Pre- and postoperative rectal manometric assessment of patients with anorectal malformations: should we preserve the fistula?

Manometric Evaluation of the Sphincter Complex in Anterior Anus and Mild Anorectal Malformations-An Important Diagnostic Tool

Background: Distinguishing between the anatomical variant of an anterior anus and mild forms of imperforate anus with rectoperineal fistula often requires inspection, calibration, and, in uncertain cases, electrical stimulation (ES) under general anesthesia. Anorectal manometry (AM), despite its ability to assess sphincter configuration and function, is rarely reported as a diagnostic tool. This study evaluated the utility of AM in such cases. Methods: A retrospective analysis of AM and clinical data from 38 patients (35 female, 3 male) with suspected anterior anus was conducted from October 2009 to September 2021. Water-perfused catheter probes with eight radial channels were used to perform pull-through maneuvers. Sphincter locations were identified through vector reconstruction, and pressure ratios of the anterior part to the circumference were recorded. Results were compared to clinical data, including ES findings. Statistical significance was assessed using Mann-Whitney U and Chi-Square tests. Results: Following AM, ES was unnecessary in 25 patients. Of the remaining patients, 83% showed abnormal sphincter configurations on ES, and seven underwent anoplasty. Patients with abnormal sphincter complexes demonstrated significantly lower mean anterior pressures (61.2 mmHg vs. 136.4 mmHg, U = 336.5, p = 0.001) and a trend toward lower anterior-to-circumferential pressure ratios (mean 0.42 vs. 0.85, U = 613, p = 0.270). Constipation was also more frequent in this group (X2(1,N = 38) = 4.1, p = 0.044). Average anterior pressures < 75 mmHg and ratios < 0.7 indicated an anus outside the sphincter complex (sensitivity 80%, specificity 90%). Conclusions: AM proves valuable for evaluating ambiguous anterior anus cases, potentially reducing reliance on ES under general anesthesia. 3D high-resolution AM may further increase diagnostic accuracy.

Normal Anal Sensibility in Patients Born With Anorectal Malformations

Normal anal sensibility can be present in ARM patients diagnosed with all types of ARM after they have been treated with corrective surgery. Anal sensibility was better in those with a functional IAS. This means that the IAS, present in the distal end of the fistula, should be spared as much as possible to preserve anal sensibility. In this way, aiming to maintain the best possible fecal continence. Furthermore, the outcomes of this study demonstrate that anal sensibility is regulated by transmural nerves.

Rethinking Fistula Preservation in Anorectal Malformation Surgery: A Histopathological Perspective

OBJECTIVE

 This study aims to assess the histopathological characteristics of the fistulous tissue in males with anorectal malformation (ARM) to determine its suitability for use in constructing a neoanus.

METHODS

 This prospective observational study included male ARM patients with recto-urethral fistula. All other types were excluded. The tissue specimens comprised 0.5 to 2.0 cm of the most distal part of the rectal pouch and the fistulous tissue. Hematoxylin and eosin-stained sections were prepared. Histological features, viz. internal sphincter, anal grand and crypts, ganglion cells, presence of subepithelial fibrosis, thickened nerve trunks, and metaplasia, were evaluated.

RESULTS

 Of 65 patients of ARM admitted, 24 met the inclusion criteria. Gross and microscopic internal sphincter was not found in any sample. The anal mucosa was visualized in all samples; however, crypts were irregular and distorted architecture was seen in 4 (16.67%) samples. Urothelial metaplasia was identified in 10 (41.67%) samples. Adequate ganglion cells were seen only in 6 (25%) samples. Significant submucosal fibrosis was seen in all samples. Thickened nerve trunks were identified in 4 (16.67%) samples.

CONCLUSIONS

 All normal anal histological features could not be found together in the fistula tissue. With the absence of normal features, such as internal anal sphincter muscles, and the presence of abnormal histopathological features, such as subepithelial fibrosis, thickened nerve trunks, and metaplasia, there are high chances of abnormal bowel function like constipation if the fistulous tissue is used for neoanus construction. It may have an impact on the quality of life of patients.

Classification and Surgical Management of Anorectal Malformations: A Systematic Review and Evidence-based Guideline From the APSA Outcomes and Evidence-based Practice Committee

OBJECTIVE

Treatment of neonates with anorectal malformations (ARMs) can be challenging due to variability in anatomic definitions, multiple approaches to surgical management, and heterogeneity of reported outcomes. The purpose of this systematic review is to summarize existing evidence, identify treatment controversies, and provide guidelines for perioperative care.

