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BackTable / Urology / Article
A Surgeon’s Guide to Retrograde PCNL: Procedure Techniques & Clinical Pearls
Kaitlin Sheppard • Updated Apr 1, 2025 • 40 hits
Percutaneous nephrolithotomy (PCNL) is a minimally invasive procedure for removing large or complex kidney stones. Retrograde PCNL offers an alternative access approach that can be advantageous in select patients, particularly those with challenging anatomy or those requiring supine positioning. In this article, urologist Dr. Julio Davalos shares his retrograde PCNL technique, including key steps for access, visualization, and efficient stone clearance.
This article features excerpts from the BackTable Urology Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable Urology Brief
• Retrograde PCNL optimizes access precision by aligning the puncture trajectory with the infundibulum, reducing renal trauma and minimizing bleeding.
• Patient selection is critical, factoring in stone size, density, and configuration, as well as patient preference and anatomical feasibility.
• Supine positioning offers advantages by maintaining alignment with preoperative CT imaging, improving procedural ergonomics, and facilitating simultaneous ureteroscopic and percutaneous manipulation.
• Intraoperative planning integrates three key domains—CT imaging, retrograde pyelography, and direct ureteroscopic visualization—to refine puncture strategy and optimize stone clearance.
• Because the initial puncture wire is prone to kinking, it should be carefully exchanged for a more durable endourology wire to ensure smooth tract dilation and minimize procedural disruptions.
• Clear nephroscopic visualization in retrograde PCNL reduces the need for nephrostomy placement in most cases.
Table of Contents
(1) Who is the Ideal Retrograde PCNL Candidate?
(2) A Stepwise Approach to Supine Access & Puncture in Retrograde PCNL
(3) Minimizing Bleeding & Trauma in Retrograde PCNL
(4) Exit Strategies & Follow-Up in Retrograde PCNL
Who is the Ideal Retrograde PCNL Candidate?
The decision to perform a percutaneous nephrolithotomy (PCNL) is influenced by more than just stone size. Factors such as stone hardness, density, and configuration, as well as patient preference and clinical circumstances, shape the treatment strategy. While PCNL offers a one-stage solution for large or complex stones, some patients may prefer staged ureteroscopy due to differences in risk profiles. Massively obese patients and those with challenging renal anatomy may not be ideal PCNL candidates, often prompting an initial ureteroscopic approach with the flexibility to convert to PCNL if stone fragmentation proves inadequate. Engaging patients in shared decision-making allows for tailored treatment strategies that optimize outcomes while balancing procedural risks and feasibility.
[Dr. Jose Silva]:
Jason, what are your criteria for PCNL in terms of stone size?
[Dr. Jason Wynberg]:
For me, it's not just the stone size. It's also the patients' wishes. I really do discuss with them what would they rather have. Two-stage procedures or one procedure. Sometimes somebody's got to go out of town and that would push us toward a PCNL, or you could go both ways. Sometimes the stone, you sense if it's a very hard stone or a soft stone. I don't really use a size criteria. I typically will give a good effort doing a ureteroscopy laser because as much as a PCNL can be done safely, generally speaking, if you can do a ureteroscopy laser in one or two cases, sometimes it's a fatigue assessment, because if you're going to spend hours lasering a stone, then boy, oh, boy, that's fatiguing.
[Dr. Jose Silva]:
Do you take how few units into consideration, or the stone density?
[Dr. Jason Wynberg]:
Yes, partly. I would say mostly size and configuration and patient wishes. I really do speak to the patients and say, "Look, there's certain risks you get with a PCNL, but I think they're acceptably low risks, or we could just laser you." I think patients are really good partners in making those types of decisions.
[Dr. Jose Silva]:
Exactly. What patient you wouldn't offer a PCNL? Is there a patient you wouldn't offer a PCNL?
[Dr. Jason Wynberg]:
I think so. I think we all think the same way. We all hate risk. If somebody looks like just a bad PCNL candidate, somebody who's massively obese, sometimes it's easier to just say, "Look, I'm just going to laser your stone twice and make sure I'm not going to embark on something," where you have truly a massively obese patient. You can see that on the CAT scan where the kidney looks very small compared to the size of the patient.
[Dr. Jose Silva]:
I do the same. I guess sometimes I start doing the ureteroscopy, but then those stones maybe don't break, so sometimes you end up just doing the PCNL at some point.
