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Surgical treatment for high anorectal malformations has evolved over the years with introduction of posterior sagittal anorectoplasty in the early 80s. Posterior sagittal anorectoplasty is being perfomed in many centres which necessitates a review of its outcomes in Benin City, Nigeria.
To report a 10-year outcome and experience gained with posterior saggital anorectoplasty for children diagnosed with high anorectal malformation.
A retrospective analyses of the records of all children with high anorectal malformation and managed with posterior sagittal anorectoplasty between April 2006 and March 2016 at the University of Benin Teaching Hospital.
A total of 96 children were managed for anorectal malformation during the period. High anorectal malformation accounted for 33 (34.4%) cases, the intermediate 15 (15.6%) and the low types were 48 (50%). The 33 radiologically confirmed high type were19 males and 14 females with a male/female ratio of 1.3: 1. They were aged between 2 days and 4 years with a mean of 6.8 ± 3 months. A child each had additional prune belly syndrome, multiple limbs anomalies and unilateral undescended testis. Recto-bladder neck/recto-prostatic and recto-vaginal fistulae were recorded in 31 (94%) children. Five (15%) clinically stable neonates had primary posterior sagittal anorectoplasty without colostomy which was well tolerated. The majority, 28 (85%), had conventional posterior sagittal anorectoplasty that involves initial colostomy. Minor postoperative morbidities recorded in 10 (30.3%) children included superficial wound infection in 3 (9%), anal stenosis in 3 (9%) and fecal incontinence in 2 (6%) children which resolved on conservative treatment while 2 (6%) with rectal mucosal prolapse required refashioning. The functional clinical anal outcomes of posterior sagittal anorectoplasty recorded showed that the majority 18 (54.5%) of children were continent while 4 (12.1%) had voluntary bowel controls corresponding with their ages. Anal stenosis in the 3 and incontinence in the 2 children were the common anal dysfunctions recorded. The child with prune belly syndrome had breakdown of colostomy closure which resulted in the one (3%) death recorded.
Anorectal malformation was common in this setting during this study with a large proportion of the children diagnosed with the high type and were managed with good outcome using posterior sagittal anorectoplasty.
Anorectal malformation is one of the commonest causes of congenital intestinal obstruction in our environment1-5. It comprises a wide spectrum of anomalies which affect the distal part of the gastrointestinal tract with or without urogenital systems and sacral involvement 6. Children born with this condition, therefore, have no anal opening in the expected site of the anal orifice. The incidence of anorectal malformation varies from 3000 to 5000 per live births. Both sexes are involved with slight male preponderance1,4,6. In Wingspread, Wisconsin, 1984, anorectal malformation was classified into high, intermediate and low anomalies for both male and female6.
While treatment for the low type of anomaly has usually been a single staged primary perineal procedure; the treatment for the intermediate and the high types has evolved over the years with different surgical procedures6,7. These include the abdominoperineal procedure, the posterior sacral, anterior sacral and perineal approaches. They were aimed at preserving the puborectalis sling of muscles which were considered to be key factor in maintaining faecal continence6. Posterior sagittal anorectoplasty which was introduced in 1980 is now generally accepted for the management of anorectal malformation6. It allows surgeons to clearly visualize the anatomy of the malformation and repair under direct vision. It usually requires an initial colostomy1-2,7-8. Posterior sagittal anorectoplasty was not a popular procedure for high anorectal malformation in this subregion until about a decade and a half ago2,6. Recently, however, some authors have described primary posterior sagittal anorectoplasty (without initial colostomy) in neonates and have recorded good outcomes8-11.
Over the last 10 years both primary and multi-staged posterior sagittal anorectoplasty have been done in this setting. The aim of this paper is to report a 10-year experience and outcomes of posterior sagittal anorectoplasty for children diagnosed with high anorectal malformation.
This ten years retrospective study was undertaken at the Paediatric Surgery Unit of the University of Benin Teaching Hospital, Benin City, Nigeria between April 2006 and March 2016.
A routine paeditric surgery unit protocol was adhered to for children diagnosed with anorectal malformation and the Wingspread classification into high, intermediate and low anomalies was adopted. All the children who presented with anorectal malformation were categorized into low, intermediate or high using a cross table lateral x-rays to determine the most distal level of the colon with respect to the pubococcygeal line. In addition, female children with vestibular fistulae had fistulogram to determine if they had anovestibular or rectovestibular types of anomalies. Pressure assisted distal colostogram were also done prior to posterior sagittal anorectoplasty to outline the extent of the distal colon and the point of fistula connection. Echocardiography, ultrasound and CT scannings were used to screen for associated congenital anomalies.
