Ureteral Ectopia

Anatomy of the Ureter

Ureters are fibromuscular tubes that transport urine through the retroperitoneal space from the renal pelvis to the urinary bladder [1,2]. Vascular supply to the ureter is derived from the cranial and caudal ureteral arteries that travel longitudinally and anastomose alongside the ureter. In males, the ureter passes dorsal to the ductus deferens, whereas in females, the ureter travels through the base of the broad ligament. Ureters exit the retroperitoneal space between the two-layer folds of peritoneum forming the lateral ligaments of the urinary bladder. Urine moves progressively through the ureters owing to organized peristaltic motion. Size of the ureter varies with species and patient size Ureters are considered to be larger than normal in dogs if the diameter is greater than 0.09 times the length of the second lumbar vertebrae. Enlarged ureters are usually greater than 3.0 mm [3]. Ureters attach to the dorsolateral surface of the bladder in the region of the bladder neck and pass through the bladder wall at an oblique angle creating a functional valve-like effect. The vesicoureteral junction can take on a "j"-shaped appearance [3].

Embryologic Development

Understanding the complex embryologic development of the urogenital system forms a foundation for the understanding of some of the congenital abnormalities encountered in clinical medicine. Developmental abnormalities of the ureteral bud do not typically occur as an isolated event, but instead impact the development of the kidneys, bladder wall, trigone, vesicourethral junction, proximal urethra, internal sphincter mechanism, and some of the reproductive structures.

Development of the "normal" kidney and drainage system is classically described as proceeding through three successive yet integrated renal systems, pronephros, mesonephros, and metanephros, that share developmental components with the reproductive systems [2,4-8]. The most primitive form of the excretory system recognized in vertebrate animals is the pronephros. It is nonfunctional and quickly replaced by the mesonephros. However, a major portion of the pronephric duct is retained and later referred to as the mesonephric or Wolffian duct. The mesonephric duct system represents the second stage of excretory system development [2,4,5]. This will become the mature excretory system in amphibians, but only parts of this system are retained in the development of the excretory system of vertebrate animals. The mesonephric ducts are paired structures that fuse with the ventrolateral aspect of the cloaca [5]. As the cloaca divides to form the rectum and the urogenital sinus, the site of attachment of the mesonephric ducts differentiates, forming the posterior or dorsal wall of the urinary bladder. In males, parts of the mesonephric duct give rise to the ductus deferens. Close to their openings into the urethra, the seminal vesicles form [2,4,5,8]. In females, the reproductive structures actually arise and differentiate from the paramesonephric or Müllerian ducts. The Müllerian ducts arise separately in the mesoderm in close apposition to the mesonephric ducts (during the period of migration of the ureteric bud to the metanephros). It has been demonstrated that the Müllerian ducts arise inside the basal membrane of the mesonephric duct and may be derived from the same cells [5]. As, the Müllerian ducts migrate toward the urogenital sinus, they fuse together forming the uterus and vagina. The site of fusion between the Müllerian ducts and urogenital sinus forms the vestibulovaginal junction. A small layer of paramesonephric tissue referred to as the hymen is positioned between the membranes of the urogenital sinus and parametanephric duct [8]. This hymenal membrane usually ruptures at birth. Ultimately, the developing mesonephric ducts are resorbed leaving only scattered Gartner's glands as the only remnant in mature females [2,4,5,8].

