If you are reading this information, the chances are that you have a puppy (probably female) with urinary incontinence and you have been told that she may have ectopic ureters. Most likely, your puppy has not responded completely to treatment for bladder infection nor to the usual urinary incontinence treatments, and seems to have more than just a house-breaking problem. If she really does have an ectopic ureter or even two, the only chance at resolving the incontinence is through surgery. This is expensive and often unsuccessful, so it is important for you to know what you're getting into.
What are Ectopic Ureters?
Illustration by Wendy Brooks, DVM
Before it is possible to understand ectopic ureters, one must understand the normal anatomy of the urinary tract. The two kidneys sit in the lower back where they are at work every moment of our lives from cradle to grave. The kidneys are a very advanced waste filtration system where the end product is urine: a water-based solution into which the body’s waste chemicals are dissolved.
Urine is made continuously and transported to the urinary bladder for storage. The tiny pipelines through which the urine is transported from the kidney to the bladder are the ureters (one for the left kidney and one for the right). The bladder stores the urine until it can be voluntarily unloaded. The chute that connects the bladder with the outside world is the urethra.
This is a good system, and it works well most of the time. We constantly filter unwanted wastes, yet we do not dribble urine constantly. We store our urine until we want to use it for territorial marking or perhaps until it is simply sanitary and convenient to get rid of it.
Ectopic ureters are an embryological error when this tract is developing. Instead of connecting to the bladder, the ureters connect to the urethra, the vagina, the colon, or even the uterus. The ureters are thus bringing urine to an area unequipped for urine storage so leaking results. Incontinence and infection are the usual outcomes. Most affected animals are female, and often there are multiple internal urinary anatomical abnormalities.
Signs of Ectopic Ureters
The patient is usually a female puppy under the age of one year with the following:
- Urine leaking or dribbling at times but normal urination at other times.
- Licking of the genital area; often urine leakage has caused a rash in this area.
- Bladder infection is in 64% of ectopic ureter patients.
It should be noted that an uncomplicated bladder infection would cause all of the above as well and would be a far more common explanation.
Ectopic ureters are rare, and it is important to look for more common explanations for the above. Many puppies demonstrate submissive urination or have house-breaking problems and these should be ruled out as well. A urinalysis and culture will determine if the dog has a bladder infection and if so, which antibiotics will work against it. A basic blood panel will assess kidney function.
If the incontinence and/or infection continues despite appropriate treatment, further diagnostic steps will be needed.
Radiographs – Plain and Contrast
Puppy with ectopic ureters (both right and left). Contrast dye shows the kidneys and ureters. There is no contrast in the bladder, indicating the urine bypasses the bladder. (Photo courtesy of Dr. Sarah Cooper)
A plain radiograph (X-ray) would be the next step after urine evaluation. A radiograph is like a photograph only instead of using light to expose a piece of film, X-rays are used to expose the film. Visible abnormalities with the shape or size of the kidneys can be seen as can certain types of bladder stones. The problem is that even when enlarged by disease, the ureters themselves are still too small to be seen on a radiograph; special contrast is needed.
Contrast media are special dyes, often iodine-based. On a radiograph, they appear white and are used to highlight small structures or separate overlapping structures.
The Intravenous Pyelogram (I.V.P.)
The I.V.P. is a contrast radiographic study used to identify the ectopic ureters. After fasting, the patient is given an enema to ensure that the GI tract is cleared of any contents that might obscure the view of the tiny ureters. Contrast dye is given intravenously, and radiographs are taken that show the dye moving through the kidneys, the ureters, and into the bladder. The normal ureter can be seen on its course to the bladder in this way. This test is associated with 60-70 percent accuracy.
Ultrasound uses the echoes of sound waves to create an image. With an experienced imager, the accuracy of ultrasound in the diagnosis of ectopic ureters is similar to that of the I.V.P. The normal ureter is too small to be seen with ultrasound but the tiny squirt of urine from the ureter into the bladder is generally visible. If the ureter is distended (often the case with ectopic ureters), this could be seen using ultrasound. Ultrasound is less invasive to the patient than the I.V.P. but not as accurate. Ultrasound is mostly used to evaluate the urinary tract for other conditions that should not be missed in the course of the workup. To answer the question about whether there are ectopic ureters, ultrasound is not the best bet for that.
Contrast Enhanced Computed Tomography (CAT or CT Scan) In humans, CT scanning is the diagnostic method of choice for the diagnosis of ectopic ureters. It is highly accurate and reveals the exact location of the ureter attachment. This form of imaging will be more accurate than ultrasound or I.V.P. but is not available as widely, requires general anesthesia, and is likely more costly than the aforementioned procedures.
