressure in the kidney.
So, if I have an infectious stone, I generally want to maintain this lower intrarenal pressure as possible. And the fact is most infection stones do happen to be larger stones. I mean, it's not that often that you do ureteroscopy and you find a small struvite stone. It happens. They obviously start at some size. But more often than not, those are large stones and I think doing those under the lowest pressure possible is optimal.

So, I might be a little more hesitant to be thinking along the lines of mini-PCNL, although I'm sure there are many urologists who would say they do mini-PCNL, really, regardless of the size or composition of a stone. You still have the ability to get the fragments out with mini-PCNL just from the Venturi effect--just you when you pull out the nephroscope, it tends to have sort of a vacuum effect that sucks the fragments out.

So, I think it's doable. I worry certainly about infections, so I don't like doing them ureteroscopically, even if they were a size that would be amenable to your ureteroscopy. Even with an access sheath, I really want that internal pressure to be low because you have the potential to make patients pretty sick.

In terms of how fields Hounsfield units, I'm not sure otherwise that would concern me as much in my selection of size of sheath that I'm using, whether it's mini, ultramini, micro-PCNL--I’m less concerned about that. It's really just a matter of how long or short it takes you to fragment the stone and how many fragments it generates.

I mean, I tend to like harder stones just in the sense that they generate finite fragments that can sort of either be pulled out or sucked out. But the softer the stone, the more you end up with fragments all over the place. So, I sort of prefer harder stones for a lot of reasons.

(3) Complex PCNL Patients: Obesity, Cerebral Palsy, Spina Bifida

[Dr. Jose Silva]
And Peggy, in terms of patient factors comorbidity, obesity, what patients will you not offer a PCNL?

[Dr. Margaret Pearle]
Honestly, there's almost no one, I think, that you can't offer PCNL. Obesity, I can't think of a time that I had someone so obese that I couldn't perc them. You just have appropriate equipment, you have to have scopes and sheaths that are long enough to span the skin to collecting system distance. And I haven't yet had a patient who was so large that my sheaths and scopes didn't reach.

Positioning is always a challenging issue. But I also haven't yet had a patient that I just couldn't position. I think as long as you have a table that has some versatility, we use a Trumpf bed, and it allows us to really manipulate just about every angle. For the arms and the legs, we treat patients in the split leg position, prone. And so, we can bend down at the waist. If the patient is very contracted, we can bend at the knees with our table.

So, we can really accommodate a lot of these cerebral palsy patients and things that have a lot of contractures and just pad them appropriately and just make sure that everything is comfortably positioned, well-padded. But for the most part, with some ingenuity, we can generally get patients positioned appropriately.

Spina bifida patients can sometimes be difficult just because they tend to have a wall of ribs that it's sometimes difficult to get in between the ribs, or they're very contracted to one side so there's not a lot of distance between the 12th rib and the superior iliac crest. But somehow, we sort of muddle through it and tend to find our way into the kidney in one way or another. So, I think we're more limited ureteroscopically or cystoscopically than we are percutaneously. We can sort of almost always find a window.

(4) PCNL Pre-operative Workup: Urine Culture Analysis, Antibiotics & Drainage

[Dr. Aditya Bagrodia]
That's super helpful, Peggy. And so, you spent quite a bit of time talking about infectious stones. Can you just talk a little bit about your, of course, we have imaging, urine cultures, kind of management of positive cultures, timing of when you like to get these, just going into this making it as safe as possible.

[Dr. Margaret Pearle]
Yeah, I mean, I'm pretty aggressive about antibiotic use and so forth, because these patients can really get sick. And so, I think we want to do everything we can to try to prevent those infectious complications because a lot of these staghorn stones that we're treating percutaneously are infection stones, so they're full of bacteria and you can treat for extended periods of time preoperatively, but you can't penetrate into the stone.

So, I think we do the best we can to sort of semi-sterilize the urine around the stone, knowing that when we start fragmenting the stone, we're going to be releasing bacteria. But I'm pretty insistent about urine cultures done within about two weeks preoperatively, treating with appropriate antibiotics beforehand. Admittedly, I don't always reculture the urine once they've been treated with antibiotics. If I'm treating with a culture-specific antibiotic, I'm usually pretty comfortable that we can proceed on antibiotics.

Even with negative cultures, I do tend to treat with antibiotics for about five to seven days preoperatively. And there's some controversy about that and some conflicting studies in terms of the length of time that you need to treat with antibiotics preoperatively, particularly in patients with negative urine cultures. We may not need to treat them preoperatively at all and just perioperative antibiotics may be adequate. I tend to still generally give at least a few days if not a week of antibiotics preoperatively.

But the positive culture ones I think we have to be really aggressive about, and I don't hesitate to put PICC lines in in advance and treat patients with a full week of antibiotics. I'm pretty reluctant to just admit patients the day before who have a positive urine culture and give them 24 hours of intravenous antibiotics. I generally want a full course.

And I know infectious disease will often argue with that. They want to really minimize the antibiotics in these patients and they'll want you to just treat for a dose beforehand and a short period of time afterward. But I have to admit, I'm much more aggressive than that. I've certainly seen my share of infectious complications and patients who end up being admitted to the intensive care unit postoperatively because of sepsis.

But for the most part, we have a relatively low rate of sepsis. I think in our practice here, with the three of us that are doing percutaneous procedures, and I attribute it to being really pretty aggressive in taking these cultures seriously. We have a system here at UT Southwestern that we worked out with the microbiology department, where we have a special code that we can use that indicates that we want all organisms to be worked up. So, even low colony counts and even multiple organisms, particularly if it's coming from any kind of indwelling tube, they will work up all the isolates.

And so I make sure that, even in someone who has multiple organisms, we make sure we're treating them with culture specific antibiotics that cover all organisms for at least a five to seven day course preoperatively. And I think that that does help us really keep our infectious complications down. So, we're aggressive about it. I take it really seriously.

[Dr. Jose Silva]
And what antibiotics do you use for an asymptomatic patient with a negative urine culture?

