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Indian J Urol. 2016 Apr-Jun; 32(2): 156–158.
PMCID: PMC4831507

Urethral duplication with unusual cause of bladder outlet obstruction

Abstract

A 12-year-old boy presented with poor flow and recurrent urinary tract infections following hypospadias repair at the age of 3 years. The evaluation revealed urethral duplication with a hypoplastic dorsal urethra and patent ventral urethra. He also had duplication of the bladder neck, and on voiding cystourethrogram the ventral bladder neck appeared hypoplastic and compressed by the dorsal bladder neck during voiding. The possibility of functional obstruction of the ventral urethra by the occluded dorsal urethra was suspected, and he underwent a successful urethro-urethrostomy.

Keywords: Bladder outflow obstruction, hypospadias, urethral duplication, urethro-urethrostomy

INTRODUCTION

Urethral duplication is a rare congenital anomaly occurring exclusively in males.[1] We describe a case of Type IIA1 urethral duplication that was treated successfully by an end-to-side dorsal-to-ventral urethro-urethrostomy.

CASE REPORT

A 12-year-old boy presented with poor flow of urine and recurrent urinary tract infections (UTIs) for 5 years. He had undergone a hypospadias repair at the age of 3 years elsewhere. On examination, his growth was normal with no dysmorphic features. Two external meati were noted – one at the tip of the glans and the other at the corona dorsally. A voiding cytourethrogram (VCUG) [Figure 1] revealed complete urethral duplication with pan-anterior narrowing of the hypoplastic dorsal urethra (red arrowhead) along with areas of mucosal irregularity. Evidence of ventral urethral reconstruction with a prepucial tube with a small diverticulum was noted (red arrow). The bladder neck appeared duplicated, and the ventral bladder neck appeared hypoplastic and compressed by the dorsal bladder neck during voiding (yellow arrow). Cystourethroscopy revealed a stenosed dorsal urethra to about 5F from 5 cm proximal to the meatus. The ventral urethra was patent with a skin tube extending till the proximal penile region admitting a 14 Fr cystourethroscope freely. The veru was seen in the ventral urethra. Since the ventral urethra was found to be a patent on urethroscopy, a possibility of functional obstruction of the ventral urethra by the occluded dorsal urethra was suspected. Hence, an end-to-side dorsal-to-ventral urethro-urethrostomy was performed via a midline perineal incision. The dilated posterior part of the dorsal urethra was disconnected from its hypoplastic anterior part and anastomosed end-to-side to the ventral urethra. We confined ourselves to the mid bulbar region, and extensive proximal dissection was not necessary thereby avoiding the region of the sphincter. In addition, placing a zebra guide wire and a 4Fr ureteric catheter through the dorsal and ventral urethra respectively helped easy identification. We felt that attempting excision of the hypoplastic dorsal urethra in the penile region could potentially damage the previously repaired ventral skin tube and was unnecessary. He made an uneventful recovery and was free from UTI with an excellent flow (Qmax 22 ml/s, voided volume 489 ml, Residue 50 ml) at 1-year follow-up. The postoperative VCUG showed a patent anastomosis [Figure 2].

Figure 1
Voiding cytourethrogram revealing complete urethral duplication with pan-anterior narrowing of the hypoplastic dorsal urethra (red arrowhead) and evidence of ventral urethral reconstruction with prepucial tube with a small diverticulum (red arrow)
Figure 2
(a) Postoperative ascending urethrogram. (b) Postoperative voiding cystourethrogram showing a patent anastomosis

DISCUSSION

Urethral duplication usually occurs in the sagittal plane.[2] The ventral urethra is most often the functional one, being hypospadic and containing the sphincteric mechanism and the veru montanum.[2,3] Effmann et al. classified the anomaly into three types depending on the completion of the duplication (partial/accessory blind tract = Type I, complete = Type II), and association with bladder duplication (Type III).[1] Type II is further subdivided into IIA (2 meati) and IIB (single meatus, rare).[1] Type IIA is subclassified depending on whether the bladder neck is duplicated (IIA1) or not (IIA2).[1] This is a detailed functional classification and incorporates all aspects of the anomaly; however, it does not differentiate sagittal from coronal duplication.[2]

