Is There a Role for Radiopaque Markers in Identifying Defecation Disorders?

Abstract

c 2021 The Korean Society of Neurogastroenterology and Motility J Neurogastroenterol Motil, Vol. 27 No. 3 July, 2021 www.jnmjournal.org Constipation is a highly prevalent condition which has negative impact on a patient’s quality of life. Functional constipation (FC) is categorized into 3 subtypes according to their pathophysiologic mechanism: normal transit constipation (NTC), slow transit constipation (STC), and defecatory disorders (DD). Classification of FC subtypes provides valuable insights to the underlying pathophysiology of FC. However, patients with FC complain of similar but diverse symptoms, and each subtype often overlaps, making it difficult to classify patients with FC based on symptoms. As a result, clinicians have difficulties choosing an appropriate treatment, and patients are often dissatisfied with the therapy prescribed. DD is characterized by difficulty in rectal evacuation from inappropriate rectal propulsive forces and/or paradoxical contraction of the pelvic floor and external anal sphincter during attempted defecation. Patients with DD do not benefit from fiber or laxatives, and their symptoms may worsen in some cases. In particular, patients with DD respond less to laxatives and respond best to biofeedback therapy. Biofeedback therapy showed a favorable outcome even in cases of DD coexisting with STC or NTC, suggesting a potential influence of outlet dysfunction on a delayed colonic transit. Thus, early subtyping of FC is crucial for selecting suitable candidates for biofeedback therapy regardless of STC overlap. According to the Rome IV criteria, DD can be demonstrated by 2 of 4 abnormal findings on objective anorectal tests such as manometry or anal surface electromyography, balloon expulsion test, or barium or magnetic resonance defecography. However, anorectal tests are not universally available in real clinical practice. Radiopaque markers are non-invasive, easily accessible, and inexpensive modality for accessing colonic transit time (CTT). Despite of the convenience of radiopaque markers, its diagnostic feasibility for DD seems to be somewhat disappointing in the existing literature. Several studies have reported that rectosigmoid (RS) accumulation of radiopaque markers was not useful to diagnose DD or discriminate DD from NTC and/or STC. However, Nullens et al suggested that regional scintigraphic transit profiles can differentiate DD from STC, suggesting diagnostic value of non-invasive measurement of colonic transit. In this regards, Abe et al evaluated the diagnostic value of RS localization of radiopaque markers in discriminating constipation subtypes. Among 169 patients with refractory constipation, 79 (46.7%) patients were confirmed to have DD based on standard anorectal tests. Notably, the RS accumulation was useful for dishttp://crossmark.crossref.org/dialog/?doi=10.5056/jnm00000&domain=pdf&date_stamp=2017-4-30