6.5 Ectopic Ureter

•In those with upper-pole system that serves a duplicated ureterocele: typically makes up less than 30 % of the unilateral renal function, and preservation of this function is usually not critical.

–If this poorly functioning moiety is not associated with reflux in other moieties, the best approach is excision.

–If this poorly functioning moiety serves a decompressed ureterocele with no reflux, there is no indication for removal.

•Each ureter drains a separate renal moiety.

–If only one moiety is involved and is poorly functioning, a single-stage nephrectomy or heminephrectomy is usually curative.

–The likelihood that this upper-tract approach will be curative diminishes as the number of other moieties involved with either reflux or obstruction increases.

–In this case, a lower-tract approach in which all problematic ureters can be simultaneously treated is a better option.

6.5Ectopic Ureter

6.5.1Introduction

•Normally the ureters drain via the internal ureteral orifice at the trigone of the urinary bladder.

•Ectopic ureter occurs when the ureter drains to an abnormally located (ectopic) orifice.

•Bilateral single-system ureteral ectopia is rare and usually coexist with other urinary tract anomalies including VUR, renal dysplasia, and rudimentary bladder development.

•Ectopic ureter (or ureteral ectopia) is a congenital malformation where the ureter, rather than terminating at the urinary bladder tri- gone, terminates at a different abnormal location. This abnormal location is as follows:

–In males, the ectopic ureter drains into:

•The lower urinary bladder

•The posterior urethra

•The seminal vesicle

•The vas deferens

•The ejaculatory duct

•The rectum rarely

–In females, the ectopic ureter drains into:

•The lower urinary bladder

•The urethra

•The vestibule

•The vagina.

•The uterus or Wolffian duct remnants rarely

•An ectopic ureter is a congenital renal anomaly that occurs as a result of abnormal caudal migration of the ureteral bud during its insertion to the urinary bladder.

•Failure of separation of ureteral bud from Wolffian duct results in caudal ectopia.

•Ectopic ureter is commonly a result of a duplicated renal collecting system, a duplex kidney with two ureters.

–One ureter drains properly to the bladder

–The duplicated ureter presenting as ectopic

•The Weigert-Meyer rule:

–In the case with complete duplication, the ureter draining the upper moiety inserts more medial and more inferior to the lower moiety ureter and liable for obstruction while the ureter draining the lower moiety is liable for reflux.

•Ectopic ureter can be associated with:

–Ectopic ureter may be solitary

–Approximately 80 % of ectopic ureters are associated with duplex kidneys

–Ectopic ureter may be part of complex congenital anomalies

–Hydronephrosis

–Ureterocele

–Renal dysplasia

–Frequent urinary tract infections

–Urinary incontinence (usually continuous drip incontinence).

•Ectopic ureters are found in 1 of every 2,000– 4,000 patients.

•Approximately 10 % are bilateral.

•Ectopic ureters occur more frequently in females than in males (F: M 10:1 or 6:1).

•In females, more than 80 % of ectopic ureters drain duplicated systems.

•In males, most ectopic ureters drain a single system.

•Approximately 80 % of all ectopic ureters drain the upper pole of a duplex kidney.

Sites of Ectopic Ureters

•In males, the ureters always terminate proximal to the external sphincter and may be found at the:

–Bladder neck/prostatic urethra (48 %)

–Seminal vesicle (40 %)

–Ejaculatory duct (8 %)

–Vas deference (3 %)

–Epididymis (0.5 %)

•In females, the ureters may terminate at the:

–Bladder neck/urethra (35 %)

–Vestibule (30 %)

–Vagina (25 %)

–Uterus (5 %)

•Single-system ureteral ectopia reveals widespread renal dysplasia in 90 % of affected kidneys.

•Duplicated-system ureteral ectopia reveals renal dysplasia in approximately 50 % of affected renal moieties.

6.5.2Embryology

and Pathophysiology

•In normal development, a single ureteral bud originates from the excretory duct of the pronephros and mesonephros, the mesonephric duct.