On the dorsal surface of the mesonephric duct, close to its attachment to the cloaca, the metanephric diverticulum or ureteral bud first arises [2,4-8]. Development of the metanephric system represents the third phase in the developmental progression. The ureteric bud extends dorsally to contact the developing metanephric blastemal ridge in the intermediate mesoderm and ultimately becomes the ureter. This contact or interaction between the ureteric bud and metanephric blastema is essential for the normal development of both the kidney and ureter, referred to as induction [2,4-10]. Within the metanephric blastema differentiation of the glomeruli, proximal and distal convoluted tubules, and the loops of Henle are initiated and maintained, forming the renal cortical structures. The proximal portion of the developing ureteral bud undergoes sequential division to form three major calyces, which, in turn, divide to form the minor calyces, papillary ducts, and collecting tubules, composing the medullary portion of the mature kidney. Synchronous migration of the kidney and ureter is occurring during this process of differentiation (Fig. 68.1). Cranial migration of the kidney occurs to assume its final sublumbar position. Concurrently, the distal end of the ureteral bud is drawn toward the urogenital sinus [4-9]. The region of the mesonephric duct located between the urogenital sinus and the proximal region of the ureteral bud is referred to as the common excretory duct [8]. Migration or absorption of the common excretory duct into the wall of the urogenital sinus results in caudal migration of the ureteral bud. The future bladder neck and internal urethral meatus forms at the site of contact between the ureteral bud and urogenital sinus. The ureteral bud is positioned medial to the common excretory duct at the site of contact with the urogenital sinus. Cranial lateral migration of the ureter and caudal medial migration of the opening of the mesonephric duct occurs. Following migration, the ureteral orifice and the mesonephric duct opening (future deferent duct opening in males) are located equidistant from the neck of the bladder [5,6,8]. The common excretory duct extending between these openings develops into the trigonal base plate and ultimately the deep and superficial muscle layers of the trigone and proximal urethra in females and pelvic urethra in males, forming the internal urethra sphincter mechanism [5-9].

Figure 68.1. Migration of the ureteral bud and mesonephric opening through extrophy of the common excretory duct. A and B. Urogenital sinus (A to become the urinary bladder, B to become the urethra). C. Mesonephric duct. D. Ureteric bud. E. Metanephric mass to become the kidney. F. Region of common excretory duct (to form the trigone). (Adapted from: Cannizzo, K.L. Uroendoscopic evaluation of ureteral ectopia in female dogs. Master’s of Science Thesis, The Ohio State University 2001).

Dysembryogenesis of the ureteral bud is the underlying cause of many congenital malformations of both the upper and lower urinary system [6,7,10]. Failure of the ureteral bud to arise from the mesonephric duct or failure of the bud to contact the metanephric blastema results in renal agenesis and may also result in failure of reproductive structures to develop. Abnormal positioning or lateral displacement of the ureteral bud on the mesonephric duct results in an altered migration pathway as the common excretory duct migrates or is absorbed into the wall of the urogenital sinus [6-8]. This subsequently results in distal displacement of the ureteral orifice, resulting in ectopic ureters and malformation of the structural integrity of the trigone (Fig. 68.2). Bifurcation of the ureteral bud or formation of multiple ureteral buds will result in the formation of the duplex collecting system as the bud contacts and induces the metanephric blastemia [6,7,9].

Figure 68.2. Association of ureteral bud position on the mesonephric duct and the resultant final position of the ureteral orifice. A. Normal position. B and C. Intravesicular ureteral ectopia. D. Urethral ureteral ectopia. E. Vestibular ureteral ectopia. (Adapted from: Cannizzo, K.L. Uroendoscopic evaluation of ureteral ectopia in female dogs. Master’s of Science Thesis, The Ohio State University 2001).

Ureteral Ectopia

Ureteral ectopia is a well-recognized congenital anomaly that may encompass a variety of malformations of both the urinary and reproductive systems. Ureteral ectopia is hallmarked by distal displacement of one or both ureteral orifice(s) to sites distal to the expected anatomic position at the tip of the trigone, frequently resulting in urinary incontinence [11-16]. Ureteral ectopia has been reported in dogs, cats, rats, horses, cattle, camelids, poultry, and humans [2,4,8-23]. The majority of the scientific literature pertaining to this developmental anomaly is focused on dogs and children. Distinct differences in the anatomy, morphology, and clinical presentation of ureteral ectopia exit between dogs and people. In humans, approximately 80% of all ectopic ureters are associated with a duplex collecting system, defined as a single kidney with complete duplication of the pyeloureteral system [24,25]. The ectopically displaced ureter is virtually always associated with the drainage of the upper moiety of the duplex system. Reports of duplex kidneys in veterinary patients are rare [22,26].