[Dr. Margaret Pearle]
Yeah, so I typically use ampicillin and cefepime. We used to use ampicillin and gentamicin and I sort of got away from gentamicin a bit just because of renal function issues and so forth, and cefepime seems to have pretty broad coverage. You can argue and some are just using cephalosporin, some are just using ciprofloxacin, or quinolone. But I tend to use ampicillin and cefepime, hoping that I'm going to catch Enterococcus if there's Enterococcus in the stone that was never picked up and any gram negatives. So, I think that's a reasonably good broad spectrum regimen.

[Dr. Aditya Bagrodia]
And are you routinely getting stone cultures and renal pelvic cultures intraoperatively?

[Dr. Margaret Pearle]
Yeah, I don't do it in every case. If the stone has the appearance of just being a pretty typical calcium oxalate type stone, patients don't have a history of recurrent urinary tract infections, and the urine culture preoperatively was negative, I'm not doing it on every patient, knowing that urine cultures preoperatively can definitely underestimate the amount of positive cultures that will be detected both from the stone and from the renal pelvis urine.

But in any patient who's had recurrent urinary tract infections, who has anything that has the appearance of an infectious stone, we certainly do send the stone for culture.

[Dr. Aditya Bagrodia]
If they're coming in with a preexisting nephrostomy tube or a stent, do you ever prophylactically treat them with the antifungals?

[Dr. Margaret Pearle]
Yeah, that's a really good question and comment because fungal sepsis, I think we all would agree, is really one of the probably worst forms of sepsis that we deal with and those patients get incredibly sick. So, sometimes I'll just think about it and think this patient's been on a lot of antibiotics preoperatively, let's just give a dose of an antifungal at the time of surgery, not necessarily preoperatively.

Sometimes I look in the kidney and I see something that looks a little fluffier than I like to see, and I'll start it then. But it is absolutely something to keep in mind preoperatively. And I know Nicole Miller has always been a proponent of being pretty liberal about placing nephrostomy tubes preoperatively if they don't have tubes in, but they have a high grade obstruction. She will often put in a nephrostomy tube so she can sample the urine preoperatively and know what she’s actually treating, which might reveal fungus. But certainly with tubes in place, they're at higher risk of that.

So, in patients with longer term indwelling tubes, I'm definitely thinking about antifungals. I may not do it routinely every time if cultures from the tube are negative. But sometimes the cultures are negative for yeast and yet intraoperatively, there'll be the appearance that maybe there's yeast. Then, I'll add it at the time.

[Dr. Aditya Bagrodia]
Okay, yeah, I think something for all of us that we come across, patients are just kind of not doing quite as well, and then things start spiraling to keep in the back of your mind. And I think this actually dovetails quite nicely into access, whether we get that prophylactically with our colleagues in interventional radiology or whether that's something that can be done on the urology side.

Before we jump into some of those considerations, I want to ask you a quick question. Patients coming in with partial stags or full stags, positive UTIs, not clinically sick, are those patients routinely getting decompressed? Or do you think it's safe to manage them with antibiotics, try to sterilize them and then treat them as you typically would down the way?

[Dr. Margaret Pearle]
Yeah, I don't typically decompress them. Patients will often come to me with a standard nephrostomy tube in place. But if I encounter them, if they're referred to me and they don't have drainage or I'm seeing for the first time and they don't have drainage, I don't routinely place a drainage tube, unless sometimes they'll have sort of the appearance of an XGP type kidney, and that might worry me more that I might want to sample that urine and save a trip to the operating room. Because if you get in there and you find pus, then you're going to put a nephrostomy tube in and get out. But I don't typically.

Now, there are times I've been burned by that and found pus at the time of obtaining access. But more often than not, I'd say usually I don't. And again, this is where Nicole Miller probably is more aggressive about putting tubes in and sampling the urine. I just obtain my routine urine cultures and treat appropriately and aggressively with antibiotics preoperatively and intraoperatively. But I don't necessarily prophylactically place nephrostomy tubes, even in a patient with a staghorn stone and a hydronephrosis.

[Dr. Jose Silva]
So, in that case, you will encounter some pus, then you cancel the nephrostomy, give antibiotics and come back on another occasion?

[Dr. Margaret Pearle]
I mean, yes and no. Yes. I mean, the board answer to that is yes. And I would say in most instances, the answer to that is yes. However, there have certainly been cases that maybe I don't want to admit, but there definitely have been cases where I just feel that I'm just not going to get the kidney adequately drained. And I'm going to drain one little calyx and I'm going to leave the rest of the kidney undrained.

So, I will sometimes go in there with a big access sheath and, maintaining as low intrarenal pressure as possible, try to just get through some of that stone till I could clear maybe into the pelvis and just get better drainage of the kidney. And I'll try to spend as little time as possible, but enough to maybe get the kidney better drained. Because sometimes you come back and you access through using the nephrostomy tube you had.

And then as soon as you get into the pelvis or you get into some other part of the kidney, you encounter pus again. So, there are some circumstances where you just don't get the kidney adequately drained until you get some of the stone out.

I've had this discussion with some of my colleagues. And I think we've all been in that situation where we've done that, and I worry about it. Am I doing the right thing? If this patient gets really sick, I'm going to regret this. But there are times that I just feel I'm not going to be able to achieve anything unless I clear some stone out to make way for better drainage.

[Dr. Jose Silva]
And in those cases, you will leave like a big Foley instead of just an 18 French or a smaller caliber nephrostomy tube?

[Dr. Margaret Pearle]
Yeah, and I don't know if that's really necessary or not. But generally, if I've been in there and I went ahead and dilated the track to 24 French or 30 French, I may leave a 16 or 18 French tube in place that is going to achieve good drainage and also leave a way for me to come back the second time. And I don't go through that procedure with the intent of finishing it. I go through with the intent of getting enough stone out to achieve better drainage.

(5) Continuation of Aspirin & Anticoagulants in Cardiac Patients

[Dr. Aditya Bagrodia]
Okay. And before we start talking about access, one last question, patients were on AFib, recent PEs, coronary artery disease, and of course, I'm assuming that we engage their cardiologist when it's safe to come off anticoagulation. But broad strokes, a couple questions, aspirin, are you okay with that? And in general, is there a timeframe after surgery where you feel comfortable resuming anticoagulation?

[Dr. Margaret Pearle]
Yeah, it's a great question. And I'd say for me, somewhat of a moving target. In terms of aspirin, I mean, if the aspirin can be safely stopped, then I'd rather stop it. I mean, I certainly don't want to take chances I don't have to take.

