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BackTable / VI / Article
Percutaneous Nephrostomy for a Dilated Collecting System
Lauren Fang • Mar 16, 2021 • 376 hits
A percutaneous nephrostomy is a surgical procedure to drain urine from a kidney. Indications for nephrostomy tube placement include urinary diversion and access for further urologic interventions such as percutaneous nephrolithotomy. Interventional radiologist Dr. David Field discusses the basics of a percutaneous nephrostomy procedure prep and technique used in a dilated collecting system, tips for working through challenges and preventing complications, as well as post-procedure care.
We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable Brief
• Urinary obstruction caused by a stone or tumor is the most common indication for nephrostomy tube placement. Referrals come from urologists who have tried to place a stent from below and were unsuccessful, oncologists whose patients have developed hydronephrosis as a result of a pelvic tumor, or emergency medicine physicians who have a septic patient with an obstructing urinary stone.
• Percutaneous nephrostomy pre-procedure workup includes examining previous CT scans to locate the relative positions of the colon, kidney, and ribs and an ultrasound scan prior to prepping the patient. Dr. Field gives patients Ceftriaxone pre-procedurally and looks at recent coagulation levels (platelets 50k or higher and INR < 1.8).
• Dr. Field uses a single stick technique for a dilated collecting system percutaneous nephrostomy. On his backtable are a 21-gauge INRAD needle, an AccuStick set, a 0.018” guidewire, an Amplatz short wire to get the floppy coil in the renal pelvis before dilating, and an 8.5 Fr Cook multipurpose drainage system.
• Pitfalls during standard nephrostomy tube placement include overpressurizing an infected kidney, causing worsening sepsis. A common challenge is passing wire around stones that fill the collecting system. Dr. Field recommends several solutions: try different wires such as stiff GLIDEWIRE or .018” Nitrex, inject more saline and/or dilute contrast to pump up the collecting system, or go directly through the stone with the INRAD needle.
• Nephrostomy tube placement post-op care involves monitoring for bleeding and appropriate urine output. Patients with non-healing perineal wounds secondary to urinary leakage who need permanent urinary diversion may require ureteral occlusion if simple diversion via nephrostomy tube does not suffice. Dr. Field occludes the ureters at the time of first access or several weeks after by using an 11-millimeter ArtVentive vascular EOS plug.
Table of Contents
(1) Referrals & Indications for Percutaneous Nephrostomy
(2) Percutaneous Nephrostomy Procedure Prep
(3) Dilated Collecting System Percutaneous Nephrostomy Placement
(4) Pitfalls and Challenges
(5) Post-op Care and Follow-up
Referrals & Indications for Percutaneous Nephrostomy
Urinary obstruction caused by a stone or tumor is the most common indication for nephrostomy tube placement. Dr. Field’s referrals for percutaneous nephrostomy mostly come from urology or the ER, and he receives both emergent and non-emergent cases.
[Aaron Fritts]
We have a lot of trainee listeners. Can you talk through just the placement of a regular neph tube, the most common indications? Where are those referrals coming from?
[David Field]
Sure. The absolute most common indication is urinary obstruction, whether that's from a stone or from a tumor. It doesn't really make a whole lot of difference for the fact that there is hydronephrosis, so most of the come from either urologists who have tried to place a stent from below and were unsuccessful, or from oncologists whose patients have developed hydronephrosis. Some of them come from the ER with urology on board as well for obstructing stones, and obviously with a great deal of variety in terms of urgency. The septic patient with an obstructing urinary stone, it's an emergency; the patient who has a hydronephrosis that has gotten slowly worse because of an obstructing pelvic tumor, it's not quite so urgent. What it comes down to, it's basically the same procedure.
[Aaron Fritts]
Both of those referrals come in from urology and maybe even the ER, GYN?
[David Field]
Yep. Not a lot from GYN, some from GYN onc, but mostly urology is probably the most common and it's certainly where we are pretty good about taking patients in the middle of the night if they have a stone that they tried to get passed from below. I don't think they dump patients on us.
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Percutaneous Nephrostomy Procedure Prep
Dr. Field prefers to ultrasound the patient before nephrostomy tube placement to have a good idea of where he will obtain access with the needle. He also examines previous CT scans to locate the relative positions of the colon, kidney, and ribs. Dr. Field gives patients Ceftriaxone pre-procedurally and looks at recent coagulation levels (platelets 50k or higher and INR < 1.8).