[Dr. Jason Wynberg]:
Exactly. You feel more comfortable converting the patient after you've really tried to do it from below.
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A Stepwise Approach to Supine Access & Puncture in Retrograde PCNL
The retrograde percutaneous nephrolithotomy technique offers a precise and streamlined approach for renal access, particularly in supine positioning. Patient selection begins in the clinic, where CT imaging helps assess renal anatomy, stone configuration, and access feasibility. A critical advantage of supine positioning is the direct translation of CT scan data to the operative field, avoiding the mental reorientation required in prone positioning.
Retrograde access is achieved by inserting a ureteroscope into the collecting system, advancing a puncture wire under direct visualization, and guiding it through the flank using minimal fluoroscopic imaging. Once the wire tents the skin, the operator transitions to percutaneous access, followed by wire exchange and tract dilation. This approach optimizes anatomic precision, improves ergonomics for simultaneous ureteroscopic and percutaneous manipulation, and simplifies wire handling for controlled dilation.
[Dr. Jose Silva]:
Jason, are you doing your own access?
[Dr. Jason Wynberg]:
Yes, I only do my own access. I don't do antegrade access. I frankly never developed that skill. Going back to the Detroit Medical Center, I spent the day with a world-renowned educator for antegrade puncture where I spent two days. I absorbed everything I could and I came back and I succeeded my first case. Got urine from my first puncture, but the wire fell out and I ended up not succeeding and I had to wake the patient up.
It was at that moment that I recalled my residency program, which is where the endourologist was Dr. Denis Hosking in Winnipeg. He used to use the old Cook Lawson set. My entire residency experience was doing retrograde access in a supine position. When I was in Detroit, and I had the opportunity to capture this line of business, and I was over one with my antegrade experience, I just went back to my experience as a resident and said, "You know what? I was doing them successfully as a resident in that other way." That really started a journey to continue with retrograde puncture.
[Dr. Jose Silva]:
Can you describe, how do you do it supine, and the process, how the patient is positioned for a retrograde access?
[Dr. Jason Wynberg]:
Sure. The first thing is, it really all begins in the clinic with a CT scan review. I prefer looking at the axial images because I can assess the renal rotation, overrotation, underrotation in the axial images. I study not only the stone configuration, but I try to assess the directionality of the infundibulae, and obviously, the perinephric fat and the rib renal relationship. Is it a high kidney, a low kidney? Is the 12th rib attenuated or is it very big and long? You can essentially get a very good sense of the procedure you're going to conduct while you're still in your clinic making a recommendation to the patient.
What you don't have at that moment is a retrograde pyelogram, which can affect your surgical plan significantly. The data from a retrograde can be acquired, either at the time of stent placement, days before your PCNL, or at the time of the PCNL. The decision-making for my puncture is really the assembly of the CT scan information and the retrograde pyelogram, and additionally, a flexible ureteroscope in the kidney. Those are the three domains of information that get assembled into a plan for puncture.
[Dr. Jose Silva]:
You mentioned that the patient is supine while you puncture them.
[Dr. Jason Wynberg]:
Yes, there's nothing wrong with doing a retrograde puncture prone, but there's benefits to the supine position in that so much of the planning is CT scan driven, and of course, the CT scan is acquired with the patient in the supine position. When you study your CAT scan and you're programming your mind and you have the patient in supine position, that data translates to the operating room better than if you put the patient prone where that information has to be rotated back in your mind, 180 degrees.
That's one of the big benefits of the supine position. It's also more amenable, of course, to access to the urethra if you use lithotomy, whatever method you use to access the urethra, whether you use Yellofin stirrups or other methods, it's a little bit easier, I think, in my hands, but other people have other experience, of course, to access from below and above at the same time.
Essentially, patient is positioned supine with some folded sheets under the hips and the shoulders. It's the Barts flank-free position with the ipsilateral arm over a pillow over the chest. Essentially, I put a ureteral access sheath in for ureteroscopy, shoot a retrograde, and then put a flexible ureteroscope into the kidney. Your positioning of the ureteroscope is direct vision and pyelography. When you add those two fields of information to your CAT scan data, you know what you're going to do.
Then there's a puncture wire that is advanced through the working channel of the ureteroscope. An assistant does it, a nurse, or a resident. You don't need skilled assistance for that. The puncture wire is shielded in tip protectors like a long thin Teflon catheter so that while the ureteroscope is held in position for puncture, that puncture-wired device is advanced through the working channel of the ureteroscope until the tip emerges out of the ureteroscope and you see that under direct vision on endoscopy.
