Faecal impaction in children aged 0–18 years: a systematic review and metanarrative analysis of definitions used

Background Faecal impaction is the result of functional constipation in the majority of cases. Surprisingly, a uniform definition for the term faecal impaction is lacking, leading to heterogeneity across study results. Aim To conduct a metanarrative systematic review to ascertain how trial studies define faecal impaction among children aged 0–18 years with functional constipation. Methods We conducted a systematic metanarrative review to uncover what criteria are used to define faecal impaction and to recommend directions for creating a globally accepted definition. A comprehensive literature search was conducted using prominent databases, including CENTRAL, MEDLINE, Embase, WHO ICTR (international clinical trials registry) and ClinicalTrials.gov. All relevant publications of RCTs on both faecal impaction and functional constipation from inception to June 2024, including children aged 0–18 years without underlying organic aetiology, were included. Results 6211 studies were screened, of which 155 were reviewed for eligibility, 76 were included in the review and five are awaiting classification. Seven studies gave an explicit definition, with three referencing a previous consensus definition. 45 studies gave an implicit definition derived from their prescreening or exclusion criteria in a larger piece of research. Clinical assessment was the most common element of definitions, with a mixture of abdominal or rectal assessments reported in 44 studies. A further six studies suggested such clinical assessments are combined with radiographs, and one study reported a definition using radiographs alone. One study reported the duration of symptoms in a definition. Conclusion There is a clear lack of consensus for defining faecal impaction in children with functional constipation. Despite the clinical, diagnostic and prognostic importance of having a unified definition of faecal impaction, currently there seems to be no universally accepted definition.