•This complex forms adjacent to the metanephric blastema, the precursor to the kidney.

•The ureteral bud migrates and rotates toward the portion of the urogenital sinus that will become the bladder and acquires a separate orifice from the mesonephric duct.

•Once in the vesical portion of the urogenital sinus, the orifice migrates superolaterally with respect to the primitive trigone as the mesonephric duct rotates caudally and medially to

the part of the urogenital sinus that will become the urethra.

•The mesonephric duct eventually becomes the epididymis, vas deferens, ejaculatory duct, and seminal vesicles in the male and the Gartner’s duct in the female.

•Ureteral ectopia occurs when the orifice of the developing ureter does not migrate into its proper location and takes its final position in an abnormal location.

•As a result of this, Ectopic ureters may terminate in:

–A male vestige of the mesonephros, such as the epididymis, vas deferens, ejaculatory duct, or seminal vesicle.

–Gartner’s duct (duct of the epoophoron), the female vestigial remnant of the mesonephric duct, which resides within the muscular wall of the genital tract extending from the internal cervical os along the lateral or anterolateral vaginal wall to the hymen.

–Nearby vestigial remnants of the Müllerian (paramesonephric) duct, such as the utriculus in the male and the upper vagina, cervix, and uterus in the female.

–The urethra in both sexes.

•Ureteral ectopy into the rectum is rare, but it may occur when the mesonephric duct inserts posteriorly on the cloaca and/or following inappropriate division of the urorectal septum.

•The persistent common excretory duct is another rare variant of ectopia (an ectopic vas deferens opens into a ureter, culminating in a common duct that opens to the trigone).

•In ureteral duplication, two ipsilateral ureteral buds migrate separately and simultaneously toward the urogenital sinus.

•According to the Weigert-Meyer law, the lower pole ureter migrates toward the vesical portion of the urogenital sinus ahead of the upper pole ureter.

–If both orifices reach the bladder, the orifice of the lower pole ureter is superolateral to the orifice of the upper pole ureter.

–Ectopia of one or both ureters may occur; however, ectopia of only the upper pole

ureter is usually present, because it is the second ureter to be incorporated onto the trigone.

–Its late arrival to the urogenital sinus causes the migrating mesonephric duct to carry the ureter to an abnormal location outside the bladder.

•Additional anomalies of the ipsilateral or contralateral system(s) are known to occur in association with upper and/or lower pole ureteral ectopia, such as:

–Ureterocele

–Ureteropelvic junction obstruction

–Renal ectopia

–Renal dysplasia

–Vesicoureteral reflux

•In females, the most common sites for an ectopic ureteral orifice, in decreasing order, are:

–The urethra

–The vestibule

–The vagina

–The cervix

–The uterus

–The Gartner’s duct

–A urethral diverticulum

•In males, the most common sites for an ectopic ureteral orifice in descending order, are:

–The posterior urethra

–The prostatic utricle

–The seminal vesicle

–The ejaculatory duct

–The vas deferens

–The epididymis

•In the male, the most common site is the pos-

terior urethra, occurring in approximately 50 % of cases.

•Other sites include the seminal vesicle (approximately one-third), vas deferens, bladder neck, prostate to the level of the ejaculatory duct orifice, and epididymis.

•In males, the ectopic ureter is always above the external urinary sphincter.

•Therefore, males with an ectopic ureter do not have urinary incontinence, but typically present secondary to a prenatal diagnosis of hydroureteronephrosis or symptomatic urinary tract infection.

•The diagnosis of an ectopic ureter associated with a duplex kidney can be difficult.

•The upper pole of a duplex kidney with an ectopic ureter may be very small and poorly functioning. Its small size makes it difficult to identify on morphological imaging. As a result of its poor function, there is no or minimal uptake of the tracer when isotope studies are performed.

•Finding the opening to an ectopic ureter at cystoscopy or vaginoscopy is also difficult.

