Female with two perineal openings: Do not forget rectovaginal fistula

Introduction

A normal female perineum is characterized by three openings: urethra, vagina, and anus. Anorectal malformations (ARM) include anomalies with the location or size of anal canal. ARM in a female may present with one, two or three openings. The most common type is Low ARM i.e. with three openings where the anal canal opens either in the vestibule (Vestibular Fistula) or anterior to the normal location of the anus (Perineal fistula).

A single opening is seen in the cloacal malformation, in which urethra, vagina and rectum meet to open conjointly.

The differential diagnosis for two perineal openings are rectal atresia without fistula, rectovestibular fistula with vaginal agenesis or rarely anorectal agenesis with recto-vaginal fistula (RVF). This accounts for only 1% of all cases and is included in ‘rare regional variants’ in the most commonly accepted Krickenbeck classification. Here, we present three cases of ARM with RVF, which were diagnosed on pressure augmented distal colostogram and/or intra-operative endoscopy and managed with Peña's posterior sagittal anorectoplasty (PSARP).

Case details

Case 1

A 1-month old female neonate presented with passage of fecal matter from the vestibule since birth. On examination, she had two openings in the vestibule with an absent anal opening. Gluteal folds were well formed. The spine was normal. 2D echocardiogram, ultrasound of spine, cranium and abdomen were normal with normal Mullerian structures.

The baby underwent diversion stoma at descending-sigmoid colon junction. Pressure augmented distal colostogram revealed opacification of a high rectal pouch with contrast entering the vagina (Figure 1).

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Figure 1.

Pressure augmented distal colostogram showing opacification of distal colon with contrast going into vagina, along with cervix indentation.

A posterior sagittal midline incision in jack-knife position was made and the rectal pouch was identified in the pre-sacral space. This pouch was opened in the midline and revealed a fistulous communication between rectum and vagina (Figure 2). The rectum was then mobilized off the vagina. The fistulous vaginal communication was closed and the rectum pulled through the muscle complex and an anorectoplasty was done. The post-operative course was uneventful and anal dilatation was started from post-operative day 14 according to protocol. Stoma reversal at nine months of age was carried out; at follow up, the baby's condition was satisfactory with grade 1 constipation according to Peña scoring.

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Figure 2.

Intra-operative picture showing midline fistulous communication of rectum and vagina (arrow).

Case 3

A 2-month old female presented with two perineal openings and passing stool per vestibule. There were no other associated malformations on work-up. Intra-operative endoscopy showed a RVF.

At operation through a posterior sagittal incision, the rectal stump was seen opening at the mid-point of the posterior vaginal wall and there was partial proximal septum in the vagina (Figure 3). The vaginal septum was divided, the vagina repaired, and the rectum mobilized and pulled-through the sphincter complex; a partial perineal body dehiscence required a secondary stoma. A redo-PSARP and stoma reversal is awaited. Summary of findings and management is presented in Table 1.

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Figure 3.

Intra-operative picture showing rectal stump posteriorly (having forceps in situ) opening into mid-body of septate vagina anteriorly.

Discussion

The incidence of ARM is 1 in 3000–5000 live births. ARM with RVF is relatively more common in Asian countries including India, than in the West. The reported incidence of RVF varies from 0 to 84% in the English literature. ¹ Peña believes RVF is an almost non-existent entity and previously reported cases were misdiagnosed cloacas, ² but many cases may be due to false labeling or incorrect diagnosis. A recent study quoted its incidence close to 1%. ³ In the Krickenbeck meeting it was accepted that rectovaginal fistula exists as a malformation but is rare enough not to be included as a major variant. It was thus included in the category of ‘rare malformations’. As it is a supra-levator defect, it was included in high and intermediate ARM in Wingspread Classification previously.

Embryologically, by 6–8 weeks of gestation, an urorectal septum forms and moves caudally to divide cloaca into anterior urogenital sinus and posterior rectal pouch. The failure of this event causes fistulous communication between the two, resulting in recto-urethral fistula in males and RVF in females. ⁴ The RVF may communicate with the vagina at various levels with some series reporting higher fistulae being more common while others included cases with lower level of fistula.^5,6 In two of our three cases, the fistula was in the mid portion of the posterior vagina, while one had it at the level of the fornix. This level of fistula is determined embryologically by the extent of caudal growth of the urorectal septum. There may be associated Mullerian structure abnormalities, which need sophisticated management. There were none in our cases, except for a proximal vaginal septum in one case.

The key step in diagnosing a female neonate with ARM is to determine the number of perineal orifices. The small size of the newborn perineum and hymen itself may cause difficulty in identification for two openings, differentiation between vestibular fistula (with vaginal agenesis) and RVF is difficult but necessary. A fine forceps may be used to probe the fistula, which in the case of vestibular fistula passes posteriorly and backwards, while it goes only upwards in RVF.

Anatomical categorization by pressure augmented colostogram helps to identify the type of malformation pre-operatively for proper planning and counseling of the parents. In patients with diversion colostomy, pressure augmented distal colostogram under fluoroscopy allows proper distension of distal rectal pouch depicting the anatomy of a terminal rectal pouch and characterization of the level of fistula. It was first described by Cremin et al. in 1972. ⁷ Under constant gentle pressure, water-soluble contrast is injected until the fistula is visualized on fluoroscopy. In one of our cases, water soluble contrast medium could delineate the fistula between rectal pouch and vagina, and also cervix indentation could be well visualized. Endoscopy has a high sensitivity for intra-operative fistula identification. Almost all cases reported in the literature have been reconstructed using Peña's approach and have had a good outcome.

PSARP described by Peña provides an excellent exposure and allows favorable long-term outcome. PSARP is the now the most accepted and widely used technique to manage patients with ARM including patients with RVF. However, some authors have used laparoscopy for the management with advantage of easier mobilization of a high pouch in cases of high RVF opening at the level of the vaginal fornix.^8,9

Conclusion

RVF is a rare variant of ARM in female neonates. Diligent clinical examination to identify the number of perineal orifices is crucial for correct diagnosis. Fluoroscopy guided pressure augmented distal colostogram and/or endoscopy helps in delineating the surgical anatomy in cases of ARM. Peña's posterior sagittal approach provides good clinical exposure and outcome.

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Table 1.

Tabular presentation of findings of cases.

Case	Age at presentation	Diagnosis method for RVF	Associated malformations	Age at PSARP	Level of RVF	Short term outcome	Long term outcome (Pena 1995) #	Follow-up period
1.	1 month	Pressure augmented distal colostogram	None	5 months	Mid body of vagina	Good	Grade 1 constipation	3 years 10 months
2.	7 months	Endoscopy	Single functioning kidney with grade 4 VUR, Tiny ASD	7 months	Proximal vagina	Good	Grade 2 constipation and grade 1 fecal soiling	3 years
3.	2 months	Endoscopy	Proximal vaginal septum	2 months	Mid body of vagina	Partial perineal body dehiscence	Awaiting redo-PSARP and stoma reversal	4 months

^#

Reference: Peña A. Anorectal malformations. Semin Pediatr Surg. 1995; 4:35–47.