Cystoscopy is generally used to clear up cases where one simply is not sure if there is an ectopic ureter or not after the above testing. Cystoscopy employs a tiny camera on the end of a probe which can be used inside the urethra, vagina, or bladder to locate the ureteral openings. Patients should weigh at least seven pounds for this procedure and, since most hospitals are not equipped for cystoscopy, a referral is likely needed. Another disadvantage of cystoscopy is that it does not evaluate the upper urinary tract. Since the state of the kidneys is an important piece of information, an ultrasound would be a nice complementary test to get the full story of what is going on in the patient's urinary tract higher up.
An advantage of cystoscopy is that laser surgery can often be performed on the same anesthesia thus confirming and correcting the problem all in one procedure.
Treatment of the Ectopic Ureter
The moment of truth comes with surgical exploration (or cystoscopy) with the intent to correct the incontinence. With surgery, the patient’s urinary bladder will be opened and the ureteral openings located. With cystoscopy, the cystoscope camera goes into the bladder and locates the ureteral openings. Some ectopic ureters go to the bladder as they are supposed to but instead of entering the bladder, simply course along the outside of the bladder to end elsewhere. During surgery, both ureters are identified and followed to their terminal points. One of the following surgical techniques will be used depending on where the ureters are going.
Candidate for neoureterostomy. Illustration by Dr. Wendy Brooks.
Neoureterostomy (read “neo-ureter-ostomy”) This word literally means “new-ureter-opening,” which is somewhat self-explanatory. This procedure is used for ureters that attach to the bladder but do not actually enter the bladder (as described above). Here, an opening into the bladder is made where the ureter attaches but has failed to penetrate. The part of the ureter beyond this opening is removed. This sounds simple enough but removing that extra piece of ureter actually involves a great deal of manipulation through the very important bladder sphincter. Sphincter scarring or other damage can result from the manipulation. Often incontinence is a continuing problem even after surgery and further treatment is needed.
A more successful approach is to use cystoscopy and a laser to cut back the ureter to a more appropriate opening. Better continence is generally achieved in this way though facilities with appropriate equipment may not be generally available. See below for information on LASER Ablation.
Candidate for Neoureterocystostomy. Ectopic ureters that attach this way are said to be "extramural" while those that attach to the bladder without properly penetrating are said to be "intramural". Illistration by Dr. Wendy Brooks
Neoureterocystostomy (read “Neo-uretero-cystostomy”)
This word means “new-ureter and bladder opening.” This technique is used for ureters that bypass the urinary bladder totally and connect elsewhere. The offending ureter is located, tied off, and gently teased away from its inappropriate connection so as to preserve its blood supply. A new opening in the urinary bladder is made, and the ureter is pulled through, snipped short, and sewn in place, being sure not to twist it. There is usually swelling at the site of the new attachment, which interrupts the urine flow into the bladder and can distend the ureter. Urine may back up into the kidney and cause damage to the kidney. The swelling generally has resolved after six weeks but if both ureters undergo the same procedure at the same time, then both kidneys may suffer enough damage to lead to kidney failure.
Nephroureterectomy (read “nephro-ureter-etomy”)
Nephroureterectomy means removal of the kidney and ureter, a self-explanatory definition. If the kidney is so infected or diseased as to be useless, it is just as well to remove the ureter and the entire kidney. This procedure would not be undertaken unless the other kidney was normal or near normal.
Several days of hospitalization are required after any of these surgeries; the patient will not be going home the next day. Expect antibiotics and pain relief medications for home use. If cystoscopy and laser ablation are used, however, these patients often do go home the same day as their procedure.
Most patients will have urinary straining and some discomfort after surgery. A urinary catheter is generally in place for a day or two after surgery to prevent bladder distension during the first days of healing.
Incontinence is likely to continue after surgery but in 55 percent of dogs, it was improved. Several studies have been done to determine the incidence of total incontinence resolution and depending on the study 33-58 percent actually were free of their incontinence. With anatomy corrected, however, medication for urinary incontinence is likely to be much more successful than it would have been prior to surgery.
If incontinence is still intractable two to three months after surgery, a new I.V.P. should assess the surgical result. Surgical procedures to specifically address urinary incontinence can be performed.
Alternatives to Surgery
Because of the special equipment needed, LASER ablation is only available in limited locations. LASER ablation is best used for intramural ectopic ureters. These are ureters that start to enter the bladder where they are supposed to but do not actually penetrate all the way in. Instead they continue inside the bladder wall and open up in the urethra or vagina. It is the tunneling effect that makes this particular type of ectopic ureter difficult to address with conventional surgery as described above.
A less invasive approach with less post-treatment incontinence involves using a cystoscope and a LASER. The cystoscope is a long instrument with a camera on the end that can be guided up the urethra to where the opening of the ectopic ureter can be seen. A LASER can be used to cut the ectopic ureter back to the level of the bladder. Most patients are able to leave the hospital within 24 hours and are completely continent. Males typically remain continent but some 40 percent of females ultimately require additional treatment to remain continent. This represents an improvement over results obtained with neoureterostomy.
VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email firstname.lastname@example.org.