Thereafter, those diagnosed with high anorectal malformation were treated with posterior sagittal anorectoplasty after an initial colostomy or primary posterior sagittal anorectoplasty in some carefully selected children. Inclusion criteria for primary posterior sagittal anorectoplasty where children who presented during the first week of life in clinically stable condition, those without a life threatening associated congenital anomaly (especially cardiac), absence of gross abdominal distension, absence of splinted diaphragm and/or evidence of aspiration before presentation, and those who have a haematogram and blood chemistry within normal ranges. Those who did not meet these criteria were excluded and offered conventional posterior sagittal anorectoplasty.
All the posterior sagittal anorectoplasty were done with the baby placed and secured in jack-knife position following general anesthesia with endotracheal intubation. Anal dilatations were commenced 14 days after posterior sagittal anorectoplasty and continued at home after discharge by the parents who had been taught to do the dilatation. The dilatation was continued for 6 months and follow up at the out-patient clinic for at least 2 years to assess for adequate functional bowels control.
The case files of all the children with high anorectal malformation and managed with posterior sagittal anorectoplasty between April 2006 and March 2016 were retrieved from medical records department and analysed. Data extracted included patients’ age, sex, types of anomaly, presence of associated congenital anomalies, outcomes of posterior sagittal anorectoplasty, complications and outcome of their management. Patients diagnosed with intermediate and low anomalies had a primary perineal procedures and were excluded from the study. Also, 2 children whose case files could not be found were excluded from the study. The data obtained were analysed for frequencies and means using SPSS version 16 and presented in simple table and figures.
During the period a total of 96 children were managed with anorectal malformations of which 33 (34.4%) who were diagnosed with high type had posterior sagittal anorectoplasty. The intermediate accounted for 15 (15.6%) and the low types were 48 (50%). The high anomaly comprise of 19 males (57.6%) and 14 females (42.6%) with a male: female ratio 1.3:1 and aged between 4 days and 4 years (mean 6.8 ± 3 months). Four (12%) of the children were diagnosed with associated congenital anomalies. Of these four children, one each had a left unilateral undescended testis, multiple limb anomalies, atrial septal defect and prune belly syndrome.
Two (6%) children, a male and a female each, had anorectal malformation without fistulous communication while the remaining 31 (94%) had fistula. These were rectobladder-neck fistula in 3 (9%) males and recto-prostatic fistula in 14 (42.4%) males (Fig. 1). Twelve (36.4%) rectoviginal fistula and 2 (6%) persistent cloaca were diagnosed in the female children.
Twenty-eight (84.8%) had initial colostomy created which was closed 3 weeks after posterior sagittal anorectoplasty while five (15.2%) who met the inclusion criteria during the period had primary posterior sagittal anorectoplasty without initial colostomy. No post-operative complications were recorded in 22 (66.6%) children, minor post-operative complications were recorded in 8 (24.2%), major morbidity in two (6%) and mortality in 1 (3%) as shown in Table 1. The minor complications were superficial surgical site infections recorded in three children which responded to regular sitz baths/antibiotics. Three had mild anal stenosis which were discovered on the third week at the follow up clinic. These responded to a closely supervised anal dilatation in the out patients clinic. Two children with fecal incontinence responded to diet modification with toilet training. The Major morbidity recorded were in two children with mucosa prolapse which required and responded to anal refashioning (Fig. 2). The functional clinical anal outcomes of posterior sagittal anorectoplasty recorded during follow up are correlated with the different subtypes of high anomaly as depicted in Table 2. The majority 18 (54.5%) of children were totally continent while 4 (12.1%) had voluntary bowel controls corresponding with their ages. Anal stenosis in 3 and incontinence 2 children were the common anal dysfunctions recorded. A child with Prune Belly syndrome had wound/anastomosis breakdown after colostomy closure following posterior sagittal anorectoplasty. He developed severe peritonitis that failed to respond to treatment which resulted in the only mortality recorded.
Findings in this study confirmed that anorectal malformation was a common cause of intestinal obstruction in children in this environment, as also reported by other workers2-8 , is amenable to surgery especially posterior sagittal anorectoplasty for high anorectal malformation with good outcomes. The majority of anorectal malformations were the low/intermediate type while the high type which were managed with posterior sagittal anorectoplasty which accounted for about a third of cases which was also consistent with other reports2-6,8,12. The management of anorectal malformation has been a cause of major concern to paediatric surgeons all around the world1,2,8. Over the years different procedures had been described aimed at giving the patients cosmetically and functionally acceptable neo-anus1,2. No single procedure ensured the above novel outcomes until the 1980s when posterior sagittal anorectoplasty became popular among paediatric surgeons 6,12-14. Posterior sagittal anorectoplasty is gaining wide acceptance as the gold standard treatment of anorectal malformation and was adopted in this subregion about two decades ago 2-8.