6.5.3Clinical Features

•Ectopic ureters are often found incidentally on radiologic imaging studies.

•The symptomatology in these patients depends on the location of the ureteral orifice, its relationship to the urinary sphincter, and the competence of the bladder neck.

•In symptomatic patients, common presentations usually include:

–Incontinence

–Flank pain

–Hematuria

–Pelvic/perineal discomfort

–Infection

–Vaginal discharge

–Hydrocolpos

–Epididymo-orchitis

–Painful intercourse

–Ejaculatory pain

–Prostatitis

–Seminal vesiculitis

–Hemospermia

–Change in bowel habits

–A mass in the abdomen, rectum, urethra, and vagina

–Irritative and obstructive voiding difficulties – with or without incontinence

•In males, incontinence does not occur because ectopic ureteral orifices always terminate proximal to the external sphincter. Extremely rare, the ectopic ureter opens in the urethra just distal to the external sphincter.

•The diagnosis of ectopic ureter is difficult and even when symptoms are present, it is common

for the diagnosis of ureteral ectopia to be delayed several years.

•Clinical examination of a girl with an ectopic ureter may identify continuous dripping of urine from the introitus.

•There may be perineal irritation from continuous leaking.

•Careful targeted cystoscopy and vaginoscopy may locate an ectopic ureteric opening, but identification can be difficult and the opening easily missed.

6.5.4Diagnosis

•Intravenous urography (IVU):

–It can defect abnormal ureteral insertion and associated anomalies such as renal duplication.

–In complete duplex kidney and ureter, the ectopic ureter usually drains the upper moiety and may be associated with ureterocele and obstruction.

•Voiding cystourethrogram (VCUG):

–Usually the ectopic ureter is associated with vesico-ureteric reflux, which can be detected and graded with VCUG.

•Abdominal and pelvic ultrasound:

–This is useful in detecting associations and complications of ectopic ureter such as duplex kidneys, hydronephrosis and ureterocoele.

•MR urography (MRU):

–This is valuable in diagnosing ectopic ureters.

–The ureter and its insertion may be visualized.

–MRU is also useful in detection of other anomalies such as renal duplication, ureterocoele and vertebral anomalies.

6.5.5Surgical Treatment

•Symptomatic ectopic ureters are treated surgically.

•The upper pole kidney associated with an ectopic ureter is usually poorly functioning

and so is appropriately treated by upper pole hemi-nephrectomy.

•Complete uretrectomy may be associated with increased morbidity.

•Retaining the distal ureteric stump on the other hand carries a less than 10 % chance of re-operation for distal ureteric removal. This however will reduce the morbidity from a complete ureterectomy.

•With the recent development in minimal invasive surgery, laparoscopic hemi-nephrectomy is feasible and safe. Laparoscopic lower pole hemi-nephrectomy may be associated with risks of retroperitoneal fluid collection, loss of renal tissue and hypertension.

•Where upper pole function is preserved, an alternative to hemi-nephrectomy is ureteric re-implantation.

–In these cases, both ureters from the duplex kidney should be re-implanted together.

–Re-implantation, however, can be avoided by draining the upper pole into the lower pole system either with an ureteroureterostomy or an uretero-pyelostomy.

–Currently, laparoscopic ureteroureterostomy and uretero-pyelostomy have been reported to be feasible and safe.

•The surgical management of systems with ectopic ureters depends on several factors:

–The function of the involved (usually the upper pole moiety) and uninvolved renal segments.

–Single versus duplicated systems

–The site of terminal insertions of the ureters

–Coexistent morbidities, such as infections, reflux, pain, infertility, incontinence, masses, and associated anatomic anomalies.

•Surgical considerations usually include:

–Total nephrectomy

–Upper pole partial nephrectomy

–Ureterectomy

–Nephroureterectomy

–Pyelopyelostomy

–Pyeloureterostomy

–Ureteroneocystostomy

–Ureteroureterostomy

–Percutaneous decompression

–Endoscopic incision