Anorectal manometry in pediatric settings: A systematic review of 227 studies

High-resolution anorectal manometry in children

Anorectal manometry is one of the motility tests in children performed by pediatric gastroenterologist. It evaluates the motility function of anorectal tract. It is helpful for diagnosing children with constipation, rectal hypersensitivity, fecal incontinence, Hirschsprung disease, anal achalasia, and anorectal malformations. The most common indication to perform anorectal manometry is to diagnose Hirschsprung disease. It is a safe procedure. This paper discusses recent advances and reviews on anorectal motility disorders in children.

Anorectal manometry findings in relation with long-term functional outcomes of the patients operated on for Hirschsprung's disease compared to the reference-based population

PURPOSE

This study investigated anorectal manometry (AM) findings and bowel function of patients operated on for Hirschsprung's disease (HD).

METHODS

A cross-sectional study was conducted at Children's Hospital 2. Patients operated on for HD from January 2015 to January 2020 were reviewed. Their clinical characteristics, bowel function, and manometric findings were investigated and compared with the references.

RESULTS

Ninety-five patients and 95 references were enrolled. Mean ages were 6.6 ± 2.2 years and 7.2 ± 2.9 years,; fecal incontinence rates were 25.3% and 2.1%, and constipation rates were 12.6% and 4.2 for the patients versus the references, respectively. Anal resting pressures were significantly decreased in the patients compared to the references (53.2 ± 16.1 mmHg versus 62.2 ± 14.0 mmHg; p < 0.05). Among the patients, the anal resting pressure was significantly decreased in the incontinents than in the continents (46.0 ± 10.6 mmHg versus 55.6 ± 16.9 mmHg, p < 0.05). During the sensation test, the value of maximum tolerated volume was significantly decreased in the incontinents than in the continents (135.9 ± 47.9 mL versus 166.6 ± 58.3 mL, p < 0.05).

CONCLUSION

AM is an objective method providing beneficial information that could guide a more adapted management in HD patients with defecation disorders.

THE FATIGUE RATE INDEX IS HIGHER IN CHILDREN WITH FUNCTIONAL CONSTIPATION AND RETENTIVE FECAL INCONTINENCE

BACKGROUND

The Fatigue Rate Index (FRI) is a parameter in anorectal manometry (ARM) to assess sustained voluntary contraction, considering the squeeze pressure and fatigability of the external anal sphincter. It is used in adults to detect fecal incontinence even in patients who present normal squeeze pressures. The FRI in adult patients with functional constipation is similar to controls.

OBJECTIVE

The aim of this study was to evaluate the feasibility and values of FRI in children in relation to the values previously established in adults and comparing children with functional constipation and retentive fecal incontinence to children without retentive fecal incontinence.

METHODS

This retrospective study evaluated 105 ARM performed from Jan 2014 to Apr 2015. 42 patients were selected (were able to perform a voluntary contraction and had no co-morbidities other than functional constipation). 14 (33.3%) of those collaborated in sustaining contraction for 40 seconds (s), allowing the evaluation of the FRI. Patients with retentive fecal incontinence secondary to functional constipation (n=7, aged 6 to 13 years, six boys) were our interest group. Patients with functional constipation without fecal incontinence (n=7, aged 6 to 13 years, four boys) were considered a reference group. The ARM were performed with a radial eight-channel perfusion catheter (DynamedTM, São Paulo, Brazil) and the FRI was calculated (Proctomaster 6.4) in the first 20 s and overall 40 s of sustained voluntary contraction.

RESULTS

14 of the selected 42 collaborated in sustaining contraction for 40 s, allowing the evaluation of the FRI. In the first 20 s of contraction, the fecal incontinence group showed a significantly higher mean FRI (2.48±1.39 min) compared to the reference group (1.13±0.72 min, P=0.042), which was not observed in the 40 s interval due to less uniform contraction. The anal resting pressure was higher in the fecal incontinence group (76.83 mmHg) than in the reference group (54.13 mmHg), but the statistical study did not reach significance (P=0.051).

CONCLUSION

The FRI is feasible in children. The mean FRI obtained in this study is lower than the reported in constipated adults. The mean FRI among children with functional constipation and retentive fecal incontinence is higher than among constipated children without retentive fecal incontinence.

Anorectal Manometry in Children: The Update on the Indications and the Protocol of the Procedure

Anorectal disorders are common in children. They are related to structural and/or functional abnormalities of the anorectum or pelvic floor with a variety of symptoms. Therefore, diagnostic tests to evaluate anorectal function can help to better understand the underlying pathophysiology and aetiology as well as facilitate patient management. During the past decades, substantial efforts have been made to improve anorectal function testing; however, more advanced investigations might lead to difficulties in interpretation. Additionally, a great diversity of equipment and protocols are used among centres, which may lead to heterogeneous interpretation of results. More studies to standardize methods of testing and validate reference values are strongly recommended in children. This review updates on the current indications and the protocol of anorectal manometry.