Urethral duplication is observably a rare disorder on the assumption that most if not all cases are reported. It is rarer in females with a male to female ratio of 12:1 from this review (Table 1). Almost all that is known about the condition come from case reports and from retrospective review of cases. Could more robust studies in terms of tissue analyses, or the like be conducted on this subject matter? This narrative review reveals that reports have come from all parts of the world and that greater proportions of reported cases in males do not have symptoms attributable to the urethral defect as is observed in this index case. In addition, associated defects of the genitalia or other organs are not common. So, it is possible that a good number of cases of UD may go undiagnosed and unreported. Beyond abnormal urine stream due to a functional duplicate urethra, challenges with cosmesis and sexual activities as in the index case (Figs. 1a and c) are reported where there are defects of the external genitalia [15, 16]. Other reasons for presentation, or other clinical findings are dependent on associated defects.
Many reports suggest that Effmann type I duplication, especially the type IA is the commonest variant [6], but this review suggests that the type IIA 2 duplication as well as the type IIA 2 “Y” variant may be as common (Table 1). The retrospective reviews of cases by Wani et al. [17] in India, Guglielmetti et al. [18] in Switzerland and AbouZeid et al. [19] in Egypt suggest also that type IIA 2 and its “Y” variant are commonly encountered. However, it is possible that because type IIA 2 duplication and type IIA 2 “Y” variant are more challenging anomalies in terms of symptoms, cosmesis and surgical correction, they usually will not pass unattended to, or unreported, thereby increasing the frequency of such reports. On the other hand, except where they are diligently searched for, many Effmann type I UD may pass unnoticed and unreported resulting in type I being relatively less commonly reported.
In line with existing literature, this review shows that duplication in the sagittal plane is by far the commoner [2]. In Effmann type III variant, however, duplication in coronal plane may constitute a reasonable proportion (about 25.0% from this review). Our patient presented with type IA duplication in the sagittal plane (Fig. 1b).
With respect to associated defects of the external genitalia, dorsal chordee of varying severity is commoner among the type IA duplications from this review (Table 2). This may be because the ambient tissue of the dorsum of the penile shaft tends to be hypoplastic just as the dorsal non-orthotopic duplicate urethra is usually atretic and non-functional. It is possible to explain this association in line with the theory of dysplastic penile tissue in close proximity to poorly developing urethral tissue [20]. In line with the meeting report by Stadler and colleagues, further studies on this possibility concept are necessary [21]. Montag and Palmer noted from a review of penile curvatures that penile chordee could be anchored at the depth of the skin, dartos fascia, Buck’s fascia, or cavernous tissue [13]. Unilateral or bilateral corporal disproportion of varying extents will determine the attendant degree of dorsal and lateral deviations of the penile shaft. Our patient presented with a complex chordee that is at the depth of the Buck’s fascia manifest as a combination of dorsal and left lateral deviations as well as left torsion of about 800 (Fig. 1c). Such a combination of penile shaft curvatures and torsion adds to the challenge of explaining penile deformities in UD. Similarly, hypoplasia of ventral penile tissue resulting in penoscrotal transposition, bifid scrotum or ventral chordee is commoner with the “Y” type duplication possibly because of the concurrent non-orthotopic ventral disposition of the dorsal duplicate urethra to the ventral penile shaft, and the ventral duplicate urethra to the anal, perineal, or scrotal area.
In correcting significant chordee associated with UD, it is therefore appropriate to deglove the penile shaft so as to tackle the chordee at the appropriate tissue plane [13, 22]. That is the strategy deployed in correcting the complex chordee in our patient, the outcome of which is acceptable to all concerned (Fig. 1d).
Our patient does not have any other structural anomaly beyond the disfigured external genitalia as is seen with some other reported cases [2, 22,23,24]. From the scoping done, only about 24% of the reported cases of urethral duplication in males had other anomalies beyond the external genitalia. The prevalent anomalies reported are vesicoureteric reflux of varying grades and renal defects of differing categories [17, 18]. The reasons for the associations are not clear. Where present, vesicoureteric reflux does not appear to be due always to infravesical obstruction as many of these patients do not have high pressure voiding [17, 25]. Anorectal anomalies are seen more with the class “Y” duplications possibly because of the proximity of the ventral duplicate urethra to the anorectal/perineal region in this class of UD. Considering that some of these associated anomalies could be life-threatening, or organ-threatening, and it is therefore pertinent that they are sought for and managed appropriately [18, 23].