The exact incidence of ureteral ectopia is unclear. Documentation of this anomaly is usually based on clinical signs of urinary incontinence in juvenile patients evident since birth or in adult female patients after ovariohysterectomy. Two previous studies have attempted to characterize the incidence of ureteral ectopia in a clinical population of dogs. One study reviewed a total of 67,721 small animal patients over a 7-year period, identifying 11 dogs with a confirmed diagnosis of ureteral ectopia. A second study reviewed 106,790 small animal patients, identifying a total of 18 affected dogs. An identical percentage incidence of occurrence was calculated at 0.016% for both studies [4,27].

The specific locations of the displaced ureteral orifices have been well documented in both female and male dogs. Common sites of ectopically displaced ureteral orifices in females include sites within the trigone or bladder neck, vesicourethral junction, along the entire length of the urethra, or within the vagina or vestibule. However, in males the majority of displaced ureteral orifices are identified at the vesicourethral junction or pre-prostatic urethra in dogs [4,12,13,15-18]. Ureteral ectopia is frequently associated with intermittent, continuous or positional urinary incontinence and is considered to be the most common cause of urinary incontinence in young female dogs [18]. Affected females are identified approximately 4 to 20 times more frequently than affected male dogs [4,13,15,16,18]. This disparity likely reflects both a true sexual predisposition and under-diagnosis incontinent male dogs. Urinary incontinence in male dogs with ectopic ureters may occur less frequently owing to the relative length of the urethra and increased pressure in the prostatic urethra and external sphincter mechanism that together oppose the passage of urine distally, resulting in retrograde bladder filling [13,23].

Ureteral ectopia is reported in both purebred and mixed-breed dogs. It has been documented with greater frequency in specific breeds including Labrador retriever, Golden retriever, Siberian husky, Newfoundland, Skye terrier, West Highland white terrier, wire-haired fox terrier, and soft-coated Wheaten terrier, as well as standard and miniature poodles [3,4,8,11-18]. The specific etiology of this developmental anomaly remains unclear. A heritable basis for ureteral ectopia has been repeatedly suggested based on an increased incidence in predisposed breeds and potentially within family lines, identification of multiple affected littermates, and a single report of parent to offspring transmission [5-8,16,28-31]. However, a genetic basis determined by a controlled breeding study, pedigree analysis, DNA analysis, or evaluation for gene mutations has not been performed. Hypervitaminosis A, deficiency in vitamin A and folic acid, and irradiation have been shown to result in urinary tract anomalies, including ureteral ectopia in rats but not in dogs [32]. Supplementation with vitamin A during gestation was also shown to eliminate these developmental defects [4,5,7,8,32]. At this point, no evidence suggests that diet or other specific environmental factors play a role in the development of ureteral ectopia.

Ectopic ureters are characterized as extramural or intramural based on their anatomic pathway. Extramural ectopic ureters bypass the urinary bladder and open directly into the vesicourethral junction, urethra, uterus, vagina, or vestibule [4,8,11-13,15-18]. Once considered to be a common finding, with improved diagnostic modalities it is now recognize that the incidence of extramural ectopic ureters in dogs is rare [33,34]. Intramural ectopic ureters attach to the serosal surface of the bladder in the expected dorsolateral position in the region of the bladder neck, but fail to open into the bladder lumen at the tip of the trigone. Intramural ureters tunnel distally below the submucosal layer to open at sites within the trigone, vesicourethral junction, urethra, vagina, or vestibule [3,4,12,15,18,33-35]. A number of anatomic variations of the terminal ureteral segment have been reported, including variations in the size and shape of the orifice, ureteral troughs, two ureteral openings on one or both ureters, multiple fenestrated openings along the submucosal tunnel, two submucosal tunnels opening through a single orifice, and presence of an ectopic ureterocele [4,13,15,18,28,33-35]. Ureteral ectopia is commonly associated with additional anomalies of the urinary system, including absent, small, or irregularly shaped kidneys, renal dysplasia, hydronephrosis, dilated ureter, tortuous ureter, pelvic bladder, shortened urethra, indistinct vesicoureteral junction, urachal remnants, and abnormal shape of the ureterovesical junction [3,5,7,10].