On the other hand, do I think aspirin makes the difference between someone with a significant bleed and someone without one? Probably not. I mean, aspirin, I don't think makes the difference between having a pseudoaneurysm and not having a pseudoaneurysm. I think that that's less of an issue. So, if someone had to stay on aspirin for cardiovascular reasons, that would not dissuade me from going ahead.

I’m much more worried about preoperative anticoagulants, especially Plavix. But aspirin is not a game stopper for me. But I'm not cavalier about it either.

In terms of postoperative anticoagulation, it's kind of a work in progress for me. I mean, I'd say for most of my career, I was willing to restart anticoagulation within a couple days, I mean, sometimes that night, sometimes the next day. But I've been burned for sure and had patients bleed postoperatively. I don't know that you can avoid a delayed bleed for that, but you might avoid those early bleeds.

And I know from talking to Jeff Cadeddu during grand rounds many times, he's pretty insistent in not starting anticoagulation for at least two weeks, longer than I typically was waiting.

But I'm starting to come around and think maybe that's the right thing to do. I mean, my philosophy has sort of always been that you can always somehow deal with a bleed. But if someone has some significant cardiovascular event, you may not see your way out of that. And so, I've always thought I'd rather have the bleed. But I don't know, in my older age, it causes more stress for me now when they have these bleeds postoperatively or solitary kidney or something. I worry that more patients can ill afford to undergo an arteriogram or embolization.

I'm starting to think maybe we should be waiting a little longer. Now, I'm sort of stretching it out to more like a week. But that's definitely longer than I used to wait. Two weeks makes me nervous from a cardiovascular standpoint. I just worry about what happens to these patients in AFib. Are they going to throw a clot? I'm a little worried about waiting that long.

(6) Gaining Percutaneous Access: Independent Access vs. Collaboration with Interventional Radiology

[Dr. Aditya Bagrodia]
Yeah, I definitely recall the kind of bimodal distribution of bleeds in that first 48 hours and then the 10 to 14 day range, which I think Jeff has actually published on, and which has certainly happened. I think we've all seen it. Okay, excellent. So, access, maybe we just start out with what are the clinical scenarios where you're typically going to kind of work in conjunction with your interventional radiology colleagues to get access?

[Dr. Margaret Pearle]
So, it's certainly variable across the field. I mean, there are some urologists who obtained their own access and some who never do and some who worked very closely with their interventional radiologists, particularly intraoperatively. I definitely think you are hurt if you don't have access being obtained in the operating room. I mean, it's innumerable cases that I have in my career that would never have been able to be done if the access wasn't obtained intraoperatively at the time.

So, whether it's an interventional radiologist or whether it's a urologist, I think it needs to be done in the operating room. Because there are times I get access and the amount of purchase I have with my guidewire is like a couple sonometers. So, I barely have a guidewire in. You could never do that outside of the operating room and somehow stably transfer that patient to the operating room and expect that you're going to maintain that guidewire in the collecting system--you're going to lose it. So, I think it needs to be done in the operating room.

I definitely have a preference for doing it as a urologist because I know what works for me and I know what doesn't. There are a lot of interventional radiologists that come into the operating room and they are there until they see you in the collecting system so they know, too, what works and what gets you in and what doesn't get you in. So, I have no problem with that and that model works very well for a lot of urologists.

The need for a second access is always a rate limiting step. Because if you have to bring someone back in, then you're sort of at the mercy of when the interventional radiologist can come back in the room to get access for you.

So, in that sense when I started my career, I didn't get my own access and I worked closely with an interventional radiologist who was phenomenal. But I would wait for him. He didn't like starting cases at 7:00 in the morning. He wasn't used to coming in until 8:00, so we would twiddle our thumbs for a little while waiting for him to come. And when we needed him to come back for a second access, it would take some time.

So, once I started learning myself, it was definitely an advantage to be able to do yourself and to get good at it and to know what works for you, and again, to be able to obtain these really precarious accesses that just barely get you in but get you close enough that you can kind of dig your way into the kidney. So, for sure in my career, that's been advantageous to be getting access myself.

But I would just say for anybody out there, it should be done in the operating room because of calyceal diverticula and very tenuous access into a collecting system with a full stag. You're just not going to be able to get stable purchase with a guidewire or a catheter reliably and transport the patient. So, I think it should be done in the operating room.

So, that said, do I ever rely on interventional radiology? Yes, I do. Because I myself don't do ultrasound-guided access. And so, I do have times where, for instance, a calyceal diverticulum that doesn't fill with contrast and doesn't have a stone in it, but nonetheless needs to be treated, then I really don't have a way to access it. And if I can't, if putting a catheter into the collecting system and opacifying with contrast doesn't fill the diverticulum, I'm kind of stuck because if I can't use ultrasound, I can't see it.

So, that would be one instance. And that's happened a couple times in my career where I've had to have interventional radiology access a tic that was nonopacified, almost an excluded calyx.

The second situation is, and again, which could potentially be overcome by ultrasound-guided access in the operating room, is if you're worried about the liver or spleen. And most of the time, I think, careful look at the CT can pretty much guide you. You know that you need to stay really medial.

[Dr. Aditya Bagrodia]
So, generally, it's going to be you're able to take in the information from your preoperative imaging, do your planning--typical liver, tip of the spleen, retrorenal, colon, et cetera--those may be rare scenarios. But it sounds like the take home message is that it should be thoughtful, not just the easiest calyx that facilitates the surgery that you intend to do and ideally done in the operating room. Is that fair?

[Dr. Margaret Pearle]
I mean, there's no question that anybody can do a PCNL if you have precise, well-thought out access. And on the other hand, even a very experienced urologist can fail at a PCNL if the access was ill-chosen.

So, I think preoperative planning and decision making in terms of where you want that percutaneous puncture is critical. And careful look at the CT scan is important. The fact is, though, we do CTs with patients in the supine position, and there's no question that things move when you're prone. So, there'll be times that I think, “Oh, if I put the patient prone, everything, the colon is going to fall forward,” but it doesn't. It tends to be just the opposite. It's like it squeezes the colon further posteriorly.