[David Field]
We do percutaneous nephrostomy, for a dilated system, under ultrasound guidance 99% of the time. I think it's very important to scan the patient in the room before the patient is prepped. A lot of times, techs will like to get their patient prepped and then you're left with a window there that is really of their choosing, so I really try to ultrasound the patient ahead of time and have a very good idea of the pathway and a very good idea of where we're going to stick on the skin before proceeding, certainly looking at prior imaging. Almost all these patients have CTs ahead of time. Even if it's non-contrast, that's fine, but it's very important to know where the colon is, obviously, how far in you're going to have get to into the kidney, what the angle is, where the kidney is related to where the ribs are, and having that in your head before you even scan the patient is important.
[Aaron Fritts]
With the pre-prep imaging, are you marking exactly where you think you're going to go in?
[David Field]
Yes. Before they prep, I will mark on the skin where I intend to start the needle, and I will mark off where I intend to put the probe so that they know where I need space, because nothing's more annoying than needing to ultrasound where there's a drape because you can't see through the drape, and you need a pretty big window in the draping, so I will let them know where I'm sticking, where the probe's going to be so it doesn't come back to bite you later.
[Aaron Fritts]
What labs are essential coags, and then what are you doing for antibiotics?
[David Field]
We used to give Cipro, but that's not the greatest anymore, so we've been giving ceftriaxone immediately pre-procedurally these days, which has been working well. Yeah, obviously, you need to know their recent coags. I think the latest guidelines suggest that an INR of 1.8 or lower is fine, so above that we would correct with FFP or whatever needs to be corrected, and platelets 50 or higher is fine.
[Aaron Fritts]
What about a patient who's been on aspirin?
[David Field]
Baby aspirin, don't care, but certainly 325 aspirin or Plavix or any of the platelet inhibitors, optimally, would be a five-day hold, but obviously if the patient is infected, you can't wait that long, so you have to balance the emergent nature of the procedure with how sick they are.
Dilated Collecting System Percutaneous Nephrostomy Placement
Dr. Field uses a single stick technique for a dilated collecting system percutaneous nephrostomy. He starts with a high-quality ultrasound and uses a 21-gauge INRAD needle. Once the needle is in the retroperitoneal fat and both the kidney and target are visualized, he uses a 0.018" Nitrex wire or the 0.018" wire that comes in the AccuStick set to get down the ureter. After injecting the AccuStick and getting to the renal pelvis, Dr. Field uses an Amplatz short wire to get the floppy coil in before dilating and inserting a Cook multipurpose drain.
[Aaron Fritts]
I did want to quickly walk through the placement of just a very straightforward dilated collecting system neph tube. Maybe talk a little bit about single stick versus double stick technique and what you prefer.
[David Field]
I definitely prefer the single stick. I remember being, certainly as a resident, a little bit intimidated by a percutaneous nephrostomy. I'm not really quite sure why, but when it comes down to it, it's really just a drain. The trick is that the target is often a little smaller than it would be for a, like an abcess drain for example, and it also is moving. It's a moving target because the patient is breathing, obviously, or hopefully, and so when the kidney is moving, it can be harder to stick.
[Aaron Fritts]
What's on your back table, and how do you get the drain in from there?
[David Field]
We make sure we use a good high-quality ultrasound, obviously, first; the diagnostic ultrasound machine, not one that we'd use for, say, just like easy vascular access. I like to use the INRAD needles for this. I typically use their 21-gauge INRAD, and the INRAD needle has the scored stylet that has scoring over the last couple of centimeters so that it makes it very, very easy to see under ultrasound. Certainly if the patient is large, some people just don't image very well, it can be very easy to lose the tip of a needle in the retroperitoneal fat and using the INRAD needle is a huge help. The trick is seeing your needle the whole way and I'll see a lot of trainees who will start the needle, and advance, and advance, and then they'll look for it. If you don't see it all the way in, it's going to be hard to find later on. Once you have your needle in the retroperitoneal fat and you can see the kidney, you can see your target, at that point, it's important to go very definitively because next time the patient takes a breath, the posterior lower pole calyx, which is hopefully dilated, will move and then you can't see it. If you can see it, and you can see your needle, then it should be one definitive move through the cortex and into the calyx. We always do these from posterior inferior, or almost always, and then once you can visualize the tip of your needle in the calyx, I will take the stylet out and if I get urine back, I don't inject at that point. I put the wire in under fluoro and if the wire goes down what can only be the ureter, I don't inject at that point because certainly if the patient's infected, you don't want to overpressurize the system. Then I usually use a 0.018" Nitrex wire, or the 0.018" wire that comes in the AccuStick set, but I think the 0.018" Nitrex is just a little bit better. I try to get it down the ureter before I dilate up with the AccuStick. Sometimes I won't go, but at least make sure you have enough stiff wire in the renal pelvis so you can upsize.
[Aaron Fritts]
Now you're at dilating.
