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Correcting ectopic ureters in juvenile dogs
Cystoscopic-guided laser ablation is a minimally invasive alternative to surgery


Problem list

  • Urinary incontinence
  • History of urinary tract infection
  • Recessed vulva
  • Bladder neck caudally displaced

Presumptive diagnosis

  • Possible ectopic ureter or ureters
  • Urethral sphincter mechanism incompetence (USMI)
  • Short urethral syndrome


  • Bilateral intramural ureteral ectopia
  • Bilateral hydroureter and hydronephrosis
  • Short urethra syndrome with a hypoplastic bladder
  • Persistent paramesonephric remnant that extended back to the cervix (vaginal septum)

Treatment decisions

During the diagnostic cystoscopy, a diode laser was used to perform a cystoscopic-guided laser ablation of the intramural bilateral ectopic ureters (CLA-EU). The right ureter was displaced in the mid urethra and the left was in the proximal urethra. Both were intramurally tunneling from the bladder into the urethral lumen where the opening was located. This was diagnosed based on the retrograde ureteropyelogram in which the ureters and renal pelvis were seen to be dilated. Once the CLA-EU was complete, the laser was used to ablate the vaginal remnant and create a normal vagina to try to prevent urine pooling and vaginitis in the future.


The patient was discharged the same afternoon as the cystoscopic procedure. The amoxicillin-clavulanic acid was continued for two weeks, and tramadol was prescribed (3 mg/kg orally t.i.d.) for two days as needed. During the next four weeks, the dog was completely continent. Urine culture results at four weeks were negative. The dog's renal pelvis size was reassessed six weeks after the procedure, and there was no evidence of renal pelvic dilation of hydroureter bilaterally.

At 7 months of age, the dog started having urine spotting at night, at which time the phenylpropanolamine was started at 1.5 mg/kg orally before bed. This made the dog 100 percent continent. At 2 years old, the dog has no evidence of urinary incontinence.


The embryologic foundation of ectopic ureters is thought to result from the abnormal differentiation of mesonephric and metanephric duct systems, resulting in inappropriate ureteral tube termination and malposition of the ureteral orifice.

Although ectopic ureters have been reported in male and female dogs, as well as both purebred and mixed-breed dogs, it seems to occur with greater frequency in female dogs and in certain breeds, including Siberian Huskies, Newfoundlands, Labrador retrievers, Golden Retrievers, terriers and poodles. The most common clinical finding is constant or intermittent urinary leaking since birth or weaning, though many dogs present after a period of continence and are only incontinent when in certain positions.

Suspected concurrent bladder and urethral functional anomalies, such as USMI, have been reported in 75 to 89 percent of female dogs evaluated, though in one study there was no significant difference in outcome after surgery in dogs with or without USMI. Other associated urinary conditions include urinary tract infections, renal dysplasia, hydroureter (34 to 50 percent) or hydronephrosis (15 to 27 percent), short urethras, persistent paramesonephric remnants and vaginal septum or dual vaginas.

Various methods of surgical fixation have been described, all of which require a laparotomy, cystotomy, ureterotomy or urethrotomy. The complication rates with surgery vary, and in one report there was a 14 percent complication rate overall, with 50 percent of dogs after ureteral reimplantation developing worsening hydroureter or hydronephrosis, 16 percent of dogs after the intravescular transplantation technique having dysuria and 8 percent of dogs that underwent ureteronephrectomy developing renal failure.

Unfortunately, the postoperative continence rates reported in female dogs continue to be low, regardless of the surgical technique performed, varying between 25 and 58 percent with or without concurrent medical management. Since many of these dogs are relinquished or euthanized because of urinary incontinence issues, these disappointing outcomes make the search for other alternatives appealing. The failure to obtain continence in these dogs is most likely due to their concurrent USMI rather than failure of the procedure.

The diagnostic method of choice for evaluating dogs for ectopic ureters is now considered to be cystoscopy. The use of the CLA-EU technique, first described in one female dog in 2006 and four male dogs in 2008, provides a minimally invasive alternative to surgery in cases with intramural ectopic ureters. This procedure enables the diagnosis to be made, while simultaneously performing a therapeutic intervention and potentially avoiding some of the complications and risks associated with the open surgical techniques described. This procedure uses cystoscopy and fluoroscopy to directly visualize the ureteral orifice, assess for any other urinary anomalies (e.g., vaginal septum, persistent paramesonephric remnant, dual vagina, hydroureter, hydronephrosis), as well as guide a laser to ablate the tissue that forms the medial ectopic ureteral wall so the orifice can be repositioned into the urinary bladder neck (Figure 1, p 10S).

Recently, we finished a prospective study evaluating 30 female dogs with ectopic ureters corrected with CLA-EU. Results showed that 77 percent of dogs were continent at more than 12 months follow-up (47 percent with CLA-EU alone, 57 percent with additional medications, 60 percent with additional collagen injections and 77 percent with the addition of a hydraulic occluder or artificial urethral sphincter). Overall, the study showed CLA-EU provided an effective, safe and minimally invasive alternative to surgery of intramural ectopic ureters in female dogs in which concurrent diagnosis and treatment were accomplished on an outpatient basis with minimal complications when compared with surgery.


Source: DVM360 MAGAZINE,
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