And there's no question that I'll think that I can do an axis that will stay below the 12th rib. When they're prone, it's always higher. The calyces are always higher when they're prone. Again, it's just sort of like pushing things up. So, we don't know exactly from the CT scan what things are going to look like when a patient is prone.

I had a small bowel injury one time. And if you look at the preoperative CT scan, the small bowel is nowhere close to being posteriorly. There's no way you could get into the small bowel. And postoperatively, I looked at the CT scan and I'm going right through the small bowel.

And somehow, the small bowel just slipped back behind the kidney when the patient was prone. It was unbelievable. And I watched the general surgeon go in laparoscopically. It was a 15-minute procedure. You can see where the tube sort of goes in and out and just clipped off a few sonometer of small bow and re-anastomosed it. But I mean it required a small bowel section. So, you would never have predicted that based on the CT.

So, we do the best we can, but I think ultrasound-guided access is helpful. And I think more and more urologist are learning that skill, and I haven't mastered it yet. But I think it's helpful and it gives us certainly more intraoperative information that we might have.

(7) PCNL Procedure Techniques

[Dr. Aditya Bagrodia]
Perfect, perfect. So, maybe now we move into the operating room. So, prone versus supine, any strong opinions there?

[Dr. Margaret Pearle]
So, I'm a prone PCNL practitioner. And I think if you look at the literature, there are many trials. There are many retrospective and prospective randomized trials that have compared patients. And the bottom line is it really doesn't matter. Certainly the operating room time is a little shorter if you do it supine because of the positioning issues. But there's really no difference in stone free rates or blood loss or any other real parameters, like hospital stay.

So, the bottom line, I think, is it's a dealer's choice. People that do the supine position love it and are big advocates of it. And it's certainly easier than placing patients prone. From a pulmonary and cardiovascular standpoint, although everyone thinks that there's a greater risk when they're prone, it's actually not. From a cardiovascular standpoint, it's not unfavorable. In fact, patients are placed in the prone position in the ICU with ARDS and other cardiovascular or pulmonary problems. So, there's not really a cardiovascular advantage to that.

In my career, how many times have I had to flip a patient supine because of some catastrophe that was happening? Once that I can think of. So, it's generally not an issue. Our team is so efficient at getting patients prone that that adds 10 minutes, maybe 15 minutes to the whole operating room time, but I just haven't found it to be a barrier. And I find much more freedom of motion in the prone position.

Certainly, if you do a lot of upper pole access that you don't do a lot of upper pole access in the supine position. Some do. Most are doing lower pole access when they're treating patients supine. So, if you're an advocate of a lot of upper pole PCNL, you probably better off doing it prone.

[Dr. Jose Silva]
What type of wires are you using? Do you always leave a safety wire?

[Dr. Margaret Pearle]
I do. I try to. I get access because I learned from an interventional radiologist. I use a Jeffrey Set, which is a 0.018 inch platinum tip guidewire or a coat Mandril wire. So, I get access with a 22 gauge or 21 gauge needle, which will only accommodate a smaller wire. So, that's a 0.018 inch guidewire.

You'd then have to transition to a standard size guidewire using some kind of an introducer set. So, as I said, I use what's called a Jeffrey Introducer Set. And it's really stiff. It's got an inner metal stiffener and an inner dilator and then an outer sheath. So, especially in an obese patient or someone who has a lot of scarring in the kidney, it's really rigid and it follows that platinum tip guidewire, which actually has a fair amount of rigidity too, even though it's so small. I find it much easier to get in using that very rigid system. It gets through the fascia and through the capsule really nicely.

Once you have the sheath in, it accommodates three standard size guidewires. So, then I can easily get my Amplatz Super Stiff guidewire, which I use as my working guidewire, and I just use a standard Benson guidewire as my safety wire. So, if I have the opportunity, I certainly routinely use a safety wire. But sometimes it's all I can do to get one wire in the kidney and then I use one wire. But when I can use a safety wire, I do. I try not to cut corners.

[Dr. Aditya Bagrodia]
Peg, I'm going to ask you to back up just a step. So, maybe I'm going to just ask you, so the patient's positioned. In your practice, I believe that you still are doing retrograde air pyelograms to understand your intraoperative collecting system anatomy. So, can you just talk us through that process, which allows you to get your percutaneous access?

[Dr. Margaret Pearle]
Yeah, so I place patients prone and I still do prone cystoscopy to pass a retrograde catheter into the collecting system. I still tend to use an occlusion balloon only because it helps prevent fragments from traveling down the ureter and it allows me to opacify the collecting system with some occlusion, so that I can get the collecting system a little more dilated.

There are lots of people that put access sheaths up. They can opacify with an access sheath as well. Some just use a 5 French angiographic catheter. But I still like an occlusion balloon because I definitely notice that I can dilate the collecting system more. And that often helps pass the guidewire.

I use air typically if I can avoid putting contrast in the collecting system. I like that because then I don't have to worry about a bunch of extravasation; if it takes more than one puncture to get in the collecting system, I don't have contrast all over the place, which sometimes can really make your visibility extremely difficult as you go from bad to worse, and you reach a point where you can't see the collecting system anatomy at all.

So, I use air if I can. I use it gently. I'm careful about it. But it also helps identify posterior calyces so the air will rise into the posterior calyces. So, that can help me identify what a posterior calyx is. By ultrasound, it's much easier to distinguish anterior from posterior. And then, I generally have an idea of where I want to access based on my preoperative imaging, but the intraoperative imaging may change my mind about where I want to go once I see where the stone is.

Sometimes an air pyelogram is not helpful if there's a lot of bowel gas or stool and you just can't see what the error is really opacifying. Then I'll use contrast. I tried to use it very dilute and as little of it as possible. And that, in combination with air, still can sometimes delineate the airfield posterior calyces and distinguish them from the contrast filled anterior calyces.

Additionally, you can distinguish anterior from posterior by just obliquing the C-arm away from the surgeon and as you oblique the C-arm away, the posterior calyces will elongate and move toward you. Anterior calyces will shorten and move away. So, by moving the C-arm, obliquing it back to straight AP and then laterally away from you, I can see which way the calyces are moving.