[David Field]
Right. Under fluoro, get the AccuStick set in, keeping the wire very straight, and the AccuStick set that we have, there's a radiopaque marker on it. The tip of the set actually sticks out a little farther, so if you overadvance it, it can make making the turn a little bit difficult. You've just got to make sure you get the metal part through the renal cortex before teeing off the first tee off and then get the final tee off into the renal pelvis. Then at that point, take everything out and you should get copious urine back. I will always inject at that time just enough to prove that the AccuStick set is in the renal pelvis and that you can get a good idea of your course through the renal parenchyma.
[Aaron Fritts]
Yeah, do you guys collect samples of the urine and send that off ever?
[David Field]
Absolutely, often, especially if a patient is obstructed and infected definitely. The flip side of not overpressurizing the system--if you decompress the system, then it's hard to work in, so you want to leave enough hydro that you can get your wire in and get your tube in behind it. If it's really dilated, I'll send a sample once we get the AccuStick set in or you can also just send it off the tube after you get the tube in.
[Aaron Fritts]
A lot of times that urine can be a little bit blood tinged, right, because of all the manipulation. For the new IR or the trainee, that was one thing that was kind of hard to get used to is how much blood is worrisome.
[David Field]
Kool-Aid is absolutely fine. If it's frank blood, it's a problem. If you get your tube in and it's just a venous bleed, it'll probably tamponade. If you've made one stick with a 21-gauge needle, the chances of really having a significant bleed are pretty low… I also wanted to say if you make a stick with your 21-gauge needle and you think you're in, but you're not, the tendency is to inject a lot of contrast. I've seen a lot of trainees who will inject some. It's not a calyx. I certainly did this a lot. I would be like, "Oh, maybe it is. Maybe I'll inject some more and maybe it'll look like a calyx." It’s fine to, sort of, puff your needle back very gently, but if you inject a lot of contrast trying to show that you're in and you're really not, it's just going to make things harder for you down the road because there's invariably a little bit of air in with the contrast so it's going to make ultrasound very hard, fluoroscopically, it's going to obscure things, so I think it's important to, if you're not in, just go back to ultrasound, try it again, and not inject too much contrast into the perinephric space.
[Aaron Fritts]
Yeah, I think that's really good advice because I've seen it'll just look like a bomb went off. And especially with the non-distended collective system, but like you said, there's a big stone in there and you're, sort of, injecting contrast and then you have no idea where you're going.
[David Field]
Right, and then later one, you can be in, you can be injecting, but you won't be able to see it.
[Aaron Fritts]
Then you take your picture, right?
[David Field]
Right, you inject the AccuStick in and just try to make sure that you are in the renal pelvis, and at that point, then you have to get your wire in, and we just use an Amplatz wire, short Amplatz and once the floppy coil is in the renal pelvis, then it's just a matter of dilating and then just put in usually an 8-1/2 French, a Cook multipurpose drain.
[Aaron Fritts]
Okay. If it's like a frank pus, do you ever upsize?
[David Field]
Yeah, sometimes we'll go to 10, sure, but, of course, every time you dilate and take out the dilator and put in the next stylet, you're also going to expose the bloodstream to the pus there, right? That's a little more manipulation, and it just depends. It's easy to upsize later. I wouldn't really go past 10 to a French.
Pitfalls and Challenges
A common pitfall during standard nephrostomy tube placement is overpressurizing, which can lead to bacteremia and sepsis. Another is establishing percutaneous access for lithotripsy before confirming the point of access with the urologist. Passing the wire around stones that fill the collecting system may be challenging. However, Dr. Field recommends several solutions: try different wires such as stiff GLIDEWIRE or .018” Nitrex, inject more saline and/or dilute contrast to pump up the collecting system, or go directly through the stone with the INRAD needle.
[Aaron Fritts]
What's the danger of overpressurizing?
[David Field]
Right, if the patient is infected and then you inject, overpressurize the system, you can cause a great deal of bacteremia and sepsis and the patient can start rigoring right in front of your eyes. It can go from bad to worse very quickly.
[Aaron Fritts]
If you've done at least a few neph tubes, you've seen that happen.
[David Field]
Yeah. That, or with biliary drains as well. I think it happens a little more often with biliary drains in my experience.
[Aaron Fritts]
If the stone fills the collecting system and I know I'm in, but I can't get my wire to pass because you can't get around the crunchy stone, what do you do in those kinds of issues?
[David Field]
Just keep trying, and use different wires. If something doesn't work, don't keep trying it. Try something else. If you have enough stiff wire to get your AccuStick set in, then you can almost always get it. Glide wire, Stiff Glide. 018” Nitrex, I think is really good for getting past stones. You can also, if you are able to once you're in, you can pump up the collecting system by just injecting more saline or contrast, or both, right, dilute contrast. You don't want to obscure your wire. But you can also, if you know that you're in, you can pump it up.
