So take it away, Michael.
Michael Guralnick: Well, thank you, Dr. Wein. Happy to participate.
We did a review article on video urodynamics versus conventional urodynamics in the evaluation of neurogenic lower urinary tract dysfunction. Just to review neurogenic lower urinary tract dysfunction is an abnormal functioning of the lower urinary tract caused by underlying neurologic conditions such as spinal cord injury, multiple sclerosis, spinal dysraphism, such as spina bifida. The main concern with that condition is that it puts the upper and lower urinary tract at risk. The big fear is kidney dysfunction, scarring, hydronephrosis, as well as the potential for vesicoureteral reflux and urinary tract infections in addition to bladder storage and emptying dysfunction such as incontinence, urinary retention. And most concerning is actually excessive or high pressures in the bladder.
We evaluate lower urinary tract function using urodynamics testing, and that's just the diagnostic procedure test that assesses bladder storage and voiding function in order to help stratify the level of risk to the patient, basically looking at storage and voiding pressures, plus or minus external sphincter activity, to basically assess the safeness of the lower urinary tract with respect to those issues, as well as to evaluate incontinence and even urinary retention issues.
Conventional urodynamics, however, doesn't show you anatomy. So you don't have an idea about the bladder's morphology or the status of the bladder outlet either during storage or during voiding, as well as the presence or absence of vesicoureteral reflux. Those issues are obtained generally through cystography, X-ray imaging. But if you just do cystography, you don't really know the bladder dynamics at the time. You're not sure, are you in the storage phase? Are you in the voiding phase? And you have no idea what are the intravesical pressures at the moment that you're seeing those findings on cystography.
So video urodynamics combines conventional urodynamics testing with fluoroscopic imaging or cystography of the bladder to provide a synchronous assessment of both lower urinary tract function and anatomy, and it allows you to have a correlation between basically form and function. So we have a few images here showing the video urodynamics tracings and the video here. Here you see reflux in an open bladder neck, but the detrusor pressures are low. This is at the bladder at rest. So this is just a quiet bladder, and yet these are the findings. On this study, we're seeing the bladder having a contraction and you can see the bladder outlet is dilated with narrowing at the level of the external sphincter. This is external sphincter dysinergy and there's even reflux into an ejaculatory duct. Here we have a patient whose bladder is clearly abnormal looking. It's what we call the classic Christmas tree bladder with diverticula, including a big one at the apex. But this is actually during his voiding phase where you have a high pressure bladder contraction and very little opening of the bladder neck. This is actually a Parkinson's patient who has outlet obstruction. So this is what videourodynamics allows for.
Basically, we have here the findings that you can see on the video or the fluoroscopy that can involve the bladder, the kidneys or the ureters with reflux, the bladder base, the bladder neck, the urethra. And the importance here is, when it comes to reflux, are you dealing with reflux that's occurring with high bladder pressures or low bladder pressures? If there are diverticuli, these diverticuli can serve as essentially pop off valves that can dissipate pressure. If you saw low bladder pressures on urodynamics without seeing the cystography, you might miss the fact that it's maybe a bladder diverticulum that's keeping the bladder pressures low. And lastly, as far as the bladder outlet goes in the voiding phase, it can actually help you pinpoint the level of an obstruction. Is it at the bladder neck? Is it from in the prostatic urethra in a male or is it at the external sphincter allowing you to diagnose anatomic obstruction, as well as functional obstructions such as internal and external sphincter dyssynergia?
So the big question is, who should you consider videourodynamics in? And by and large, you're trying to make sure that the upper urinary tracts are safe. So you want to do it in patients who are going to be at risk for upper urinary tract issues. And these are generally spinal cord-injured patients, especially with suprasacral lesions because they're at higher risk for hostile bladder pressures and upper urinary tract damage. Patients with spinal dysraphism, which is obviously congenital, have a high frequency of congenital lower urinary tract anatomical abnormalities and are at increased risk for upper tract deterioration. In those cases, you really want to see what the anatomy is in association with the urodynamics parameters.