So, between that and air, you usually distinguish what's anterior and posterior and try to choose the posterior calyx, unless for some reason I have to puncture an anterior calyx because that's where the stone is and it's the only chance I have of getting there.

So, then I obtain access again using my 22 gauge needle and try to get a wire down the ureter if I can. I don't torture myself trying to negotiate something down the ureter, but I certainly prefer it. In an obese patient, I really prefer it because I want as much stability with my guidewire as possible because it's so easy to lose a guidewire in an obese patient. You just move your scope a little bit and it just pulls out of the kidney. And it's remarkable how little wire you have in the kidney when it's just coiled in a calyx. So, if I can get it down the ureter, I do. And again, if I can get a safety wire in, which in most cases I can, I do.

And then I typically use balloon dilation.

[Dr. Aditya Bagrodia]
One question that kind of came to mind as you mentioned contrast extravasation, patients with an iodine allergy. Are you premedicating? I mean, of course you're intrarenal, but there can be some non negligible systemic absorption.

[Dr. Margaret Pearle]
Yeah, I definitely do. I give all those patients standard steroid preps beforehand. I'm pretty adamant about that because for sure, they can absorb contrast. And there are definitely times where there's a fair amount of contrast extravasating out, whether it's during access or whether it's later in the procedure when we're opacifying the collecting system to map out the calyceal system and to assure that we've entered and inspected all the calyces, we inject contrast. And it's certainly easy to get extravasation and absorption. So, yeah, I do steroid prep routinely.

[Dr. Aditya Bagrodia]
Okay. So, you've used your balloon to dilate. And then, is there a preferred sheath that you typically go with?

[Dr. Margaret Pearle]
I mean, I still as a standard am using a 30 French sheath. We can use a 24 French sheath sometimes. If you do that, you can't use the sheath of your nephroscope. So, if I use, for instance, a 24 French nephroscope, you have to take the sheath off to use it through a 24 French sheath.

I'm not sure the difference between 24 French and 30 French makes enough difference to warrant that. I think if you really want to get into smaller accesses, then you have to be looking at something less than 18 French, ideally less than 16 French. So, between 24 and 30 French to me isn't a real big difference. So, I still tend to use a bigger access sheath.

And that doesn't have to impact the size of the tube you leave postoperatively. You can still leave a smaller tube whether it's an 8 or a 10 French Cope loop or a 16 French or 18 French council catheter over an angiographic catheter. We know that you can leave smaller nephrostomy tubes despite larger access tracts.

[Dr. Jose Silva]
And are you using the clear sheath?

[Dr. Margaret Pearle]
I am not. The clear sheath originally came out several years ago. There were companies that made the clear sheath, and I thought it was such a brilliant idea until I used it, and it is frightening. I mean, you are literally seeing everything outside the sheath. You're seeing the fat, you're seeing everything. And it's really hard to see when the sheath is actually in or when it's not.

And when they first came out, I talked to them about it and they put a stripe on it. And the stripe was to help you know when you were in the sheath or not. But when you're in the collecting system or not, it still is hard to see it.

So, that's one of those ideas that I thought was brilliant, theoretically. But in practice, I hated it. I really hated it. It was not helpful. It was very confusing and very disconcerting. I don't want to see the parenchyma. I don't want to see that. I just want to know my sheath is in.

[Dr. Aditya Bagrodia]
Okay. So, having done a bunch of these cases with Peggy, somehow she miraculously always manages to find her way into the collecting system with very little to do. But what are the kinds of red flags? I mean, when you see nice yellow urothelium, it's obviously a sign of relief. And to me, it was somewhat your experience, I think it's expected. But what are red flags as something is not quite right?

[Dr. Margaret Pearle]
I think when there's a lot of bleeding, then usually you're either not in far enough or you've split the infundibulum and you're in too far. I mean, the goal is to dilate the track to get your radiopaque mark on the balloon just inside the calyx. You don't need to go further. Your scope isn't as big as your sheath.

So, even though your scope, a 24 French nephroscope, may get through an infundibulum, a 30 French sheath may not. And same with smaller scopes and smaller sheaths. So, you really just want your sheath into the collecting system.

So, if I'm short, then I just carefully follow the guidewire. Oftentimes, I'll just use a grasping forcep and try to follow it and sort of spread along the way if I have underdilated. I'd rather underdilate than overdilate because you can underdilate and find your way in. If you overdilate and you split the infundibulum, there's no turning back.

But when you're following the guidewire in, you have to be really careful because as you torque your scope and you're looking for the guidewire, and you're sort of moving your scope and moving your sheath, you can pull the guidewire right out of the collecting system. So, the key is you have to follow the guidewire and try to keep the guidewire in one place and adjust your scope to follow the guidewire and not move your scope such that you move the guidewire out. So, that's tricky.

I have to say I tend to grab the scope away from a resident or fellow when we're in that situation because I've been there. I've made every mistake you can make and just learned from experience how to try to negotiate that scope along a guidewire or following a guidewire without losing your access.

[Dr. Aditya Bagrodia]
Okay. And in a more typical case, you're in good visibility, let's just say moderate-sized stone burden, what's your kind of standard approach in terms of what type of lithotripters are you using? When do you have to break out your kind of second line guns? If you could just kind of walk us through your tools there.

[Dr. Margaret Pearle]
Yeah. So, I guess my go-to is the Olympus ShockPulse. And conventionally, it's a single probe that has sort of dual lithotrite actions--ultrasonic and pneumatic action through a single probe.

Now, there's a Trilogy, which is a Boston Scientific instrument that also has sort of a dual lithotrite action. And there's some studies suggesting that it may be more efficient in fragmenting stones quicker, so more rapid stone clearance.

The one thing that's really missing is there was a device on the market that has subsequently been withdrawn called the StoneBreaker that just was a mechanical impacting device that used a compressed CO2 cartridge. And it just used the cartridge for power. It wasn't connected to any electricity or no foot pedal and it was incredibly effective for hard stones.

And we don't have that anymore. There was a problem with the sterilization of it. And I miss that. Because there are some uric acid stags that are incredibly hard, like the hardest stones that you deal with, that any of the other lithotrites just don't effectively breakup at all. And I've been in situations where I'm just fragmenting and fragmenting and fragmenting, and nothing's happening.

