Radiopaque markers in children with functional constipation: Potential role in diagnosis, therapy, and outcomes

To evaluate the clinical utility of the simplified colon transit protocol of radiopaque markers (SROM) in pediatric functional constipation (FC).

Retrospective study of children meeting Rome IV criteria for FC undergoing an SROM. We compared the SROM (interpretation, number, and distribution of retained markers) with demographics, symptoms, results of diagnostic studies (contrast enema [CE], anorectal manometry [ARM], and colon manometry [CM]), and therapeutic outcomes (successful when ≥3 bowel movements per week and/or <1 episode of fecal incontinence per week).

A total of 315 patients were included (median age 9.9 years, 54% were male). We found no association between SROM and age, gender, and body mass index (BMI), but abnormal SROM was associated with low BMI Z score (p = 0.004) and presence of comorbidities (obesity, developmental delay, behavioral problems, autism, attention-deficit/hyperactivity disorder) (p = 0.020). SROM also correlated with bowel habits (p = 0.003) and fecal incontinence (p = 0.012). SROM did not predict the results of the CE and ARM. We observed a concordance with CM in 64% of patients and discrepancy in 36% with a low overall agreement (k = -0.259). SROM predicted response to medical therapy (p = 0.04) but not the eventual need for surgery (p = 0.46).

SROM correlates well with symptoms, low BMI Z score and comorbidities. SROM does not predict CE and ARM results but can guide the performance of the CM in two-thirds of patients. SROM predicts response to medical therapy but not the need for surgery, suggesting it may help guiding escalating medical therapy and the performance of the CM.