Once that comes out, the assistant will unlock a pin vise, which allows the wire to be advanced. Then under the surgeon's verbal direction, the assistant will advance the wire with a very few fluoroscopy shots. You can see the wire advancing through the flank, and you can follow that along the wire advancing with the C-arm by moving the C-arm laterally. AP only. You don't use multi-plane C-arm. It's just single plane.
When you see that the wires tend to the skin, I typically have my assistant hold the handle of the ureteroscope while I leave from between the legs and core on the side and usually, you see the skin tenting and it's consistently in a good location. You cut the skin and capture the wire, and then you've achieved a puncture.
[Dr. Jose Silva]:
Then you just start dilating over the wire.
[Dr. Jason Wynberg]:
Yes. The puncture wire is stainless steel and it has a propensity to kink. It's designed for puncture. It's not really designed for endourology. At that point, you just go through a couple of steps to exchange that puncture wire for an endourology wire of your choice. That's done with a separate catheter at the flank.
Minimizing Bleeding & Trauma in Retrograde PCNL
Retrograde PCNL leverages direct ureteroscopic visualization to optimize access by aligning the puncture with the infundibular long axis. This approach ensures that wire placement, tract dilation, and sheath docking follow a predictable path, reducing the likelihood of parenchymal injury and minimizing bleeding. By using the ureteroscope to establish the ideal entry point at the papilla, this technique provides a controlled puncture and limits vascular disruption.
While procedural bleeding can still occur from over-advancing the balloon or intraoperative nephroscopy trauma, the structured alignment of the retrograde approach inherently enhances safety and efficiency. Proper wire exchanges and careful sheath placement further reinforce stability, reducing the risk of kinking and facilitating a seamless transition from access to stone extraction, as Dr. Wynberg explains.
[Dr. Jose Silva]:
Jason, in terms of the procedure per se or using the retrograde fashion, is there a difference in terms of safety or bleeding in terms of the patient?
[Dr. Jason Wynberg]:
I can speak from my experience and I can speak from some anatomic concepts. When you have a ureteroscope that is staring at a papilla, the ureteroscope is in the infundibulum. If the infundibulum is two or three centimeters or whatever, 15 millimeters to 30 millimeters in length, that infundibulum long axis has three coordinates, X, Y, Z in space. When your ureteroscope is in that long axis of the infundibulum to allow you to stare at the papilla with your ureteroscope, your flexible ureteroscope has matched perfectly the infundibular long axis.
It's the ureteroscope that creates the safety. It's not the papillary puncture. Because your ureteroscope is matching the long axis of your infundibulum, the wire that travels through the working channel matches the long axis of the infundibulum and all of the series of exchanges that follow which manifest with a balloon and a nephrostomy sheath or mini-perc set, those will always dock into the infundibulum, matching the long axis, which means that from a surgical experience, aesthetic standpoint, there's always certainty that when you take your balloon down and you remove it from your sheath, for example, there's different technologies, of course, mini-perc, et cetera. You just don't see blood come out. You see air, nothing. It's dry. Maybe you get a bit of urine.
I think that the renal trauma is diminished by virtue of that. Of course, it's a papillary puncture, but it's more than a papillary puncture. It's a papillary puncture that's aligned with the infundibula. Now, of course, there's other ways that you can have bleeding just because you ask about bleeding. If you over-advance your balloon and you sneeze, you'll get bleeding. Of course, if during your nephroscopy, you can cause bleeding. From a tract creation standpoint, I think this is a superior method of nephroscopy creation from an anatomic standpoint.
Exit Strategies & Follow-Up in Retrograde PCNL
Postoperative management following retrograde PCNL hinges on precise tract closure and strategic stent placement to minimize complications and facilitate recovery. Given the consistent clarity of the nephroscopic field, nephrostomy placement is rarely required, and most patients can be managed with a ureteral stent and same-day discharge. A Foley catheter is typically used intraoperatively to assess for bleeding before removal in the post-anesthesia care unit. Ensuring the stent is independent of the nephrostomy tract prevents complications and streamlines postoperative monitoring.
For urologists interested in adopting this technique, proctoring, case observations, and peer-to-peer learning provide valuable support for integrating retrograde PCNL into clinical practice.
