Urethral duplication in the male: Review of 16 cases

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URETHRAL DUPLICATION IN THE MALE: REVIEW OF 16 CASES

JOA ˜ O LUIZ PIPPI SALLE, HICHAM SIBAI, DANIEL ROSENSTEIN, ALEX ELIAS BRZEZINSKI

AND

JACQUES CORCOS

From the Division of Pediatric Urology, Montreal Children’s Hospital, McGill University Health Center, Montreal, Quebec, Canada

ABSTRACT

Purpose: Urethral duplication is a rare congenital anomaly. The clinical presentation varies because of the different anatomical patterns of this abnormality. We describe our experience with 16 male patients with this anomaly.

Materials and Methods: We retrospectively reviewed the records of 16 male patients treated for urethral duplication in the last 10 years. Age at presentation ranged from newborn to 8 years.

Evaluation included ultrasound, voiding cystourethrography, retrograde urethrography and endoscopy.

Results: A blind ending duplicated urethra (type I) was present in 4 patients, 2 independent urethras with distinct bladder necks (type IIA1) in 6, 2 urethras originating from a common bladder neck (type IIA2) in 4, and complete urethral and bladder duplication (type III) in 2. Six patients had associated vesicoureteral reflux. Duplication was an incidental finding at epispadias repair in 3 patients with bladder exstrophy, at hypospadias repair in 1 and at hydrocele repair in 1. One patient with bilateral dysplastic kidneys died in the newborn period. Surgical man- agement included excision of the duplicated urethra in 8 cases and urethroplasty using a pedicle flap in 2, while surgical management was not required in 3.

Conclusions: Urethral duplication is a rare congenital anomaly with a variable clinical pre- sentation. This pathological condition may easily be under diagnosed, especially in patients with other associated anomalies, such as hypospadias or bladder exstrophy. Surgical management should be planned individually according to the anatomical findings of the abnormality.

KEYWORDS: urethra, abnormalities, epispadias, hypospadias Urethral duplication is a rare congenital abnormality. The

clinical presentation differs according to the anatomical vari- ant present. Duplication may begin from the bladder neck proximal to the distal urethra and may be complete or incomplete. Urethral duplication is most common in the sagittal plane with a dorsal and ventral urethra. Usually the ventral urethra is most functional and contains the sphincteric mechanism as well as the verumontanum. Some duplications may be associated with an open symphysis pubis or urine dribbling from the epispadiac urethra. Management may be complex and depends on the duplication subtype. We review our experience with 16 cases of significant urethral duplication during the last 10 years and propose an appro- priate management scheme for this unusual problem.

MATERIALS AND METHODS

We treated 16 patients with urethral duplication during the last 10 years. We retrospectively analyzed clinical presentation, evaluation, management, and outcome in these cases. Our series includes all significant cases of urethral duplication treated by one of us (J. L. P. S.). Mild cases of distal type I duplication often associated with hypospadias were excluded from study.

All patients underwent renal ultrasound and voiding cystourethrography. In select cases retrograde urethrography and urethrocystoscopy or excretory urography (IVP) were done. Cases were divided according to the classification of Effmann et al as type I— blind incomplete urethral duplication or an accessory urethra, type IA— common distal type in which an accessory urethra opens on the dorsal or ventral penile surface but does not communicate with the urethra or bladder, type IB—proximal type that may be difficult to

differentiate from a urethral diverticulum or Cowper’s ducts in which an accessory urethra opens from the urethral channel and ends blindly in the periurethral tissue, type II—

complete patent urethral duplication, type IIA—2 meatus, type IIA1—2 noncommunicating urethras arising independently from the bladder, type IIA2—second channel arising from the first independently courses into a second meatus, type IIB—1 meatus, type IIB1—rare type in which 2 urethras arising from the bladder or posterior urethra unite into a common channel distally and type III— urethral duplication as a component of partial or complete caudal duplication¹(fig. 1).

RESULTS

Of the 16 patients 11 were older than 1 and 5 were older than 2 years. The diagnosis was made neonatally in 3 cases.

Mean age at diagnosis was 29 months (see table). A double urethral meatus or urinary stream was the clinical presen- tating sign in 11 cases (61%). Urethral duplication was de- tected incidentally in 3 patients at time of epispadias repair several months after bladder exstrophy closure and in 2 others at hypospadias and hydrocele repair, respectively.