And the StoneBreaker used to just break them up into pieces really effectively. And you could just grasp and remove the fragments and we just don't have anything like that anymore that you can count on with an incredibly hard stone. So, I miss that device a lot.

Lasers are always available, especially when there are stones remote from the nephrostomy tract that you can only access with a flexible scope. And so, if you use a flexible nephroscope and you'd get into another calyx, then you need to break up a stone with just standard holmium or thulium fiber laser. So, those are really the two devices that I really keep at my disposal.

[Dr. Jose Silva]
Do you routinely do multiple access rather than using the flexible scope?

[Dr. Margaret Pearle]
No, I definitely much more commonly use a flexible scope if I can access it, but I don't shy away from multiple accesses at all. And I certainly have my share of cases where I've had eight accesses or twelve accesses in a case in patients with stenotic infundibulum.

I mean, there are times that even if you can get there flexibly if the volume of stone is so great, and if you have to pull all those fragments out of the calyx, you're just better off with another access. So, those are definitely the exceptions rather than the rule. But I think you always have to be prepared for that. There are times that it's so much faster to get a second access than to do it flexibly that it's just worthwhile.

[Dr. Aditya Bagrodia]
Fantastic, fantastic. So, stones are cleared. I can certainly tell you as a person who's trained with Peggy that that kidney system is going to be cleared out by any metric before you leave. And I kind of want to just pick your brain on exit strategies in a moment. But before we do that, we talked about pus and how that's generally going to be a cause for aborting the procedure. Any other kind of intraoperative occurrences that would tell you, okay, we've got to fight this one another day.

[Dr. Margaret Pearle]
I think if you have a significant perforation of the collecting system, you're losing fragments out of a hole, and--even more importantly--you're just getting significant extravasation of fluid, then it's time to get out.

I mean, a small perforation, again, it's a relatively low pressure system. I think you can get away with spending a little time. If I can advance my access sheath a bit to cover a hole, I'll do that if it's a split somewhere in the infundibulum. But if you have a big hole in the renal pelvis, there's not much getting around that. And you don't want to spend a whole lot of time with your nephroscope through a hole out in the retroperitoneum trying to retrieve fragments. And you can get significant absorption of fluid if you do that.

So, I think that if you have a significant real pelvic perforation, you should be thinking about getting out as quickly as you can, as soon as you can adequately establish drainage with a nephrostomy tube. So, that would be one reason for aborting.

Significant bleeding, certainly, a more common reason for aborting. You reach a point where you're just collecting clots in the bag, it's probably time to get out. Because almost always, once you get your nephrostomy tube in, the bleeding will cease. So, I think as much as we have a tendency, and I'm completely guilty of this, of sort of pushing on thinking I'm almost done, I'm almost done, probably a better part of valor is to put in a nephrostomy tube and come back 48 hours later to have a clear field. And it's going to be a lot safer for the patient.

(8) Post-Operative PCNL Care: Nephrostomy Tubes, Ureteral Stents, Chest Imaging & Antegrade Nephrostogram

[Dr. Aditya Bagrodia]
Okay. And maybe just if you could talk a little bit about when you're inclined to leave stents in place, tubes, which types of tubes and even tubeless, for instance, would be helpful.

[Dr. Margaret Pearle]
Yeah, so there's definitely a trend toward more tubeless procedures, I'd say. More and more urologists are doing tubeless procedures. And we certainly know that we can do that safely and compared to standard PCNL, with nephrostomy tubes in place, the risk of bleeding or needing transfusion is really pretty comparable. So, I think we can do it safely.

In my mind, the issue has always been the residual fragments. And almost 100% of the time when I finish a PCNL, I think that my patients are stone-free. I do thorough flexible nephroscopy at the end of every case, multiple trips around the kidney with a flexible nephroscope, imaging and looking at every calyx. And I'm wrong, at least 30% of the time, probably more like 60% of the time.

You do CTs postoperatively and patients have residual stones, and I think it just depends on your philosophy about residual fragments. And Aditya, you did seminal work in this area. But my feeling is that if you're going to make a hole in someone's kidney, you've got an obligation to get them stone free. You can put a nephrostomy tube and you can come back and you can get those residual fragments out. So, until we have a better way of assuring that we have gotten every fragment out, I don't want to burn a bridge.

And so, I like to leave a nephrostomy tube in place. I get a CT scan on postoperative day one. And if they have residual fragments, they come back for a planned second look procedure 48 hours later. Some urologists don't have the luxury of being able to schedule two procedures 48 hours apart, but just because of operating room time. We established that practice a long time ago, and we have the luxury of being able to do that. If patients are stone free, we cancel the second look. But we always have that time available to look back. So, in my mind, I just don't want to burn the bridge.

I also find that patients hate stents. They hate stents. When they go home, they want to go home with no tubes. And by leaving a tube in place postoperatively, imaging with a CT on postoperative day one, I can take out their nephrostomy tube and postoperative day one, if they're stone free and send them home with no tubes and with an assurance that they have no residual fragments.

If I have to look back in the kidney a second time, I have the ability to do that, I leave the nephrostomy tube out after the second procedure. And again, they go home free, go home stone free and with no nephrostomy tube.

Those who perform tubeless will state that they'll do imaging maybe or maybe not with a CT, I'd say most often not. And if there are residual fragments, they'll bring them back and do ureteroscopy in a couple weeks.

I would argue, this is just my guess, is that most of the time, those patients aren't brought back for a second procedure. So, just a whole lot less push for you to go back a second time once they leave the hospital. They don't want to go back for another procedure. Once they leave the hospital, they want to be done. And I just think that we have a much lower or much higher threshold for going back for residual stones once they leave the hospital with a stent in place.

So, at least in my mind, I think if it was me, I'd rather go home with no tubes and know that it's over and that all my stones are out. But I would have to say, I'm probably the minority in that. I think there's more and more tubeless PCNL that's being done because they are less invasive and everybody pretty much goes home on post op day one and they're left with no nephrostomy tube, so there's certainly less pain and that's definitely been shown in randomized trials to be the case.

[Dr. Aditya Bagrodia]
Routine chest imaging just to evaluate for hydrothorax--is that still a part of your rhythm?