Obviously, anybody who already has upper urinary tract concerns, either hydronephrosis or atrophy or scarring, you'd like to determine is that a consequence of hostile storage pressures and maybe it's associated with reflux. Well, that's where video urodynamics can actually show you it. Most of the major urologic societies will actually recommend video urodynamics as the optimal procedure, at least for the initial evaluation, of high-risk neurourologic disorders. Obviously, if it's not available, you still want to at least do conventional, but if you have the ability to get the video as well, it provides you a more complete assessment.
Other indications in patients who have reflux, as I said, you'd like to know are you dealing with a defective anti-reflux mechanism at the UVJ, which would be considered primary or passive reflux, versus reflux that's only occurring because of high intravesical pressures. You might treat those differently. Someone who's got high intravesical pressures causing the reflux, improving their storage pressures will often get rid of the reflux, but that's not the case if it's a passive reflux.
In patients who you're contemplating reconstructive surgery, like a bladder augmentation, or if they already have known history of anomalies or previous lower urinary tract reconstruction, having the simultaneous video or cystography with the urodynamics pressures gives you that much more information, especially when it comes to the status of the bladder neck and someone, let's say, who you're considering a bladder augment, the big question is, well, do you need to do anything for the bladder outlet? Knowing what the status of the bladder neck is at rest can actually lead to changing your decision on whether or not to deal with the outlet.
Similarly, if someone has reflux and you're considering a bladder augment, you have to decide, do I need to re-implant the ureters or not? If the reflux is associated with high bladder pressures, i.e. it's secondary or active reflux, often just improving the storage pressures with the augment is good enough to alleviate the reflux and you don't have to worry about the ureters.
As I said, if you're looking to identify the location of outlet obstruction, that's where video really comes in handy because it allows you to differentiate a bladder neck obstruction that can occur with internal sphincter dyssynergy or in a patient with primary bladder neck obstruction versus anatomic obstruction and someone who has, let's say BPH versus external sphincter dyssynergy, which is very common in suprasacral spinal lesions. Video urodynamics allows you to make that determination.
Someone with recurring UTIs, especially afebrile, you want to know are their bladder pressures possibly contributing to it, but also, do they have reflux and is it occurring at various pressures? Video urodynamics allows you to assess that.
And finally, in patients who've had conventional urodynamics, but the findings on those urodynamics don't seem to fit the clinical presentation or if they're experiencing upper tract deterioration despite normal conventional urodynamics, it makes you wonder, were we being fooled by the conventional urodynamics because of perhaps some abnormality that could only be identified with the addition of fluoroscopy.
Now, as far as the research to prove all of this, it's actually rather limited, which is surprising that we don't have more research on it than we do, but the few presentations that have been made have shown that the addition of the fluoroscopy to conventional urodynamics does have the potential to impact the diagnosis, as well as the management. Francot et al found that two thirds of their patients had their management impacted with video urodynamics compared to conventional. More recently, Geretto et al found that the video urodynamics affected the diagnosis and altered treatment in about 20%, but even in the remainder, it allowed them to exclude risky pathology to help stratify these patients' risk. So it was still thought to be of benefit. On the other hand, Wyndaele and colleagues actually thought that the video added very little to the conventional urodynamics when renal imaging thought was normal. So normal kidney ultrasound, the addition of videourodynamics didn't add all that much over conventional. So clearly, we still don't have the full story, but I think there's still definitely some benefit that can be obtained, even if it just means reassuring yourself that you're not missing something.
Now, video urodynamics isn't universally available. It requires specialized equipment, fluoroscopy equipment, a room that can handle X-ray, as well as appropriately trained staffing. That adds to the cost of it. And then of course, there's always the concern about radiation exposure. You always want to use the ALARA principle as low as reasonably possible, but studies that have actually looked at this, and the big concern is obviously in pediatrics where they're potentially exposed to radiation and have a long life ahead of them, but studies have actually shown that the radiation risk associated with video urodynamics was below the threshold for harm, and in fact was actually lower than conventional cystography done by radiologists. In addition, there are modifications to fluoroscopy protocols that can be used for video urodynamics that have been shown to significantly reduce radiation exposure and it's generally thought that the clinical benefits of videourodynamics usually outweighs the risks of radiation exposure in the appropriate patient.
