Congenital Urethral Fistula

(1)

Pediatric Surgery, Al Azher University, Cairo, Egypt

Abstract

Congenital abnormal fistulas between urethra and anorectum or vagina are usually associated with imperforate anus. Congenital recto or anourethral fistulas without anorectal malformations are extremely rare in males and have been called N-type or H-type fistulas¹. In many series, this fistulas are not considered under the types of congenital urethra fistula, because these abnormalities have been included as a subtype of anorectal malformation (ARM), even in cases of normally located anus. There is no general agreement about urethral fistula as an identified anomaly, as it may be considered as a sort of urethral duplication or an associated anomaly with other congenital malformations.

Keywords

Congenital urethral fistulaUrethroanorectal fistulaUrethroperineal fistulaN-typeH-type fistulasUrethrocutaneous fistula

Congenital abnormal fistulas between urethra and anorectum or vagina are usually associated with imperforate anus. Congenital recto or anourethral fistulas without anorectal malformations are extremely rare in males and have been called N-type or H-type fistulas [1]. In many series, this fistulas are not considered under the types of congenital urethra fistula, because these abnormalities have been included as a subtype of anorectal malformation (ARM), even in cases of normally located anus. There is no general agreement about urethral fistula as an identified anomaly, as it may be considered as a sort of urethral duplication (Chap. 27) or an associated anomaly with other congenital malformations (Fig. 28.1).

Fig. 28.1

Urethral fistula

28.1 Classifications: Congenital Urethral Fistula Could be Classified Simply to:

Primary anterior urethrocutaneous fistula: opens in the penile shaft or scrotum (Fig. 28.2).

Fig. 28.2

Congenital urethrocutaneous fistula, opening in the mid penile shaft
Congenital urethroperineal fistula: opens in the perineum, between scrotum and anus.
Congenital urethroanorectal fistula:
- With anorectal malformation (Fig. 28.3)
  
  Fig. 28.3
  
  Rectourethral fistula in a neonate with imperforate anus, meconium coming from the the fistula
- Without anorectal malformation.
  
  Y type (Figs. 28.4 and 28.5)
  
  Fig. 28.4
  
  Y shaped urethroanal fistula, without anorectal anomalies
  
  Fig. 28.5
  
  Another Y type fistula without any associated anomalies
  
  N Type (Fig. 28.6)
  
  Fig. 28.6
  
  N type urethrorectal fistula, from perineal approach

Wagner et al. classified all congenital urethroperineal fistulas as urethral duplications, and the presence of a normal orthotopic channel has to be looked for and identified [2]. The occurrence of a Y-type duplication might be related to an anomalous persistence of the urogenital duct that is bounded posteriorly by the urorectal septum, anteriorly by the ventral part of the cloacal membrane, and laterally by the superficial parts of the cloacal folds.

28.2 Incidence

Primary anterior urethrocutaneous fistula is a very rare malformation with only 28 cases reported in English-language literature from 1962 to 2012 [3]. In a large series of 1992 patients with anorectal malformations, the rectourethral fistula detected in 17 % of the cases [4].

H-type anorectal malformations (ARM) are extremely rare variants in the spectrum of anorectal deformities. This configuration is more commonly described in females, and its presence in males has only been reported in case reports or small series. with an estimated incidence of 3 % of all ARM

28.3 Aetiology

The etiology of congenital urethrocutaneous fistula is not clear yet. It has been demonstrated that ionizing radiation can be the cause of congenital urogenital malformation [5].

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