[Dr. Jose Silva]:
Do you usually put a stent afterwards or a nephrostomy and for how long?
[Dr. Jason Wynberg]:
Because these are generally a clear view, when your nephroscope goes in, it's quite a pleasurable experience that you have no intrarenal collecting system bleeding consistently. You can really work and get as much of the stone from your access site as possible, and so the vast majority of our cases, we have exhausted the potential of the track that we created.
If for some reason we had to abort the case, which frankly doesn't happen, but just to show the other side, and you say, "There's so much potential in this track left and I just couldn't do it," then I would want to keep my access. The vast majority of the time, the tract has been maximized and exhausted, the potential of the tract. My personal practice is to remove the sheath and there's no named vessels where we puncture. There's no named vessels, meaning, there are just small vessels for the parenchyma that is behind the papilla.
I use a 24-French nephrostomy sheath in almost every case. It's a fairly small renal injury and I normally just pull the sheath out and then close the skin with Monocryl. I do put in a stent and a Foley, and then in PACU, I can know exactly what's going on with any bleeding or no bleeding or a little bit of bleeding. Then I'll often leave them there for a few hours and make a judgment. If the urine is light pink, light peach color, like no blood at all, and the case was nothing, then I would send them home. I think I send home most people the same day.
[Dr. Jose Silva]:
With the Foley and the stent?
[Dr. Jason Wynberg]:
I'll take the Foley out. The Foley serves really just as a window so I don't have to have a visit to the patient and have no idea because there's no Foley. The Foley is just really a tool for me to know what's happening.
[Dr. Jose Silva]:
During the procedure, while you're closing the back, the patient still has the ureteral access sheath.
[Dr. Jason Wynberg]:
You mean, how do I actually exit?
[Dr. Jose Silva]:
Let's say, you already pulled the nephroscope out and the sheath and you close the skin. At that time, does the patient already has the stent inside?
[Dr. Jason Wynberg]:
I usually have a juncture where I have two wires in, where I have a wire from below. I stent from below, just like if you're on call, putting a stent in a patient with a ureterocele. Through my ureteral access sheath, I throw a second wire into the upper pole. The beauty of that is I know that my stent will have nothing to do with my nephrostomy tract.
At the end of a case, if you do an antegrade stent placement, it can be very annoying if you don't know if you're in the tract or not. By throwing a wire up to the upper pole from below, it's just a simple stent. I'll have one point where I'm exiting where I'll have just two wires, one wire up in the upper pole and one wire going down. I'll remove the nephrostomy wire inside of a ureteral catheter just to make it smooth and easy. Then I only have one wire in for my stent, and then I just put a regular stent with a cystoscope in and a Foley.
[Dr. Jose Silva]:
Interesting. For the urologists out there that are not familiar with or haven't trained, for example, for me, I haven't done any retrograde cases. I trained in antegrade and that's what I do. What do you recommend? Can we go and see you, something like that?
[Dr. Jason Wynberg]:
Sure. Of course. Yes. There's several people who are doing this around the country that are more than happy to teach. I think that it's worth noting that every urologist that's doing PCNL is bringing tremendous amount of skill and knowledge to the case. It's not just the access. It's everything that follows, like put the balloon, the sheath, the nephroscopy, the lithotripsy.
Tremendous respect for everybody who's doing PCNLs. The reason I'm partly saying that is that just because this kit and retrograde technique can allow a less experienced endourologist or a general urologist to do PCNL, it's very wise to partner with somebody if you don't have experience doing the second part of the procedure because there's lots of risk that's managed by skilled surgeons doing PCNLs.
There's lots of people doing the retrograde access. I think the learning curve is really two domains. The first domain is the careful CT scan study and planning, and assembling that with a retrograde, so you really have confidence with what you're going to experience. I think the second thing is just wire handling, and that takes a couple of cases. There's many surgeons who have a proctor come to them. There's many surgeons who go and see somebody. I think that universally, we have people with very good experiences.
Podcast Contributors
Dr. Jason Wynberg
Dr. Jason Wynberg is the director of endourology at NYU Langone Health in Brooklyn, New York
Dr. Jose Silva
Dr. Jose Silva is a board certified urologist practicing in Central Florida.
Cite This Podcast
BackTable, LLC (Producer). (2023, March 1). Ep. 84 – Novel Approach to PCNLs [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com 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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