Hydroureter is the most frequently reported abnormality associated with ureteral ectopia. It results from intermittent or partial urinary outflow obstruction. Ureteral dilation is most commonly associated with intramural ureters that are displaced to the distal aspect of the urethra or vestibule [3,4,13,28,33,34]. Intraluminal pressure within the urethra is increased between periods of micturition to maintain urinary continence. As urethral pressure increases and the lumen collapses, the ureteral remnant tunneling below the urethral mucosa also collapses, obstructing urine outflow. It is important to note that not all intramural ureters are dilated. Ureters that are minimally displaced, located within the trigone or vesicourethral junction, submucosal tunnels with multiple fenestrated openings, and ureters associated with a "trough-like" orifice are dilated less frequently [4,12,13,33].

Clinical Presentation

Ureteral ectopia is the most common cause of urinary incontinence in young female dogs [18]. Ureteral ectopia should also be considered as a primary rule-out for patients with history of urinary incontinence developing after ovariohysterectomy, especially in breeds with a known predisposition for this anomaly. Normal voiding patterns and behavior can also be observed in affected patients. The cause of urinary incontinence associated with ureteral ectopia is considered multifactorial. Incontinence results from ureteral discharge of urine distal to the bladder neck and urethral sphincter mechanism or from functional and structural abnormalities of the vesicourethral junction and urethra, which result in primary sphincter mechanism incompetence [4,12,13]. The degree of urinary incontinence and patterns of urination cannot be used to confirm the diagnosis of ureteral ectopia nor determine if unilateral or bilateral disease exists [4,12,13,16]. Physical examination findings are often normal with the exception of moist or urine stained hair in the perivulvar or prepucial region. Secondary dermatitis or urine scalding may be observed. Abdominal palpation may detect marked abnormalities in kidney size or structure that can result from hydronephrosis or dysplasia. Hematologic and serum biochemical evaluations are normal unless associated abnormalities that diminish renal function exist. Urinary tract infections resulting from ascending bacterial pathogens are frequently identified [2,36].

Methods of Diagnosis

The specific diagnosis of ureteral ectopia is based on identification of the ureteral orifice(s) distal to the expected position at the tip of the trigone. Historically, the diagnosis of ureteral ectopia has focused on the use of contrast radiographic procedures.

Plain and contrast radiography are frequently used to evaluate the upper and lower urinary tract of patients with suspected congenital anomalies and/or urinary incontinence. Excretory urography (IVU) and retrograde urethrography have long been considered the primary methods of diagnosis for ureteral ectopia in small animal patients [4,11-13,16,33]. These methods have been shown to provide a positive and anatomically accurate diagnosis in 62% to 77% of the confirmed cases of ureteral ectopia [33]. However, a variety of factors has been shown to compromise the diagnostic utility of these contrast procedures, including patient positioning and preparation, caudal displacement of the bladder (pelvic bladder syndrome), obscured visualization of the trigone and proximal urethra by overlying pelvic structures, degree of ureteral dilation or retrograde contrast accumulation [33].

Intravenous urography provides valuable information regarding the upper urinary tract including renal structure and function, location, size and morphology of the ureters, and has the potential to determine location of the ureteral orifices. Lateral, ventrodorsal, and oblique radiographic views are necessary to assist in delineating the distal ureteral segment in the pelvic region. However, the diagnosis of ureteral ectopia often remains elusive following appropriate radiographic evaluation [12,13,33].

Retrograde urethrography or vaginourethrography may provide additional information regarding length of the urethra, structure of the vesicourethral junction, identification of the ureteral orifices, and distal ureteral morphology [33,37,38]. One study demonstrated that retrograde ureteral filling with iodinated contrast was not observed in patients diagnosed with ectopic ureters unless the ureters were abnormally dilated. Dilation of the displaced ureters is reported in only 59% of the affected patients [33].