Three patients who presented with urinary tract infection had associated vesicoureteral reflux. In 1 case duplication was diagnosed by urinary dribbling from the penile tip and voiding through the anus. This abnormality was associated with type IIA2 or Y-type duplication (fig. 2,A). One patient had multiple abnormalities, including bilateral renal dysplasia, oligohydramnios and severe renal failure.

Type I partial urethral duplication was present in 25% of cases and type II complete duplication in 62.5% (fig. 3). Only 2 patients (12.5%) had type III complete urethral and bladder duplication. With respect to the plane of duplication only 1 patient had coronal (collateral) urethral duplication with 2 Accepted for publication January 14, 2000.

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apical meatus and each bladder received the ipsilateral ureter (fig. 4). Of the remaining patients 94% had sagittal urethral duplication, including a nonfunctioning anterior bladder in another case of type III duplication (see table). The most common associated abnormality was vesicoureteral reflux in 6 patients (37.5%), which was bilateral in 5. Other anomalies included bladder exstrophy in 3 cases (19%), and hypospadias, cryptorchidism and anal stenosis in 1 each. One patient had bilateral renal dysplasia with terminal renal failure (see table).

Only symptomatic patients or those with a significant cosmetic problem were treated surgically (see table). Two patients underwent simple meatoplasty. In another case meatoplasty was performed as part of onlay island flap urethroplasty. Eight patients (50%) underwent excision of the accessory dorsal urethra, including those with bladder exstrophy in whom the epispadiac urethra was removed and the ventral urethra was used. Urethroplasty with chordee correction was necessary in the patient with a duplicated hypospadiac urethra. In the patient with complete type IIA2 or Y-type duplication 2-stage repair involved displacement of the urethra from the anal canal to the perineum at stage 1 and subsequent urethral reconstruction using a long tubularized preputial island flap at stage 2 (fig. 2,BandC). Two patients underwent ureteral reimplantation. Vesicostomy was performed in 1 case for stenosis of the ventral hypospadiac urethra and in 1 for bilateral renal dysplasia with 2 hypoplastic urethras. Observation was elected in 2 of the 16 patients with type III complete but asymptomatic bladder and urethral duplication.

Mean followup was 45 months (range 9 months to 5 years).

Of the 16 patients 13 (81%) had an uncomplicated outcome.

The patient with Y-type duplication presented with urethral stenosis at the proximal anastomosis after stage 2 urethroplasty. Stenosis was treated with dilation with a good outcome. In a patient with bladder exstrophy a vesicocutaneous fistula was successfully closed 12 months after it developed.

One patient died of terminal renal failure associated with bilateral renal dysplasia.

DISCUSSION

Urethral duplication is a rare anomaly with approximately 172 cases described in the literature. This anomaly is most common in males with few cases reported in females.²Sev- eral theories have been proposed to explain urethral duplication, including misalignment of the termination of the cloacal membrane with the genital tubercle.³However, to our knowledge no single theory explains all of the various types of anomalies.

Effmann et al established the most commonly used classification.¹This classification is functional, represents all clinical aspects of urethral duplication, and groups type III bladder and urethral duplication as a more complex abnormality.

However, it does not distinguish sagittal from coronal collateral duplication. In the classification of Woodhouse and Williams sagittal and coronal duplication was divided but this classification does not include many anatomical details that are important for therapeutic decision making.⁴For this reason we prefer to use the classification of Effmann et al,¹ adding the term coronal when duplication is in the coronal plane.

Urethral duplication is rarely associated with bladder duplication, which may be in the coronal or sagittal plane.⁵ Woodhouse and Williams noted that bladder duplication is more commonly coronal, representing a type of cloacal duplication.⁴Two hemitrigones are usually present and each re- ceives the ipsilateral ureter. Conversely sagittal bladder duplication is extremely rare but when it was present others described a nonfunctional anterior bladder.^{6, 7}In our series 1 of the 2 bladder duplications was coronal and the other sagittal, while in the latter the anterior bladder was not functional. In contrast with bladder duplication, urethral duplication is more often sagittal. Woodhouse and Williams reported that 25 of 27 cases were of the sagittal type.⁴How- ever, when coronal urethral duplication is present, it is often associated with complex caudal duplication.^{2, 4, 6, 8}