METHODS

The American Pediatric Surgical Association Outcomes and Evidence Based Practice Committee (OEBP) drafted five consensus-based questions regarding management of children with ARMs. These questions were related to categorization of ARMs and optimal methods and timing of surgical management. A comprehensive search strategy was performed, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to perform the systematic review to attempt to answer five questions related to surgical care of ARM.

RESULTS

A total of 10,843 publications were reviewed, of which 90 were included in final recommendations, and some publications addressed more than one question (question: 1 n = 6, 2 n = 63, n = 15, 4 n = 44). Studies contained largely heterogenous groups of ARMs, making direct comparison for each subtype challenging and therefore, no specific recommendation for optimal surgical approach based on outcomes can be made. Both loop and divided colostomy may be acceptable methods of fecal diversion for patients with a diagnosis of anorectal malformation, however, loop colostomies have higher rates of prolapse in the literature reviewed. In terms of timing of repair, there did not appear to be significant differences in outcomes between early and late repair groups. Clear and uniform definitions are needed in order to ensure similar populations of patients are compared moving forward. Recommendations are provided based primarily on A-D levels of evidence.

CONCLUSIONS

Evidence-based best practices for ARMs are lacking for many aspects of care. Multi-institutional registries have made progress to address some of these gaps. Further prospective and comparative studies are needed to improve care and provide consensus guidelines for this complex patient population.

LEVEL OF EVIDENCE: 3

Relation between the internal anal sphincter and defecation disorders in patients with anorectal malformations

OBJECTIVES

To investigate associations between the rectoanal inhibitory reflex (RAIR), type of congenital anorectal malformations (ARMs), type of operation that patients with ARM had undergone, and objectively measured fecal incontinence and defecation problems.

METHODS

We retrospectively included 69 pediatric patients with ARM. All underwent anorectal function tests at the University Medical Center of Groningen during the last 10 years. We assessed anorectal physiology using the Rome IV criteria and anorectal function tests.

RESULTS

We found the reflex in 67% of patients and all types of ARMs. All patients who had not been operated on, and those who had undergone less extensive surgery possessed the reflex. In contrast, patients who underwent posterior sagittal anorectoplasty, 44% possessed it. We found no difference between mean rectal volumes in patients with and without the reflex (251  vs. 325 mL, respectively, p = 0.266). We found that over time, patients without the reflex seemed to develop significantly higher rectal volumes than patients who had it. We did not find a significant difference between the reflex and fecal incontinence; however, it seems that the absence of the reflex, resting anal sphincter pressure, and fecal incontinence are related.

CONCLUSION

The RAIR seems present in patients with ARM irrespective of their malformation type. Corrective surgery, however, may impair this reflex. Seemingly, its absence results in constipation with enlarged rectal volumes and fecal incontinence. Every effort should be made to preserve this reflex during surgery and to use extensive surgical procedures as sparingly as possible.

Post-Operative Anorectal Manometry in Children following Anorectal Malformation Repair: A Systematic Review

Despite surgical correction, children with anorectal malformations may experience long-term bowel dysfunction, including fecal incontinence and/or disorders of evacuation. Anorectal manometry is the most widely used test of anorectal function. Although considerable attention has been devoted to its application in the anorectal malformation cohort, there have been few attempts to consolidate the findings obtained. This systematic review aimed to (1) synthesize and evaluate the existing data regarding anorectal manometry results in children following anorectal malformation repair, and (2) evaluate the manometry protocols utilized, including equipment, assessment approach, and interpretation. We reviewed four databases (Embase, MEDLINE, the Cochrane Library, and PubMed) for relevant articles published between 1 January 1985 and 10 March 2022. Studies reporting post-operative anorectal manometry in children (<18 years) following anorectal malformation repair were evaluated for eligibility. Sixty-three studies were eligible for inclusion. Of the combined total cohort of 2155 patients, anorectal manometry results were reported for 1755 children following repair of anorectal malformations. Reduced resting pressure was consistently identified in children with anorectal malformations, particularly in those with more complex malformation types and/or fecal incontinence. Significant variability was identified in relation to manometry equipment, protocols, and interpretation. Few studies provided adequate cohort medical characteristics to facilitate interpretation of anorectal manometry findings within the context of the broader continence mechanism. This review highlights a widespread lack of standardization in the anorectal manometry procedure used to assess anorectal function in children following anorectal malformation repair. Consequently, interpretation and comparison of findings, both within and between institutions, is exceedingly challenging, if not impossible. Standardized manometry protocols, accompanied by a consistent approach to analysis, including definitions of normality and abnormality, are essential to enhance the comparability and clinical relevance of results.