Contrast-enhanced computed tomography (CT) is now considered the method of choice for evaluating ureteral ectopia in humans [33]. Improved spatial and temporal resolution characteristics of helical or axially acquired transverse imaging allows a more detailed evaluation of the anatomy because it is not obscured by overlying structures. A study to determine the diagnostic utility of helical CT for the diagnosis of ureteral ectopia was performed in 24 incontinent dogs with suspected ureteral ectopia. CT imaging reliably and accurately diagnosed ureteral ectopia and the specific location of the displaced ureteral orifices compared with traditional methods in 17 affected dogs [33]. Although CT imaging may be more costly, the superior diagnostic information obtained with CT as compared with other established techniques warrants its use. CT image interpretation does require experience and can be made more difficult by the need for systematic review of multiple image frames [33].

Direct visualization of the lumenal surface of the lower urinary and reproductive tracts using a rigid or flexible endoscope can be performed in patients larger than 3 kg. Uroendoscopy has dramatically improved our ability to accurately diagnose ureteral ectopia and associated malformations of the ureteral orifices, vesicourethral junction, trigone, urethra, vestibule and vagina. This procedure also provides additional information regarding the anatomic pathway and morphology of the terminal ureteral segment [12,13,16,28]. Endoscopic evaluation of the distal segment of a dilated ureter can also be performed by gently passing an appropriately sized endoscope through the ureteral orifice into a dilated ureter. Radiographic evaluation of the upper urinary system should also be performed when the diagnosis of ureteral ectopia has been made by means of uroendoscopy. Contrast radiography, ultrasonography, or CT can be performed to assess the kidneys and ureters. Ultrasonographic examination is noninvasive and has been shown to be a reliable method of diagnosing ureteral ectopia when performed by a skilled operator. The confirmation of ureteral ectopia is made by identifying the location of the ureteral jet in addition to evaluating the size and structure of the ureter [39,40].

Urodynamic evaluation, including cystometrogram and urethral pressure profile (UPP), has been shown to be a useful tool in the evaluation of the function of the bladder and urethra in patients with urinary incontinence and other voiding disorders. Results of urodynamic measurements have been reported in nine incontinent female dogs diagnosed with ureteral ectopia prior to surgical correction. Reduced bladder capacity and abnormalities in the urethral pressure profile consistent with urethral incompetence were noted in 89% of the dogs. Urodynamic assessment of dogs with ureteral ectopia may be valuable in identifying concurrent functional abnormalities of the lower urinary tract, but it may have limited use in predicting postoperative continence [41].

Treatment

The goal of medical or surgical treatment of ureteral ectopia is resolution of urinary incontinence, re-establishment of anatomic integrity of the lower urinary system, and preservation of renal function. The treatment of ureteral ectopia is based on location and morphology of the ectopic ureter(s), and associated abnormalities of the urogenital systems [4,12,13,16,35]. Evaluation of renal function is necessary prior to instituting any type of therapy. Ultrasonographic evaluation of the kidneys and ureters combined with either IVU or renal nuclear scintigraphy is used to characterize renal function. Nephroureterectomy is performed when a kidney is determined to be nonfunctional and contralateral renal function is normal. A renal biopsy and culture are obtained if structural abnormalities of a functional kidney are noted or pyleonephritis is suspected.

Medical Treatment

Urinary incontinence associated with ureteral ectopia often is unresponsive or minimally responsive to accepted medical therapies, including the alpha-adrenergic agonists ephedrine sulfate or phenylpropanolamine, anticholinergic therapy such as oxybutinin, or hormonal therapy such as diethylstilbestrol (DES) in females or testosterone cypionate in males [42,43].

Minimally Invasive Treatments

The treatment of primary sphincter mechanism incompetence using submucosal urethral bulking with bovine gluteraldehyde cross-linked collagen has been shown to be successful in female dogs with clinical signs of urinary incontinence [44]. The use of collagen injected both periurethrally and submucosally to treat urinary incontinence in women has been reported [44]. Urologic collagen is composed of highly purified bovine dermal collagen that is cross-linked with gluteraldehyde in phosphate buffered saline. This product is composed of approximately 95% Type I collagen with 5% or less Type III collagen. A 14 or 19 French rigid endoscope with a 30-degree angle and a 4 French biopsy channel is used for uroendoscopy and placement of submucosal urethral bulking agents.