[Dr. Margaret Pearle]
Oh, so I look fluoroscopically at the end of the procedure as a matter of routine. If I don't see a hydrothorax, then I don't typically do any further imaging in the recovery room. We looked at that a long time ago and we imaged everybody with a chest x-ray in the PACU and then did CT imaging of the chest on postop day one. And the proportion of patients in whom you miss or that you will pick up a hydrothorax that was missed intraoperatively is extremely low.

Most of the time, patients will develop a hydrothorax in a delayed setting and chest x-ray in PACU wouldn't have picked that up. So, we do more often than not, pick it up on the postop day one CT scan because we include the lung bases on the CT so we'll see a hydrothorax.

And then we can either have interventional radiology place a tube or if we go back for a second look, we'll place an 8 or 10 French Locking Loop nephrostomy tube into the chest at the time we go back for our second look procedure. But we haven't done chest x-rays in PACU for a long time. Fluoroscopy is a really effective way to detect a hydrothorax.

[Dr. Aditya Bagrodia]
Okay. And any test to assess whether the kidney is draining antegrade?

[Dr. Margaret Pearle]
So, that's sort of controversial as well. We always do an antegrade nephrostogram at the end of the procedure. When we're looking with our flexible nephroscope, we either look down the ureter with a ureteroscope or nephroscope or we at the very least will inject contrast in an antegrade fashion to clear the ureter.

I still sort of believe in antegrade nephrostogram postoperatively. Although we have a protocol where we use contrast enhanced ultrasound to assess antegrade drainage, if the patients are stone free or have less than two millimeter residual fragments.

So, in other words, if all we need to do is establish whether or not patients are draining, we use contrast enhanced ultrasound. If they have a significant residual stone leftover, that I will take them back to the operating room for anything two millimeters or greater, then I like to have the anatomy that an antegrade nephrostogram provides.

Because between a CT and an antegrade nephrostogram, I can pretty precisely identify where that residual stone is located. And it gives me so much more information for when I go back for my second look that I know that that stone is anterior to my calyx of entry or it's the next most superior calyx. I really kind of know where I need to go. So, I like to have a contrast study at that time if I'm going to go back for a second look.

But otherwise, contrast enhanced ultrasound has worked very well for us. We've rarely gotten burned on a contrast enhanced ultrasound that showed drainage and then patients subsequently had a problem. But occasionally, I mean, they can pass a clot down the ureter that may not have been there at the time of their contrast enhanced ultrasound.

(9) Dealing with Early and Delayed Postoperative Bleeds: Interventional Radiology Involvement, CTAs, & Arteriograms

[Dr. Aditya Bagrodia]
Okay, okay. So, hopefully, as to be the case, stone free, tubes coming out, tube comes out and you encounter bleeding. Can you walk us through kind of the management of your preferred way to deal with an early or even a delayed postoperative bleed?

[Dr. Margaret Pearle]
So, outside the operating room, typically, if we have, for instance, a council catheter in the kidney, which we advance over like a 5 French angiographic catheter into the bladder, we typically remove the council catheter first, leaving the angiographic catheter in place. So, if there's bleeding encountered immediately, you can just slip the council catheter back over the angiographic catheter into the collecting system. And that will almost always stop the bleeding until you can get interventional radiology.

So, we sort of give it just a little time before burning that angiographic catheter. In rare cases, and I've certainly had them through my career, we had to take them straight to interventional radiology because of a significant bleed. We've done so. But we've almost always been able to get a tube back in. So, we've had very few real sort of dire emergency, big bleeds that were critical in terms of wheeling pretty much down to IR right away.

But if you can get a nephrostomy tube back in, it'll generally stop and then we would subsequently take them to interventional radiology. And I think the key, in terms of arteriograms, is that you sometimes have to deflate the balloon to find the bleeder or find the pseudoaneurysm, or you have to back the nephrostomy tube out. So, again, we'll put a wire down our angiographic catheter.

And then if they do an arteriogram on a first run and don't see a bleed, then we deflate the balloon and then we back the nephrostomy tube out. And sometimes, there's significant bleeding as you back it out, but you're not going to be able to find the pseudoaneurysm sometimes until you get the tube out of the way. So, we're always kind of prepared to do that. And our interventional radiologists are aware that they may need to contact us to come and move the tube if need be.

[Dr. Aditya Bagrodia]
Okay. And if it's a little bit more equivocal, do you have any strong opinions on going straight to IR versus getting like a CT angio? Just to kind of delineate things.

[Dr. Margaret Pearle]
Yeah, that's an ongoing controversy. The interventional radiologist almost always will ask for a CTA. And we tend to not like it because it's a contrast load. And it's a contrast load that I still don't trust if it's negative. If the CTA is negative, I don't know that an arteriogram is negative. And really, there's no good literature on it. There are no prospective studies that do both.

And I think that's what you really need. You need to do a CTA and then you need to take them into an arteriogram because I don't trust it. I mean, I've had patients that I've insisted on as many as three arteriograms, saying it comes back negative twice. It's like, "Look, this patient has a pseudoaneurysm." I mean, they're bleeding episodically. This is clearly an arteriogram. And on the third try, they find it.

So, Jose, I'm sure you can speak to this. But the CTA always worries me because, if it’s negative and somebody is coming back with a classic bleed, I'm not going to trust it till they have an arteriogram. I'm worried about sending someone home with a possibility of another big bleed at home until I know that the arteriogram is negative, and that's not 100% either. I don't know. I'd be interested in hearing your opinion about CTA versus going straight to an arteriogram.

[Dr. Jose Silva]
So, like you said, interventional radiologists would always ask for a CTA first. So, I mean, I usually let them decide. And then, the patient will need the arteriogram because they continue the bleeding, dropping hemoglobin, so eventually, they're doing the arteriogram anyway. But it's a matter of just not fighting, I guess.

[Dr. Margaret Pearle]
Right. It's an ongoing battle. I just feel like it delays the inevitable. I mean, the argument is if they can identify pseudoaneurysm on a CTA, then when they do an arteriogram, they can use less contrast because they kind of know where to look for it.

But in patients who already have some compromised renal function, I'm always concerned about giving them two contrast loads in a row, basically. And I just feel like it's just delaying the inevitable and maybe wasting some valuable time and encountering more blood loss in the process. We're looking at that. We've actually been trying to sort of retrospectively look at our series.

