Unusual variants of congenital pouch colon with anorectal malformations

Management options of congenital pouch colon--a rare variant of anorectal malformation

PURPOSE

Congenital pouch colon (CPC) was analysed for anatomical variations and surgical options.

METHODS

Records of CPC patients managed between 1999 and 2014 were studied. CPC was classified as complete (CCPC) and incomplete (ICPC) pouch.

RESULTS

Of 400 cases of high anorectal malformations, 68 cases were CPC (17%). Male:female ratio was 2:1. Fistulous communication was colovesical, colocloacal, colovaginal and absent in 42, 15, 8 and 3 cases. ICPC and CCPC was 48 (70%) and 20 (30%). In neonatal period, proximal/end colostomy (31), ileostomy (6), pouch excision with abdominoperineal pull-through (18 cases) and coloplasty with end colostomy (7) were done. 6 presented as infants including 3 referred cases of CCPC with a window colostomy. Definitive surgery was completed in 56. Severe colonic dilatation after coloplasty was noted in 5, requiring excision of coloplasty segment in 2. Histopathology of excised pouch (45) showed muscle layer disorganization, widened sub mucosa, prominent vasculature and mature and immature ganglion cells, with no hypertrophy of nerve fibres. Diarrhoea and faecal incontinence (soiling) were more frequent in patients with CCPC versus ICPC. Six neonates with CCPC died. Six are awaiting definitive surgery.

CONCLUSION

CPC had 8.8% neonatal mortality. Pouch excision and definitive procedure are feasible in neonates with CPC. Coloplasty in CCPC may result in postoperative colonic dilatation.

Anorectal atresia with gross terminal colonic distension in Africa

Anorectal malformation (ARM) is a group of significant birth defects with geographic variation in incidence, individual phenotypes and regional geographic subtypes occurring in approximately 1:5,000 live births. Anorectal atresia with gross terminal colonic distension in the presence of an absent anal canal has also been known as 'pouch colon' which is mainly associated with the Indian subcontinent. Its prevalence is unknown but it is rare, possibly representing a fraction of 1 % of ARM. The problem seems to revolve around the gross terminal distension of the distal pouch which remains a significant surgical challenge to surgeons resulting in poorer postoperative continence in many instances.

AIM

This study set out to collate data on ARM patients with gross terminal distension of the distal pouch from Africa to evaluate its epidemiology and outcome in African patients.

METHODS

Fifteen African paediatric surgical centres (7 South African and 8 African centres) were polled on the occurrence of anorectal atresia with gross terminal distension of the terminal bowel, an ARM variant. Data included ethnic group, age, gender as well as the anatomical pathology, classification and presence or absence of associated anomalies.

RESULTS

Of 12 respondents, 8 (67 %) responded and sufficient data to classify and analyse were obtained from six of the eight positive replies (7 new cases). Abdominal X-ray showed a grossly dilated terminal portion of the colon in the presence of an imperforate anus. A colovesical fistula was observed in four (three males and one female cloaca). Three were associated with a colonic atresia, of which two were in the transverse colon and one in the sigmoid colon. Surgical corrective procedures were carried out in six, but one patient, with a cloaca, died prior to surgical correction.

CONCLUSIONS

In this survey of 15 African centres, we have attempted to document the occurrence and presentation of anorectal atresia with gross terminal distension in Africa and report seven additional new cases. A possible association with associated conditions like colonic atresia requires further investigation.

The anomalous clinical anatomy of congenital pouch colon in girls

BACKGROUND/PURPOSE

The aim of this study was to evaluate the anomalous clinical anatomy of congenital pouch colon (CPC) associated with anorectal agenesis in 22 consecutive girls managed over a study period of 7 years.

METHODS

The 22 patients were categorized into 2 groups. Group A consisted of 10 patients who presented during the neonatal period (n = 9) or as a young infant (n = 1). In these patients, only preliminary assessment results were available. Group B (12 patients) comprised 5 newborns who remained on follow-up and 7 patients who presented after the age of 1 year. These 12 patients were assessed and investigated in more detail.

RESULTS

In group A patients, apart from absence of the normal anal opening, the appearance of the external genitalia and perineum was essentially normal. Retraction of the labial folds showed radiation of folds inward from the margins of the vulval vestibule toward the center, at a point of confluence located at a higher level. At laparotomy, the subtypes of CPC were type I (n = 4), type II (n = 5), and type III (n = 1). In 8 patients, uterus didelphys was present. In all group B patients, the appearance of the external genitalia was similar to that in group A patients. However, separate openings of the urethra, septate vagina, and vestibular fistula (if present) were visible in 5 patients, whereas in 3 patients, a single perineal opening was identified. A total of 9/12 patients (75%) had urinary incontinence. Examination under anesthesia and endoscopy revealed a septate vagina in all 12 patients and an open, incompetent bladder neck with reduced bladder capacity in the 9 patients with urinary incontinence. The terminal fistula of the colonic pouch opened just distal to the bladder neck (n = 1), just posterior and cephalad to the urethral opening (n = 2), low in the vestibule (n = 5), and undetermined (n = 4). The subtypes of CPC were type I CPC (n = 2), type II CPC (n = 9), and type III CPC (n = 1). All 12 patients had uterus didelphys.

CONCLUSIONS

The characteristics in the anomalous clinical anatomy of CPC in girls, as described here, appear to be almost invariable and, especially in regions where CPC is common, should alert the clinician to the presence of this malformation.