Complete evaluation of the lower urinary tract is performed prior to the injection of collagen. The tip of the endoscope is positioned to visualize the bladder neck and proximal urethra. The injection instrument is passed through the biopsy channel of the endoscope. The sites for injection are located approximately 1.5 cm. distal to the vesicourethral junction. Positioning of the endoscope facilitates inserting the beveled tip of the injection device below the urethral mucosa. Collagen is injected slowly while visualizing the distention of the urethral mucosa into the urethral lumen. Three to four sites are usually injected in a circular manner [44]. The procedure is considered complete when the injection sites appose one another. Complete urethral obstruction has not been reported in dogs.

Submucosal collagen implants have also been used to successfully treat selected dogs with proximally displaced ureteral ectopia without surgical intervention. The submucosal injection sites are positioned 1 to 1.5 cm distal to the displaced ureteral orifices, resulting in reflux of urine into the bladder lumen as well as creating obstruction to urine outflow. Ectopic ureter patients with moderate or severe ureteral dilatation or diminished renal function would not be consider a candidate for this noninvasive procedure.

Surgery

Evaluation of the upper and lower urinary tract is performed following a ventral midline celiotomy extending to the pubis. A stay suture placed in the apex of the bladder provides manipulation and retraction during the surgical exploratory and corrective procedures. The intrapelvic aspect of the female urethra can be exposed into the abdominal cavity by gentle traction on the apex of the bladder. A ventral midline cystotomy and urethrotomy are performed for direct visualization of the lumenal surface of the trigone, bladder neck, and urethra permitting identification of intramural ureters, submucosal tunnels, ureteral troughs, and most of the ectopically displaced ureteral orifices. Ureteral orifices located at the extreme terminal aspect of the urethra or vestibule may not be visualized from this approach without performing an osteotomy of the pubis to extend the urethral incision.

Ureteral Reimplantation/ Transposition

Transposition of a displaced ureter and ureteral orifice is indicated if the site of ureteral attachment is distal to the bladder neck. Surgical conformation of extramural ureters is infrequently reported [12,13,28,33]. Persistent urinary incontinence may result because the ureteral orifice is positioned distal to the bladder neck and urethral sphincter mechanism. Repositioning the distal segment of the ureter and ureteral orifice directly into the bladder may restore urinary continence if additional structural and/or functional abnormalities of the primary sphincter mechanism do not exist.

A ventral midline celiotomy is performed, and the extramural ureter is isolated distally where it attaches to the dorsal or dorsolateral surface of the bladder neck, vesicourethral junction, urethra, vagina, or uterus. The ureter is ligated at its most distal point of attachment with an absorbable suture and transected cranial to the ligature. The distal ureteral segment is isolated from the retroperitoneal space, respecting the ureteral blood supply that is positioned longitudinally within the fascial attachment. A ventral midline cystotomy is performed and the site of ureteral transposition is identified. This site can be located at any point between the apex of the bladder and the trigone. A mosquito hemostat is passed through a mucosal defect at an oblique angle and gently passed through the bladder wall. A small stay suture placed through the incised edge of the ureter is grasped to manipulate the ureter through the bladder wall. Once positioned within the bladder lumen, the terminal aspect (3-4 mm) of the ureter is excised and discarded. Intravesicular ureteral anastomosis is performed by suturing the ureteral mucosa to the bladder mucosa with a 5-0 absorbable monofilament suture material in an interrupted pattern. Surgical magnification may be necessary to accurately position these sutures. The bladder is closed in a routine manner [2,4,12,13,35,45,46].

Neoureterostomy and Urethral/Trigonal Reconstruction

Intramural ectopic ureters pass through the bladder wall but fail to terminate and open into the bladder lumen at the tip of the trigone. This type of ectopic ureter continues to tunnel submucosally through the trigone to open at a site within or distal to the bladder neck. Urinary incontinence results owing to the ectopic location of the ureteral orifice and/or disruption of the smooth muscle layer of the urethral sphincter mechanism by the submucosal pathway of the ureteral remnant. Historically, surgical repair of intramural ectopic ureters has focused on the creation of a new ureteral opening within the bladder lumen and ligation of the distal submucosal ureteral segment, redirecting urine flow into the bladder lumen [2,4,12,13,35,45-47]. Persistent or recurrent urinary incontinence has been frequently reported after surgery [2,12,13,35]. To restore the functional anatomy of the internal urethral sphincter mechanism to improve continence after surgery, the terminal segment of the intramural ureter is resected from the surrounding tissues of the bladder neck and urethra. Surgical apposition of the mucosa and smooth muscle layers of the remaining defect are performed to realign the smooth muscle layer of the internal urethral sphincter mechanism [12,13].