Type II duplication with an epispadiac dorsal urethra is embryologically assimilated into complex exstrophy- epispadias, in which the mesodermal structures fail to separate the 2 primitive layers of cloacal membrane during their normal inward migration.⁴ Clinically even when there are some similarities in those abnormalities, such as a wide symphysis pubis and incontinence, the association of complete bladder exstrophy and urethral duplication is rare.^{9 –11} As in our 3 cases, urethral duplication is usually unrecog- nized at bladder exstrophy closure. We also observed that the bladder plate is less everted and the exstrophied bladder is larger than in isolated bladder exstrophy. This larger bladder combined with a continent ventral urethra improves the chance of continence, as in our 3 patients who were continent and voiding normally via the normally located ventral urethra.

Controversy exists regarding the subclassification of type II duplications. Some suggested that Y-type duplication exists only when the ventral urethra is the functional urethra.

However, when the ventral urethra is hypoplastic, the anomaly is classified as a congenital urethroperineal fistula.¹² Bates and Lebowitz supported this theory, reporting that in all cases of urethral duplication the ventral urethra is the functional organ.¹³ Wagner et al classified all congenital FIG. 1. Classification of urethral duplication¹

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urethroperineal fistulas as urethral duplication with a hypoplastic ventral urethra.¹⁴In the absence of exact knowledge of the embryology of this anomaly it is difficult to differentiate the 2 entities. A patient in our series had complete duplication with a functional ventral urethra, as reported by Bates and Lebowitz.¹³In practice it is important to recognize and preserve the functional urethra. It is a serious mistake to discard the functional ventral urethra while preserving the more normally located hypoplastic urethra. Urethrocysto- scopy may be necessary to confirm radiological findings. Rec- ognizing the functional urethra is critical for determining treatment. The functional urethra usually has a wide caliber to empty the bladder, a good sphincteric mechanism and a normal verumontanum.^{1, 15–17}

Evaluating this condition should accomplish anatomical delineation of the abnormality, recognition of the functional urethra and investigation of other anomalies. We believe that voiding cystourethrography is adequate if it shows the 2 urethras with 1 clearly larger and continent (fig. 3).¹⁶ Podesta et al believed that retrograde cystourethrography was mandatory but may potentially be reserved for cases in

which the hypoplastic accessory urethra is not visualized on voiding cystourethrography.¹⁵ Occasionally cystoscopy is necessary to visualize the verumontanum and other urethral characteristics.¹ Others perform abdominal ultrasound and/or IVP to rule out other abnormalities, especially in the upper urinary tract.^{16, 18}We believe that ultrasound should be done in all patients because it is noninvasive and reveals the majority of associated anomalies. IVP may be reserved for type III duplication to identify the course of the ureters.

In our experience IVP was done in all cases of type III duplication as well as in the case of Y-type duplication. Other evaluations may be performed to rule out anomalies of the spine, intestinal tract or internal genital organs in patients with type III duplication.¹⁶

Several surgical techniques have been described to treat urethral duplication. Some prefer to use the apical urethra even when it is hypoplastic. In these cases Ortolano and Nasrallah attempted urethral dilation.¹⁸In our opinion the accessory urethra should not be used because it is hypoplastic and the risk of inadequate urine flow is high. Using the ventral urethra is easy when its meatus is close to the apical Clinical data on and management of urethral duplication

Pt. No. — Age Presentation Type Associated Anomalies Treatment

1 — 12 Mos. Double apical⫹epispadiac meatus I None Excision of accessory urethra

2 — Newborn Partial anal stenosis⫹anal voiding IIA2 Partial anal stenosis Proctoplasty, perineal urethrostomy⫹urethroplasty 3 — 20 Mos. Double meatus⫹stream,⫹urinary tract

infection

IIA1 Vesicoureteral reflux Conservative reflux management

4 — 7 Yrs. Diagnosed at hypospadias repair I None Excision of accessory urethra

5 — 8 Yrs. Double glanular meatus I None Meatoplasty

6 — 18 Mos. Bladder exstrophy diagnosed at epispadias repair

IIA1 Bladder exstrophy⫹bilat. vesicoureteral reflux

Bladder closure⫹urethral plate excision

7 — 7 Mos. Double apical⫹epispadiac meatus,⫹ recurrent urinary tract infection

IIA1 Bilat. vesicoureteral reflux Urethral plate excision⫹ureteral reimplantation 8 — Newborn Double meatus⫹oligohydramnios IIA2 Bilat. renal dysplasia⫹oligohy-

dramnios

Vesicostomy

9 — 1 Yr. Double apical⫹epispadiac meatus IIA1 None Excision of accessory urethra

