Congenital rectovestibular fistula associated with rectal atresia: A rare occurrence.

We report a rare variety of anorectal malformation, rectal atresia associated with rectovestibular fistula. The case was successfully treated by posterior sagittal repair. The fistula was mobilized and the continuity of the rectum was established by circumferential anastomosis.

INTRODUCTION

Rectal atresia is an extremely rare variant of anorectal malformation. It is predominantly seen in males with an incidence of 1-2% of all anorectal anomalies.[1] There are many case reports in the literature describing the occurrence of rectal atresia with urinary fistula in a male baby.[23] The presence of rectal atresia in a female with associated rectovestibular fistula is an extremely rare condition and has been reported once earlier.[4] We present one such case and its management.

CASE REPORT

A 7-month-old female baby was referred to us with complaints of abnormal anal opening. The baby was full-term with no significant perinatal history. The mother gave history of a non-functioning normally located anal opening with passage of stools from the vestibule. Examination revealed three openings in the vestibule with a normally located anal opening. On probing, the anal opening was blind and permitting only 1.5 cm of the Hegar's dilator inside [Figure 1]. Using the posterior sagittal approach, the fistula was mobilized and circumferential anastomosis was established with the rectal segment. The patient made an uneventful recovery. At 1-year follow-up, the baby is doing well and has voluntary bowel movements.

Figure 1

Perineal examination revealed urethral opening (catheter in situ), vaginal opening (empty black arrow head), rectovestibular fistula (bold arrow head), and anal canal (white arrow head)

DISCUSSION

Rectal atresia is a rare condition in which the anus and sphincter muscles are normally developed. It is mostly seen in male babies. Isolated rectal atresia in a female baby is a very rare condition and its association with any fistulous communication is even rarer. The exact pathogenesis of rectal atresia is unknown, but it is postulated to be secondary to intravascular thrombosis.[4] A good perineal examination is required to make the exact diagnosis. Gentle use of the probe is suggested for locating any fistulous communication which is a rare association with rectal atresia. As a definitive procedure, transanal end-to-end rectorectal anastomosis, mucosal proctectomy and coloanal anastomosis, and posterior sagittal approach have been suggested by different authors.[45] Only one case of rectal atresia with rectovestibular fistula was reported by Kulshrestha in 1997.[6] They had initially done a diverting loop colostomy followed by definitive repair of the defect by posterior sagittal approach. During the definitive repair they had split open the blind anorectum followed by the mobilization of the vestibular fistula. Subsequently the anorectum was approximated and this was followed by the circumferential anastomosis of the anorectum and the mobilized fistula. In our case, the sphincter muscles were normally developed, and the posterior sagittal approach was used for the definitive repair. With a racket-shaped incision the fistulous communication was first mobilized by extending the incision posteriorly and separating the muscle complex in the midline. Further dividing the levator ani in the midline, the anorectal pouch was mobilized. The anorectal stump was opened at the apex and the continuity with the mobilized rectovestibular fistula was established end to end by circumferential anastomosis without compromising the rectal musculature [Figure 2]. As in any anorectal malformation, good continence is the main objective in the treatment of rectal atresia as well.

Figure 2

Diagrammatic representation of the procedure

CONCLUSION

Rectal atresia with a fistulous communication to the perineum is a rare condition. But the perineal examination must focus on such a possibility. Management with posterior sagittal approach is recommended and gives good results.