UP Vet School Lecture on EU

The following was reprinted from a 1998 University of Pennsylvania School of Veterinary Medicine lecture that a student (thoughtfully :) posted to the web. The full lecture can be found at

NOTE: This lecture is heavy on scientific terminology, but still, I think, relatively easy to follow and full of information.

Ureteric ectopia is the most common cause of urinary incontinence in juvenile animals. It is a developmental abnormality resulting in abnormal ureter position; typically instead of entering the trigone it will enter low down in the neck, in the proximal urethra, or into the vagina. Occasionally will join into the uterus. In males, most common site is for it to join in prostatic urethra.

Can be unilateral or bilateral abnormality; in most cases it is bilateral but one side is more severely affected than the other. There's also something called ureterocoele, and this is a bit confusing - it is an intracystic dilation of a ureter - that ureter may be ectopic, or orthotopic, and if orthotopic has a pinpoint opening creating the dilation. It's common to have a diploid collecting system with these - two ureters coming from the same kidney. But usually you just see, with ectopic ureter, a normal ureter in the wrong place.

Breed predisposition - Siberian husky, Labs, Goldens. Typically these animals present early in life, when they've reached the point where they should be housebroken - 2-3 mos of age, the owner stops forgiving them for the accidents b/c it is a puppy, and brings it in. Typically they present with urine all over tail and perineum.

Slide: Irish wolfhound with marked discoloration of fur around this area, caused by constant urine soaking. Owners typically say dogs can posture and urinate what looks like normal volume, but will also drip urine constantly. This is typical of a situation where one ureter gets urine into bladder, and the other doesn't go into bladder at all. This is good. If one ureter is filling bladder, at least the bladder is well developed. If neither empties into bladder, bladder won't be well developed. Oh, these dogs are smelly, too. They also have UTIs, almost all of them, most commonly with e.coli - ascending infection that goes up the abnormal ureter. so, if you are presented with young animal with dribbling incontinence, you need to do diagnostic imaging.

Ureteric Ectopia is dxed more often in females. male dogs may have it just as often, but b/c the ectopic ureter joins the prostatic urethra, and the urethra is so long, they remain continent despite the ectopia. So, for imaging kidneys and ureters, logical study is the IV excretory urogram. This will fill kidneys and ureters with contrast. remember to do an enema first. Also do a negative contrast cystogram if possible so you can see the trigone better.

Slides: Excretory urogram showing modestly dilated left renal pelvis, severely dilated left ureter, and dilation at the ureteric vesicular junction. We can't really see where the ureter is going into the bladder though. The right kidney looks fine, and right ureter looks fine. We can't really see if it goes to trigone and makes J hook - at least, I can't see. But this hydronephrosis and hydroureter on the other side is blatant. Probably b/c the ureter is going through the urethral sphincter mechanism. What now? We could do fluoroscopy and watch contrast go down the ureter and see where it enters the bladder; we could do another contrast study - retrograde vaginal urogram - foley in vagina - contrast is injected to fill the vaginal vestibule and vagina, and also fills the urethra and bladder in retrograde fashion. And we see here that the ureter is filling with contrast as it leaves the urethra in the proximal 1/3 of urethra. Shouldn't be there.

In the other dog, we see an ectopic ureter filling in retrograde fashion from the vagina. retrograde vaginal urography is very useful for dx of this problem. Surgical problem is this - ureter comes down into bladder typically joins it in a normal place, but then tunnels submucosally down the urethra. we have to create a neostoma, if you will, in the trigone area, and somehow ablate or ligate or remove the distal portion of the ectopic ureter. or, if the ureter totally bypassed bladder, you reimplant it into the bladder. In dogs, this is very uncommon - very rare. Dr. Brockman has not ever seen one. Intramural ectopic ureter is more common. Neostoma and ligation of distal portion is the tx - but there are also abnormalities of kidney and ureter that might prevent success.

Slide: VD of abdomen of dog. Supposed to be neg contrast cystogram - but is pneumoureterogram - hugely dilated ureter and renal pelvis are obviously so severe that surgical movement of ureter isn't going to help that much - should probably remove the affected kidney and ureter to prevent recurrent pyelonephritis.

Slide: Husky who presented with massive cystic abdominal growth. excretory urogram shows hugely dilated ureter on one side, and a HUGE kidney occupying entire ventral abdomen. Bilat ureteric ectopia was present - one kidney had undergone irreversible hydronephrosis to a huge degree. Removed that. The other one was moved over and hopefully since hydronephrosis was less severe was able to function. We know he lasted at least 5 years post-op :)

Slides: Intraoperative examples of ureteric ectopia - when approaching trigone, btw, we always make ventral cystotomy. Stay sutures are used to hold bladder open relatively atraumatically. We can see a dilated intramural tunneling of the ureter (well, he sees it, I don't), tx is to open this tunneling thing in the trigone, suture it open, and place sutures distal to the opening, to ablate/occlude the distal portion of the tunneling ectopic ureter. Can do this bilaterally or unilaterally as needed. However, sorting the plumbing out is just part of the story. Dogs considered favorable for surgery (no irreversible renal changes, free of infection) success rate is still only about 50% - half stay incontinent. Why? these animals often have congenital abnormalities of the urethra as well - the length and sphincter may be affected. Most failures are incontinent due to sphincter problems. However, you can't assume b/c surgery failed that this is the case. You have to work it up.

Slide: Case in point to explain the motives for some of the more recent surgical developments - we have found that the intramural tunneling part of ureter sometimes opens back up, even after we suture it closed. this retrograde vaginal urethrogram shows us the intramural ectopic ureter connecting and communicating with the bladder again. so then you would want to close that again. Vesicourethral fistulas, etc. also treat surgically. so, now, some people doing sx on these dogs do another technique that is more effective than just ligating the intramural tunneling part - here, they create the neostoma in trigone as before, but bladder is opened all the way down the urethra so also a ventral urethrotomy - to dissect out this intramural ureter all the way down. if you completely remove it, then you can suture the neostoma and repair your trough you've created, and hopefully you end up with a small defect in mucosa and no potential for future problems...right? right? this seems like you should be ok - you've got no ectopic ureter left in there. Preliminary investigations suggest a higher continence rate. But only reduced incontinence from 50% to about 30% - the rest have a sphincter problem. The intramural portion, BTW, is submucosal - your surgery shouldn't be involving the muscle of the trigone - but there will be some inflammation, which might also affect the sphincter mechanism, so you know - we think these animals have a congenital sphincter problem but maybe some also get that from surgery? This is again the most common cause of juvenile incontinence. You have to treat the infection that is usually present before sx. At sx, you remove the ureter and kidney if severely damaged.

The surgical tx is "fun" but quite delicate, and success rate in 60-65% area isn't as high as we'd like. Don't forget -this isn't just seen in bitches, also in male dog. Final comment about patent urachus/persistent urachal remnant -

Slide: Bladder of dog with ectopic ureters and an obvious urachal remnant - embryonic structure attaching bladder to umbilicus - what happens is it is a nidus of infection - if UTI occurs, this won't clear up. The cranial part of bladder is a fairly weak area anyway, and infection may create a radiographic abnormality here so sometimes you have a diagnostic chicken/egg situation, which came first, infection or diverticulum? But often we do see this diverticulum or remnant, and surgical resection with submission for culture and biopsy will generally cure these animals that have persistent problems.

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