10 — 8 Mos. Double glanular meatus III None Abstention

11 — 8 Mos. Double apical⫹epispadiac meatus IIA2 None Excision of accessory urethra

12 — 18 Mos. Bladder exstrophy diagnosed at epispadias repair

IIA1 Bladder exstrophy⫹bilat. vesicoureteral reflux

Bladder closure⫹urethral plate excision

13 — 2 Yrs. Double apical⫹hypospadiac with ste- nosed meatus,⫹urinary tract infection

IIA2 Lt. vesicoureteral reflux⫹Hutch diverticulum

Vesicostomy, onlay⫹ureteral reimplantation

14 — 5 Yrs. Double glanular meatus III None Abstention

15 — 5 Yrs. Bladder exstrophy diagnosed at epispadias repair

IIA1 Bladder exstrophy, bilat. vesicoureteral reflux⫹lt. cryp- torchid testis

Bladder closure, urethral plate excision⫹orchiopexy 16 — 2 Yrs. Hydrocele⫹double meatus discovered at

hydrocele repair

I Hydrocele Meatoplasty⫹hydrocele re-

pair

FIG. 2. Y-type urethral duplication.A, urine dribbling from penile tip and voiding through anus.B, tubularized transverse preputial island flap used to reconstruct urethra, which was previously advanced from anus to perineum.C, completed urethroplasty.

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meatus. Simple meatoplasty provides a good cosmetic and functional result. When the ventral urethra is more posterior, urethroplasty is necessary. Vascularized preputial island flaps, which may be applied as an onlay or tubularized graft, are the best choice for urethral reconstruction (fig. 2).

For Y-type duplication Williams and Bloomberg proposed urethroplasty using scrotal flaps.¹⁹However, experience using scrotal flaps for hypospadias has been disappointing because of the possibility of creating a hairy urethra. When no foreskin is available for repair, buccal mucosa is a reasonably good option for urethroplasty.^{15, 16, 18}In a few cases others described anastomosis of the ventral urethra to the dorsal apical urethra when the latter had adequate caliber.^{18, 20} When the dorsal urethra causes incontinence or a double stream, some perform fulguration or sclerosis by injecting this accessory channel, although this technique may result in corporeal thrombosis or chordee due to fibrosis.^{15, 16}We believe that the best method is surgical excision of this acces-

sory dorsal urethra using the penile approach sometimes combined with the retropubic approach.¹⁶Total excision of this dorsal urethra is a delicate procedure because of the risk of damaging the external sphincter and neurovascular bun- dle. We performed this excision in 8 of our 16 patients without complications. A consensus exists on treating only symptomatic patients, or those with significant cosmetic or functional anomalies (see Appendix).1, 4, 15, 16, 18

CONCLUSIONS

Urethral duplication is a rare congenital anomaly with a variable clinical presentation depending on urethral anat- omy. Usually the ventral urethra is most functional and is maintained after surgical correction. This pathological condition may easily be under diagnosed, especially in patients with associated anomalies, such as exstrophy, epispadias and hypospadias. Surgical management should be individual and depend on the anatomical configuration of the duplicated urethras. Outcome is favorable in the majority of cases and urinary continence as well as excellent cosmesis is usually achieved.

APPENDIX: PROPOSED MANAGEMENT OF URETHRAL DUPLICATION

Type

IA Meatoplasty or excision of accessory urethra

IB Abstention

IIA1 Urethro-urethrostomy or excision of accessory urethra with or without urethroplasty

IIA2 Urethroplasty

IIB Abstention

III Coronal:

No diphallus Excision of bladder septum or of hemibladder with ureteral reimplantation in contralateral bladder, urethra treated as type IIA1

Diphallus Penoplasty⫹glanuloplasty, bladder treated as type III coronal with no diphallus

III Sagittal Nonfunctional anterior bladder excision, urethra treated as type IIA1

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FIG. 3. Complete urethral duplication.A, type IIA1 with separate bladder necks.B, type IIA2 with second channel arising from first and coursing independently into second meatus.

FIG. 4. Urethral duplication in coronal plane with double urethral meatus.

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