[Aaron Fritts]
Yeah, it's like you kind of know if you're in or not if you get that resistance or not. I would always try a little bit of saline just to create some space around the stone and then try to wire again real quick.
[David Field]
Right, right. A couple of times I've actually gotten through a stone with like the INRAD needle or whatever we're using, and if you're doing it for a urology access, they don't usually mind that because you're just basically leaving them a pathway to get to the stone. They just need solid access to the bladder, right, so if you go through a stone, they're fine with that. I certainly would say before I do any perc access for lithotripsy, I always make sure that I know exactly where the urologist wants to approach the stone, make sure everybody's on the same page about access point.
[Aaron Fritts]
That's a very good point. Starting out, I made the mistake of not calling the urologist ahead of time-
[David Field]
Ah!
[Aaron Fritts]
And I would just put it where I thought they were wanting to go based on experience and then I got some angry phone calls and so I just made a policy like any of these stone ones for lithotripsy, I just call the urologist ahead of time and say, "Hey, I'm looking at the CT right now, where would you like this access?", and usually they really appreciate you asking them.
[David Field]
Absolutely, and you develop relationships with them and then everybody's much happier.
[Aaron Fritts]
Do you have anything to add for the trainee or any young people out there, any other pitfalls to avoid?
[David Field]
I typically will do standard nephrostomies with the 21-gauge needle and then an .018” wire and then the conversion to an .035” wire. I think it would be fine to do a very dilated perc neph in a not very fat patient with a 19-gauge INRAD needle and then go straight to an .035” system, especially if you are really in a rush, right, so you don't necessarily have to go conversion of an .018” to .035”, but certainly that's the way I trained, and probably you as well.
[Aaron Fritts]
Yeah. I mean, the obese patient with that dilator, you've got to have a track, a steady track to go over. In a skinny patient who is septic, and you just want to get a tube in real quick, I agree with you.
Post-op Care and Follow-up
Following nephrostomy tube placement, patients are monitored for bleeding and appropriate urine output. Nephrostomy tube exchanges are performed every three months. For patients requiring chronic urine diversion, Dr. Field occludes the ureters at the time of first access or several weeks after. He uses an 11 mm EOS vascular plug made by ArtVentive.
[Aaron Fritts]
How about postop care? Once you got the tube in, you get them cleaned up. What's to follow?
[David Field]
Well, we obviously check them. We follow them while they're in house, make sure they're not bleeding and that their urine clears over time, that their output is what it should be. Typically these are permanent tubes, so they will come for an exchange every three months. A lot of these patients who need diversion because they have radiation cystitis, or they have a pelvic tumor, or what have you, and need really permanent diversion. We have been occluding the ureters either at the same time we get the first access, or a couple of weeks later. The moment you have access to the collecting system, it's quite straightforward. We've been using this EOS plug that is made by ArtVentive, and it's actually a vascular plug, but it comes in an 11-millimeter size that works very well for occluding ureters. It's very easy to deploy. We basically get an Amplatz wire down the ureter and it goes in very nicely through a destination sheath, one of the Terumo destination sheaths, a six French sheath, and we get that sheath right down, sort of, two-thirds of the way down the ureter and then deploy this plug through the sheath. It's a two-step process of deployment and it has this, almost like a manual spring that opens up and it's PTFE covered so they're quite good at occluding ureters.
[Aaron Fritts]
That's just for the purpose of chronic diversion?
[David Field]
Yeah, patients who have non-healing wounds because they have urinary leakage or perineal wounds and who we know are going to need really permanent urinary diversion. Neph tubes will divert most of the flow. But, there's still the path of least resistance flow down the ureters for some of the urine, so if simple diversion is not enough, then ureteral occlusion can, sort of, finish the job. Typically, one plug per side, and it's a 20-minute thing and you're done.
[Aaron Fritts]
What should the expectation be in terms of the timing of clearing of the urine? When should you be worried when it doesn't clear?
[David Field]
If it's not clearing, I would make sure that you're checking the hemoglobin, right, and then see if the hemoglobin is falling at all. If it's not falling, then I wouldn't be too worried about it, but if there's a steady drop, then I'd be worried about a pseudoaneurysm or something like that. Sometimes, if we're really worried, we’ll do an actual renal angiography. You've got to pull the tube out like in a biliary. In almost all cases, it clears after a couple of days.
Podcast Contributors
Dr. David Field
Dr. David Field is a practicing Interventional Radiologist at MedStar Georgetown University Hospital in Washington DC.
Dr. Aaron Fritts
Dr. Aaron Fritts is a Co-Founder of BackTable and a practicing interventional radiologist in Dallas, Texas.
Cite This Podcast
BackTable, LLC (Producer). (2020, November 30). Ep. 97 – Nephrostomy Tube Placement: Basic to Advanced [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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