Diagnosing Mild Forms of Anorectal Malformation With Anorectal Manometry: A Prospective Study

INTRODUCTION

Rectoperineal congenital anorectal malformations (CARMs) are diagnosed by examining the perineum, combined with electric stimulation (ES) of the anal sphincter performed under anesthesia. This procedure may be troublesome because it is based on the observed contractibility of the sphincter. We aimed to add 3-dimensional high-resolution anorectal manometry (3D-HRAM) to the procedure and to assess its value for diagnosing rectoperineal forms of CARM.

METHODS

We prospectively included 66 patients younger than 24 months who presented with constipation and were suspected of CARM, idiopathic constipation, or Hirschsprung disease. The patients were assessed between 2015 and 2021 at University Medical Center Groningen, the Netherlands. All patients underwent 3D-HRAM, followed by the standard diagnostic procedure for either CARM or Hirschsprung disease.

RESULTS

Of the 51 patients who underwent both 3D-HRAM and ES, we observed that patients with rectoperineal CARM revealed a pressure gap along the anterior part of the anal sphincter. Based on this observation, we diagnosed 35 patients with CARM. Subsequently, all 35 diagnoses were confirmed with ES. Sixteen patients were diagnosed as not having CARM, 100% of whom were in agreement with the gold standard-ES. Both the specificity and sensitivity of 3D-HRAM for diagnosing rectoperineal CARM were 100%.

DISCUSSION

We consider 3D-HRAM a reliable tool for diagnosing and excluding rectoperineal CARM. Using this method in patients suspected of CARM might keep infants from undergoing unnecessary interventions requiring anesthetics, such as ES. By providing objective insight into the functional capabilities of the anal sphincter, anorectal manometry adds to the diagnosis.

Clinical Differentiation between a Normal Anus, Anterior Anus, Congenital Anal Stenosis, and Perineal Fistula: Definitions and Consequences—The ARM-Net Consortium Consensus

In the past, an anteriorly located anus was often misdiagnosed and treated as an anorectal malformation (ARM) with a perineal fistula (PF). The paper aims to define the criteria for a normal anus, an anterior anus (AA) as an anatomic variant, and milder types of ARM such as congenital anal stenosis (CAS) and PF. An extensive literature search was performed by a working group of the ARM-Net Consortium concerning the subject “Normal Anus, AA, and mild ARM”. A consensus on definitions, clinical characteristics, diagnostic management, and treatment modalities was established, and a diagnostic algorithm was proposed. The algorithm enables pediatricians, midwives, gynecologists, and surgeons to make a timely correct diagnosis of any abnormally looking anus and initiate further management if needed. Thus, the routine physical inspection of a newborn should include the inspection of the anus and define its position, relation to the external sphincter, and caliber. A correct diagnosis and use of the presented terminology will avoid misclassifications and allow the initiation of correct management. This will provide a reliable comparison of different therapeutic management and outcomes of these patient cohorts in the future.

Scientific solution to a complex problem: physiology and multidisciplinary team improve understanding and outcome in chronic constipation and faecal incontinence

PURPOSE

There is a lack of diagnostic credibility to direct focused management for children with chronic constipation (CC) and faecal incontinence (FI). The aim is to assess the impact of an innovative Children's Anorectal Physiology Service (CAPS) focusing on improving outcomes in children with CC/FI.

METHODS

Prospective data: demographics, bowel and quality of life (QoL)/risk of distress questionnaires. Diagnostics: awake high-resolution anorectal manometry (AHRAM), endoanal ultrasound and transit marker studies (TMS).

RESULTS

Total patients: 112; 66 males (59%); median 9 years (17 months to 16 years). Patient groups included: 89 (79%) had functional CC/FI; 9 (8%), Hirschsprung's disease; 12 (11%), anorectal malformations and 2 (2%), trauma. St Marks Incontinence score (SMIS) abnormal in 91 (81%) and Cleveland Constipation Score (CCS) in 101 (90%) patients. Anorectal manometry: 94 (84%) awake and 18 (17%) under anaesthesia. Play specialist input 37 (33%) patients. AHRAM abnormal 65 (58%): sphincter dysfunction 36 (32%) and altered rectal sensation: hyposensitive 22% (20/91); 21% (19/91) hypersensitive. TMS normal in 64 (57%), 17 (15%) slow transit and 27 (24%) rectal evacuatory disorder. Risk of distress in 38% and poor QoL in 55% patients which correlated with abnormal SMIS (p = 0.02). Patient/parent satisfaction improved significantly (p < 0.05).