A number of theories have been postulated to explain urethral duplication, with no one theory being able to account for all types.[2] Usually, the ventral urethra is most functional and contains the veru and sphincter mechanism.[2] Woodhouse and Williams classified duplication as sagittal and lateral.[4] The sagittal was classified into epispadiac, hypospadiac, spindle-type and Y-type depending on the position of the ectopic channel.[4] The epispadiac variety is usually associated with the exstrophy-epispadias complex.[2,3,4] In the study by Woodhouse and Williams, the epispadiac variety was more common, but Podesta reported the hypospadiac variety more often.[3,4] In the series by Podesta et al. the hypospadiac variety was usually associated with a urinary tract anomaly, indicating that abnormal Mullerian duct insertion and improper development of the urogenital sinus could be involved in the genesis of these anomalies.[3] Mild cases of distal Effmann type 1 are often associated with hypospadias and could be due to the uncoordinated growth of the urogenital sinus and urethral plate.[2,3]

The traditional treatment protocol for Type IIA1 duplication involves excision or marsupialization of the hypoplastic urethra, or urethro-urethrostomy, with or without urethroplasty.[2,3] Salle et al. described 6 cases of Type IIA1 duplication, 5 of which were managed with excision of the hypoplastic urethra and 1 was managed conservatively.[2] They utilised a penile approach for the excision, occasionally in combination with a retropubic approach.[2] This procedure is challenging and carries the risk of damaging the neurovascular bundle and external sphincter.[2] Podesta et al. described 5 such patients in their series, all of whom underwent single-stage reconstruction with proximal dorsal-to-ventral urethro-urethrostomy and reconstruction of the distal end of the hypospadiac ventral channel with the prepucial or penile skin.[3] A circumferential subcoronal incision was made extending ventrally just proximal to the hypospadiac meatus. The penis was degloved and the hypoplastic dorsal urethra incised longitudinally up to its dilated proximal segment. The proximal dilated dorsal urethra was disconnected and anastomosed end-to-end to the ventral channel at the level of the penoscrotal junction. The distal end of the hypospadiac ventral channel was then reconstructed with the preputial or penile skin at the same stage.[3]

Our patient had already undergone urethroplasty of the ventral hypospadiac urethra using penile skin, and the lumen of this urethra was adequate on cystoscopy. The distal part of the dorsal urethra was hypoplastic, but the proximal part was dilated as seen on the MCU hence an end-to-side dorsal-to-ventral urethro-urethrostomy was performed. Our contention is that the ballooning of the proximal dorsal urethra was causing a functional obstruction of the ventral urethra during voiding. The significant improvement in flow after diverting the dilated dorsal urethra with no other intervention supports this possibility.

CONCLUSION

Urethral duplication is a rare anomaly and can have a complicated anatomy. A thorough evaluation to determine the exact anatomy and pathophysiology allows the surgeon to individualize the treatment appropriately.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

REFERENCES

1. Effmann EL, Lebowitz RL, Colodny AH. Duplication of the urethra. Radiology. 1976;119:179–85. [PubMed]
2. Salle JL, Sibai H, Rosenstein D, Brzezinski AE, Corcos J. Urethral duplication in the male: Review of 16 cases. J Urol. 2000;163:1936–40. [PubMed]
3. Podesta ML, Medel R, Castera R, Ruarte AC. Urethral duplication in children: Surgical treatment and results. J Urol. 1998;160:1830–3. [PubMed]
4. Woodhouse CR, Williams DI. Duplications of the lower urinary tract in children. Br J Urol. 1979;51:481–7. [PubMed]

Articles from Indian Journal of Urology : IJU : Journal of the Urological Society of India are provided here courtesy of Medknow Publications