So to summarize, video urodynamics adds the fluoroscopic imaging cystography to conventional urodynamics to provide a synchronous functional and anatomic assessment of the lower urinary tract. It's generally recommended in those patients at risk for upper urinary tract dysfunction related to neurogenic lower urinary tract dysfunction, such as suprasacral spinal cord injury, spinal dysraphism and that's generally to assess for reflux in patients with congenital anomalies or prior lower urinary tract reconstructive surgery, or if you're planning reconstructive surgery, in patients in whom you think there's potential outlet obstruction and you really want to try to pinpoint it, and in those patients in whom conventional urodynamics are providing inconclusive or incongruent results.
Alan Wein: Right. I mean, that's an unbelievably short, succinct and really easy to understand presentation of why video is considered the Cadillac or I guess the Rolls-Royce of evaluations. I noticed on your figures,, just as the British have, that there's no EMG channel. And I would think that if you did videos that you really don't need an EMG, especially surface EMG that is prone to so many artifacts?
Michael Guralnick: Well, that's always been the big concern about EMG, especially when you use patch EMGs. You're not even necessarily obtaining-
Alan Wein: Exactly.
Michael Guralnick: That EMG from the sphincter. So you're getting a lot of artifact. To be honest, we used to do both EMGs and the video and you wouldn't uncommonly get discordant results and I would always go with what the fluoroscopy showed me as opposed to the EMG. So I think the fact that it's so unreliable and it's so operator-dependent, we've just gotten rid of it.
Alan Wein: So in a well-staffed unit with someone who really knows how to do the studies and you come in, you do the fluoroscopy part, how many of those studies can you actually do in one day?
Michael Guralnick: We usually do about three, sometimes four. A lot of it has to do with the patients themselves. These are often wheelchair patients, just the setup can actually take a while. And that's regardless of whether you're doing video or not. We only have two staff, a nurse. Actually, they're both generally nurses that are doing them. And it can be a lot just to transfer patients. Sometimes you have to use a Hoyer lift. So we're limited in the numbers that we can do in one day.
Alan Wein: So do you use the same room for conventional studies that you do for videos?
Michael Guralnick: We do. We only have one unit. We actually generally do video pretty much in everyone just because we can.
Alan Wein: It's obviously a great advantage. I mean, it's pretty incredible. I mean, would you suggest that someone, let's say out somewhere in Wisconsin, let's say a couple hours away who doesn't have video equipment, but yet is dealing with a high-risk patient, like spinal cord injury, honestly, would you suggest that they just send them for the better study for those patients?
Michael Guralnick: If that's feasible, I think that would be ideal. We actually do get that quite a bit where we get outside referrals to have their video urodynamics done. In some cases, they've already done their standard urodynamics, but we find a lot of them are doing them... They do it coupled with a cystoscopy. So they have the patient up in stirrups and they do their urodynamics and then they split the scope in. Whereas as much as possible, we'll try and do our patients if they sit in a wheelchair, that would be the ideal way to do their urodynamics, though we still sometimes will do them supine, but we don't couple it with a cystoscopy. So you don't have their legs up, which can add to a diuresis. It often is the case in spinal cord patients that alters the fluid volumes. And then, again, having that fluoroscopy to show you the simultaneous anatomy, it just gives me that much more reassurance that I'm really studying the full picture.
Alan Wein: Does anybody have a mobile unit where they go out to communities and do videos or not?
Michael Guralnick: Not to my knowledge. Not here. Not that I know of.
Alan Wein: So if you were going to another place, let's say the chair of urology, and they said, "Okay, what do you need?" I mean, that's one of the things on your list. You definitely say, "Okay, I need a leadline room because I want to do videos. I need a video machine. I need the proper equipment, et cetera." I mean, that's one thing that would definitely be on your checklist.
Michael Guralnick: 100%, absolutely.
Alan Wein: Well, listen, that's been really informative and I think it's a great thing for people out there to watch to get a really short but complete and extremely informative talk about videos over conventional urodynamics, not just for neurogenic but for other cases as well.
Michael Guralnick: Oh, absolutely. Even just the standard BPH patient, I still find that it's really nice to actually see what the prostatic urethra looks like in the context.
Alan Wein: It's a great teaching aid for the residents too.
Michael Guralnick: Absolutely.
Alan Wein: Yeah.
Michael Guralnick: Absolutely.
Alan Wein: Well, listen, thank you so much. Thanks for your time.
Michael Guralnick: Sounds good. Take care.