CONCLUSIONS

Scientific investigations combined with multidisciplinary team improve patient satisfaction and reduces patient self-report illness severity. A complex problem requires a scientific solution.

Histology with immunohistochemistry of the fistula region in female anorectal malformation: Can it be used for neo-anus reconstruction?

AIM

Female anorectal malformation is characterised by communication to the exterior by a fistula. There are conflicting reports of the presence of normal anus in the fistula region. This study was undertaken to assess the histopathology and immunohistochemical correlation of the terminal portion of the fistula in female patients and suitability of fistula incorporation in the reconstruction of the neo-anus.

METHODS

This prospective study included 13 patients of female anorectal malformation. Of these, seven had a vestibular fistula (VF), and the rest had an anterior ectopic anus (AEA). Histopathology of the fistula region was undertaken, along with immunohistochemistry. Various findings were evaluated.

RESULTS

Of seven VF patients, four showed atrophic or disrupted internal sphincter smooth muscle, whereas the remaining three showed hypertropic internal sphincteric smooth muscle. Six patients showed hypertrophic nerve bundle. Five VF patients showed subepithelial fibrosis, and none of them showed ganglion cells. Of six patients of AEA, internal sphincteric smooth muscle was normal in five. It was hypertrophic in one patient. Transitional epithelium was present in four patients. All patients showed hypertrophic nerve bundle and aganglionosis. Subepithelial fibrosis was observed in six patients.

CONCLUSION

The fistula region in VF and AEA patients appears to be an abnormal structure. Rather than preservation of the terminal fistulous region, resection followed by anoplasty may be a viable option.

Post-operative strictures in anorectal malformation: trends over 15 years

AIM

For decades, paediatric surgeons have employed the standard posterior sagittal anorectoplasty (PSARP) approach to deal with patients with anorectal malformations (ARM). In recent years, we noted an apparent increase in the incidence of anal stricture after surgical repair of ARM following the introduction of laparoscopic pull-through and techniques aiming to preserve the internal sphincter-the internal sphincter sparing approach (ISSA). We decided to analyse our data to find out if these new trends had added to the problem of post-operative strictures.

METHODS

All patients with ARM at our institution from January 2000 to December 2015 were identified. A retrospective case note review was carried out. Data collected included patient demographics, type of ARM, operative details, and post-operative outcomes.

RESULTS

114 patients were identified. Ten patients were excluded. Of the remaining 104 children, 48 (46%) were female. Median age was 8.3 (range 1.2-16.8) years. Types of ARM were as follows: perineal fistula (15 patients), anterior stenotic anus (12), imperforate anus without fistula (10), vestibular fistula (32), rectourethral (bulbar) fistula (11), rectourethral (prostatic) fistula (14), rectovesical fistula (7), and cloaca (3). Twenty-seven patients with a perineal fistula or anterior stenotic anus underwent perineal procedures that were variably described by the different operating surgeons. The majority (15 patients) had an anoplasty, 5 had anal transposition, 5 had limited PSARP, and 2 patients had ISSA. Two patients with a cloacal anomaly underwent open cloacal reconstruction. Of the remaining 75 patients, 45 had a PSARP approach, 6 had a laparoscopic-assisted pull-through, and 18 had ISSA. Four girls with vestibular fistula had anal transposition and two boys with imperforate anus without fistula had anoplasty. 15 (14%) children developed anal stricture. Stricture incidence differed according to operation type. PSARP was the most commonly performed procedure, with only 6% developing a stricture. In contrast, 30% of ISSA patients and 50% of children who had laparoscopic pull-through developed a stricture. Strictures also occurred in 11 and 12% of children having anal transposition and anoplasty, respectively.

CONCLUSION

The laparoscopic-assisted pull-through involves tunnelling the sphincter muscle complex. We found that often the tunnels were not wide enough, resulting in narrowing not just at the ano-cutaneous junction but also at the deeper level. 50% developed strictures. We have modified our technique by ensuring that the tunnels are generous enough to allow the rectum to be pulled through without any resistance. ISSA unfortunately resulted in 30% of our patients developing strictures. This approach, started in 2004, was, therefore, abandoned in 2013. The standard Pena's PSARP, with or without a laparotomy, has stood the test of time. Any modification of this approach must be carefully thought through and audited meticulously. Strictures can cause significant morbidity, which may need several revisions, and the resulting redo anoplasties run the risk of sphincter damage, ironically which the newer modifications of ISSA were trying to conserve.