Regional colon transit in patients with dys-synergic defaecation or slow transit in patients with constipation

Objective To differentiate dys-synergic defaecation (DD) from normal function and slow transit constipation (STC). Methods The medical records of 1411 patients evaluated by a single gastroenterologist over a 16-year period at a tertiary medical centre were reviewed. DD was characterised by anorectal manometry and balloon expulsion test. There were 390 patients with DD, and 61 with STC without DD. Transit data from 211 healthy individuals served as controls. The primary endpoints were overall colonic transit (geometric centre) at 24 h and 48 h (GC24 and GC48). Regional transit was measured as ascending colon half-emptying time (AC t(1/2)) and residual content in descending rectosigmoid colon and stool (DRS). Results Age and body mass index were similar in the STC and DD groups. DD was associated with smaller perineal descent and a greater difference in rectoanal pressure than STC. Both STC and DD were associated with lower GC24 and GC48 and slower AC t(1/2) than controls. GC48 differentiated DD from healthy controls (p<0.001) and DD from STC (p=0.007). AC t(1/2) values differentiated healthy controls from DD (p=0.006) and STC (p<0.001) and were associated with constipation (DD vs STC, p=0.007). The regional content of DRS at 48 h discriminated DD from STC (AUC=0.82) and stool content at 48 h, increasing the odds for DD over STC (OR per 5% in stool 2.4, 95% CI 1.1 to 5.5, p=0.03). Conclusions DD is associated with delayed overall colonic transit at 48 h and AC t(1/2) compared with healthy controls. Regional scintigraphic transit profiles differentiate DD from STC and facilitate identification of a subgroup of patients with constipation.