The problem is you have to have done both on everybody until you really know. You've got to have the full denominator to really know if an arteriogram is picking up leads at the CTA doesn't.

[Dr. Aditya Bagrodia]
Another complication that I would say is not common or that uncommon, hydrothorax, they've got a tube in, whether that was intraoperatively placed by you or picked up and placed with IR. Can you just give us broad strokes about your algorithm in terms of timing of x-rays tube removal when you think it's safe to get the patient out?

[Dr. Margaret Pearle]
Yeah. So, if I put an 8 or 10 French Cope Loop drainage tube into the chest, say intraoperatively, I put it to wall suction overnight, not because I'm worried about a pneumothorax. Occasionally you'll have a pneumothorax, mostly not. So, I'm not so worried about that. I just want to maximize the drainage.

The next morning, I'll check a chest x-ray. And if it looks like the chest is well drained, then I take it off. I just put it to water seal and watch for drainage. Whenever the drainage from the chest tube ceases and a chest x-ray is negative, then I pull it out.

And I would say more often than not, it's 24 hours. And usually, there's a lot of drainage at first, and then it just slows down and stops overnight. So, I'd say it costs an extra day to two days in the hospital. So I try to get the nephrostomy tube out right away once I have a chest tube and I want the nephrostomy tube out because nothing's happening until you stop traversing the pleural space.

So, I think it's just a matter of waiting till there's no more drainage and then assuring that there's no fluid accumulating in the chest which would explain the fact that you're not seeing any more drainage. The chest x-ray is good, there's no more drainage, then I pull the tube out, and wait four or five hours, repeat a chest x-ray. And if it's okay, the patient goes home. So, it's an extra 24 or 48 hour process.

[Dr. Aditya Bagrodia]
Okay, okay. So, as these patients get out and convalesce, they are getting full metabolic evaluations. They're going to get a stone composition analysis and receive appropriate counseling to prevent these stones that really do require a lot of work to get them stone free. Is that fair?

[Dr. Margaret Pearle]
Yeah, absolutely. I mean for the most part, anybody who's requiring a PCNL is going to have probably a significant enough stone burden, even if it's their first stone, to warrant metabolic evaluation. So, I typically will do follow-up imaging about six to eight weeks after PCNL, just an ultrasound on KUB. And at that point, I initiate a metabolic evaluation, have them collect two 24-hour urines. I do a screening. I do screening bloodwork at the time I initially see them even before surgery just to assure that they don't have any suggestion of underlying conditions associated with stones like renal tubular acidosis or primary hyperparathyroidism.

[Dr. Aditya Bagrodia]
Tremendous. So, Peggy, I mean, an absolute wealth of information. Really, really enjoyed it--a nostalgic walk down memory lane. Any kind of take home messages for general urologist, trainees, people interested in endourology, that kind of you'd like to leave as parting thoughts?

[Dr. Margaret Pearle]
Yeah, I mean, I think PCNL is a really important part of our armamentarium now. There's maybe a trend toward more and more ureteroscopy. Ralph Clayman likes to sort of promote, provoke controversy in saying that PCNL is dead because as we're getting better and better ureteroscopically and the ability to use larger access sheaths, maybe it makes a difference.

But I also think as we've decreased the morbidity of PCNL with mini-PCNL and micro-PCNL and ultramini, I think we lower the threshold for performing procedures in an antegrade fashion and I think anything that avoids the use of a stent, if you can avoid the use of a stent, is a win in patient's eyes.

So, I think it's an important skill to have. I think if you really want to treat stones, you need to have that available or you're sort of doing patients a disservice if you don't offer it. So, I think in training more and more programs, I think they are exposed to more and more PCNL. And it just lets you be a bit more comprehensive stone doctor in the end. So, it's an important skill to learn.

And the more you do, the better you are at it, and the less daunting a procedure it is. So, it's just a matter of numbers. And I think in any practice, there's probably a fair number of patients that need to be treated percutaneously that could keep your skills up in the course of a year, for instance.

[Dr. Aditya Bagrodia]
Amazing. Yeah, I think learning curve, education, number of reps, these are all fascinating topics that you've actually I think studied and published on over the course of your career. So, thank you for your insight. Thank you for your perspective. We really, really appreciate it. And thanks for the audience, of course.

Podcast Contributors

Dr. Margaret Pearle discusses Tips & Tricks for Percutaneous Nephrolithotomy (PCNL) on the BackTable 9 Podcast

Dr. Margaret Pearle

Dr. Margaret Pearl is a Professor and Vice Chair of Urology at UT Southwestern Medical Center in Dallas, TX.

Dr. Aditya Bagrodia discusses Tips & Tricks for Percutaneous Nephrolithotomy (PCNL) on the BackTable 9 Podcast

Dr. Aditya Bagrodia

Dr. Aditya Bagrodia is an associate professor of urology and genitourinary oncology team leader at UC San Diego Health in California and adjunct professor of urology at UT Southwestern.

Dr. Jose Silva discusses Tips & Tricks for Percutaneous Nephrolithotomy (PCNL) on the BackTable 9 Podcast

Dr. Jose Silva

Dr. Jose Silva is a board certified urologist practicing in Central Florida.

Cite This Podcast

BackTable, LLC (Producer). (2021, June 16). Ep. 9 – Tips & Tricks for Percutaneous Nephrolithotomy (PCNL) [Audio podcast]. Retrieved from

Disclaimer: The Materials available on are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.

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Tips & Tricks for Difficult Ureteroscopy with Dr. Jodi Antonelli and Dr. Aditya Bagrodia on the BackTable Urology Podcast)
New Technologies for Prostate Screening with Dr. Ali Kasraeian on the BackTable Urology Podcast)


PCNL nephrostomy tube placement for kidney stones

PCNL Nephrostomy Tube Placement For Kidney Stones

PCNL Surgery Procedure Steps & Techniques for kidney stones

PCNL Surgery Procedure Steps & Techniques


Kidney Stones Condition Overview
Nephrostomy Tube Insertion Procedure Prep
Percutaneous Nephrolithotomy (PCNL) Procedure Prep
Ureteral Stent Placement Procedure Prep
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