A ventral midline cystotomy and urethrotomy are performed, identifying the displaced ureteral orifices within the bladder neck and urethra. However, if a displaced ureteral orifice is located distally beyond the extent of this approach, in the terminal aspect of the urethra, a small incision is made through the distal urethral mucosa directly into the lumen of the submucosal ureter creating an orifice and avoiding the surgical morbidity of pelvic osteotomy. An appropriately sized urethral catheter (5, 8, or 10 French) is passed retrograde through each displaced ureteral orifice or distal ureterotomy incision. The catheter is passed retrograde to the site where the ureter passes through the bladder wall. It is essential to determine that this site is appropriately positioned near the tip of the trigone; if not, ureteral transposition should be performed. With the catheter in place, the submucosal ureter is sharply dissected from the surrounding urethral tissues including the mucosa, submucosa, and muscularis. Primary closure of the remaining defect in the bladder neck and urethra is performed using a 5-0 synthetic absorbable, monofilament suture material in a continuous or interrupted pattern. Closure of the urethral mucosa including a deep bite of the underlying smooth muscle layer is performed. Local hemorrhage is controlled by placement of the suture pattern to close the urethral defect. It may be necessary to dissect a portion of the submucosal ureter, immediately followed by closure of the defect to control hemorrhage before continuing with the complete dissection. The ureteral remnant is completely dissected from its submucosal position distally to the site where the ureter passes through the bladder wall. The ureter is transected approximately 0.5 cm from this site and sutured to create a new permanent ureteral opening within the bladder. Ureteral mucosa is sutured to the bladder mucosa using a 5-0 absorbable monofilament suture in an interrupted pattern. A balloon-tipped urethral catheter is passed into the bladder lumen, and a closed urine collection system is maintained for 24 to 36 hours after surgery. The cystotomy and urethrotomy are closed using 4-0 absorbable monofilament suture in a single or double layer continuous or interrupted pattern. Following removal of the urinary catheter, stranguria is frequently noted for several weeks after surgery [12,13].

Nephroureterectomy

Removal of a nonfunctional kidney and associated ureter is indicated as a salvage procedure provided renal function in the contralateral kidney is normal. Aerobic bacteriologic cultures from the renal pelvis are obtained if a urinary tract infection has been documented or pyelonephritis is suspected. The ureter is sharply dissected from the ureteral fascia and retroperitoneal space to its termination. The ureter is ligated at its most distal point of attachment and transected cranial to the ligature. Removal of a nonfunctional kidney without the removal of an associated intramural ureter remnant will likely result in persistent urinary incontinence after surgery. The submucosal portion of the ectopic ureter is excised as previously described.

Post-Surgical Considerations

Persistent urinary incontinence is the most common complication after surgical repair of unilateral or bilateral ectopic ureters. Urinary incontinence has been reported to occur in 44% to 67% of patients after surgery [2-4,15,18,27,35,36,41]. Incontinence has been reported after ureteral reimplantation of extramural ectopic ureters as well as with neoureterostomy of intramural ectopic ureters and nephroureterectomy of a nonfunctional kidney associated with an ectopic ureter [36]. Associated primary sphincter mechanism incompetence is hypothesized to be an underlying cause of persistent urinary incontinence. Identification and treatment of urinary tract infection are the first steps in the management of any patient with persistent or recurrent urinary incontinence. Standard medical treatments with alpha-adrenergic agonist or anticholinergic drugs may have improved success in some patients with mild incontinence after surgery. Endoscopic injection of glutaraldehyde cross-linked collagen submucosally within the urethra has also been used successfully to treat persistent urinary incontinence [1,2,44].