Endoscopic Treatment of Ectopic Ureters: Short & Long Term Outcomes Using Cystoscopic-guided Laser Ablation (cla-eu)

Ureteral ectopia (UE) is a congenital anomaly of the urinary system where the ureteral orifice is inappropriately positioned caudal to the urinary bladder (i.e. the bladder neck, urethra, vagina, vestibule or uterus). This is the most common cause of urinary incontinence in juvenile female dogs accounting for over 50% of cases in one study, compared to only 5% of incontinent adult dogs. Although ectopic ureters have been reported in male and female dogs, as well as both pure and mixed breed dogs, it seems to occur with greater frequency in female than male dogs (>20:1), as well as certain breeds (i.e. Siberian Huskies, Newfoundlands, Retrievers [Laborador or Golden], Terriers, and Poodles [miniature and toy]). The most common clinical finding in these dogs is constant or intermittent urinary leaking since birth or weaning, though many dogs present after a period of continence, and are only incontinent in certain positions. Suspected concurrent bladder and/or urethral functional anomalies, like urethral sphincter mechanism incompetence (USMI), has been reported in 75-89% 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 such as urinary tract infections (64%), renal agenesis (5%), renal dysplasia, hydroureter (34-50%) or hydronephrosis (15-27%), short urethras (21%), persistent paramesonephric remnants (83%) and/or vaginal septum or dual vaginas (8%), hormonal imbalances, and ureteroceles have all been reported concurrently. The embryological basis of this condition is suggested to result from inappropriate differentiation of the mesonephric and metanephric duct systems. This results in inappropriate ureteral tube termination and ultimate malposition of the ureteral orifice. The urogenital sinus, which becomes bladder and urethra, may also differentiate inappropriately, resulting in termination of the ureters in the bladder neck, prostate, or urethra. Ectopic ureters tunnel either intramurally or extramurally, with over 95% reported to be intramural in dogs. The typical intramural ectopic ureter(s) will enter the distal bladder neck in a relatively normal position but fail to open into the bladder lumen, traversing the urethra to the level of the prostate, vestibule or vagina in the submucosal tissue, where it terminates. Traditional therapeutic intervention for UE includes 3 main surgical techniques: neoureterostomy with ligation of the distal ureteric tunnel, neoureterostomy with urethraltrigonal reconstruction, and neoureterocystostomy (ureteral re-implantation). These procedures require an open laparotomy, cystotomy, ureterotomy, and urethrotomy. The complication rates with surgery vary and in one report there was a 14% complication rate overall, with 50% of dogs after ureteral re-implantation developing worsening hydroureter or hydronephrosis, 16% of dogs after the intravesciular transplantation technique having dysuria, and 8% of dogs with ureteronephrectomy developing renal failure. Unfortunately, the post-operative continence rates reported in dogs continue to be low, regardless of the surgical technique performed, varying between 25 and 58% with or without concurrent medical management. When comparing unilateral to bilateral UE, no difference in female dogs treated surgically has been reported. Recently a study comparing neoureterostomy with ligation of the distal portion of the tract and neoureterostomy with urethral-trigonal reconstruction was unable to detect substantial differences between the success of these two techniques; both resulted in high rates of persistent