In this series, posterior sagittal anorectoplasty allowed direct view of the anatomy of the anorectal malformation, precise identification of the muscle complex and its component and delineation of fistula connection which was similar to the experiences of other authors8. Although electrical nerve and muscle stimulator was not readily available in this setting during the period, the adoption of posterior sagittal anorectoplasty aided visual identification of the muscle complex and reconstruction of the neo-anus with acceptable outcomes which were comparable to other reports 15-18.
Complication rates in earlier studies18,19 excluding superficial surgical site infections which healed on conservative treatment, were reported to range between 26-44%. Most of these complications were said to be preventable if attention was given to good surgical technique2,12,13. In this study, good outcomes without post-operative complications were recorded in 66.6 % children, comparable to other earlier reports 15-18. Superficial surgical site infection which healed on conservative treatment, was recorded in 9% of cases while 6% with rectal mucosal prolapse required refashioning. The mortality recorded occurred following anastomosis breakdown after colostomy closure in prune belly syndrome. Postoperative anal complication rate following traditional Pull-through surgeries have been found to be between 15-78% which compare well with this series where 21% of the cases had anal complications20,21. As also noted by these authors, anal stenosis was due to inadequate anal dilatation during the follow up period. This also held true in this study. After achieving the desired anal size calibrated for the patient, the parents were taught to do the dilatation for about 2-3 days in the ward before they were subsequently discharged home. During follow up, however, it was noted that anal dilatation was not properly done in some of the patients which accounted for the 9% anal stenosis recorded in the series 20,21. This was perhaps due to poor parents’ motivation during follow up. Nevertheless, adequate parents counselling, reduction in follow up visits intervals and dilation under direct supervision by surgical team in clinic was able to resolve the problem. The functional clinical anal outcomes of posterior sagittal anorectoplasty recorded during follow up showed that the majority of children were either totally continent or had voluntary bowel controls corresponding with their ages which is similar to the experiences of other authors7,8. The frequencies of anal stenosis and incontinence recorded were also similar to common anal dysfunctions recorded in other studies7,8. Except in the two female children with cloacal anomaly, the subtype of high anorectal malformation did not appear to influence functional clinical anal outcomes in this study as also earlier reported by others16,19.
The two children who developed post-operative rectal mucosal prolapse underwent anal refashioning which involved excision of the prolapsed mucosa and reconstruction of the neo-anus with a flap of skin tucked into the neo-anus to aid anal sensation. The anal refashioning done gave acceptable functional results which were comparable to earlier experiences by other authors19-22. Improper placement of the rectum in the muscle complex, sacral agenesis and rectal mucosal prolapse are some of the factors identified to be responsible for fecal incontinence1,2. None of these factors were identified in the two children who had fecal incontinence in this study. The low rate of incontinence and the encouraging functional clinical anal outcomes recorded in this study were perhaps attributable to the adoption of posterior sagittal anorectoplasty for correcting high anorectal malformation because it aided direct vision and proper placement of the rectum within the sphicteric muscle complex. The incontinence recorded in the two cases could have been diet related as a change of the type of formula feeds were helpful in improving continence. Consequently in both cases, fecal continence improved over time with toilet training and dietary management protocol. Incontinence has been reported1,2 not to improve if there is sacral agenesis or when the rectum is placed outside the sphicteric muscle complex.
Some authors 22-24 also noted constipation as a major problem in patients who have undergone posterior sagittal anorectoplasty for high anorectal malformation. Some reasons they adduced for this were rectal end innervation damage during surgery and a possibility of recto-anal inhibitory reflex. Another possible explanation was the development of a wider upper portion as against a narrower lower portion of the intestine created during tailoring of the distal end of the rectum to an appropriate rectal size. These were reported 20,22 to lead to fecal accumulation, obstruction and constipation but were not encountered in this study. The absence of constipation in this study may be in support of earlier authors6-10,25 who postulated that constipation is more commonly associated with low and intermediate anomalies while incontinence is associated with high anomaly. The limitations in this study were the retrospective nature of the study and non-availability of electrical stimulator for proper identification of superficial muscle complex necessary to place the neo-anus in the right position to prevent incontinence and constipation.
Anorectal malformation was common in this setting during this study with a large proportion of the children diagnosed with the high type and were managed with good outcomes using posterior sagittal anorectoplasty.
Competing Interests: The authors have declared that no competing interests exist.
Grant support: None